drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/export.h>
  35 #include <linux/sched/rt.h>
  36 #include <linux/delay.h>
  37 #include <linux/kthread.h>
  38 #include <linux/ioport.h>
  39 #include <linux/acpi.h>
  40
  41 #define CREATE_TRACE_POINTS
  42 #include <trace/events/spi.h>
  43
  44 static void spidev_release(struct device *dev)
  45 {
  46         struct spi_device       *spi = to_spi_device(dev);
  47
  48         /* spi masters may cleanup for released devices */
  49         if (spi->master->cleanup)
  50                 spi->master->cleanup(spi);
  51
  52         spi_master_put(spi->master);
  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 #define SPI_STATISTICS_ATTRS(field, file)                               \
  71 static ssize_t spi_master_##field##_show(struct device *dev,            \
  72                                          struct device_attribute *attr, \
  73                                          char *buf)                     \
  74 {                                                                       \
  75         struct spi_master *master = container_of(dev,                   \
  76                                                  struct spi_master, dev); \
  77         return spi_statistics_##field##_show(&master->statistics, buf); \
  78 }                                                                       \
  79 static struct device_attribute dev_attr_spi_master_##field = {          \
  80         .attr = { .name = file, .mode = S_IRUGO },                      \
  81         .show = spi_master_##field##_show,                              \
  82 };                                                                      \
  83 static ssize_t spi_device_##field##_show(struct device *dev,            \
  84                                          struct device_attribute *attr, \
  85                                         char *buf)                      \
  86 {                                                                       \
  87         struct spi_device *spi = to_spi_device(dev);                    \
  88         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  89 }                                                                       \
  90 static struct device_attribute dev_attr_spi_device_##field = {          \
  91         .attr = { .name = file, .mode = S_IRUGO },                      \
  92         .show = spi_device_##field##_show,                              \
  93 }
  94
  95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  97                                             char *buf)                  \
  98 {                                                                       \
  99         unsigned long flags;                                            \
 100         ssize_t len;                                                    \
 101         spin_lock_irqsave(&stat->lock, flags);                          \
 102         len = sprintf(buf, format_string, stat->field);                 \
 103         spin_unlock_irqrestore(&stat->lock, flags);                     \
 104         return len;                                                     \
 105 }                                                                       \
 106 SPI_STATISTICS_ATTRS(name, file)
 107
 108 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 109         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 110                                  field, format_string)
 111
 112 SPI_STATISTICS_SHOW(messages, "%lu");
 113 SPI_STATISTICS_SHOW(transfers, "%lu");
 114 SPI_STATISTICS_SHOW(errors, "%lu");
 115 SPI_STATISTICS_SHOW(timedout, "%lu");
 116
 117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 119 SPI_STATISTICS_SHOW(spi_async, "%lu");
 120
 121 SPI_STATISTICS_SHOW(bytes, "%llu");
 122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 124
 125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 126         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 127                                  "transfer_bytes_histo_" number,        \
 128                                  transfer_bytes_histo[index],  "%lu")
 129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 146
 147 static struct attribute *spi_dev_attrs[] = {
 148         &dev_attr_modalias.attr,
 149         NULL,
 150 };
 151
 152 static const struct attribute_group spi_dev_group = {
 153         .attrs  = spi_dev_attrs,
 154 };
 155
 156 static struct attribute *spi_device_statistics_attrs[] = {
