drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/of_gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/pm_domain.h>
  25 #include <linux/property.h>
  26 #include <linux/export.h>
  27 #include <linux/sched/rt.h>
  28 #include <uapi/linux/sched/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/kthread.h>
  31 #include <linux/ioport.h>
  32 #include <linux/acpi.h>
  33 #include <linux/highmem.h>
  34 #include <linux/idr.h>
  35 #include <linux/platform_data/x86/apple.h>
  36 #include <linux/ptp_clock_kernel.h>
  37
  38 #define CREATE_TRACE_POINTS
  39 #include <trace/events/spi.h>
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  41 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  42
  43 #include "internals.h"
  44
  45 static DEFINE_IDR(spi_master_idr);
  46
  47 static void spidev_release(struct device *dev)
  48 {
  49         struct spi_device       *spi = to_spi_device(dev);
  50
  51         spi_controller_put(spi->controller);
  52         kfree(spi->driver_override);
  53         kfree(spi);
  54 }
  55
  56 static ssize_t
  57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  58 {
  59         const struct spi_device *spi = to_spi_device(dev);
  60         int len;
  61
  62         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  63         if (len != -ENODEV)
  64                 return len;
  65
  66         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  67 }
  68 static DEVICE_ATTR_RO(modalias);
  69
  70 static ssize_t driver_override_store(struct device *dev,
  71                                      struct device_attribute *a,
  72                                      const char *buf, size_t count)
  73 {
  74         struct spi_device *spi = to_spi_device(dev);
  75         const char *end = memchr(buf, '\n', count);
  76         const size_t len = end ? end - buf : count;
  77         const char *driver_override, *old;
  78
  79         /* We need to keep extra room for a newline when displaying value */
  80         if (len >= (PAGE_SIZE - 1))
  81                 return -EINVAL;
  82
  83         driver_override = kstrndup(buf, len, GFP_KERNEL);
  84         if (!driver_override)
  85                 return -ENOMEM;
  86
  87         device_lock(dev);
  88         old = spi->driver_override;
  89         if (len) {
  90                 spi->driver_override = driver_override;
  91         } else {
  92                 /* Empty string, disable driver override */
  93                 spi->driver_override = NULL;
  94                 kfree(driver_override);
  95         }
  96         device_unlock(dev);
  97         kfree(old);
  98
  99         return count;
 100 }
 101
 102 static ssize_t driver_override_show(struct device *dev,
 103                                     struct device_attribute *a, char *buf)
 104 {
 105         const struct spi_device *spi = to_spi_device(dev);
 106         ssize_t len;
 107
 108         device_lock(dev);
 109         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
 110         device_unlock(dev);
 111         return len;
 112 }
 113 static DEVICE_ATTR_RW(driver_override);
 114
 115 #define SPI_STATISTICS_ATTRS(field, file)                               \
 116 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 117                                              struct device_attribute *attr, \
 118                                              char *buf)                 \
 119 {                                                                       \
 120         struct spi_controller *ctlr = container_of(dev,                 \
 121                                          struct spi_controller, dev);   \
 122         return spi_statistics_##field##_show(&ctlr->statistics, buf);   \
 123 }                                                                       \
 124 static struct device_attribute dev_attr_spi_controller_##field = {      \
 125         .attr = { .name = file, .mode = 0444 },                         \
 126         .show = spi_controller_##field##_show,                          \
 127 };                                                                      \
 128 static ssize_t spi_device_##field##_show(struct device *dev,            \
 129                                          struct device_attribute *attr, \
 130                                         char *buf)                      \
 131 {                                                                       \
 132         struct spi_device *spi = to_spi_device(dev);                    \
 133         return spi_statistics_##field##_show(&spi->statistics, buf);    \
 134 }                                                                       \
 135 static struct device_attribute dev_attr_spi_device_##field = {          \
 136         .attr = { .name = file, .mode = 0444 },                         \
 137         .show = spi_device_##field##_show,                              \
 138 }
 139
 140 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
 141 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
 142                                             char *buf)                  \
 143 {                                                                       \
 144         unsigned long flags;                                            \
 145         ssize_t len;                                                    \
 146         spin_lock_irqsave(&stat->lock, flags);                          \
 147         len = sprintf(buf, format_string, stat->field);                 \
 148         spin_unlock_irqrestore(&stat->lock, flags);                     \
 149         return len;                                                     \
 150 }                                                                       \
 151 SPI_STATISTICS_ATTRS(name, file)
 152
 153 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 154         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 155                                  field, format_string)
 156
 157 SPI_STATISTICS_SHOW(messages, "%lu");
 158 SPI_STATISTICS_SHOW(transfers, "%lu");
 159 SPI_STATISTICS_SHOW(errors, "%lu");
 160 SPI_STATISTICS_SHOW(timedout, "%lu");
 161
 162 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 163 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 164 SPI_STATISTICS_SHOW(spi_async, "%lu");
 165
 166 SPI_STATISTICS_SHOW(bytes, "%llu");
 167 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 168 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 169
 170 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 171         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 172                                  "transfer_bytes_histo_" number,        \
 173                                  transfer_bytes_histo[index],  "%lu")
 174 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 175 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 176 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 177 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 178 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 179 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 180 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 181 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 182 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 183 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 184 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 185 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 186 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 187 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 188 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 189 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 190 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 191
 192 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 193
 194 static struct attribute *spi_dev_attrs[] = {
 195         &dev_attr_modalias.attr,
 196         &dev_attr_driver_override.attr,
 197         NULL,
 198 };
 199
 200 static const struct attribute_group spi_dev_group = {
 201         .attrs  = spi_dev_attrs,
 202 };
 203
 204 static struct attribute *spi_device_statistics_attrs[] = {
 205         &dev_attr_spi_device_messages.attr,
 206         &dev_attr_spi_device_transfers.attr,
 207         &dev_attr_spi_device_errors.attr,
 208         &dev_attr_spi_device_timedout.attr,
 209         &dev_attr_spi_device_spi_sync.attr,
 210         &dev_attr_spi_device_spi_sync_immediate.attr,
 211         &dev_attr_spi_device_spi_async.attr,
 212         &dev_attr_spi_device_bytes.attr,
 213         &dev_attr_spi_device_bytes_rx.attr,
 214         &dev_attr_spi_device_bytes_tx.attr,
 215         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 216         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 217         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 218         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 219         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 220         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 221         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 222         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 223         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 224         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 225         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 226         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 227         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 228         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 229         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 230         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 231         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 232         &dev_attr_spi_device_transfers_split_maxsize.attr,
 233         NULL,
 234 };
 235
 236 static const struct attribute_group spi_device_statistics_group = {
 237         .name  = "statistics",
 238         .attrs  = spi_device_statistics_attrs,
 239 };
 240
 241 static const struct attribute_group *spi_dev_groups[] = {
 242         &spi_dev_group,
 243         &spi_device_statistics_group,
 244         NULL,
 245 };
 246
 247 static struct attribute *spi_controller_statistics_attrs[] = {
 248         &dev_attr_spi_controller_messages.attr,
 249         &dev_attr_spi_controller_transfers.attr,
 250         &dev_attr_spi_controller_errors.attr,
 251         &dev_attr_spi_controller_timedout.attr,
 252         &dev_attr_spi_controller_spi_sync.attr,
 253         &dev_attr_spi_controller_spi_sync_immediate.attr,
 254         &dev_attr_spi_controller_spi_async.attr,
 255         &dev_attr_spi_controller_bytes.attr,
 256         &dev_attr_spi_controller_bytes_rx.attr,
 257         &dev_attr_spi_controller_bytes_tx.attr,
 258         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 259         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 260         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 261         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 262         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 263         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 264         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 265         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 266         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 267         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 268         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 269         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 270         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 271         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 272         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 273         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 274         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 275         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 276         NULL,
 277 };
 278
 279 static const struct attribute_group spi_controller_statistics_group = {
 280         .name  = "statistics",
 281         .attrs  = spi_controller_statistics_attrs,
 282 };
 283
 284 static const struct attribute_group *spi_master_groups[] = {
 285         &spi_controller_statistics_group,
 286         NULL,
 287 };
 288
 289 static void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 290                                               struct spi_transfer *xfer,
 291                                               struct spi_controller *ctlr)
 292 {
 293         unsigned long flags;
 294         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 295
 296         if (l2len < 0)
 297                 l2len = 0;
 298
 299         spin_lock_irqsave(&stats->lock, flags);
 300
 301         stats->transfers++;
 302         stats->transfer_bytes_histo[l2len]++;
 303
 304         stats->bytes += xfer->len;
 305         if ((xfer->tx_buf) &&
 306             (xfer->tx_buf != ctlr->dummy_tx))
 307                 stats->bytes_tx += xfer->len;
 308         if ((xfer->rx_buf) &&
 309             (xfer->rx_buf != ctlr->dummy_rx))
 310                 stats->bytes_rx += xfer->len;
 311
 312         spin_unlock_irqrestore(&stats->lock, flags);
 313 }
 314
 315 /*
 316  * modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 317  * and the sysfs version makes coldplug work too.
 318  */
 319 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
 320 {
 321         while (id->name[0]) {
 322                 if (!strcmp(name, id->name))
 323                         return id;
 324                 id++;
 325         }
 326         return NULL;
 327 }
 328
 329 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 330 {
 331         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 332
 333         return spi_match_id(sdrv->id_table, sdev->modalias);
 334 }
 335 EXPORT_SYMBOL_GPL(spi_get_device_id);
 336
 337 static int spi_match_device(struct device *dev, struct device_driver *drv)
 338 {
 339         const struct spi_device *spi = to_spi_device(dev);
 340         const struct spi_driver *sdrv = to_spi_driver(drv);
 341
 342         /* Check override first, and if set, only use the named driver */
 343         if (spi->driver_override)
 344                 return strcmp(spi->driver_override, drv->name) == 0;
 345
 346         /* Attempt an OF style match */
 347         if (of_driver_match_device(dev, drv))
 348                 return 1;
 349
 350         /* Then try ACPI */
 351         if (acpi_driver_match_device(dev, drv))
 352                 return 1;
 353
 354         if (sdrv->id_table)
 355                 return !!spi_match_id(sdrv->id_table, spi->modalias);
 356
 357         return strcmp(spi->modalias, drv->name) == 0;
 358 }
 359
 360 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 361 {
 362         const struct spi_device         *spi = to_spi_device(dev);
 363         int rc;
 364
 365         rc = acpi_device_uevent_modalias(dev, env);
 366         if (rc != -ENODEV)
 367                 return rc;
 368
 369         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 370 }
 371
 372 static int spi_probe(struct device *dev)
 373 {
 374         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 375         struct spi_device               *spi = to_spi_device(dev);
 376         int ret;
 377
 378         ret = of_clk_set_defaults(dev->of_node, false);
 379         if (ret)
 380                 return ret;
 381
 382         if (dev->of_node) {
 383                 spi->irq = of_irq_get(dev->of_node, 0);
 384                 if (spi->irq == -EPROBE_DEFER)
 385                         return -EPROBE_DEFER;
 386                 if (spi->irq < 0)
 387                         spi->irq = 0;
 388         }
 389
 390         ret = dev_pm_domain_attach(dev, true);
 391         if (ret)
 392                 return ret;
 393
 394         if (sdrv->probe) {
 395                 ret = sdrv->probe(spi);
 396                 if (ret)
 397                         dev_pm_domain_detach(dev, true);
 398         }
 399
 400         return ret;
 401 }
 402
 403 static void spi_remove(struct device *dev)
 404 {
 405         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 406
 407         if (sdrv->remove) {
 408                 int ret;
 409
 410                 ret = sdrv->remove(to_spi_device(dev));
 411                 if (ret)
 412                         dev_warn(dev,
 413                                  "Failed to unbind driver (%pe), ignoring\n",
 414                                  ERR_PTR(ret));
 415         }
 416
 417         dev_pm_domain_detach(dev, true);
 418 }
 419
 420 static void spi_shutdown(struct device *dev)
 421 {
 422         if (dev->driver) {
 423                 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
 424
 425                 if (sdrv->shutdown)
 426                         sdrv->shutdown(to_spi_device(dev));
 427         }
 428 }
 429
 430 struct bus_type spi_bus_type = {
 431         .name           = "spi",
 432         .dev_groups     = spi_dev_groups,
 433         .match          = spi_match_device,
 434         .uevent         = spi_uevent,
 435         .probe          = spi_probe,
 436         .remove         = spi_remove,
 437         .shutdown       = spi_shutdown,
 438 };
 439 EXPORT_SYMBOL_GPL(spi_bus_type);
 440
 441 /**
 442  * __spi_register_driver - register a SPI driver
 443  * @owner: owner module of the driver to register
 444  * @sdrv: the driver to register
 445  * Context: can sleep
 446  *
 447  * Return: zero on success, else a negative error code.
 448  */
 449 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 450 {
 451         sdrv->driver.owner = owner;
 452         sdrv->driver.bus = &spi_bus_type;
 453
 454         /*
 455          * For Really Good Reasons we use spi: modaliases not of:
 456          * modaliases for DT so module autoloading won't work if we
 457          * don't have a spi_device_id as well as a compatible string.
 458          */
 459         if (sdrv->driver.of_match_table) {
 460                 const struct of_device_id *of_id;
 461
 462                 for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
 463                      of_id++) {
 464                         const char *of_name;
 465
 466                         /* Strip off any vendor prefix */
 467                         of_name = strnchr(of_id->compatible,
 468                                           sizeof(of_id->compatible), ',');
 469                         if (of_name)
 470                                 of_name++;
 471                         else
 472                                 of_name = of_id->compatible;
 473
 474                         if (sdrv->id_table) {
 475                                 const struct spi_device_id *spi_id;
 476
 477                                 spi_id = spi_match_id(sdrv->id_table, of_name);
 478                                 if (spi_id)
 479                                         continue;
 480                         } else {
 481                                 if (strcmp(sdrv->driver.name, of_name) == 0)
 482                                         continue;
 483                         }
 484
 485                         pr_warn("SPI driver %s has no spi_device_id for %s\n",
 486                                 sdrv->driver.name, of_id->compatible);
 487                 }
 488         }
 489
 490         return driver_register(&sdrv->driver);
 491 }
 492 EXPORT_SYMBOL_GPL(__spi_register_driver);
 493
 494 /*-------------------------------------------------------------------------*/
 495
 496 /*
 497  * SPI devices should normally not be created by SPI device drivers; that
 498  * would make them board-specific.  Similarly with SPI controller drivers.
 499  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 500  * with other readonly (flashable) information about mainboard devices.
 501  */
 502
 503 struct boardinfo {
 504         struct list_head        list;
 505         struct spi_board_info   board_info;
 506 };
 507
 508 static LIST_HEAD(board_list);
 509 static LIST_HEAD(spi_controller_list);
 510
 511 /*
 512  * Used to protect add/del operation for board_info list and
 513  * spi_controller list, and their matching process also used
 514  * to protect object of type struct idr.
 515  */
 516 static DEFINE_MUTEX(board_lock);
 517
 518 /**
 519  * spi_alloc_device - Allocate a new SPI device
 520  * @ctlr: Controller to which device is connected
 521  * Context: can sleep
 522  *
 523  * Allows a driver to allocate and initialize a spi_device without
 524  * registering it immediately.  This allows a driver to directly
 525  * fill the spi_device with device parameters before calling
 526  * spi_add_device() on it.
 527  *
 528  * Caller is responsible to call spi_add_device() on the returned
 529  * spi_device structure to add it to the SPI controller.  If the caller
 530  * needs to discard the spi_device without adding it, then it should
 531  * call spi_dev_put() on it.
 532  *
 533  * Return: a pointer to the new device, or NULL.
 534  */
 535 static struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 536 {
 537         struct spi_device       *spi;
 538
 539         if (!spi_controller_get(ctlr))
 540                 return NULL;
 541
 542         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 543         if (!spi) {
 544                 spi_controller_put(ctlr);
 545                 return NULL;
 546         }
 547
 548         spi->master = spi->controller = ctlr;
 549         spi->dev.parent = &ctlr->dev;
 550         spi->dev.bus = &spi_bus_type;
 551         spi->dev.release = spidev_release;
 552         spi->cs_gpio = -ENOENT;
 553         spi->mode = ctlr->buswidth_override_bits;
 554
 555         spin_lock_init(&spi->statistics.lock);
 556
 557         device_initialize(&spi->dev);
 558         return spi;
 559 }
 560
 561 static void spi_dev_set_name(struct spi_device *spi)
 562 {
 563         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 564
 565         if (adev) {
 566                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 567                 return;
 568         }
 569
 570         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 571                      spi->chip_select);
 572 }
 573
 574 static int spi_dev_check(struct device *dev, void *data)
 575 {
 576         struct spi_device *spi = to_spi_device(dev);
 577         struct spi_device *new_spi = data;
 578
 579         if (spi->controller == new_spi->controller &&
 580             spi->chip_select == new_spi->chip_select)
 581                 return -EBUSY;
 582         return 0;
 583 }
 584
 585 static void spi_cleanup(struct spi_device *spi)
 586 {
 587         if (spi->controller->cleanup)
 588                 spi->controller->cleanup(spi);
 589 }
 590
 591 static int __spi_add_device(struct spi_device *spi)
 592 {
 593         struct spi_controller *ctlr = spi->controller;
 594         struct device *dev = ctlr->dev.parent;
 595         int status;
 596
 597         /*
 598          * We need to make sure there's no other device with this
 599          * chipselect **BEFORE** we call setup(), else we'll trash
 600          * its configuration.