 157         &dev_attr_spi_device_messages.attr,
 158         &dev_attr_spi_device_transfers.attr,
 159         &dev_attr_spi_device_errors.attr,
 160         &dev_attr_spi_device_timedout.attr,
 161         &dev_attr_spi_device_spi_sync.attr,
 162         &dev_attr_spi_device_spi_sync_immediate.attr,
 163         &dev_attr_spi_device_spi_async.attr,
 164         &dev_attr_spi_device_bytes.attr,
 165         &dev_attr_spi_device_bytes_rx.attr,
 166         &dev_attr_spi_device_bytes_tx.attr,
 167         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 168         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 169         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 184         NULL,
 185 };
 186
 187 static const struct attribute_group spi_device_statistics_group = {
 188         .name  = "statistics",
 189         .attrs  = spi_device_statistics_attrs,
 190 };
 191
 192 static const struct attribute_group *spi_dev_groups[] = {
 193         &spi_dev_group,
 194         &spi_device_statistics_group,
 195         NULL,
 196 };
 197
 198 static struct attribute *spi_master_statistics_attrs[] = {
 199         &dev_attr_spi_master_messages.attr,
 200         &dev_attr_spi_master_transfers.attr,
 201         &dev_attr_spi_master_errors.attr,
 202         &dev_attr_spi_master_timedout.attr,
 203         &dev_attr_spi_master_spi_sync.attr,
 204         &dev_attr_spi_master_spi_sync_immediate.attr,
 205         &dev_attr_spi_master_spi_async.attr,
 206         &dev_attr_spi_master_bytes.attr,
 207         &dev_attr_spi_master_bytes_rx.attr,
 208         &dev_attr_spi_master_bytes_tx.attr,
 209         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 210         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 211         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 212         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 226         NULL,
 227 };
 228
 229 static const struct attribute_group spi_master_statistics_group = {
 230         .name  = "statistics",
 231         .attrs  = spi_master_statistics_attrs,
 232 };
 233
 234 static const struct attribute_group *spi_master_groups[] = {
 235         &spi_master_statistics_group,
 236         NULL,
 237 };
 238
 239 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 240                                        struct spi_transfer *xfer,
 241                                        struct spi_master *master)
 242 {
 243         unsigned long flags;
 244         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 245
 246         if (l2len < 0)
 247                 l2len = 0;
 248
 249         spin_lock_irqsave(&stats->lock, flags);
 250
 251         stats->transfers++;
 252         stats->transfer_bytes_histo[l2len]++;
 253
 254         stats->bytes += xfer->len;
 255         if ((xfer->tx_buf) &&
 256             (xfer->tx_buf != master->dummy_tx))
 257                 stats->bytes_tx += xfer->len;
 258         if ((xfer->rx_buf) &&
 259             (xfer->rx_buf != master->dummy_rx))
 260                 stats->bytes_rx += xfer->len;
 261
 262         spin_unlock_irqrestore(&stats->lock, flags);
 263 }
 264 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 265
 266 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 267  * and the sysfs version makes coldplug work too.
 268  */
 269
 270 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 271                                                 const struct spi_device *sdev)
 272 {
 273         while (id->name[0]) {
 274                 if (!strcmp(sdev->modalias, id->name))
 275                         return id;
 276                 id++;
 277         }
 278         return NULL;
 279 }
 280
 281 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 282 {
 283         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 284
 285         return spi_match_id(sdrv->id_table, sdev);
 286 }
 287 EXPORT_SYMBOL_GPL(spi_get_device_id);
 288
 289 static int spi_match_device(struct device *dev, struct device_driver *drv)
 290 {
 291         const struct spi_device *spi = to_spi_device(dev);
 292         const struct spi_driver *sdrv = to_spi_driver(drv);
 293
 294         /* Attempt an OF style match */
 295         if (of_driver_match_device(dev, drv))
 296                 return 1;
 297
 298         /* Then try ACPI */
 299         if (acpi_driver_match_device(dev, drv))
 300                 return 1;
 301
 302         if (sdrv->id_table)
 303                 return !!spi_match_id(sdrv->id_table, spi);
 304
 305         return strcmp(spi->modalias, drv->name) == 0;
 306 }
 307
 308 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 309 {
 310         const struct spi_device         *spi = to_spi_device(dev);
 311         int rc;
 312
 313         rc = acpi_device_uevent_modalias(dev, env);
 314         if (rc != -ENODEV)
 315                 return rc;
 316
 317         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 318         return 0;
 319 }
 320
 321 struct bus_type spi_bus_type = {
 322         .name           = "spi",
 323         .dev_groups     = spi_dev_groups,
 324         .match          = spi_match_device,
 325         .uevent         = spi_uevent,
 326 };
 327 EXPORT_SYMBOL_GPL(spi_bus_type);
 328
 329
 330 static int spi_drv_probe(struct device *dev)
 331 {
 332         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 333         struct spi_device               *spi = to_spi_device(dev);
 334         int ret;
 335
 336         ret = of_clk_set_defaults(dev->of_node, false);
 337         if (ret)
 338                 return ret;
 339
 340         if (dev->of_node) {
 341                 spi->irq = of_irq_get(dev->of_node, 0);
 342                 if (spi->irq == -EPROBE_DEFER)
 343                         return -EPROBE_DEFER;
 344                 if (spi->irq < 0)
 345                         spi->irq = 0;
 346         }
 347
 348         ret = dev_pm_domain_attach(dev, true);
 349         if (ret != -EPROBE_DEFER) {
 350                 ret = sdrv->probe(spi);
 351                 if (ret)
 352                         dev_pm_domain_detach(dev, true);
 353         }
 354
 355         return ret;
 356 }
 357
 358 static int spi_drv_remove(struct device *dev)
 359 {
 360         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 361         int ret;
 362
 363         ret = sdrv->remove(to_spi_device(dev));
 364         dev_pm_domain_detach(dev, true);
 365
 366         return ret;
 367 }
 368
 369 static void spi_drv_shutdown(struct device *dev)
 370 {
 371         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 372
 373         sdrv->shutdown(to_spi_device(dev));
 374 }
 375
 376 /**
 377  * __spi_register_driver - register a SPI driver
 378  * @owner: owner module of the driver to register
 379  * @sdrv: the driver to register
 380  * Context: can sleep
 381  *
 382  * Return: zero on success, else a negative error code.
 383  */
 384 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 385 {
 386         sdrv->driver.owner = owner;
 387         sdrv->driver.bus = &spi_bus_type;
 388         if (sdrv->probe)
 389                 sdrv->driver.probe = spi_drv_probe;
 390         if (sdrv->remove)
 391                 sdrv->driver.remove = spi_drv_remove;
 392         if (sdrv->shutdown)
 393                 sdrv->driver.shutdown = spi_drv_shutdown;
 394         return driver_register(&sdrv->driver);
 395 }
 396 EXPORT_SYMBOL_GPL(__spi_register_driver);
 397
 398 /*-------------------------------------------------------------------------*/
 399
 400 /* SPI devices should normally not be created by SPI device drivers; that
 401  * would make them board-specific.  Similarly with SPI master drivers.
 402  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 403  * with other readonly (flashable) information about mainboard devices.
 404  */
 405
 406 struct boardinfo {
 407         struct list_head        list;
 408         struct spi_board_info   board_info;
 409 };
 410
 411 static LIST_HEAD(board_list);
 412 static LIST_HEAD(spi_master_list);
 413
 414 /*
 415  * Used to protect add/del opertion for board_info list and
 416  * spi_master list, and their matching process
 417  */
 418 static DEFINE_MUTEX(board_lock);
 419
 420 /**
 421  * spi_alloc_device - Allocate a new SPI device
 422  * @master: Controller to which device is connected
 423  * Context: can sleep
 424  *
 425  * Allows a driver to allocate and initialize a spi_device without
 426  * registering it immediately.  This allows a driver to directly
 427  * fill the spi_device with device parameters before calling
 428  * spi_add_device() on it.
 429  *
 430  * Caller is responsible to call spi_add_device() on the returned
 431  * spi_device structure to add it to the SPI master.  If the caller
 432  * needs to discard the spi_device without adding it, then it should
 433  * call spi_dev_put() on it.
 434  *
 435  * Return: a pointer to the new device, or NULL.