 601          */
 602         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 603         if (status) {
 604                 dev_err(dev, "chipselect %d already in use\n",
 605                                 spi->chip_select);
 606                 return status;
 607         }
 608
 609         /* Controller may unregister concurrently */
 610         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 611             !device_is_registered(&ctlr->dev)) {
 612                 return -ENODEV;
 613         }
 614
 615         /* Descriptors take precedence */
 616         if (ctlr->cs_gpiods)
 617                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 618         else if (ctlr->cs_gpios)
 619                 spi->cs_gpio = ctlr->cs_gpios[spi->chip_select];
 620
 621         /*
 622          * Drivers may modify this initial i/o setup, but will
 623          * normally rely on the device being setup.  Devices
 624          * using SPI_CS_HIGH can't coexist well otherwise...
 625          */
 626         status = spi_setup(spi);
 627         if (status < 0) {
 628                 dev_err(dev, "can't setup %s, status %d\n",
 629                                 dev_name(&spi->dev), status);
 630                 return status;
 631         }
 632
 633         /* Device may be bound to an active driver when this returns */
 634         status = device_add(&spi->dev);
 635         if (status < 0) {
 636                 dev_err(dev, "can't add %s, status %d\n",
 637                                 dev_name(&spi->dev), status);
 638                 spi_cleanup(spi);
 639         } else {
 640                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 641         }
 642
 643         return status;
 644 }
 645
 646 /**
 647  * spi_add_device - Add spi_device allocated with spi_alloc_device
 648  * @spi: spi_device to register
 649  *
 650  * Companion function to spi_alloc_device.  Devices allocated with
 651  * spi_alloc_device can be added onto the spi bus with this function.
 652  *
 653  * Return: 0 on success; negative errno on failure
 654  */
 655 static int spi_add_device(struct spi_device *spi)
 656 {
 657         struct spi_controller *ctlr = spi->controller;
 658         struct device *dev = ctlr->dev.parent;
 659         int status;
 660
 661         /* Chipselects are numbered 0..max; validate. */
 662         if (spi->chip_select >= ctlr->num_chipselect) {
 663                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 664                         ctlr->num_chipselect);
 665                 return -EINVAL;
 666         }
 667
 668         /* Set the bus ID string */
 669         spi_dev_set_name(spi);
 670
 671         mutex_lock(&ctlr->add_lock);
 672         status = __spi_add_device(spi);
 673         mutex_unlock(&ctlr->add_lock);
 674         return status;
 675 }
 676
 677 static int spi_add_device_locked(struct spi_device *spi)
 678 {
 679         struct spi_controller *ctlr = spi->controller;
 680         struct device *dev = ctlr->dev.parent;
 681
 682         /* Chipselects are numbered 0..max; validate. */
 683         if (spi->chip_select >= ctlr->num_chipselect) {
 684                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 685                         ctlr->num_chipselect);
 686                 return -EINVAL;
 687         }
 688
 689         /* Set the bus ID string */
 690         spi_dev_set_name(spi);
 691
 692         WARN_ON(!mutex_is_locked(&ctlr->add_lock));
 693         return __spi_add_device(spi);
 694 }
 695
 696 /**
 697  * spi_new_device - instantiate one new SPI device
 698  * @ctlr: Controller to which device is connected
 699  * @chip: Describes the SPI device
 700  * Context: can sleep
 701  *
 702  * On typical mainboards, this is purely internal; and it's not needed
 703  * after board init creates the hard-wired devices.  Some development
 704  * platforms may not be able to use spi_register_board_info though, and
 705  * this is exported so that for example a USB or parport based adapter
 706  * driver could add devices (which it would learn about out-of-band).
 707  *
 708  * Return: the new device, or NULL.
 709  */
 710 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 711                                   struct spi_board_info *chip)
 712 {
 713         struct spi_device       *proxy;
 714         int                     status;
 715
 716         /*
 717          * NOTE:  caller did any chip->bus_num checks necessary.
 718          *
 719          * Also, unless we change the return value convention to use
 720          * error-or-pointer (not NULL-or-pointer), troubleshootability
 721          * suggests syslogged diagnostics are best here (ugh).
 722          */
 723
 724         proxy = spi_alloc_device(ctlr);
 725         if (!proxy)
 726                 return NULL;
 727
 728         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 729
 730         proxy->chip_select = chip->chip_select;
 731         proxy->max_speed_hz = chip->max_speed_hz;
 732         proxy->mode = chip->mode;
 733         proxy->irq = chip->irq;
 734         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 735         proxy->dev.platform_data = (void *) chip->platform_data;
 736         proxy->controller_data = chip->controller_data;
 737         proxy->controller_state = NULL;
 738
 739         if (chip->swnode) {
 740                 status = device_add_software_node(&proxy->dev, chip->swnode);
 741                 if (status) {
 742                         dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
 743                                 chip->modalias, status);
 744                         goto err_dev_put;
 745                 }
 746         }
 747
 748         status = spi_add_device(proxy);
 749         if (status < 0)
 750                 goto err_dev_put;
 751
 752         return proxy;
 753
 754 err_dev_put:
 755         device_remove_software_node(&proxy->dev);
 756         spi_dev_put(proxy);
 757         return NULL;
 758 }
 759 EXPORT_SYMBOL_GPL(spi_new_device);
 760
 761 /**
 762  * spi_unregister_device - unregister a single SPI device
 763  * @spi: spi_device to unregister
 764  *
 765  * Start making the passed SPI device vanish. Normally this would be handled
 766  * by spi_unregister_controller().
 767  */
 768 void spi_unregister_device(struct spi_device *spi)
 769 {
 770         if (!spi)
 771                 return;
 772
 773         if (spi->dev.of_node) {
 774                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 775                 of_node_put(spi->dev.of_node);
 776         }
 777         if (ACPI_COMPANION(&spi->dev))
 778                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 779         device_remove_software_node(&spi->dev);
 780         device_del(&spi->dev);
 781         spi_cleanup(spi);
 782         put_device(&spi->dev);
 783 }
 784 EXPORT_SYMBOL_GPL(spi_unregister_device);
 785
 786 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 787                                               struct spi_board_info *bi)
 788 {
 789         struct spi_device *dev;
 790
 791         if (ctlr->bus_num != bi->bus_num)
 792                 return;
 793
 794         dev = spi_new_device(ctlr, bi);
 795         if (!dev)
 796                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 797                         bi->modalias);
 798 }
 799
 800 /**
 801  * spi_register_board_info - register SPI devices for a given board
 802  * @info: array of chip descriptors
 803  * @n: how many descriptors are provided
 804  * Context: can sleep
 805  *
 806  * Board-specific early init code calls this (probably during arch_initcall)
 807  * with segments of the SPI device table.  Any device nodes are created later,
 808  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 809  * this table of devices forever, so that reloading a controller driver will
 810  * not make Linux forget about these hard-wired devices.
 811  *
 812  * Other code can also call this, e.g. a particular add-on board might provide
 813  * SPI devices through its expansion connector, so code initializing that board
 814  * would naturally declare its SPI devices.
 815  *
 816  * The board info passed can safely be __initdata ... but be careful of
 817  * any embedded pointers (platform_data, etc), they're copied as-is.
 818  *
 819  * Return: zero on success, else a negative error code.
 820  */
 821 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 822 {
 823         struct boardinfo *bi;
 824         int i;
 825
 826         if (!n)
 827                 return 0;
 828
 829         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 830         if (!bi)
 831                 return -ENOMEM;
 832
 833         for (i = 0; i < n; i++, bi++, info++) {
 834                 struct spi_controller *ctlr;
 835
 836                 memcpy(&bi->board_info, info, sizeof(*info));
 837
 838                 mutex_lock(&board_lock);
 839                 list_add_tail(&bi->list, &board_list);
 840                 list_for_each_entry(ctlr, &spi_controller_list, list)
 841                         spi_match_controller_to_boardinfo(ctlr,
 842                                                           &bi->board_info);
 843                 mutex_unlock(&board_lock);
 844         }
 845
 846         return 0;
 847 }
 848
 849 /*-------------------------------------------------------------------------*/
 850
 851 /* Core methods for SPI resource management */
 852
 853 /**
 854  * spi_res_alloc - allocate a spi resource that is life-cycle managed
 855  *                 during the processing of a spi_message while using
 856  *                 spi_transfer_one
 857  * @spi:     the spi device for which we allocate memory
 858  * @release: the release code to execute for this resource
 859  * @size:    size to alloc and return
 860  * @gfp:     GFP allocation flags
 861  *
 862  * Return: the pointer to the allocated data
 863  *
 864  * This may get enhanced in the future to allocate from a memory pool
 865  * of the @spi_device or @spi_controller to avoid repeated allocations.
 866  */
 867 static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
 868                            size_t size, gfp_t gfp)
 869 {
 870         struct spi_res *sres;
 871
 872         sres = kzalloc(sizeof(*sres) + size, gfp);
 873         if (!sres)
 874                 return NULL;
 875
 876         INIT_LIST_HEAD(&sres->entry);
 877         sres->release = release;
 878
 879         return sres->data;
 880 }
 881
 882 /**
 883  * spi_res_free - free an spi resource
 884  * @res: pointer to the custom data of a resource
 885  */
 886 static void spi_res_free(void *res)
 887 {
 888         struct spi_res *sres = container_of(res, struct spi_res, data);
 889
 890         if (!res)
 891                 return;
 892
 893         WARN_ON(!list_empty(&sres->entry));
 894         kfree(sres);
 895 }
 896
 897 /**
 898  * spi_res_add - add a spi_res to the spi_message
 899  * @message: the spi message
 900  * @res:     the spi_resource
 901  */
 902 static void spi_res_add(struct spi_message *message, void *res)
 903 {
 904         struct spi_res *sres = container_of(res, struct spi_res, data);
 905
 906         WARN_ON(!list_empty(&sres->entry));
 907         list_add_tail(&sres->entry, &message->resources);
 908 }
 909
 910 /**
 911  * spi_res_release - release all spi resources for this message
 912  * @ctlr:  the @spi_controller
 913  * @message: the @spi_message
 914  */
 915 static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
 916 {
 917         struct spi_res *res, *tmp;
 918
 919         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
 920                 if (res->release)
 921                         res->release(ctlr, message, res->data);
 922
 923                 list_del(&res->entry);
 924
 925                 kfree(res);
 926         }
 927 }
 928
 929 /*-------------------------------------------------------------------------*/
 930
 931 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 932 {
 933         bool activate = enable;
 934
 935         /*
 936          * Avoid calling into the driver (or doing delays) if the chip select
 937          * isn't actually changing from the last time this was called.
 938          */
 939         if (!force && (spi->controller->last_cs_enable == enable) &&
 940             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 941                 return;
 942
 943         trace_spi_set_cs(spi, activate);
 944
 945         spi->controller->last_cs_enable = enable;
 946         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 947
 948         if ((spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
 949             !spi->controller->set_cs_timing) && !activate) {
 950                 spi_delay_exec(&spi->cs_hold, NULL);
 951         }
 952
 953         if (spi->mode & SPI_CS_HIGH)
 954                 enable = !enable;
 955
 956         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio)) {
 957                 if (!(spi->mode & SPI_NO_CS)) {
 958                         if (spi->cs_gpiod) {
 959                                 /*
 960                                  * Historically ACPI has no means of the GPIO polarity and
 961                                  * thus the SPISerialBus() resource defines it on the per-chip
 962                                  * basis. In order to avoid a chain of negations, the GPIO
 963                                  * polarity is considered being Active High. Even for the cases
 964                                  * when _DSD() is involved (in the updated versions of ACPI)
 965                                  * the GPIO CS polarity must be defined Active High to avoid
 966                                  * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
 967                                  * into account.
 968                                  */
 969                                 if (has_acpi_companion(&spi->dev))
 970                                         gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
 971                                 else
 972                                         /* Polarity handled by GPIO library */
 973                                         gpiod_set_value_cansleep(spi->cs_gpiod, activate);
 974                         } else {
 975                                 /*
 976                                  * Invert the enable line, as active low is
 977                                  * default for SPI.
 978                                  */
 979                                 gpio_set_value_cansleep(spi->cs_gpio, !enable);
 980                         }
 981                 }
 982                 /* Some SPI masters need both GPIO CS & slave_select */
 983                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 984                     spi->controller->set_cs)
 985                         spi->controller->set_cs(spi, !enable);
 986         } else if (spi->controller->set_cs) {
 987                 spi->controller->set_cs(spi, !enable);
 988         }
 989
 990         if (spi->cs_gpiod || gpio_is_valid(spi->cs_gpio) ||
 991             !spi->controller->set_cs_timing) {
 992                 if (activate)
 993                         spi_delay_exec(&spi->cs_setup, NULL);
 994                 else
 995                         spi_delay_exec(&spi->cs_inactive, NULL);
 996         }
 997 }
 998
 999 #ifdef CONFIG_HAS_DMA
1000 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
1001                 struct sg_table *sgt, void *buf, size_t len,
1002                 enum dma_data_direction dir)
1003 {
1004         const bool vmalloced_buf = is_vmalloc_addr(buf);
1005         unsigned int max_seg_size = dma_get_max_seg_size(dev);
1006 #ifdef CONFIG_HIGHMEM
1007         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
1008                                 (unsigned long)buf < (PKMAP_BASE +
1009                                         (LAST_PKMAP * PAGE_SIZE)));
1010 #else
1011         const bool kmap_buf = false;
1012 #endif
1013         int desc_len;
1014         int sgs;
1015         struct page *vm_page;
1016         struct scatterlist *sg;
1017         void *sg_buf;
1018         size_t min;
1019         int i, ret;
1020
1021         if (vmalloced_buf || kmap_buf) {
1022                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
1023                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
1024         } else if (virt_addr_valid(buf)) {
1025                 desc_len = min_t(int, max_seg_size, ctlr->max_dma_len);
1026                 sgs = DIV_ROUND_UP(len, desc_len);
1027         } else {
1028                 return -EINVAL;
1029         }
1030
1031         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
1032         if (ret != 0)
1033                 return ret;
1034
1035         sg = &sgt->sgl[0];
1036         for (i = 0; i < sgs; i++) {
1037
1038                 if (vmalloced_buf || kmap_buf) {
1039                         /*
1040                          * Next scatterlist entry size is the minimum between
1041                          * the desc_len and the remaining buffer length that
1042                          * fits in a page.
1043                          */
1044                         min = min_t(size_t, desc_len,
1045                                     min_t(size_t, len,
1046                                           PAGE_SIZE - offset_in_page(buf)));
1047                         if (vmalloced_buf)
1048                                 vm_page = vmalloc_to_page(buf);
1049                         else
1050                                 vm_page = kmap_to_page(buf);
1051                         if (!vm_page) {
1052                                 sg_free_table(sgt);
1053                                 return -ENOMEM;
1054                         }
1055                         sg_set_page(sg, vm_page,
1056                                     min, offset_in_page(buf));
1057                 } else {
1058                         min = min_t(size_t, len, desc_len);
1059                         sg_buf = buf;
1060                         sg_set_buf(sg, sg_buf, min);
1061                 }
1062
1063                 buf += min;
1064                 len -= min;
1065                 sg = sg_next(sg);
1066         }
1067
1068         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
1069         if (!ret)
1070                 ret = -ENOMEM;
1071         if (ret < 0) {
1072                 sg_free_table(sgt);
1073                 return ret;
1074         }
1075
1076         sgt->nents = ret;
1077
1078         return 0;
1079 }
1080
1081 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
1082                    struct sg_table *sgt, enum dma_data_direction dir)
1083 {
1084         if (sgt->orig_nents) {
1085                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
1086                 sg_free_table(sgt);
1087         }
1088 }
1089
1090 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1091 {
1092         struct device *tx_dev, *rx_dev;
1093         struct spi_transfer *xfer;
1094         int ret;
1095
1096         if (!ctlr->can_dma)
1097                 return 0;
1098
1099         if (ctlr->dma_tx)
1100                 tx_dev = ctlr->dma_tx->device->dev;
1101         else if (ctlr->dma_map_dev)
1102                 tx_dev = ctlr->dma_map_dev;
1103         else
1104                 tx_dev = ctlr->dev.parent;
1105
1106         if (ctlr->dma_rx)
1107                 rx_dev = ctlr->dma_rx->device->dev;
1108         else if (ctlr->dma_map_dev)
1109                 rx_dev = ctlr->dma_map_dev;
1110         else
1111                 rx_dev = ctlr->dev.parent;
1112
1113         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1114                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1115                         continue;
1116
1117                 if (xfer->tx_buf != NULL) {
1118                         ret = spi_map_buf(ctlr, tx_dev, &xfer->tx_sg,
1119                                           (void *)xfer->tx_buf, xfer->len,
1120                                           DMA_TO_DEVICE);
1121                         if (ret != 0)
1122                                 return ret;
1123                 }
1124
1125                 if (xfer->rx_buf != NULL) {
1126                         ret = spi_map_buf(ctlr, rx_dev, &xfer->rx_sg,
1127                                           xfer->rx_buf, xfer->len,
1128                                           DMA_FROM_DEVICE);
1129                         if (ret != 0) {
1130                                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg,
1131                                               DMA_TO_DEVICE);
1132                                 return ret;
1133                         }
1134                 }
1135         }
1136
1137         ctlr->cur_msg_mapped = true;
1138
1139         return 0;
1140 }
1141
1142 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1143 {
1144         struct spi_transfer *xfer;
1145         struct device *tx_dev, *rx_dev;
1146
1147         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1148                 return 0;
1149
1150         if (ctlr->dma_tx)
1151                 tx_dev = ctlr->dma_tx->device->dev;
1152         else
1153                 tx_dev = ctlr->dev.parent;
1154
1155         if (ctlr->dma_rx)
1156                 rx_dev = ctlr->dma_rx->device->dev;
1157         else
1158                 rx_dev = ctlr->dev.parent;
1159
1160         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1161                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1162                         continue;
1163
1164                 spi_unmap_buf(ctlr, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1165                 spi_unmap_buf(ctlr, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1166         }
1167
1168         ctlr->cur_msg_mapped = false;
1169
1170         return 0;
1171 }
1172 #else /* !CONFIG_HAS_DMA */
1173 static inline int __spi_map_msg(struct spi_controller *ctlr,
1174                                 struct spi_message *msg)
1175 {
1176         return 0;
1177 }
1178
1179 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1180                                   struct spi_message *msg)
1181 {
1182         return 0;
1183 }
1184 #endif /* !CONFIG_HAS_DMA */
1185
1186 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1187                                 struct spi_message *msg)
1188 {
1189         struct spi_transfer *xfer;
1190
1191         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1192                 /*
1193                  * Restore the original value of tx_buf or rx_buf if they are
1194                  * NULL.
1195                  */
1196                 if (xfer->tx_buf == ctlr->dummy_tx)
1197                         xfer->tx_buf = NULL;
1198                 if (xfer->rx_buf == ctlr->dummy_rx)
1199                         xfer->rx_buf = NULL;
1200         }
1201
1202         return __spi_unmap_msg(ctlr, msg);
1203 }
1204
1205 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1206 {
1207         struct spi_transfer *xfer;
1208         void *tmp;
1209         unsigned int max_tx, max_rx;
1210
1211         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1212                 && !(msg->spi->mode & SPI_3WIRE)) {
1213                 max_tx = 0;
1214                 max_rx = 0;
1215
1216                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1217                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1218                             !xfer->tx_buf)
1219                                 max_tx = max(xfer->len, max_tx);
1220                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1221                             !xfer->rx_buf)
1222                                 max_rx = max(xfer->len, max_rx);
1223                 }
1224
1225                 if (max_tx) {
1226                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1227                                        GFP_KERNEL | GFP_DMA | __GFP_ZERO);
1228                         if (!tmp)
1229                                 return -ENOMEM;
1230                         ctlr->dummy_tx = tmp;
1231                 }
1232
1233                 if (max_rx) {
1234                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1235                                        GFP_KERNEL | GFP_DMA);
1236                         if (!tmp)
1237                                 return -ENOMEM;
1238                         ctlr->dummy_rx = tmp;
1239                 }
1240
1241                 if (max_tx || max_rx) {
1242                         list_for_each_entry(xfer, &msg->transfers,
1243                                             transfer_list) {
1244                                 if (!xfer->len)
1245                                         continue;
1246                                 if (!xfer->tx_buf)
1247                                         xfer->tx_buf = ctlr->dummy_tx;
1248                                 if (!xfer->rx_buf)
1249                                         xfer->rx_buf = ctlr->dummy_rx;
1250                         }
1251                 }
1252         }
1253
1254         return __spi_map_msg(ctlr, msg);
1255 }
1256
1257 static int spi_transfer_wait(struct spi_controller *ctlr,
1258                              struct spi_message *msg,
1259                              struct spi_transfer *xfer)
1260 {
1261         struct spi_statistics *statm = &ctlr->statistics;
1262         struct spi_statistics *stats = &msg->spi->statistics;
1263         u32 speed_hz = xfer->speed_hz;
1264         unsigned long long ms;
1265
1266         if (spi_controller_is_slave(ctlr)) {
1267                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1268                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1269                         return -EINTR;
1270                 }
1271         } else {
1272                 if (!speed_hz)
1273                         speed_hz = 100000;
1274
1275                 /*
1276                  * For each byte we wait for 8 cycles of the SPI clock.
1277                  * Since speed is defined in Hz and we want milliseconds,
1278                  * use respective multiplier, but before the division,
1279                  * otherwise we may get 0 for short transfers.
1280                  */
1281                 ms = 8LL * MSEC_PER_SEC * xfer->len;
1282                 do_div(ms, speed_hz);
1283
1284                 /*
1285                  * Increase it twice and add 200 ms tolerance, use
1286                  * predefined maximum in case of overflow.
1287                  */
1288                 ms += ms + 200;
1289                 if (ms > UINT_MAX)
1290                         ms = UINT_MAX;
1291
1292                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1293                                                  msecs_to_jiffies(ms));
1294
1295                 if (ms == 0) {
1296                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1297                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1298                         dev_err(&msg->spi->dev,
1299                                 "SPI transfer timed out\n");
1300                         return -ETIMEDOUT;
1301                 }
1302         }
1303
1304         return 0;
1305 }
1306
1307 static void _spi_transfer_delay_ns(u32 ns)
1308 {
1309         if (!ns)
1310                 return;
1311         if (ns <= NSEC_PER_USEC) {
1312                 ndelay(ns);
1313         } else {
1314                 u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1315
1316                 if (us <= 10)
1317                         udelay(us);
1318                 else
1319                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1320         }
1321 }
1322
1323 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1324 {
1325         u32 delay = _delay->value;
1326         u32 unit = _delay->unit;
1327         u32 hz;
1328
1329         if (!delay)
1330                 return 0;
1331
1332         switch (unit) {
1333         case SPI_DELAY_UNIT_USECS:
1334                 delay *= NSEC_PER_USEC;
1335                 break;
1336         case SPI_DELAY_UNIT_NSECS:
1337                 /* Nothing to do here */
1338                 break;
1339         case SPI_DELAY_UNIT_SCK:
1340                 /* clock cycles need to be obtained from spi_transfer */
1341                 if (!xfer)
1342                         return -EINVAL;
1343                 /*
1344                  * If there is unknown effective speed, approximate it
1345                  * by underestimating with half of the requested hz.
1346                  */
1347                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1348                 if (!hz)
1349                         return -EINVAL;
1350
1351                 /* Convert delay to nanoseconds */
1352                 delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1353                 break;
1354         default:
1355                 return -EINVAL;
1356         }
1357
1358         return delay;
1359 }
1360 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1361
1362 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1363 {
1364         int delay;
1365
1366         might_sleep();
1367
1368         if (!_delay)
1369                 return -EINVAL;
1370
1371         delay = spi_delay_to_ns(_delay, xfer);
1372         if (delay < 0)
1373                 return delay;
1374
1375         _spi_transfer_delay_ns(delay);
1376
1377         return 0;
1378 }
1379 EXPORT_SYMBOL_GPL(spi_delay_exec);
1380
1381 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1382                                           struct spi_transfer *xfer)
1383 {
1384         u32 default_delay_ns = 10 * NSEC_PER_USEC;
1385         u32 delay = xfer->cs_change_delay.value;
1386         u32 unit = xfer->cs_change_delay.unit;
1387         int ret;
1388
1389         /* return early on "fast" mode - for everything but USECS */
1390         if (!delay) {
1391                 if (unit == SPI_DELAY_UNIT_USECS)
1392                         _spi_transfer_delay_ns(default_delay_ns);
1393                 return;
1394         }
1395
1396         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1397         if (ret) {
1398                 dev_err_once(&msg->spi->dev,
1399                              "Use of unsupported delay unit %i, using default of %luus\n",
1400                              unit, default_delay_ns / NSEC_PER_USEC);
1401                 _spi_transfer_delay_ns(default_delay_ns);
1402         }
1403 }
1404
1405 /*
1406  * spi_transfer_one_message - Default implementation of transfer_one_message()
1407  *
1408  * This is a standard implementation of transfer_one_message() for
1409  * drivers which implement a transfer_one() operation.  It provides
1410  * standard handling of delays and chip select management.
1411  */
1412 static int spi_transfer_one_message(struct spi_controller *ctlr,
1413                                     struct spi_message *msg)
1414 {
1415         struct spi_transfer *xfer;
1416         bool keep_cs = false;
1417         int ret = 0;
1418         struct spi_statistics *statm = &ctlr->statistics;
1419         struct spi_statistics *stats = &msg->spi->statistics;
1420
1421         spi_set_cs(msg->spi, true, false);
1422
1423         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1424         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1425
1426         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1427                 trace_spi_transfer_start(msg, xfer);
1428
1429                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1430                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1431
1432                 if (!ctlr->ptp_sts_supported) {
1433                         xfer->ptp_sts_word_pre = 0;
1434                         ptp_read_system_prets(xfer->ptp_sts);
1435                 }
1436
1437                 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1438                         reinit_completion(&ctlr->xfer_completion);
1439
1440 fallback_pio:
1441                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1442                         if (ret < 0) {
1443                                 if (ctlr->cur_msg_mapped &&
1444                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1445                                         __spi_unmap_msg(ctlr, msg);
1446                                         ctlr->fallback = true;
1447                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1448                                         goto fallback_pio;
1449                                 }
1450
1451                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1452                                                                errors);
1453                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1454                                                                errors);
1455                                 dev_err(&msg->spi->dev,
1456                                         "SPI transfer failed: %d\n", ret);
1457                                 goto out;
1458                         }
1459
1460                         if (ret > 0) {
1461                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1462                                 if (ret < 0)
1463                                         msg->status = ret;
1464                         }
1465                 } else {
1466                         if (xfer->len)
1467                                 dev_err(&msg->spi->dev,
1468                                         "Bufferless transfer has length %u\n",
1469                                         xfer->len);
1470                 }
1471
1472                 if (!ctlr->ptp_sts_supported) {
1473                         ptp_read_system_postts(xfer->ptp_sts);
1474                         xfer->ptp_sts_word_post = xfer->len;
1475                 }
1476
1477                 trace_spi_transfer_stop(msg, xfer);
1478
1479                 if (msg->status != -EINPROGRESS)
1480                         goto out;
1481
1482                 spi_transfer_delay_exec(xfer);
1483
1484                 if (xfer->cs_change) {
1485                         if (list_is_last(&xfer->transfer_list,
1486                                          &msg->transfers)) {
1487                                 keep_cs = true;
1488                         } else {
1489                                 spi_set_cs(msg->spi, false, false);
1490                                 _spi_transfer_cs_change_delay(msg, xfer);
1491                                 spi_set_cs(msg->spi, true, false);
1492                         }
1493                 }
1494
1495                 msg->actual_length += xfer->len;
1496         }
1497
1498 out:
1499         if (ret != 0 || !keep_cs)
1500                 spi_set_cs(msg->spi, false, false);
1501
1502         if (msg->status == -EINPROGRESS)
1503                 msg->status = ret;
1504
1505         if (msg->status && ctlr->handle_err)
1506                 ctlr->handle_err(ctlr, msg);
1507
1508         spi_finalize_current_message(ctlr);
1509
1510         return ret;
1511 }
1512
1513 /**
1514  * spi_finalize_current_transfer - report completion of a transfer
1515  * @ctlr: the controller reporting completion
1516  *
1517  * Called by SPI drivers using the core transfer_one_message()
1518  * implementation to notify it that the current interrupt driven
1519  * transfer has finished and the next one may be scheduled.
1520  */
1521 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1522 {
1523         complete(&ctlr->xfer_completion);
1524 }
1525 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1526
1527 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1528 {
1529         if (ctlr->auto_runtime_pm) {
1530                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1531                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1532         }
1533 }
1534
1535 /**
1536  * __spi_pump_messages - function which processes spi message queue
1537  * @ctlr: controller to process queue for
1538  * @in_kthread: true if we are in the context of the message pump thread
1539  *
1540  * This function checks if there is any spi message in the queue that
1541  * needs processing and if so call out to the driver to initialize hardware
1542  * and transfer each message.
1543  *
1544  * Note that it is called both from the kthread itself and also from
1545  * inside spi_sync(); the queue extraction handling at the top of the
1546  * function should deal with this safely.
1547  */
1548 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1549 {
1550         struct spi_transfer *xfer;
1551         struct spi_message *msg;
1552         bool was_busy = false;
1553         unsigned long flags;
1554         int ret;
1555
1556         /* Lock queue */
1557         spin_lock_irqsave(&ctlr->queue_lock, flags);
1558
1559         /* Make sure we are not already running a message */
1560         if (ctlr->cur_msg) {
1561                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1562                 return;
1563         }
1564
1565         /* If another context is idling the device then defer */
1566         if (ctlr->idling) {
1567                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1568                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1569                 return;
1570         }
1571
1572         /* Check if the queue is idle */
1573         if (list_empty(&ctlr->queue) || !ctlr->running) {
1574                 if (!ctlr->busy) {
1575                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1576                         return;
1577                 }
1578
1579                 /* Defer any non-atomic teardown to the thread */
1580                 if (!in_kthread) {
1581                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1582                             !ctlr->unprepare_transfer_hardware) {
1583                                 spi_idle_runtime_pm(ctlr);
1584                                 ctlr->busy = false;
1585                                 trace_spi_controller_idle(ctlr);
1586                         } else {
1587                                 kthread_queue_work(ctlr->kworker,
1588                                                    &ctlr->pump_messages);
1589                         }
1590                         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1591                         return;
1592                 }
1593
1594                 ctlr->busy = false;
1595                 ctlr->idling = true;
1596                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1597
1598                 kfree(ctlr->dummy_rx);
1599                 ctlr->dummy_rx = NULL;
1600                 kfree(ctlr->dummy_tx);
1601                 ctlr->dummy_tx = NULL;
1602                 if (ctlr->unprepare_transfer_hardware &&
1603                     ctlr->unprepare_transfer_hardware(ctlr))
1604                         dev_err(&ctlr->dev,
1605                                 "failed to unprepare transfer hardware\n");
1606                 spi_idle_runtime_pm(ctlr);
1607                 trace_spi_controller_idle(ctlr);
1608
1609                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1610                 ctlr->idling = false;
1611                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1612                 return;
1613         }
1614
1615         /* Extract head of queue */
1616         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1617         ctlr->cur_msg = msg;
1618
1619         list_del_init(&msg->queue);
1620         if (ctlr->busy)
1621                 was_busy = true;
1622         else
1623                 ctlr->busy = true;
1624         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1625
1626         mutex_lock(&ctlr->io_mutex);
1627
1628         if (!was_busy && ctlr->auto_runtime_pm) {
1629                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1630                 if (ret < 0) {
1631                         pm_runtime_put_noidle(ctlr->dev.parent);
1632                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1633                                 ret);
1634                         mutex_unlock(&ctlr->io_mutex);
1635                         return;
1636                 }
1637         }
1638
1639         if (!was_busy)
1640                 trace_spi_controller_busy(ctlr);
1641
1642         if (!was_busy && ctlr->prepare_transfer_hardware) {
1643                 ret = ctlr->prepare_transfer_hardware(ctlr);
1644                 if (ret) {
1645                         dev_err(&ctlr->dev,
1646                                 "failed to prepare transfer hardware: %d\n",
1647                                 ret);
1648
1649                         if (ctlr->auto_runtime_pm)
1650                                 pm_runtime_put(ctlr->dev.parent);
1651
1652                         msg->status = ret;
1653                         spi_finalize_current_message(ctlr);
1654
1655                         mutex_unlock(&ctlr->io_mutex);
1656                         return;
1657                 }
1658         }
1659
1660         trace_spi_message_start(msg);
1661
1662         if (ctlr->prepare_message) {
1663                 ret = ctlr->prepare_message(ctlr, msg);
1664                 if (ret) {
1665                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1666                                 ret);
1667                         msg->status = ret;
1668                         spi_finalize_current_message(ctlr);
1669                         goto out;
1670                 }
1671                 ctlr->cur_msg_prepared = true;
1672         }
1673
1674         ret = spi_map_msg(ctlr, msg);
1675         if (ret) {
1676                 msg->status = ret;
1677                 spi_finalize_current_message(ctlr);
1678                 goto out;
1679         }
1680
1681         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1682                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1683                         xfer->ptp_sts_word_pre = 0;
1684                         ptp_read_system_prets(xfer->ptp_sts);
1685                 }
1686         }
1687
1688         ret = ctlr->transfer_one_message(ctlr, msg);
1689         if (ret) {
1690                 dev_err(&ctlr->dev,
1691                         "failed to transfer one message from queue\n");
1692                 goto out;
1693         }
1694
1695 out:
1696         mutex_unlock(&ctlr->io_mutex);
1697
1698         /* Prod the scheduler in case transfer_one() was busy waiting */
1699         if (!ret)
1700                 cond_resched();
1701 }
1702
1703 /**
1704  * spi_pump_messages - kthread work function which processes spi message queue
1705  * @work: pointer to kthread work struct contained in the controller struct
1706  */
1707 static void spi_pump_messages(struct kthread_work *work)
1708 {
1709         struct spi_controller *ctlr =
1710                 container_of(work, struct spi_controller, pump_messages);
1711
1712         __spi_pump_messages(ctlr, true);
1713 }
1714
1715 /**
1716  * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
1717  * @ctlr: Pointer to the spi_controller structure of the driver
1718  * @xfer: Pointer to the transfer being timestamped
1719  * @progress: How many words (not bytes) have been transferred so far
1720  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1721  *            transfer, for less jitter in time measurement. Only compatible
1722  *            with PIO drivers. If true, must follow up with
1723  *            spi_take_timestamp_post or otherwise system will crash.