 436  */
 437 struct spi_device *spi_alloc_device(struct spi_master *master)
 438 {
 439         struct spi_device       *spi;
 440
 441         if (!spi_master_get(master))
 442                 return NULL;
 443
 444         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 445         if (!spi) {
 446                 spi_master_put(master);
 447                 return NULL;
 448         }
 449
 450         spi->master = master;
 451         spi->dev.parent = &master->dev;
 452         spi->dev.bus = &spi_bus_type;
 453         spi->dev.release = spidev_release;
 454         spi->cs_gpio = -ENOENT;
 455
 456         spin_lock_init(&spi->statistics.lock);
 457
 458         device_initialize(&spi->dev);
 459         return spi;
 460 }
 461 EXPORT_SYMBOL_GPL(spi_alloc_device);
 462
 463 static void spi_dev_set_name(struct spi_device *spi)
 464 {
 465         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 466
 467         if (adev) {
 468                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 469                 return;
 470         }
 471
 472         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 473                      spi->chip_select);
 474 }
 475
 476 static int spi_dev_check(struct device *dev, void *data)
 477 {
 478         struct spi_device *spi = to_spi_device(dev);
 479         struct spi_device *new_spi = data;
 480
 481         if (spi->master == new_spi->master &&
 482             spi->chip_select == new_spi->chip_select)
 483                 return -EBUSY;
 484         return 0;
 485 }
 486
 487 /**
 488  * spi_add_device - Add spi_device allocated with spi_alloc_device
 489  * @spi: spi_device to register
 490  *
 491  * Companion function to spi_alloc_device.  Devices allocated with
 492  * spi_alloc_device can be added onto the spi bus with this function.
 493  *
 494  * Return: 0 on success; negative errno on failure
 495  */
 496 int spi_add_device(struct spi_device *spi)
 497 {
 498         static DEFINE_MUTEX(spi_add_lock);
 499         struct spi_master *master = spi->master;
 500         struct device *dev = master->dev.parent;
 501         int status;
 502
 503         /* Chipselects are numbered 0..max; validate. */
 504         if (spi->chip_select >= master->num_chipselect) {
 505                 dev_err(dev, "cs%d >= max %d\n",
 506                         spi->chip_select,
 507                         master->num_chipselect);
 508                 return -EINVAL;
 509         }
 510
 511         /* Set the bus ID string */
 512         spi_dev_set_name(spi);
 513
 514         /* We need to make sure there's no other device with this
 515          * chipselect **BEFORE** we call setup(), else we'll trash
 516          * its configuration.  Lock against concurrent add() calls.
 517          */
 518         mutex_lock(&spi_add_lock);
 519
 520         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 521         if (status) {
 522                 dev_err(dev, "chipselect %d already in use\n",
 523                                 spi->chip_select);
 524                 goto done;
 525         }
 526
 527         if (master->cs_gpios)
 528                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 529
 530         /* Drivers may modify this initial i/o setup, but will
 531          * normally rely on the device being setup.  Devices
 532          * using SPI_CS_HIGH can't coexist well otherwise...
 533          */
 534         status = spi_setup(spi);
 535         if (status < 0) {
 536                 dev_err(dev, "can't setup %s, status %d\n",
 537                                 dev_name(&spi->dev), status);
 538                 goto done;
 539         }
 540
 541         /* Device may be bound to an active driver when this returns */
 542         status = device_add(&spi->dev);
 543         if (status < 0)
 544                 dev_err(dev, "can't add %s, status %d\n",
 545                                 dev_name(&spi->dev), status);
 546         else
 547                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 548
 549 done:
 550         mutex_unlock(&spi_add_lock);
 551         return status;
 552 }
 553 EXPORT_SYMBOL_GPL(spi_add_device);
 554
 555 /**
 556  * spi_new_device - instantiate one new SPI device
 557  * @master: Controller to which device is connected
 558  * @chip: Describes the SPI device
 559  * Context: can sleep
 560  *
 561  * On typical mainboards, this is purely internal; and it's not needed
 562  * after board init creates the hard-wired devices.  Some development
 563  * platforms may not be able to use spi_register_board_info though, and
 564  * this is exported so that for example a USB or parport based adapter
 565  * driver could add devices (which it would learn about out-of-band).