1724  *            WARNING: for fully predictable results, the CPU frequency must
1725  *            also be under control (governor).
1726  *
1727  * This is a helper for drivers to collect the beginning of the TX timestamp
1728  * for the requested byte from the SPI transfer. The frequency with which this
1729  * function must be called (once per word, once for the whole transfer, once
1730  * per batch of words etc) is arbitrary as long as the @tx buffer offset is
1731  * greater than or equal to the requested byte at the time of the call. The
1732  * timestamp is only taken once, at the first such call. It is assumed that
1733  * the driver advances its @tx buffer pointer monotonically.
1734  */
1735 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1736                             struct spi_transfer *xfer,
1737                             size_t progress, bool irqs_off)
1738 {
1739         if (!xfer->ptp_sts)
1740                 return;
1741
1742         if (xfer->timestamped)
1743                 return;
1744
1745         if (progress > xfer->ptp_sts_word_pre)
1746                 return;
1747
1748         /* Capture the resolution of the timestamp */
1749         xfer->ptp_sts_word_pre = progress;
1750
1751         if (irqs_off) {
1752                 local_irq_save(ctlr->irq_flags);
1753                 preempt_disable();
1754         }
1755
1756         ptp_read_system_prets(xfer->ptp_sts);
1757 }
1758 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1759
1760 /**
1761  * spi_take_timestamp_post - helper to collect the end of the TX timestamp
1762  * @ctlr: Pointer to the spi_controller structure of the driver
1763  * @xfer: Pointer to the transfer being timestamped
1764  * @progress: How many words (not bytes) have been transferred so far
1765  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1766  *
1767  * This is a helper for drivers to collect the end of the TX timestamp for
1768  * the requested byte from the SPI transfer. Can be called with an arbitrary
1769  * frequency: only the first call where @tx exceeds or is equal to the
1770  * requested word will be timestamped.
1771  */
1772 void spi_take_timestamp_post(struct spi_controller *ctlr,
1773                              struct spi_transfer *xfer,
1774                              size_t progress, bool irqs_off)
1775 {
1776         if (!xfer->ptp_sts)
1777                 return;
1778
1779         if (xfer->timestamped)
1780                 return;
1781
1782         if (progress < xfer->ptp_sts_word_post)
1783                 return;
1784
1785         ptp_read_system_postts(xfer->ptp_sts);
1786
1787         if (irqs_off) {
1788                 local_irq_restore(ctlr->irq_flags);
1789                 preempt_enable();
1790         }
1791
1792         /* Capture the resolution of the timestamp */
1793         xfer->ptp_sts_word_post = progress;
1794
1795         xfer->timestamped = true;
1796 }
1797 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1798
1799 /**
1800  * spi_set_thread_rt - set the controller to pump at realtime priority
1801  * @ctlr: controller to boost priority of
1802  *
1803  * This can be called because the controller requested realtime priority
1804  * (by setting the ->rt value before calling spi_register_controller()) or
1805  * because a device on the bus said that its transfers needed realtime
1806  * priority.
1807  *
1808  * NOTE: at the moment if any device on a bus says it needs realtime then
1809  * the thread will be at realtime priority for all transfers on that
1810  * controller.  If this eventually becomes a problem we may see if we can
1811  * find a way to boost the priority only temporarily during relevant
1812  * transfers.
1813  */
1814 static void spi_set_thread_rt(struct spi_controller *ctlr)
1815 {
1816         dev_info(&ctlr->dev,
1817                 "will run message pump with realtime priority\n");
1818         sched_set_fifo(ctlr->kworker->task);
1819 }
1820
1821 static int spi_init_queue(struct spi_controller *ctlr)
1822 {
1823         ctlr->running = false;
1824         ctlr->busy = false;
1825
1826         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1827         if (IS_ERR(ctlr->kworker)) {
1828                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1829                 return PTR_ERR(ctlr->kworker);
1830         }
1831
1832         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1833
1834         /*
1835          * Controller config will indicate if this controller should run the
1836          * message pump with high (realtime) priority to reduce the transfer
1837          * latency on the bus by minimising the delay between a transfer
1838          * request and the scheduling of the message pump thread. Without this
1839          * setting the message pump thread will remain at default priority.
1840          */
1841         if (ctlr->rt)
1842                 spi_set_thread_rt(ctlr);
1843
1844         return 0;
1845 }
1846
1847 /**
1848  * spi_get_next_queued_message() - called by driver to check for queued
1849  * messages
1850  * @ctlr: the controller to check for queued messages
1851  *
1852  * If there are more messages in the queue, the next message is returned from
1853  * this call.
1854  *
1855  * Return: the next message in the queue, else NULL if the queue is empty.
1856  */
1857 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1858 {
1859         struct spi_message *next;
1860         unsigned long flags;
1861
1862         /* get a pointer to the next message, if any */
1863         spin_lock_irqsave(&ctlr->queue_lock, flags);
1864         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1865                                         queue);
1866         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1867
1868         return next;
1869 }
1870 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1871
1872 /**
1873  * spi_finalize_current_message() - the current message is complete
1874  * @ctlr: the controller to return the message to
1875  *
1876  * Called by the driver to notify the core that the message in the front of the
1877  * queue is complete and can be removed from the queue.
1878  */
1879 void spi_finalize_current_message(struct spi_controller *ctlr)
1880 {
1881         struct spi_transfer *xfer;
1882         struct spi_message *mesg;
1883         unsigned long flags;
1884         int ret;
1885
1886         spin_lock_irqsave(&ctlr->queue_lock, flags);
1887         mesg = ctlr->cur_msg;
1888         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1889
1890         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1891                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
1892                         ptp_read_system_postts(xfer->ptp_sts);
1893                         xfer->ptp_sts_word_post = xfer->len;
1894                 }
1895         }
1896
1897         if (unlikely(ctlr->ptp_sts_supported))
1898                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
1899                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
1900
1901         spi_unmap_msg(ctlr, mesg);
1902
1903         /*
1904          * In the prepare_messages callback the SPI bus has the opportunity
1905          * to split a transfer to smaller chunks.
1906          *
1907          * Release the split transfers here since spi_map_msg() is done on
1908          * the split transfers.
1909          */
1910         spi_res_release(ctlr, mesg);
1911
1912         if (ctlr->cur_msg_prepared && ctlr->unprepare_message) {
1913                 ret = ctlr->unprepare_message(ctlr, mesg);
1914                 if (ret) {
1915                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
1916                                 ret);
1917                 }
1918         }
1919
1920         spin_lock_irqsave(&ctlr->queue_lock, flags);
1921         ctlr->cur_msg = NULL;
1922         ctlr->cur_msg_prepared = false;
1923         ctlr->fallback = false;
1924         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1925         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1926
1927         trace_spi_message_done(mesg);
1928
1929         mesg->state = NULL;
1930         if (mesg->complete)
1931                 mesg->complete(mesg->context);
1932 }
1933 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1934
1935 static int spi_start_queue(struct spi_controller *ctlr)
1936 {
1937         unsigned long flags;
1938
1939         spin_lock_irqsave(&ctlr->queue_lock, flags);
1940
1941         if (ctlr->running || ctlr->busy) {
1942                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1943                 return -EBUSY;
1944         }
1945
1946         ctlr->running = true;
1947         ctlr->cur_msg = NULL;
1948         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1949
1950         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1951
1952         return 0;
1953 }
1954
1955 static int spi_stop_queue(struct spi_controller *ctlr)
1956 {
1957         unsigned long flags;
1958         unsigned limit = 500;
1959         int ret = 0;
1960
1961         spin_lock_irqsave(&ctlr->queue_lock, flags);
1962
1963         /*
1964          * This is a bit lame, but is optimized for the common execution path.
1965          * A wait_queue on the ctlr->busy could be used, but then the common
1966          * execution path (pump_messages) would be required to call wake_up or
1967          * friends on every SPI message. Do this instead.
1968          */
1969         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
1970                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1971                 usleep_range(10000, 11000);
1972                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1973         }
1974
1975         if (!list_empty(&ctlr->queue) || ctlr->busy)
1976                 ret = -EBUSY;
1977         else
1978                 ctlr->running = false;
1979
1980         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1981
1982         if (ret) {
1983                 dev_warn(&ctlr->dev, "could not stop message queue\n");
1984                 return ret;
1985         }
1986         return ret;
1987 }
1988
1989 static int spi_destroy_queue(struct spi_controller *ctlr)
1990 {
1991         int ret;
1992
1993         ret = spi_stop_queue(ctlr);
1994
1995         /*
1996          * kthread_flush_worker will block until all work is done.
1997          * If the reason that stop_queue timed out is that the work will never
1998          * finish, then it does no good to call flush/stop thread, so
1999          * return anyway.
2000          */
2001         if (ret) {
2002                 dev_err(&ctlr->dev, "problem destroying queue\n");
2003                 return ret;
2004         }
2005
2006         kthread_destroy_worker(ctlr->kworker);
2007
2008         return 0;
2009 }
2010
2011 static int __spi_queued_transfer(struct spi_device *spi,
2012                                  struct spi_message *msg,
2013                                  bool need_pump)
2014 {
2015         struct spi_controller *ctlr = spi->controller;
2016         unsigned long flags;
2017
2018         spin_lock_irqsave(&ctlr->queue_lock, flags);
2019
2020         if (!ctlr->running) {
2021                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2022                 return -ESHUTDOWN;
2023         }
2024         msg->actual_length = 0;
2025         msg->status = -EINPROGRESS;
2026
2027         list_add_tail(&msg->queue, &ctlr->queue);
2028         if (!ctlr->busy && need_pump)
2029                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2030
2031         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2032         return 0;
2033 }
2034
2035 /**
2036  * spi_queued_transfer - transfer function for queued transfers
2037  * @spi: spi device which is requesting transfer
2038  * @msg: spi message which is to handled is queued to driver queue
2039  *
2040  * Return: zero on success, else a negative error code.
2041  */
2042 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
2043 {
2044         return __spi_queued_transfer(spi, msg, true);
2045 }
2046
2047 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
2048 {
2049         int ret;
2050
2051         ctlr->transfer = spi_queued_transfer;
2052         if (!ctlr->transfer_one_message)
2053                 ctlr->transfer_one_message = spi_transfer_one_message;
2054
2055         /* Initialize and start queue */
2056         ret = spi_init_queue(ctlr);
2057         if (ret) {
2058                 dev_err(&ctlr->dev, "problem initializing queue\n");
2059                 goto err_init_queue;
2060         }
2061         ctlr->queued = true;
2062         ret = spi_start_queue(ctlr);
2063         if (ret) {
2064                 dev_err(&ctlr->dev, "problem starting queue\n");
2065                 goto err_start_queue;
2066         }
2067
2068         return 0;
2069
2070 err_start_queue:
2071         spi_destroy_queue(ctlr);
2072 err_init_queue:
2073         return ret;
2074 }
2075
2076 /**
2077  * spi_flush_queue - Send all pending messages in the queue from the callers'
2078  *                   context
2079  * @ctlr: controller to process queue for
2080  *
2081  * This should be used when one wants to ensure all pending messages have been
2082  * sent before doing something. Is used by the spi-mem code to make sure SPI
2083  * memory operations do not preempt regular SPI transfers that have been queued
2084  * before the spi-mem operation.
2085  */
2086 void spi_flush_queue(struct spi_controller *ctlr)
2087 {
2088         if (ctlr->transfer == spi_queued_transfer)
2089                 __spi_pump_messages(ctlr, false);
2090 }
2091
2092 /*-------------------------------------------------------------------------*/
2093
2094 #if defined(CONFIG_OF)
2095 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
2096                            struct device_node *nc)
2097 {
2098         u32 value;
2099         int rc;
2100
2101         /* Mode (clock phase/polarity/etc.) */
2102         if (of_property_read_bool(nc, "spi-cpha"))
2103                 spi->mode |= SPI_CPHA;
2104         if (of_property_read_bool(nc, "spi-cpol"))
2105                 spi->mode |= SPI_CPOL;
2106         if (of_property_read_bool(nc, "spi-3wire"))
2107                 spi->mode |= SPI_3WIRE;
2108         if (of_property_read_bool(nc, "spi-lsb-first"))
2109                 spi->mode |= SPI_LSB_FIRST;
2110         if (of_property_read_bool(nc, "spi-cs-high"))
2111                 spi->mode |= SPI_CS_HIGH;
2112
2113         /* Device DUAL/QUAD mode */
2114         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2115                 switch (value) {
2116                 case 0:
2117                         spi->mode |= SPI_NO_TX;
2118                         break;
2119                 case 1:
2120                         break;
2121                 case 2:
2122                         spi->mode |= SPI_TX_DUAL;
2123                         break;
2124                 case 4:
2125                         spi->mode |= SPI_TX_QUAD;
2126                         break;
2127                 case 8:
2128                         spi->mode |= SPI_TX_OCTAL;
2129                         break;
2130                 default:
2131                         dev_warn(&ctlr->dev,
2132                                 "spi-tx-bus-width %d not supported\n",
2133                                 value);
2134                         break;
2135                 }
2136         }
2137
2138         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2139                 switch (value) {
2140                 case 0:
2141                         spi->mode |= SPI_NO_RX;
2142                         break;
2143                 case 1:
2144                         break;
2145                 case 2:
2146                         spi->mode |= SPI_RX_DUAL;
2147                         break;
2148                 case 4:
2149                         spi->mode |= SPI_RX_QUAD;
2150                         break;
2151                 case 8:
2152                         spi->mode |= SPI_RX_OCTAL;
2153                         break;
2154                 default:
2155                         dev_warn(&ctlr->dev,
2156                                 "spi-rx-bus-width %d not supported\n",
2157                                 value);
2158                         break;
2159                 }
2160         }
2161
2162         if (spi_controller_is_slave(ctlr)) {
2163                 if (!of_node_name_eq(nc, "slave")) {
2164                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2165                                 nc);
2166                         return -EINVAL;
2167                 }
2168                 return 0;
2169         }
2170
2171         /* Device address */
2172         rc = of_property_read_u32(nc, "reg", &value);
2173         if (rc) {
2174                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2175                         nc, rc);
2176                 return rc;
2177         }
2178         spi->chip_select = value;
2179
2180         /* Device speed */
2181         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2182                 spi->max_speed_hz = value;
2183
2184         return 0;
2185 }
2186
2187 static struct spi_device *
2188 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2189 {
2190         struct spi_device *spi;
2191         int rc;
2192
2193         /* Alloc an spi_device */
2194         spi = spi_alloc_device(ctlr);
2195         if (!spi) {
2196                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2197                 rc = -ENOMEM;
2198                 goto err_out;
2199         }
2200
2201         /* Select device driver */
2202         rc = of_modalias_node(nc, spi->modalias,
2203                                 sizeof(spi->modalias));
2204         if (rc < 0) {
2205                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2206                 goto err_out;
2207         }
2208
2209         rc = of_spi_parse_dt(ctlr, spi, nc);
2210         if (rc)
2211                 goto err_out;
2212
2213         /* Store a pointer to the node in the device structure */
2214         of_node_get(nc);
2215         spi->dev.of_node = nc;
2216         spi->dev.fwnode = of_fwnode_handle(nc);
2217
2218         /* Register the new device */
2219         rc = spi_add_device(spi);
2220         if (rc) {
2221                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2222                 goto err_of_node_put;
2223         }
2224
2225         return spi;
2226
2227 err_of_node_put:
2228         of_node_put(nc);
2229 err_out:
2230         spi_dev_put(spi);
2231         return ERR_PTR(rc);
2232 }
2233
2234 /**
2235  * of_register_spi_devices() - Register child devices onto the SPI bus
2236  * @ctlr:       Pointer to spi_controller device
2237  *
2238  * Registers an spi_device for each child node of controller node which
2239  * represents a valid SPI slave.
2240  */
2241 static void of_register_spi_devices(struct spi_controller *ctlr)
2242 {
2243         struct spi_device *spi;
2244         struct device_node *nc;
2245
2246         if (!ctlr->dev.of_node)
2247                 return;
2248
2249         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2250                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2251                         continue;
2252                 spi = of_register_spi_device(ctlr, nc);
2253                 if (IS_ERR(spi)) {
2254                         dev_warn(&ctlr->dev,
2255                                  "Failed to create SPI device for %pOF\n", nc);
2256                         of_node_clear_flag(nc, OF_POPULATED);
2257                 }
2258         }
2259 }
2260 #else
2261 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2262 #endif
2263
2264 /**
2265  * spi_new_ancillary_device() - Register ancillary SPI device
2266  * @spi:         Pointer to the main SPI device registering the ancillary device
2267  * @chip_select: Chip Select of the ancillary device
2268  *
2269  * Register an ancillary SPI device; for example some chips have a chip-select
2270  * for normal device usage and another one for setup/firmware upload.
2271  *
2272  * This may only be called from main SPI device's probe routine.
2273  *
2274  * Return: 0 on success; negative errno on failure
2275  */
2276 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2277                                              u8 chip_select)
2278 {
2279         struct spi_device *ancillary;
2280         int rc = 0;
2281
2282         /* Alloc an spi_device */
2283         ancillary = spi_alloc_device(spi->controller);
2284         if (!ancillary) {
2285                 rc = -ENOMEM;
2286                 goto err_out;
2287         }
2288
2289         strlcpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2290
2291         /* Use provided chip-select for ancillary device */
2292         ancillary->chip_select = chip_select;
2293
2294         /* Take over SPI mode/speed from SPI main device */
2295         ancillary->max_speed_hz = spi->max_speed_hz;
2296         ancillary->mode = spi->mode;
2297
2298         /* Register the new device */
2299         rc = spi_add_device_locked(ancillary);
2300         if (rc) {
2301                 dev_err(&spi->dev, "failed to register ancillary device\n");
2302                 goto err_out;
2303         }
2304
2305         return ancillary;
2306
2307 err_out:
2308         spi_dev_put(ancillary);
2309         return ERR_PTR(rc);
2310 }
2311 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2312
2313 #ifdef CONFIG_ACPI
2314 struct acpi_spi_lookup {
2315         struct spi_controller   *ctlr;
2316         u32                     max_speed_hz;
2317         u32                     mode;
2318         int                     irq;
2319         u8                      bits_per_word;
2320         u8                      chip_select;
2321 };
2322
2323 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2324                                             struct acpi_spi_lookup *lookup)
2325 {
2326         const union acpi_object *obj;
2327
2328         if (!x86_apple_machine)
2329                 return;
2330
2331         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2332             && obj->buffer.length >= 4)
2333                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2334
2335         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2336             && obj->buffer.length == 8)
2337                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2338
2339         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2340             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2341                 lookup->mode |= SPI_LSB_FIRST;
2342
2343         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2344             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2345                 lookup->mode |= SPI_CPOL;
2346
2347         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2348             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2349                 lookup->mode |= SPI_CPHA;
2350 }
2351
2352 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2353 {
2354         struct acpi_spi_lookup *lookup = data;
2355         struct spi_controller *ctlr = lookup->ctlr;
2356
2357         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2358                 struct acpi_resource_spi_serialbus *sb;
2359                 acpi_handle parent_handle;
2360                 acpi_status status;
2361
2362                 sb = &ares->data.spi_serial_bus;
2363                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2364
2365                         status = acpi_get_handle(NULL,
2366                                                  sb->resource_source.string_ptr,
2367                                                  &parent_handle);
2368
2369                         if (ACPI_FAILURE(status) ||
2370                             ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2371                                 return -ENODEV;
2372
2373                         /*
2374                          * ACPI DeviceSelection numbering is handled by the
2375                          * host controller driver in Windows and can vary
2376                          * from driver to driver. In Linux we always expect
2377                          * 0 .. max - 1 so we need to ask the driver to
2378                          * translate between the two schemes.
2379                          */
2380                         if (ctlr->fw_translate_cs) {
2381                                 int cs = ctlr->fw_translate_cs(ctlr,
2382                                                 sb->device_selection);
2383                                 if (cs < 0)
2384                                         return cs;
2385                                 lookup->chip_select = cs;
2386                         } else {
2387                                 lookup->chip_select = sb->device_selection;
2388                         }
2389
2390                         lookup->max_speed_hz = sb->connection_speed;
2391                         lookup->bits_per_word = sb->data_bit_length;
2392
2393                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2394                                 lookup->mode |= SPI_CPHA;
2395                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2396                                 lookup->mode |= SPI_CPOL;
2397                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2398                                 lookup->mode |= SPI_CS_HIGH;
2399                 }
2400         } else if (lookup->irq < 0) {
2401                 struct resource r;
2402
2403                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2404                         lookup->irq = r.start;
2405         }
2406
2407         /* Always tell the ACPI core to skip this resource */
2408         return 1;
2409 }
2410
2411 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2412                                             struct acpi_device *adev)
2413 {
2414         acpi_handle parent_handle = NULL;
2415         struct list_head resource_list;
2416         struct acpi_spi_lookup lookup = {};
2417         struct spi_device *spi;
2418         int ret;
2419
2420         if (acpi_bus_get_status(adev) || !adev->status.present ||
2421             acpi_device_enumerated(adev))
2422                 return AE_OK;
2423
2424         lookup.ctlr             = ctlr;
2425         lookup.irq              = -1;
2426
2427         INIT_LIST_HEAD(&resource_list);
2428         ret = acpi_dev_get_resources(adev, &resource_list,
2429                                      acpi_spi_add_resource, &lookup);
2430         acpi_dev_free_resource_list(&resource_list);
2431
2432         if (ret < 0)
2433                 /* found SPI in _CRS but it points to another controller */
2434                 return AE_OK;
2435
2436         if (!lookup.max_speed_hz &&
2437             ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2438             ACPI_HANDLE(ctlr->dev.parent) == parent_handle) {
2439                 /* Apple does not use _CRS but nested devices for SPI slaves */
2440                 acpi_spi_parse_apple_properties(adev, &lookup);
2441         }
2442
2443         if (!lookup.max_speed_hz)
2444                 return AE_OK;
2445
2446         spi = spi_alloc_device(ctlr);
2447         if (!spi) {
2448                 dev_err(&ctlr->dev, "failed to allocate SPI device for %s\n",
2449                         dev_name(&adev->dev));
2450                 return AE_NO_MEMORY;
2451         }
2452
2453
2454         ACPI_COMPANION_SET(&spi->dev, adev);
2455         spi->max_speed_hz       = lookup.max_speed_hz;
2456         spi->mode               |= lookup.mode;
2457         spi->irq                = lookup.irq;
2458         spi->bits_per_word      = lookup.bits_per_word;
2459         spi->chip_select        = lookup.chip_select;
2460
2461         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2462                           sizeof(spi->modalias));
2463
2464         if (spi->irq < 0)
2465                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2466
2467         acpi_device_set_enumerated(adev);
2468
2469         adev->power.flags.ignore_parent = true;
2470         if (spi_add_device(spi)) {
2471                 adev->power.flags.ignore_parent = false;
2472                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2473                         dev_name(&adev->dev));
2474                 spi_dev_put(spi);
2475         }
2476
2477         return AE_OK;
2478 }
2479
2480 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2481                                        void *data, void **return_value)
2482 {
2483         struct spi_controller *ctlr = data;
2484         struct acpi_device *adev;
2485
2486         if (acpi_bus_get_device(handle, &adev))
2487                 return AE_OK;
2488
2489         return acpi_register_spi_device(ctlr, adev);
2490 }
2491
2492 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2493
2494 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2495 {
2496         acpi_status status;
2497         acpi_handle handle;
2498
2499         handle = ACPI_HANDLE(ctlr->dev.parent);
2500         if (!handle)
2501                 return;
2502
2503         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2504                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2505                                      acpi_spi_add_device, NULL, ctlr, NULL);
2506         if (ACPI_FAILURE(status))
2507                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2508 }
2509 #else
2510 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2511 #endif /* CONFIG_ACPI */
2512
2513 static void spi_controller_release(struct device *dev)
2514 {
2515         struct spi_controller *ctlr;
2516
2517         ctlr = container_of(dev, struct spi_controller, dev);
2518         kfree(ctlr);
2519 }
2520
2521 static struct class spi_master_class = {
2522         .name           = "spi_master",
2523         .owner          = THIS_MODULE,
2524         .dev_release    = spi_controller_release,
2525         .dev_groups     = spi_master_groups,
2526 };
2527
2528 #ifdef CONFIG_SPI_SLAVE
2529 /**
2530  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2531  *                   controller
2532  * @spi: device used for the current transfer
2533  */
2534 int spi_slave_abort(struct spi_device *spi)
2535 {
2536         struct spi_controller *ctlr = spi->controller;
2537
2538         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2539                 return ctlr->slave_abort(ctlr);
2540
2541         return -ENOTSUPP;
2542 }
2543 EXPORT_SYMBOL_GPL(spi_slave_abort);
2544
2545 static int match_true(struct device *dev, void *data)
2546 {
2547         return 1;
2548 }
2549
2550 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2551                           char *buf)
2552 {
2553         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2554                                                    dev);
2555         struct device *child;
2556
2557         child = device_find_child(&ctlr->dev, NULL, match_true);
2558         return sprintf(buf, "%s\n",
2559                        child ? to_spi_device(child)->modalias : NULL);
2560 }
2561
2562 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2563                            const char *buf, size_t count)
2564 {
2565         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2566                                                    dev);
2567         struct spi_device *spi;
2568         struct device *child;
2569         char name[32];
2570         int rc;
2571
2572         rc = sscanf(buf, "%31s", name);
2573         if (rc != 1 || !name[0])
2574                 return -EINVAL;
2575
2576         child = device_find_child(&ctlr->dev, NULL, match_true);
2577         if (child) {
2578                 /* Remove registered slave */
2579                 device_unregister(child);
2580                 put_device(child);
2581         }
2582
2583         if (strcmp(name, "(null)")) {
2584                 /* Register new slave */
2585                 spi = spi_alloc_device(ctlr);
2586                 if (!spi)
2587                         return -ENOMEM;
2588
2589                 strlcpy(spi->modalias, name, sizeof(spi->modalias));
2590
2591                 rc = spi_add_device(spi);
2592                 if (rc) {
2593                         spi_dev_put(spi);
2594                         return rc;
2595                 }
2596         }
2597
2598         return count;
2599 }
2600
2601 static DEVICE_ATTR_RW(slave);
2602
2603 static struct attribute *spi_slave_attrs[] = {
2604         &dev_attr_slave.attr,
2605         NULL,
2606 };
2607
2608 static const struct attribute_group spi_slave_group = {
2609         .attrs = spi_slave_attrs,
2610 };
2611
2612 static const struct attribute_group *spi_slave_groups[] = {
2613         &spi_controller_statistics_group,
2614         &spi_slave_group,
2615         NULL,
2616 };
2617
2618 static struct class spi_slave_class = {
2619         .name           = "spi_slave",
2620         .owner          = THIS_MODULE,
2621         .dev_release    = spi_controller_release,
2622         .dev_groups     = spi_slave_groups,
2623 };
2624 #else
2625 extern struct class spi_slave_class;    /* dummy */
2626 #endif
2627
2628 /**
2629  * __spi_alloc_controller - allocate an SPI master or slave controller
2630  * @dev: the controller, possibly using the platform_bus
2631  * @size: how much zeroed driver-private data to allocate; the pointer to this
2632  *      memory is in the driver_data field of the returned device, accessible
2633  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2634  *      drivers granting DMA access to portions of their private data need to
2635  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2636  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2637  *      slave (true) controller
2638  * Context: can sleep
2639  *
2640  * This call is used only by SPI controller drivers, which are the
2641  * only ones directly touching chip registers.  It's how they allocate
2642  * an spi_controller structure, prior to calling spi_register_controller().
2643  *
2644  * This must be called from context that can sleep.
2645  *
2646  * The caller is responsible for assigning the bus number and initializing the
2647  * controller's methods before calling spi_register_controller(); and (after
2648  * errors adding the device) calling spi_controller_put() to prevent a memory
2649  * leak.
2650  *
2651  * Return: the SPI controller structure on success, else NULL.
2652  */
2653 struct spi_controller *__spi_alloc_controller(struct device *dev,
2654                                               unsigned int size, bool slave)
2655 {
2656         struct spi_controller   *ctlr;
2657         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2658
2659         if (!dev)
2660                 return NULL;
2661
2662         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2663         if (!ctlr)
2664                 return NULL;
2665
2666         device_initialize(&ctlr->dev);
2667         INIT_LIST_HEAD(&ctlr->queue);
2668         spin_lock_init(&ctlr->queue_lock);
2669         spin_lock_init(&ctlr->bus_lock_spinlock);
2670         mutex_init(&ctlr->bus_lock_mutex);
2671         mutex_init(&ctlr->io_mutex);
2672         mutex_init(&ctlr->add_lock);
2673         ctlr->bus_num = -1;
2674         ctlr->num_chipselect = 1;
2675         ctlr->slave = slave;
2676         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2677                 ctlr->dev.class = &spi_slave_class;
2678         else
2679                 ctlr->dev.class = &spi_master_class;
2680         ctlr->dev.parent = dev;
2681         pm_suspend_ignore_children(&ctlr->dev, true);
2682         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2683
2684         return ctlr;
2685 }
2686 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2687
2688 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2689 {
2690         spi_controller_put(*(struct spi_controller **)ctlr);
2691 }
2692
2693 /**
2694  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2695  * @dev: physical device of SPI controller
2696  * @size: how much zeroed driver-private data to allocate
2697  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2698  * Context: can sleep
2699  *
2700  * Allocate an SPI controller and automatically release a reference on it
2701  * when @dev is unbound from its driver.  Drivers are thus relieved from
2702  * having to call spi_controller_put().
2703  *
2704  * The arguments to this function are identical to __spi_alloc_controller().
2705  *
2706  * Return: the SPI controller structure on success, else NULL.