 566  *
 567  * Return: the new device, or NULL.
 568  */
 569 struct spi_device *spi_new_device(struct spi_master *master,
 570                                   struct spi_board_info *chip)
 571 {
 572         struct spi_device       *proxy;
 573         int                     status;
 574
 575         /* NOTE:  caller did any chip->bus_num checks necessary.
 576          *
 577          * Also, unless we change the return value convention to use
 578          * error-or-pointer (not NULL-or-pointer), troubleshootability
 579          * suggests syslogged diagnostics are best here (ugh).
 580          */
 581
 582         proxy = spi_alloc_device(master);
 583         if (!proxy)
 584                 return NULL;
 585
 586         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 587
 588         proxy->chip_select = chip->chip_select;
 589         proxy->max_speed_hz = chip->max_speed_hz;
 590         proxy->mode = chip->mode;
 591         proxy->irq = chip->irq;
 592         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 593         proxy->dev.platform_data = (void *) chip->platform_data;
 594         proxy->controller_data = chip->controller_data;
 595         proxy->controller_state = NULL;
 596
 597         status = spi_add_device(proxy);
 598         if (status < 0) {
 599                 spi_dev_put(proxy);
 600                 return NULL;
 601         }
 602
 603         return proxy;
 604 }
 605 EXPORT_SYMBOL_GPL(spi_new_device);
 606
 607 /**
 608  * spi_unregister_device - unregister a single SPI device
 609  * @spi: spi_device to unregister
 610  *
 611  * Start making the passed SPI device vanish. Normally this would be handled
 612  * by spi_unregister_master().
 613  */
 614 void spi_unregister_device(struct spi_device *spi)
 615 {
 616         if (!spi)
 617                 return;
 618
 619         if (spi->dev.of_node)
 620                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 621         device_unregister(&spi->dev);
 622 }
 623 EXPORT_SYMBOL_GPL(spi_unregister_device);
 624
 625 static void spi_match_master_to_boardinfo(struct spi_master *master,
 626                                 struct spi_board_info *bi)
 627 {
 628         struct spi_device *dev;
 629
 630         if (master->bus_num != bi->bus_num)
 631                 return;
 632
 633         dev = spi_new_device(master, bi);
 634         if (!dev)
 635                 dev_err(master->dev.parent, "can't create new device for %s\n",
 636                         bi->modalias);
 637 }
 638
 639 /**
 640  * spi_register_board_info - register SPI devices for a given board
 641  * @info: array of chip descriptors
 642  * @n: how many descriptors are provided
 643  * Context: can sleep
 644  *
 645  * Board-specific early init code calls this (probably during arch_initcall)
 646  * with segments of the SPI device table.  Any device nodes are created later,
 647  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 648  * this table of devices forever, so that reloading a controller driver will
 649  * not make Linux forget about these hard-wired devices.
 650  *
 651  * Other code can also call this, e.g. a particular add-on board might provide
 652  * SPI devices through its expansion connector, so code initializing that board
 653  * would naturally declare its SPI devices.
 654  *
 655  * The board info passed can safely be __initdata ... but be careful of
 656  * any embedded pointers (platform_data, etc), they're copied as-is.
 657  *
 658  * Return: zero on success, else a negative error code.