2707  */
2708 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2709                                                    unsigned int size,
2710                                                    bool slave)
2711 {
2712         struct spi_controller **ptr, *ctlr;
2713
2714         ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2715                            GFP_KERNEL);
2716         if (!ptr)
2717                 return NULL;
2718
2719         ctlr = __spi_alloc_controller(dev, size, slave);
2720         if (ctlr) {
2721                 ctlr->devm_allocated = true;
2722                 *ptr = ctlr;
2723                 devres_add(dev, ptr);
2724         } else {
2725                 devres_free(ptr);
2726         }
2727
2728         return ctlr;
2729 }
2730 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2731
2732 #ifdef CONFIG_OF
2733 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2734 {
2735         int nb, i, *cs;
2736         struct device_node *np = ctlr->dev.of_node;
2737
2738         if (!np)
2739                 return 0;
2740
2741         nb = of_gpio_named_count(np, "cs-gpios");
2742         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2743
2744         /* Return error only for an incorrectly formed cs-gpios property */
2745         if (nb == 0 || nb == -ENOENT)
2746                 return 0;
2747         else if (nb < 0)
2748                 return nb;
2749
2750         cs = devm_kcalloc(&ctlr->dev, ctlr->num_chipselect, sizeof(int),
2751                           GFP_KERNEL);
2752         ctlr->cs_gpios = cs;
2753
2754         if (!ctlr->cs_gpios)
2755                 return -ENOMEM;
2756
2757         for (i = 0; i < ctlr->num_chipselect; i++)
2758                 cs[i] = -ENOENT;
2759
2760         for (i = 0; i < nb; i++)
2761                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
2762
2763         return 0;
2764 }
2765 #else
2766 static int of_spi_get_gpio_numbers(struct spi_controller *ctlr)
2767 {
2768         return 0;
2769 }
2770 #endif
2771
2772 /**
2773  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2774  * @ctlr: The SPI master to grab GPIO descriptors for
2775  */
2776 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2777 {
2778         int nb, i;
2779         struct gpio_desc **cs;
2780         struct device *dev = &ctlr->dev;
2781         unsigned long native_cs_mask = 0;
2782         unsigned int num_cs_gpios = 0;
2783
2784         nb = gpiod_count(dev, "cs");
2785         if (nb < 0) {
2786                 /* No GPIOs at all is fine, else return the error */
2787                 if (nb == -ENOENT)
2788                         return 0;
2789                 return nb;
2790         }
2791
2792         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2793
2794         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2795                           GFP_KERNEL);
2796         if (!cs)
2797                 return -ENOMEM;
2798         ctlr->cs_gpiods = cs;
2799
2800         for (i = 0; i < nb; i++) {
2801                 /*
2802                  * Most chipselects are active low, the inverted
2803                  * semantics are handled by special quirks in gpiolib,
2804                  * so initializing them GPIOD_OUT_LOW here means
2805                  * "unasserted", in most cases this will drive the physical
2806                  * line high.
2807                  */
2808                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2809                                                       GPIOD_OUT_LOW);
2810                 if (IS_ERR(cs[i]))
2811                         return PTR_ERR(cs[i]);
2812
2813                 if (cs[i]) {
2814                         /*
2815                          * If we find a CS GPIO, name it after the device and
2816                          * chip select line.
2817                          */
2818                         char *gpioname;
2819
2820                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2821                                                   dev_name(dev), i);
2822                         if (!gpioname)
2823                                 return -ENOMEM;
2824                         gpiod_set_consumer_name(cs[i], gpioname);
2825                         num_cs_gpios++;
2826                         continue;
2827                 }
2828
2829                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
2830                         dev_err(dev, "Invalid native chip select %d\n", i);
2831                         return -EINVAL;
2832                 }
2833                 native_cs_mask |= BIT(i);
2834         }
2835
2836         ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
2837
2838         if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
2839             ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
2840                 dev_err(dev, "No unused native chip select available\n");
2841                 return -EINVAL;
2842         }
2843
2844         return 0;
2845 }
2846
2847 static int spi_controller_check_ops(struct spi_controller *ctlr)
2848 {
2849         /*
2850          * The controller may implement only the high-level SPI-memory like
2851          * operations if it does not support regular SPI transfers, and this is
2852          * valid use case.
2853          * If ->mem_ops is NULL, we request that at least one of the
2854          * ->transfer_xxx() method be implemented.
2855          */
2856         if (ctlr->mem_ops) {
2857                 if (!ctlr->mem_ops->exec_op)
2858                         return -EINVAL;
2859         } else if (!ctlr->transfer && !ctlr->transfer_one &&
2860                    !ctlr->transfer_one_message) {
2861                 return -EINVAL;
2862         }
2863
2864         return 0;
2865 }
2866
2867 /**
2868  * spi_register_controller - register SPI master or slave controller
2869  * @ctlr: initialized master, originally from spi_alloc_master() or
2870  *      spi_alloc_slave()
2871  * Context: can sleep
2872  *
2873  * SPI controllers connect to their drivers using some non-SPI bus,
2874  * such as the platform bus.  The final stage of probe() in that code
2875  * includes calling spi_register_controller() to hook up to this SPI bus glue.
2876  *
2877  * SPI controllers use board specific (often SOC specific) bus numbers,
2878  * and board-specific addressing for SPI devices combines those numbers
2879  * with chip select numbers.  Since SPI does not directly support dynamic
2880  * device identification, boards need configuration tables telling which
2881  * chip is at which address.
2882  *
2883  * This must be called from context that can sleep.  It returns zero on
2884  * success, else a negative error code (dropping the controller's refcount).
2885  * After a successful return, the caller is responsible for calling
2886  * spi_unregister_controller().
2887  *
2888  * Return: zero on success, else a negative error code.
2889  */
2890 int spi_register_controller(struct spi_controller *ctlr)
2891 {
2892         struct device           *dev = ctlr->dev.parent;
2893         struct boardinfo        *bi;
2894         int                     status;
2895         int                     id, first_dynamic;
2896
2897         if (!dev)
2898                 return -ENODEV;
2899
2900         /*
2901          * Make sure all necessary hooks are implemented before registering
2902          * the SPI controller.
2903          */
2904         status = spi_controller_check_ops(ctlr);
2905         if (status)
2906                 return status;
2907
2908         if (ctlr->bus_num >= 0) {
2909                 /* devices with a fixed bus num must check-in with the num */
2910                 mutex_lock(&board_lock);
2911                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2912                         ctlr->bus_num + 1, GFP_KERNEL);
2913                 mutex_unlock(&board_lock);
2914                 if (WARN(id < 0, "couldn't get idr"))
2915                         return id == -ENOSPC ? -EBUSY : id;
2916                 ctlr->bus_num = id;
2917         } else if (ctlr->dev.of_node) {
2918                 /* allocate dynamic bus number using Linux idr */
2919                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
2920                 if (id >= 0) {
2921                         ctlr->bus_num = id;
2922                         mutex_lock(&board_lock);
2923                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
2924                                        ctlr->bus_num + 1, GFP_KERNEL);
2925                         mutex_unlock(&board_lock);
2926                         if (WARN(id < 0, "couldn't get idr"))
2927                                 return id == -ENOSPC ? -EBUSY : id;
2928                 }
2929         }
2930         if (ctlr->bus_num < 0) {
2931                 first_dynamic = of_alias_get_highest_id("spi");
2932                 if (first_dynamic < 0)
2933                         first_dynamic = 0;
2934                 else
2935                         first_dynamic++;
2936
2937                 mutex_lock(&board_lock);
2938                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
2939                                0, GFP_KERNEL);
2940                 mutex_unlock(&board_lock);
2941                 if (WARN(id < 0, "couldn't get idr"))
2942                         return id;
2943                 ctlr->bus_num = id;
2944         }
2945         ctlr->bus_lock_flag = 0;
2946         init_completion(&ctlr->xfer_completion);
2947         if (!ctlr->max_dma_len)
2948                 ctlr->max_dma_len = INT_MAX;
2949
2950         /*
2951          * Register the device, then userspace will see it.
2952          * Registration fails if the bus ID is in use.
2953          */
2954         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
2955
2956         if (!spi_controller_is_slave(ctlr)) {
2957                 if (ctlr->use_gpio_descriptors) {
2958                         status = spi_get_gpio_descs(ctlr);
2959                         if (status)
2960                                 goto free_bus_id;
2961                         /*
2962                          * A controller using GPIO descriptors always
2963                          * supports SPI_CS_HIGH if need be.
2964                          */
2965                         ctlr->mode_bits |= SPI_CS_HIGH;
2966                 } else {
2967                         /* Legacy code path for GPIOs from DT */
2968                         status = of_spi_get_gpio_numbers(ctlr);
2969                         if (status)
2970                                 goto free_bus_id;
2971                 }
2972         }
2973
2974         /*
2975          * Even if it's just one always-selected device, there must
2976          * be at least one chipselect.
2977          */
2978         if (!ctlr->num_chipselect) {
2979                 status = -EINVAL;
2980                 goto free_bus_id;
2981         }
2982
2983         status = device_add(&ctlr->dev);
2984         if (status < 0)
2985                 goto free_bus_id;
2986         dev_dbg(dev, "registered %s %s\n",
2987                         spi_controller_is_slave(ctlr) ? "slave" : "master",
2988                         dev_name(&ctlr->dev));
2989
2990         /*
2991          * If we're using a queued driver, start the queue. Note that we don't
2992          * need the queueing logic if the driver is only supporting high-level
2993          * memory operations.
2994          */
2995         if (ctlr->transfer) {
2996                 dev_info(dev, "controller is unqueued, this is deprecated\n");
2997         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
2998                 status = spi_controller_initialize_queue(ctlr);
2999                 if (status) {
3000                         device_del(&ctlr->dev);
3001                         goto free_bus_id;
3002                 }
3003         }
3004         /* add statistics */
3005         spin_lock_init(&ctlr->statistics.lock);
3006
3007         mutex_lock(&board_lock);
3008         list_add_tail(&ctlr->list, &spi_controller_list);
3009         list_for_each_entry(bi, &board_list, list)
3010                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
3011         mutex_unlock(&board_lock);
3012
3013         /* Register devices from the device tree and ACPI */
3014         of_register_spi_devices(ctlr);
3015         acpi_register_spi_devices(ctlr);
3016         return status;
3017
3018 free_bus_id:
3019         mutex_lock(&board_lock);
3020         idr_remove(&spi_master_idr, ctlr->bus_num);
3021         mutex_unlock(&board_lock);
3022         return status;
3023 }
3024 EXPORT_SYMBOL_GPL(spi_register_controller);
3025
3026 static void devm_spi_unregister(void *ctlr)
3027 {
3028         spi_unregister_controller(ctlr);
3029 }
3030
3031 /**
3032  * devm_spi_register_controller - register managed SPI master or slave
3033  *      controller
3034  * @dev:    device managing SPI controller
3035  * @ctlr: initialized controller, originally from spi_alloc_master() or
3036  *      spi_alloc_slave()
3037  * Context: can sleep
3038  *
3039  * Register a SPI device as with spi_register_controller() which will
3040  * automatically be unregistered and freed.
3041  *
3042  * Return: zero on success, else a negative error code.
3043  */
3044 int devm_spi_register_controller(struct device *dev,
3045                                  struct spi_controller *ctlr)
3046 {
3047         int ret;
3048
3049         ret = spi_register_controller(ctlr);
3050         if (ret)
3051                 return ret;
3052
3053         return devm_add_action_or_reset(dev, devm_spi_unregister, ctlr);
3054 }
3055 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
3056
3057 static int __unregister(struct device *dev, void *null)
3058 {
3059         spi_unregister_device(to_spi_device(dev));
3060         return 0;
3061 }
3062
3063 /**
3064  * spi_unregister_controller - unregister SPI master or slave controller
3065  * @ctlr: the controller being unregistered
3066  * Context: can sleep
3067  *
3068  * This call is used only by SPI controller drivers, which are the
3069  * only ones directly touching chip registers.
3070  *
3071  * This must be called from context that can sleep.
3072  *
3073  * Note that this function also drops a reference to the controller.
3074  */
3075 void spi_unregister_controller(struct spi_controller *ctlr)
3076 {
3077         struct spi_controller *found;
3078         int id = ctlr->bus_num;
3079
3080         /* Prevent addition of new devices, unregister existing ones */
3081         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3082                 mutex_lock(&ctlr->add_lock);
3083
3084         device_for_each_child(&ctlr->dev, NULL, __unregister);
3085
3086         /* First make sure that this controller was ever added */
3087         mutex_lock(&board_lock);
3088         found = idr_find(&spi_master_idr, id);
3089         mutex_unlock(&board_lock);
3090         if (ctlr->queued) {
3091                 if (spi_destroy_queue(ctlr))
3092                         dev_err(&ctlr->dev, "queue remove failed\n");
3093         }
3094         mutex_lock(&board_lock);
3095         list_del(&ctlr->list);
3096         mutex_unlock(&board_lock);
3097
3098         device_del(&ctlr->dev);
3099
3100         /* free bus id */
3101         mutex_lock(&board_lock);
3102         if (found == ctlr)
3103                 idr_remove(&spi_master_idr, id);
3104         mutex_unlock(&board_lock);
3105
3106         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3107                 mutex_unlock(&ctlr->add_lock);
3108
3109         /* Release the last reference on the controller if its driver
3110          * has not yet been converted to devm_spi_alloc_master/slave().
3111          */
3112         if (!ctlr->devm_allocated)
3113                 put_device(&ctlr->dev);
3114 }
3115 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3116
3117 int spi_controller_suspend(struct spi_controller *ctlr)
3118 {
3119         int ret;
3120
3121         /* Basically no-ops for non-queued controllers */
3122         if (!ctlr->queued)
3123                 return 0;
3124
3125         ret = spi_stop_queue(ctlr);
3126         if (ret)
3127                 dev_err(&ctlr->dev, "queue stop failed\n");
3128
3129         return ret;
3130 }
3131 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3132
3133 int spi_controller_resume(struct spi_controller *ctlr)
3134 {
3135         int ret;
3136
3137         if (!ctlr->queued)
3138                 return 0;
3139
3140         ret = spi_start_queue(ctlr);
3141         if (ret)
3142                 dev_err(&ctlr->dev, "queue restart failed\n");
3143
3144         return ret;
3145 }
3146 EXPORT_SYMBOL_GPL(spi_controller_resume);
3147
3148 /*-------------------------------------------------------------------------*/
3149
3150 /* Core methods for spi_message alterations */
3151
3152 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3153                                             struct spi_message *msg,
3154                                             void *res)
3155 {
3156         struct spi_replaced_transfers *rxfer = res;
3157         size_t i;
3158
3159         /* call extra callback if requested */
3160         if (rxfer->release)
3161                 rxfer->release(ctlr, msg, res);
3162
3163         /* insert replaced transfers back into the message */
3164         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3165
3166         /* remove the formerly inserted entries */
3167         for (i = 0; i < rxfer->inserted; i++)
3168                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3169 }
3170
3171 /**
3172  * spi_replace_transfers - replace transfers with several transfers
3173  *                         and register change with spi_message.resources
3174  * @msg:           the spi_message we work upon
3175  * @xfer_first:    the first spi_transfer we want to replace
3176  * @remove:        number of transfers to remove
3177  * @insert:        the number of transfers we want to insert instead
3178  * @release:       extra release code necessary in some circumstances
3179  * @extradatasize: extra data to allocate (with alignment guarantees
3180  *                 of struct @spi_transfer)
3181  * @gfp:           gfp flags
3182  *
3183  * Returns: pointer to @spi_replaced_transfers,
3184  *          PTR_ERR(...) in case of errors.
3185  */
3186 static struct spi_replaced_transfers *spi_replace_transfers(
3187         struct spi_message *msg,
3188         struct spi_transfer *xfer_first,
3189         size_t remove,
3190         size_t insert,
3191         spi_replaced_release_t release,
3192         size_t extradatasize,
3193         gfp_t gfp)
3194 {
3195         struct spi_replaced_transfers *rxfer;
3196         struct spi_transfer *xfer;
3197         size_t i;
3198
3199         /* allocate the structure using spi_res */
3200         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3201                               struct_size(rxfer, inserted_transfers, insert)
3202                               + extradatasize,
3203                               gfp);
3204         if (!rxfer)
3205                 return ERR_PTR(-ENOMEM);
3206
3207         /* the release code to invoke before running the generic release */
3208         rxfer->release = release;
3209
3210         /* assign extradata */
3211         if (extradatasize)
3212                 rxfer->extradata =
3213                         &rxfer->inserted_transfers[insert];
3214
3215         /* init the replaced_transfers list */
3216         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3217
3218         /*
3219          * Assign the list_entry after which we should reinsert
3220          * the @replaced_transfers - it may be spi_message.messages!
3221          */
3222         rxfer->replaced_after = xfer_first->transfer_list.prev;
3223
3224         /* remove the requested number of transfers */
3225         for (i = 0; i < remove; i++) {
3226                 /*
3227                  * If the entry after replaced_after it is msg->transfers
3228                  * then we have been requested to remove more transfers
3229                  * than are in the list.