 659  */
 660 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 661 {
 662         struct boardinfo *bi;
 663         int i;
 664
 665         if (!n)
 666                 return -EINVAL;
 667
 668         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 669         if (!bi)
 670                 return -ENOMEM;
 671
 672         for (i = 0; i < n; i++, bi++, info++) {
 673                 struct spi_master *master;
 674
 675                 memcpy(&bi->board_info, info, sizeof(*info));
 676                 mutex_lock(&board_lock);
 677                 list_add_tail(&bi->list, &board_list);
 678                 list_for_each_entry(master, &spi_master_list, list)
 679                         spi_match_master_to_boardinfo(master, &bi->board_info);
 680                 mutex_unlock(&board_lock);
 681         }
 682
 683         return 0;
 684 }
 685
 686 /*-------------------------------------------------------------------------*/
 687
 688 static void spi_set_cs(struct spi_device *spi, bool enable)
 689 {
 690         if (spi->mode & SPI_CS_HIGH)
 691                 enable = !enable;
 692
 693         if (gpio_is_valid(spi->cs_gpio))
 694                 gpio_set_value(spi->cs_gpio, !enable);
 695         else if (spi->master->set_cs)
 696                 spi->master->set_cs(spi, !enable);
 697 }
 698
 699 #ifdef CONFIG_HAS_DMA
 700 static int spi_map_buf(struct spi_master *master, struct device *dev,
 701                        struct sg_table *sgt, void *buf, size_t len,
 702                        enum dma_data_direction dir)
 703 {
 704         const bool vmalloced_buf = is_vmalloc_addr(buf);
 705         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 706         int desc_len;
 707         int sgs;
 708         struct page *vm_page;
 709         void *sg_buf;
 710         size_t min;
 711         int i, ret;
 712
 713         if (vmalloced_buf) {
 714                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 715                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 716         } else {
 717                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
 718                 sgs = DIV_ROUND_UP(len, desc_len);
 719         }
 720
 721         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 722         if (ret != 0)
 723                 return ret;
 724
 725         for (i = 0; i < sgs; i++) {
 726
 727                 if (vmalloced_buf) {
 728                         min = min_t(size_t,
 729                                     len, desc_len - offset_in_page(buf));
 730                         vm_page = vmalloc_to_page(buf);
 731                         if (!vm_page) {
 732                                 sg_free_table(sgt);
 733                                 return -ENOMEM;
 734                         }
 735                         sg_set_page(&sgt->sgl[i], vm_page,
 736                                     min, offset_in_page(buf));
 737                 } else {
 738                         min = min_t(size_t, len, desc_len);
 739                         sg_buf = buf;
 740                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
 741                 }
 742
 743                 buf += min;
 744                 len -= min;
 745         }
 746
 747         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 748         if (!ret)
 749                 ret = -ENOMEM;
 750         if (ret < 0) {
 751                 sg_free_table(sgt);
 752                 return ret;
 753         }
 754
 755         sgt->nents = ret;
 756
 757         return 0;
 758 }
 759
 760 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 761                           struct sg_table *sgt, enum dma_data_direction dir)
 762 {
 763         if (sgt->orig_nents) {
 764                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 765                 sg_free_table(sgt);
 766         }
 767 }
 768
 769 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 770 {
 771         struct device *tx_dev, *rx_dev;
 772         struct spi_transfer *xfer;
 773         int ret;
 774
 775         if (!master->can_dma)
 776                 return 0;
 777
 778         if (master->dma_tx)
 779                 tx_dev = master->dma_tx->device->dev;
 780         else
 781                 tx_dev = &master->dev;
 782
 783         if (master->dma_rx)
 784                 rx_dev = master->dma_rx->device->dev;
 785         else
 786                 rx_dev = &master->dev;
 787
 788         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 789                 if (!master->can_dma(master, msg->spi, xfer))
 790                         continue;
 791
 792                 if (xfer->tx_buf != NULL) {
 793                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 794                                           (void *)xfer->tx_buf, xfer->len,
 795                                           DMA_TO_DEVICE);
 796                         if (ret != 0)
 797                                 return ret;
 798                 }
 799
 800                 if (xfer->rx_buf != NULL) {
 801                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 802                                           xfer->rx_buf, xfer->len,
 803                                           DMA_FROM_DEVICE);
 804                         if (ret != 0) {
 805                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 806                                               DMA_TO_DEVICE);
 807                                 return ret;
 808                         }
 809                 }
 810         }
 811
 812         master->cur_msg_mapped = true;
 813
 814         return 0;
 815 }
 816
 817 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 818 {
 819         struct spi_transfer *xfer;
 820         struct device *tx_dev, *rx_dev;
 821
 822         if (!master->cur_msg_mapped || !master->can_dma)
 823                 return 0;
 824
 825         if (master->dma_tx)
 826                 tx_dev = master->dma_tx->device->dev;
 827         else
 828                 tx_dev = &master->dev;
 829
 830         if (master->dma_rx)
 831                 rx_dev = master->dma_rx->device->dev;
 832         else
 833                 rx_dev = &master->dev;
 834
 835         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 836                 if (!master->can_dma(master, msg->spi, xfer))
 837                         continue;
 838
 839                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 840                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 841         }
 842
 843         return 0;
 844 }
 845 #else /* !CONFIG_HAS_DMA */
 846 static inline int __spi_map_msg(struct spi_master *master,
 847                                 struct spi_message *msg)
 848 {
 849         return 0;
 850 }
 851
 852 static inline int __spi_unmap_msg(struct spi_master *master,
 853                                   struct spi_message *msg)
 854 {
 855         return 0;
 856 }
 857 #endif /* !CONFIG_HAS_DMA */
 858
 859 static inline int spi_unmap_msg(struct spi_master *master,
 860                                 struct spi_message *msg)
 861 {
 862         struct spi_transfer *xfer;
 863
 864         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 865                 /*
 866                  * Restore the original value of tx_buf or rx_buf if they are
 867                  * NULL.
 868                  */
 869                 if (xfer->tx_buf == master->dummy_tx)
 870                         xfer->tx_buf = NULL;
 871                 if (xfer->rx_buf == master->dummy_rx)
 872                         xfer->rx_buf = NULL;
 873         }
 874
 875         return __spi_unmap_msg(master, msg);
 876 }
 877
 878 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 879 {
 880         struct spi_transfer *xfer;
 881         void *tmp;
 882         unsigned int max_tx, max_rx;
 883
 884         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 885                 max_tx = 0;
 886                 max_rx = 0;
 887
 888                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 889                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 890                             !xfer->tx_buf)
 891                                 max_tx = max(xfer->len, max_tx);
 892                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 893                             !xfer->rx_buf)
 894                                 max_rx = max(xfer->len, max_rx);
 895                 }
 896
 897                 if (max_tx) {
 898                         tmp = krealloc(master->dummy_tx, max_tx,
 899                                        GFP_KERNEL | GFP_DMA);
 900                         if (!tmp)
 901                                 return -ENOMEM;
 902                         master->dummy_tx = tmp;
 903                         memset(tmp, 0, max_tx);
 904                 }
 905
 906                 if (max_rx) {
 907                         tmp = krealloc(master->dummy_rx, max_rx,
 908                                        GFP_KERNEL | GFP_DMA);
 909                         if (!tmp)
 910                                 return -ENOMEM;
 911                         master->dummy_rx = tmp;
 912                 }
 913
 914                 if (max_tx || max_rx) {
 915                         list_for_each_entry(xfer, &msg->transfers,
 916                                             transfer_list) {
 917                                 if (!xfer->tx_buf)
 918                                         xfer->tx_buf = master->dummy_tx;
 919                                 if (!xfer->rx_buf)
 920                                         xfer->rx_buf = master->dummy_rx;
 921                         }
 922                 }
 923         }
 924
 925         return __spi_map_msg(master, msg);
 926 }
 927
 928 /*
 929  * spi_transfer_one_message - Default implementation of transfer_one_message()
 930  *
 931  * This is a standard implementation of transfer_one_message() for
 932  * drivers which impelment a transfer_one() operation.  It provides
 933  * standard handling of delays and chip select management.