3230                  */
3231                 if (rxfer->replaced_after->next == &msg->transfers) {
3232                         dev_err(&msg->spi->dev,
3233                                 "requested to remove more spi_transfers than are available\n");
3234                         /* insert replaced transfers back into the message */
3235                         list_splice(&rxfer->replaced_transfers,
3236                                     rxfer->replaced_after);
3237
3238                         /* free the spi_replace_transfer structure */
3239                         spi_res_free(rxfer);
3240
3241                         /* and return with an error */
3242                         return ERR_PTR(-EINVAL);
3243                 }
3244
3245                 /*
3246                  * Remove the entry after replaced_after from list of
3247                  * transfers and add it to list of replaced_transfers.
3248                  */
3249                 list_move_tail(rxfer->replaced_after->next,
3250                                &rxfer->replaced_transfers);
3251         }
3252
3253         /*
3254          * Create copy of the given xfer with identical settings
3255          * based on the first transfer to get removed.
3256          */
3257         for (i = 0; i < insert; i++) {
3258                 /* we need to run in reverse order */
3259                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3260
3261                 /* copy all spi_transfer data */
3262                 memcpy(xfer, xfer_first, sizeof(*xfer));
3263
3264                 /* add to list */
3265                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3266
3267                 /* clear cs_change and delay for all but the last */
3268                 if (i) {
3269                         xfer->cs_change = false;
3270                         xfer->delay.value = 0;
3271                 }
3272         }
3273
3274         /* set up inserted */
3275         rxfer->inserted = insert;
3276
3277         /* and register it with spi_res/spi_message */
3278         spi_res_add(msg, rxfer);
3279
3280         return rxfer;
3281 }
3282
3283 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3284                                         struct spi_message *msg,
3285                                         struct spi_transfer **xferp,
3286                                         size_t maxsize,
3287                                         gfp_t gfp)
3288 {
3289         struct spi_transfer *xfer = *xferp, *xfers;
3290         struct spi_replaced_transfers *srt;
3291         size_t offset;
3292         size_t count, i;
3293
3294         /* calculate how many we have to replace */
3295         count = DIV_ROUND_UP(xfer->len, maxsize);
3296
3297         /* create replacement */
3298         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3299         if (IS_ERR(srt))
3300                 return PTR_ERR(srt);
3301         xfers = srt->inserted_transfers;
3302
3303         /*
3304          * Now handle each of those newly inserted spi_transfers.
3305          * Note that the replacements spi_transfers all are preset
3306          * to the same values as *xferp, so tx_buf, rx_buf and len
3307          * are all identical (as well as most others)
3308          * so we just have to fix up len and the pointers.
3309          *
3310          * This also includes support for the depreciated
3311          * spi_message.is_dma_mapped interface.
3312          */
3313
3314         /*
3315          * The first transfer just needs the length modified, so we
3316          * run it outside the loop.
3317          */
3318         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3319
3320         /* all the others need rx_buf/tx_buf also set */
3321         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3322                 /* update rx_buf, tx_buf and dma */
3323                 if (xfers[i].rx_buf)
3324                         xfers[i].rx_buf += offset;
3325                 if (xfers[i].rx_dma)
3326                         xfers[i].rx_dma += offset;
3327                 if (xfers[i].tx_buf)
3328                         xfers[i].tx_buf += offset;
3329                 if (xfers[i].tx_dma)
3330                         xfers[i].tx_dma += offset;
3331
3332                 /* update length */
3333                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3334         }
3335
3336         /*
3337          * We set up xferp to the last entry we have inserted,
3338          * so that we skip those already split transfers.
3339          */
3340         *xferp = &xfers[count - 1];
3341
3342         /* increment statistics counters */
3343         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3344                                        transfers_split_maxsize);
3345         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
3346                                        transfers_split_maxsize);
3347
3348         return 0;
3349 }
3350
3351 /**
3352  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3353  *                               when an individual transfer exceeds a
3354  *                               certain size
3355  * @ctlr:    the @spi_controller for this transfer
3356  * @msg:   the @spi_message to transform
3357  * @maxsize:  the maximum when to apply this
3358  * @gfp: GFP allocation flags
3359  *
3360  * Return: status of transformation
3361  */
3362 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3363                                 struct spi_message *msg,
3364                                 size_t maxsize,
3365                                 gfp_t gfp)
3366 {
3367         struct spi_transfer *xfer;
3368         int ret;
3369
3370         /*
3371          * Iterate over the transfer_list,
3372          * but note that xfer is advanced to the last transfer inserted
3373          * to avoid checking sizes again unnecessarily (also xfer does
3374          * potentially belong to a different list by the time the
3375          * replacement has happened).
3376          */
3377         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3378                 if (xfer->len > maxsize) {
3379                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3380                                                            maxsize, gfp);
3381                         if (ret)
3382                                 return ret;
3383                 }
3384         }
3385
3386         return 0;
3387 }
3388 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3389
3390 /*-------------------------------------------------------------------------*/
3391
3392 /* Core methods for SPI controller protocol drivers.  Some of the
3393  * other core methods are currently defined as inline functions.
3394  */
3395
3396 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3397                                         u8 bits_per_word)
3398 {
3399         if (ctlr->bits_per_word_mask) {
3400                 /* Only 32 bits fit in the mask */
3401                 if (bits_per_word > 32)
3402                         return -EINVAL;
3403                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3404                         return -EINVAL;
3405         }
3406
3407         return 0;
3408 }
3409
3410 /**
3411  * spi_setup - setup SPI mode and clock rate
3412  * @spi: the device whose settings are being modified
3413  * Context: can sleep, and no requests are queued to the device
3414  *
3415  * SPI protocol drivers may need to update the transfer mode if the
3416  * device doesn't work with its default.  They may likewise need
3417  * to update clock rates or word sizes from initial values.  This function
3418  * changes those settings, and must be called from a context that can sleep.
3419  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3420  * effect the next time the device is selected and data is transferred to
3421  * or from it.  When this function returns, the spi device is deselected.
3422  *
3423  * Note that this call will fail if the protocol driver specifies an option
3424  * that the underlying controller or its driver does not support.  For
3425  * example, not all hardware supports wire transfers using nine bit words,
3426  * LSB-first wire encoding, or active-high chipselects.
3427  *
3428  * Return: zero on success, else a negative error code.
3429  */
3430 int spi_setup(struct spi_device *spi)
3431 {
3432         unsigned        bad_bits, ugly_bits;
3433         int             status;
3434
3435         /*
3436          * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3437          * are set at the same time.
3438          */
3439         if ((hweight_long(spi->mode &
3440                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3441             (hweight_long(spi->mode &
3442                 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3443                 dev_err(&spi->dev,
3444                 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3445                 return -EINVAL;
3446         }
3447         /* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
3448         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3449                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3450                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3451                 return -EINVAL;
3452         /*
3453          * Help drivers fail *cleanly* when they need options
3454          * that aren't supported with their current controller.
3455          * SPI_CS_WORD has a fallback software implementation,
3456          * so it is ignored here.
3457          */
3458         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3459                                  SPI_NO_TX | SPI_NO_RX);
3460         /*
3461          * Nothing prevents from working with active-high CS in case if it
3462          * is driven by GPIO.
3463          */
3464         if (gpio_is_valid(spi->cs_gpio))
3465                 bad_bits &= ~SPI_CS_HIGH;
3466         ugly_bits = bad_bits &
3467                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3468                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3469         if (ugly_bits) {
3470                 dev_warn(&spi->dev,
3471                          "setup: ignoring unsupported mode bits %x\n",
3472                          ugly_bits);
3473                 spi->mode &= ~ugly_bits;
3474                 bad_bits &= ~ugly_bits;
3475         }
3476         if (bad_bits) {
3477                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3478                         bad_bits);
3479                 return -EINVAL;
3480         }
3481
3482         if (!spi->bits_per_word)
3483                 spi->bits_per_word = 8;
3484
3485         status = __spi_validate_bits_per_word(spi->controller,
3486                                               spi->bits_per_word);
3487         if (status)
3488                 return status;
3489
3490         if (spi->controller->max_speed_hz &&
3491             (!spi->max_speed_hz ||
3492              spi->max_speed_hz > spi->controller->max_speed_hz))
3493                 spi->max_speed_hz = spi->controller->max_speed_hz;
3494
3495         mutex_lock(&spi->controller->io_mutex);
3496
3497         if (spi->controller->setup) {
3498                 status = spi->controller->setup(spi);
3499                 if (status) {
3500                         mutex_unlock(&spi->controller->io_mutex);
3501                         dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3502                                 status);
3503                         return status;
3504                 }
3505         }
3506
3507         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3508                 status = pm_runtime_get_sync(spi->controller->dev.parent);
3509                 if (status < 0) {
3510                         mutex_unlock(&spi->controller->io_mutex);
3511                         pm_runtime_put_noidle(spi->controller->dev.parent);
3512                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3513                                 status);
3514                         return status;
3515                 }
3516
3517                 /*
3518                  * We do not want to return positive value from pm_runtime_get,
3519                  * there are many instances of devices calling spi_setup() and
3520                  * checking for a non-zero return value instead of a negative
3521                  * return value.
3522                  */
3523                 status = 0;
3524
3525                 spi_set_cs(spi, false, true);
3526                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3527                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3528         } else {
3529                 spi_set_cs(spi, false, true);
3530         }
3531
3532         mutex_unlock(&spi->controller->io_mutex);
3533
3534         if (spi->rt && !spi->controller->rt) {
3535                 spi->controller->rt = true;
3536                 spi_set_thread_rt(spi->controller);
3537         }
3538
3539         trace_spi_setup(spi, status);
3540
3541         dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3542                         spi->mode & SPI_MODE_X_MASK,
3543                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3544                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3545                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3546                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3547                         spi->bits_per_word, spi->max_speed_hz,
3548                         status);
3549
3550         return status;
3551 }
3552 EXPORT_SYMBOL_GPL(spi_setup);
3553
3554 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3555                                        struct spi_device *spi)
3556 {
3557         int delay1, delay2;
3558
3559         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3560         if (delay1 < 0)
3561                 return delay1;
3562
3563         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3564         if (delay2 < 0)
3565                 return delay2;
3566
3567         if (delay1 < delay2)
3568                 memcpy(&xfer->word_delay, &spi->word_delay,
3569                        sizeof(xfer->word_delay));
3570
3571         return 0;
3572 }
3573
3574 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3575 {
3576         struct spi_controller *ctlr = spi->controller;
3577         struct spi_transfer *xfer;
3578         int w_size;
3579
3580         if (list_empty(&message->transfers))
3581                 return -EINVAL;
3582
3583         /*
3584          * If an SPI controller does not support toggling the CS line on each
3585          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3586          * for the CS line, we can emulate the CS-per-word hardware function by
3587          * splitting transfers into one-word transfers and ensuring that
3588          * cs_change is set for each transfer.
3589          */
3590         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3591                                           spi->cs_gpiod ||
3592                                           gpio_is_valid(spi->cs_gpio))) {
3593                 size_t maxsize;
3594                 int ret;
3595
3596                 maxsize = (spi->bits_per_word + 7) / 8;
3597
3598                 /* spi_split_transfers_maxsize() requires message->spi */
3599                 message->spi = spi;
3600
3601                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3602                                                   GFP_KERNEL);
3603                 if (ret)
3604                         return ret;
3605
3606                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3607                         /* don't change cs_change on the last entry in the list */
3608                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3609                                 break;
3610                         xfer->cs_change = 1;
3611                 }
3612         }
3613
3614         /*
3615          * Half-duplex links include original MicroWire, and ones with
3616          * only one data pin like SPI_3WIRE (switches direction) or where
3617          * either MOSI or MISO is missing.  They can also be caused by
3618          * software limitations.
3619          */
3620         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3621             (spi->mode & SPI_3WIRE)) {
3622                 unsigned flags = ctlr->flags;
3623
3624                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3625                         if (xfer->rx_buf && xfer->tx_buf)
3626                                 return -EINVAL;
3627                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3628                                 return -EINVAL;
3629                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3630                                 return -EINVAL;
3631                 }
3632         }
3633
3634         /*
3635          * Set transfer bits_per_word and max speed as spi device default if
3636          * it is not set for this transfer.
3637          * Set transfer tx_nbits and rx_nbits as single transfer default
3638          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3639          * Ensure transfer word_delay is at least as long as that required by
3640          * device itself.
3641          */
3642         message->frame_length = 0;
3643         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3644                 xfer->effective_speed_hz = 0;
3645                 message->frame_length += xfer->len;
3646                 if (!xfer->bits_per_word)
3647                         xfer->bits_per_word = spi->bits_per_word;
3648
3649                 if (!xfer->speed_hz)
3650                         xfer->speed_hz = spi->max_speed_hz;
3651
3652                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3653                         xfer->speed_hz = ctlr->max_speed_hz;
3654
3655                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3656                         return -EINVAL;
3657
3658                 /*
3659                  * SPI transfer length should be multiple of SPI word size
3660                  * where SPI word size should be power-of-two multiple.
3661                  */
3662                 if (xfer->bits_per_word <= 8)
3663                         w_size = 1;
3664                 else if (xfer->bits_per_word <= 16)
3665                         w_size = 2;
3666                 else
3667                         w_size = 4;
3668
3669                 /* No partial transfers accepted */
3670                 if (xfer->len % w_size)
3671                         return -EINVAL;
3672
3673                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3674                     xfer->speed_hz < ctlr->min_speed_hz)
3675                         return -EINVAL;
3676
3677                 if (xfer->tx_buf && !xfer->tx_nbits)
3678                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3679                 if (xfer->rx_buf && !xfer->rx_nbits)
3680                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3681                 /*
3682                  * Check transfer tx/rx_nbits:
3683                  * 1. check the value matches one of single, dual and quad
3684                  * 2. check tx/rx_nbits match the mode in spi_device
3685                  */
3686                 if (xfer->tx_buf) {
3687                         if (spi->mode & SPI_NO_TX)
3688                                 return -EINVAL;
3689                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3690                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3691                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3692                                 return -EINVAL;
3693                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3694                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3695                                 return -EINVAL;
3696                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3697                                 !(spi->mode & SPI_TX_QUAD))
3698                                 return -EINVAL;
3699                 }
3700                 /* check transfer rx_nbits */
3701                 if (xfer->rx_buf) {
3702                         if (spi->mode & SPI_NO_RX)
3703                                 return -EINVAL;
3704                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3705                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3706                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3707                                 return -EINVAL;
3708                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3709                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3710                                 return -EINVAL;
3711                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3712                                 !(spi->mode & SPI_RX_QUAD))
3713                                 return -EINVAL;
3714                 }
3715
3716                 if (_spi_xfer_word_delay_update(xfer, spi))
3717                         return -EINVAL;
3718         }
3719
3720         message->status = -EINPROGRESS;
3721
3722         return 0;
3723 }
3724
3725 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3726 {
3727         struct spi_controller *ctlr = spi->controller;
3728         struct spi_transfer *xfer;
3729
3730         /*
3731          * Some controllers do not support doing regular SPI transfers. Return
3732          * ENOTSUPP when this is the case.
3733          */
3734         if (!ctlr->transfer)
3735                 return -ENOTSUPP;
3736
3737         message->spi = spi;
3738
3739         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_async);
3740         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
3741
3742         trace_spi_message_submit(message);
3743
3744         if (!ctlr->ptp_sts_supported) {
3745                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3746                         xfer->ptp_sts_word_pre = 0;
3747                         ptp_read_system_prets(xfer->ptp_sts);
3748                 }
3749         }
3750
3751         return ctlr->transfer(spi, message);
3752 }
3753
3754 /**
3755  * spi_async - asynchronous SPI transfer
3756  * @spi: device with which data will be exchanged
3757  * @message: describes the data transfers, including completion callback
3758  * Context: any (irqs may be blocked, etc)
3759  *
3760  * This call may be used in_irq and other contexts which can't sleep,
3761  * as well as from task contexts which can sleep.
3762  *
3763  * The completion callback is invoked in a context which can't sleep.
3764  * Before that invocation, the value of message->status is undefined.
3765  * When the callback is issued, message->status holds either zero (to
3766  * indicate complete success) or a negative error code.  After that
3767  * callback returns, the driver which issued the transfer request may
3768  * deallocate the associated memory; it's no longer in use by any SPI
3769  * core or controller driver code.
3770  *
3771  * Note that although all messages to a spi_device are handled in
3772  * FIFO order, messages may go to different devices in other orders.
3773  * Some device might be higher priority, or have various "hard" access
3774  * time requirements, for example.
3775  *
3776  * On detection of any fault during the transfer, processing of
3777  * the entire message is aborted, and the device is deselected.
3778  * Until returning from the associated message completion callback,
3779  * no other spi_message queued to that device will be processed.
3780  * (This rule applies equally to all the synchronous transfer calls,
3781  * which are wrappers around this core asynchronous primitive.)
3782  *
3783  * Return: zero on success, else a negative error code.
3784  */
3785 int spi_async(struct spi_device *spi, struct spi_message *message)
3786 {
3787         struct spi_controller *ctlr = spi->controller;
3788         int ret;
3789         unsigned long flags;
3790
3791         ret = __spi_validate(spi, message);
3792         if (ret != 0)
3793                 return ret;
3794
3795         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3796
3797         if (ctlr->bus_lock_flag)
3798                 ret = -EBUSY;
3799         else
3800                 ret = __spi_async(spi, message);
3801
3802         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3803
3804         return ret;
3805 }
3806 EXPORT_SYMBOL_GPL(spi_async);
3807
3808 /**
3809  * spi_async_locked - version of spi_async with exclusive bus usage
3810  * @spi: device with which data will be exchanged
3811  * @message: describes the data transfers, including completion callback
3812  * Context: any (irqs may be blocked, etc)
3813  *
3814  * This call may be used in_irq and other contexts which can't sleep,
3815  * as well as from task contexts which can sleep.
3816  *
3817  * The completion callback is invoked in a context which can't sleep.
3818  * Before that invocation, the value of message->status is undefined.
3819  * When the callback is issued, message->status holds either zero (to
3820  * indicate complete success) or a negative error code.  After that
3821  * callback returns, the driver which issued the transfer request may
3822  * deallocate the associated memory; it's no longer in use by any SPI
3823  * core or controller driver code.
3824  *
3825  * Note that although all messages to a spi_device are handled in
3826  * FIFO order, messages may go to different devices in other orders.
3827  * Some device might be higher priority, or have various "hard" access
3828  * time requirements, for example.
3829  *
3830  * On detection of any fault during the transfer, processing of
3831  * the entire message is aborted, and the device is deselected.
3832  * Until returning from the associated message completion callback,
3833  * no other spi_message queued to that device will be processed.
3834  * (This rule applies equally to all the synchronous transfer calls,
3835  * which are wrappers around this core asynchronous primitive.)
3836  *
3837  * Return: zero on success, else a negative error code.
3838  */
3839 static int spi_async_locked(struct spi_device *spi, struct spi_message *message)
3840 {
3841         struct spi_controller *ctlr = spi->controller;
3842         int ret;
3843         unsigned long flags;
3844
3845         ret = __spi_validate(spi, message);
3846         if (ret != 0)
3847                 return ret;
3848
3849         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3850
3851         ret = __spi_async(spi, message);
3852
3853         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3854
3855         return ret;
3856
3857 }
3858
3859 /*-------------------------------------------------------------------------*/
3860
3861 /*
3862  * Utility methods for SPI protocol drivers, layered on
3863  * top of the core.  Some other utility methods are defined as
3864  * inline functions.
3865  */
3866
3867 static void spi_complete(void *arg)
3868 {
3869         complete(arg);
3870 }
3871
3872 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
3873 {
3874         DECLARE_COMPLETION_ONSTACK(done);
3875         int status;
3876         struct spi_controller *ctlr = spi->controller;
3877         unsigned long flags;
3878
3879         status = __spi_validate(spi, message);
3880         if (status != 0)
3881                 return status;
3882
3883         message->complete = spi_complete;
3884         message->context = &done;
3885         message->spi = spi;
3886
3887         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics, spi_sync);
3888         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
3889
3890         /*
3891          * If we're not using the legacy transfer method then we will
3892          * try to transfer in the calling context so special case.
3893          * This code would be less tricky if we could remove the
3894          * support for driver implemented message queues.
3895          */
3896         if (ctlr->transfer == spi_queued_transfer) {
3897                 spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3898
3899                 trace_spi_message_submit(message);
3900
3901                 status = __spi_queued_transfer(spi, message, false);
3902
3903                 spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3904         } else {
3905                 status = spi_async_locked(spi, message);
3906         }
3907
3908         if (status == 0) {
3909                 /* Push out the messages in the calling context if we can */
3910                 if (ctlr->transfer == spi_queued_transfer) {
3911                         SPI_STATISTICS_INCREMENT_FIELD(&ctlr->statistics,
3912                                                        spi_sync_immediate);
3913                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
3914                                                        spi_sync_immediate);
3915                         __spi_pump_messages(ctlr, false);
3916                 }
3917
3918                 wait_for_completion(&done);
3919                 status = message->status;
3920         }
3921         message->context = NULL;
3922         return status;
3923 }
3924
3925 /**
3926  * spi_sync - blocking/synchronous SPI data transfers
3927  * @spi: device with which data will be exchanged
3928  * @message: describes the data transfers
3929  * Context: can sleep
3930  *
3931  * This call may only be used from a context that may sleep.  The sleep
3932  * is non-interruptible, and has no timeout.  Low-overhead controller
3933  * drivers may DMA directly into and out of the message buffers.
3934  *
3935  * Note that the SPI device's chip select is active during the message,
3936  * and then is normally disabled between messages.  Drivers for some
3937  * frequently-used devices may want to minimize costs of selecting a chip,
3938  * by leaving it selected in anticipation that the next message will go
3939  * to the same chip.  (That may increase power usage.)
3940  *
3941  * Also, the caller is guaranteeing that the memory associated with the
3942  * message will not be freed before this call returns.
3943  *
3944  * Return: zero on success, else a negative error code.
3945  */
3946 int spi_sync(struct spi_device *spi, struct spi_message *message)
3947 {
3948         int ret;
3949
3950         mutex_lock(&spi->controller->bus_lock_mutex);
3951         ret = __spi_sync(spi, message);
3952         mutex_unlock(&spi->controller->bus_lock_mutex);
3953
3954         return ret;
3955 }
3956 EXPORT_SYMBOL_GPL(spi_sync);
3957
3958 /**
3959  * spi_sync_locked - version of spi_sync with exclusive bus usage
3960  * @spi: device with which data will be exchanged
3961  * @message: describes the data transfers
3962  * Context: can sleep
3963  *
3964  * This call may only be used from a context that may sleep.  The sleep
3965  * is non-interruptible, and has no timeout.  Low-overhead controller
3966  * drivers may DMA directly into and out of the message buffers.
3967  *
3968  * This call should be used by drivers that require exclusive access to the
3969  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
3970  * be released by a spi_bus_unlock call when the exclusive access is over.
3971  *
3972  * Return: zero on success, else a negative error code.
3973  */
3974 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
3975 {
3976         return __spi_sync(spi, message);
3977 }
3978 EXPORT_SYMBOL_GPL(spi_sync_locked);
3979
3980 /**
3981  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
3982  * @ctlr: SPI bus master that should be locked for exclusive bus access
3983  * Context: can sleep
3984  *
3985  * This call may only be used from a context that may sleep.  The sleep
3986  * is non-interruptible, and has no timeout.
3987  *
3988  * This call should be used by drivers that require exclusive access to the
3989  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
3990  * exclusive access is over. Data transfer must be done by spi_sync_locked
3991  * and spi_async_locked calls when the SPI bus lock is held.
3992  *
3993  * Return: always zero.
3994  */
3995 int spi_bus_lock(struct spi_controller *ctlr)
3996 {
3997         unsigned long flags;
3998
3999         mutex_lock(&ctlr->bus_lock_mutex);
4000
4001         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4002         ctlr->bus_lock_flag = 1;
4003         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4004
4005         /* mutex remains locked until spi_bus_unlock is called */
4006
4007         return 0;
4008 }
4009 EXPORT_SYMBOL_GPL(spi_bus_lock);
4010
4011 /**
4012  * spi_bus_unlock - release the lock for exclusive SPI bus usage
4013  * @ctlr: SPI bus master that was locked for exclusive bus access
4014  * Context: can sleep
4015  *
4016  * This call may only be used from a context that may sleep.  The sleep
4017  * is non-interruptible, and has no timeout.
4018  *
4019  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4020  * call.
4021  *
4022  * Return: always zero.
4023  */
4024 int spi_bus_unlock(struct spi_controller *ctlr)
4025 {
4026         ctlr->bus_lock_flag = 0;
4027
4028         mutex_unlock(&ctlr->bus_lock_mutex);
4029
4030         return 0;
4031 }
4032 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4033
4034 /* portable code must never pass more than 32 bytes */
4035 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
4036
4037 static u8       *buf;
4038
4039 /**
4040  * spi_write_then_read - SPI synchronous write followed by read
4041  * @spi: device with which data will be exchanged
4042  * @txbuf: data to be written (need not be dma-safe)
4043  * @n_tx: size of txbuf, in bytes
4044  * @rxbuf: buffer into which data will be read (need not be dma-safe)
4045  * @n_rx: size of rxbuf, in bytes
4046  * Context: can sleep
4047  *
4048  * This performs a half duplex MicroWire style transaction with the
4049  * device, sending txbuf and then reading rxbuf.  The return value
4050  * is zero for success, else a negative errno status code.
4051  * This call may only be used from a context that may sleep.
4052  *
4053  * Parameters to this routine are always copied using a small buffer.
4054  * Performance-sensitive or bulk transfer code should instead use
4055  * spi_{async,sync}() calls with dma-safe buffers.
4056  *
4057  * Return: zero on success, else a negative error code.
4058  */
4059 int spi_write_then_read(struct spi_device *spi,
4060                 const void *txbuf, unsigned n_tx,
4061                 void *rxbuf, unsigned n_rx)
4062 {
4063         static DEFINE_MUTEX(lock);
4064
4065         int                     status;
4066         struct spi_message      message;
4067         struct spi_transfer     x[2];
4068         u8                      *local_buf;
4069
4070         /*
4071          * Use preallocated DMA-safe buffer if we can. We can't avoid
4072          * copying here, (as a pure convenience thing), but we can
4073          * keep heap costs out of the hot path unless someone else is
4074          * using the pre-allocated buffer or the transfer is too large.
4075          */
4076         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4077                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4078                                     GFP_KERNEL | GFP_DMA);
4079                 if (!local_buf)
4080                         return -ENOMEM;
4081         } else {
4082                 local_buf = buf;
4083         }
4084
4085         spi_message_init(&message);
4086         memset(x, 0, sizeof(x));
4087         if (n_tx) {
4088                 x[0].len = n_tx;
4089                 spi_message_add_tail(&x[0], &message);
4090         }
4091         if (n_rx) {
4092                 x[1].len = n_rx;
4093                 spi_message_add_tail(&x[1], &message);
4094         }
4095
4096         memcpy(local_buf, txbuf, n_tx);
4097         x[0].tx_buf = local_buf;
4098         x[1].rx_buf = local_buf + n_tx;
4099
4100         /* do the i/o */
4101         status = spi_sync(spi, &message);
4102         if (status == 0)
4103                 memcpy(rxbuf, x[1].rx_buf, n_rx);
4104
4105         if (x[0].tx_buf == buf)
4106                 mutex_unlock(&lock);
4107         else
4108                 kfree(local_buf);
4109
4110         return status;
4111 }
4112 EXPORT_SYMBOL_GPL(spi_write_then_read);
4113
4114 /*-------------------------------------------------------------------------*/
4115
4116 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4117 /* must call put_device() when done with returned spi_device device */
4118 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4119 {
4120         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4121
4122         return dev ? to_spi_device(dev) : NULL;
4123 }
4124
4125 /* the spi controllers are not using spi_bus, so we find it with another way */
4126 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4127 {
4128         struct device *dev;
4129
4130         dev = class_find_device_by_of_node(&spi_master_class, node);
4131         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4132                 dev = class_find_device_by_of_node(&spi_slave_class, node);
4133         if (!dev)
4134                 return NULL;
4135
4136         /* reference got in class_find_device */
4137         return container_of(dev, struct spi_controller, dev);
4138 }
4139
4140 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4141                          void *arg)
4142 {
4143         struct of_reconfig_data *rd = arg;
4144         struct spi_controller *ctlr;
4145         struct spi_device *spi;
4146
4147         switch (of_reconfig_get_state_change(action, arg)) {
4148         case OF_RECONFIG_CHANGE_ADD:
4149                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4150                 if (ctlr == NULL)
4151                         return NOTIFY_OK;       /* not for us */
4152
4153                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4154                         put_device(&ctlr->dev);
4155                         return NOTIFY_OK;
4156                 }
4157
4158                 spi = of_register_spi_device(ctlr, rd->dn);
4159                 put_device(&ctlr->dev);
4160
4161                 if (IS_ERR(spi)) {
4162                         pr_err("%s: failed to create for '%pOF'\n",
4163                                         __func__, rd->dn);
4164                         of_node_clear_flag(rd->dn, OF_POPULATED);
4165                         return notifier_from_errno(PTR_ERR(spi));
4166                 }
4167                 break;
4168
4169         case OF_RECONFIG_CHANGE_REMOVE:
4170                 /* already depopulated? */
4171                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4172                         return NOTIFY_OK;
4173
4174                 /* find our device by node */
4175                 spi = of_find_spi_device_by_node(rd->dn);
4176                 if (spi == NULL)
4177                         return NOTIFY_OK;       /* no? not meant for us */
4178
4179                 /* unregister takes one ref away */
4180                 spi_unregister_device(spi);
4181
4182                 /* and put the reference of the find */
4183                 put_device(&spi->dev);
4184                 break;
4185         }
4186
4187         return NOTIFY_OK;
4188 }
4189
4190 static struct notifier_block spi_of_notifier = {
4191         .notifier_call = of_spi_notify,
4192 };
4193 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4194 extern struct notifier_block spi_of_notifier;
4195 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4196
4197 #if IS_ENABLED(CONFIG_ACPI)
4198 static int spi_acpi_controller_match(struct device *dev, const void *data)
4199 {
4200         return ACPI_COMPANION(dev->parent) == data;
4201 }
4202
4203 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4204 {
4205         struct device *dev;
4206
4207         dev = class_find_device(&spi_master_class, NULL, adev,
4208                                 spi_acpi_controller_match);
4209         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4210                 dev = class_find_device(&spi_slave_class, NULL, adev,
4211                                         spi_acpi_controller_match);
4212         if (!dev)
4213                 return NULL;
4214
4215         return container_of(dev, struct spi_controller, dev);
4216 }
4217
4218 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4219 {
4220         struct device *dev;
4221
4222         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4223         return to_spi_device(dev);
4224 }
4225
4226 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4227                            void *arg)
4228 {
4229         struct acpi_device *adev = arg;
4230         struct spi_controller *ctlr;
4231         struct spi_device *spi;
4232
4233         switch (value) {
4234         case ACPI_RECONFIG_DEVICE_ADD:
4235                 ctlr = acpi_spi_find_controller_by_adev(adev->parent);
4236                 if (!ctlr)
4237                         break;
4238
4239                 acpi_register_spi_device(ctlr, adev);
4240                 put_device(&ctlr->dev);
4241                 break;
4242         case ACPI_RECONFIG_DEVICE_REMOVE:
4243                 if (!acpi_device_enumerated(adev))
4244                         break;
4245
4246                 spi = acpi_spi_find_device_by_adev(adev);
4247                 if (!spi)
4248                         break;
4249
4250                 spi_unregister_device(spi);
4251                 put_device(&spi->dev);
4252                 break;
4253         }
4254
4255         return NOTIFY_OK;
4256 }
4257
4258 static struct notifier_block spi_acpi_notifier = {
4259         .notifier_call = acpi_spi_notify,
4260 };
4261 #else
4262 extern struct notifier_block spi_acpi_notifier;
4263 #endif
4264
4265 static int __init spi_init(void)
4266 {
4267         int     status;
4268
4269         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4270         if (!buf) {
4271                 status = -ENOMEM;
4272                 goto err0;
4273         }
4274
4275         status = bus_register(&spi_bus_type);
4276         if (status < 0)
4277                 goto err1;
4278
4279         status = class_register(&spi_master_class);
4280         if (status < 0)
4281                 goto err2;
4282
4283         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4284                 status = class_register(&spi_slave_class);
4285                 if (status < 0)
4286                         goto err3;
4287         }
4288
4289         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4290                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4291         if (IS_ENABLED(CONFIG_ACPI))
4292                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4293
4294         return 0;
4295
4296 err3:
4297         class_unregister(&spi_master_class);
4298 err2:
4299         bus_unregister(&spi_bus_type);
4300 err1:
4301         kfree(buf);
4302         buf = NULL;
4303 err0:
4304         return status;
4305 }
4306
4307 /*
4308  * A board_info is normally registered in arch_initcall(),
4309  * but even essential drivers wait till later.
4310  *
4311  * REVISIT only boardinfo really needs static linking. The rest (device and
4312  * driver registration) _could_ be dynamically linked (modular) ... Costs
4313  * include needing to have boardinfo data structures be much more public.
4314  */
4315 postcore_initcall(spi_init);