 934  */
 935 static int spi_transfer_one_message(struct spi_master *master,
 936                                     struct spi_message *msg)
 937 {
 938         struct spi_transfer *xfer;
 939         bool keep_cs = false;
 940         int ret = 0;
 941         unsigned long ms = 1;
 942         struct spi_statistics *statm = &master->statistics;
 943         struct spi_statistics *stats = &msg->spi->statistics;
 944
 945         spi_set_cs(msg->spi, true);
 946
 947         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 948         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 949
 950         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 951                 trace_spi_transfer_start(msg, xfer);
 952
 953                 spi_statistics_add_transfer_stats(statm, xfer, master);
 954                 spi_statistics_add_transfer_stats(stats, xfer, master);
 955
 956                 if (xfer->tx_buf || xfer->rx_buf) {
 957                         reinit_completion(&master->xfer_completion);
 958
 959                         ret = master->transfer_one(master, msg->spi, xfer);
 960                         if (ret < 0) {
 961                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 962                                                                errors);
 963                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 964                                                                errors);
 965                                 dev_err(&msg->spi->dev,
 966                                         "SPI transfer failed: %d\n", ret);
 967                                 goto out;
 968                         }
 969
 970                         if (ret > 0) {
 971                                 ret = 0;
 972                                 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
 973                                 ms += ms + 100; /* some tolerance */
 974
 975                                 ms = wait_for_completion_timeout(&master->xfer_completion,
 976                                                                  msecs_to_jiffies(ms));
 977                         }
 978
 979                         if (ms == 0) {
 980                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 981                                                                timedout);
 982                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 983                                                                timedout);
 984                                 dev_err(&msg->spi->dev,
 985                                         "SPI transfer timed out\n");
 986                                 msg->status = -ETIMEDOUT;
 987                         }
 988                 } else {
 989                         if (xfer->len)
 990                                 dev_err(&msg->spi->dev,
 991                                         "Bufferless transfer has length %u\n",
 992                                         xfer->len);
 993                 }
 994
 995                 trace_spi_transfer_stop(msg, xfer);
 996
 997                 if (msg->status != -EINPROGRESS)
 998                         goto out;
 999
1000                 if (xfer->delay_usecs)
1001                         udelay(xfer->delay_usecs);
1002
1003                 if (xfer->cs_change) {
1004                         if (list_is_last(&xfer->transfer_list,
1005                                          &msg->transfers)) {
1006                                 keep_cs = true;
1007                         } else {
1008                                 spi_set_cs(msg->spi, false);
1009                                 udelay(10);
1010                                 spi_set_cs(msg->spi, true);
1011                         }
1012                 }
1013
1014                 msg->actual_length += xfer->len;
1015         }
1016
1017 out:
1018         if (ret != 0 || !keep_cs)
1019                 spi_set_cs(msg->spi, false);
1020
1021         if (msg->status == -EINPROGRESS)
1022                 msg->status = ret;
1023
1024         if (msg->status && master->handle_err)
1025                 master->handle_err(master, msg);
1026
1027         spi_finalize_current_message(master);
1028
1029         return ret;
1030 }
1031
1032 /**
1033  * spi_finalize_current_transfer - report completion of a transfer
1034  * @master: the master reporting completion
1035  *
1036  * Called by SPI drivers using the core transfer_one_message()
1037  * implementation to notify it that the current interrupt driven
1038  * transfer has finished and the next one may be scheduled.
1039  */
1040 void spi_finalize_current_transfer(struct spi_master *master)
1041 {
1042         complete(&master->xfer_completion);
1043 }
1044 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1045
1046 /**
1047  * __spi_pump_messages - function which processes spi message queue
1048  * @master: master to process queue for
1049  * @in_kthread: true if we are in the context of the message pump thread
1050  * @bus_locked: true if the bus mutex is held when calling this function
1051  *
1052  * This function checks if there is any spi message in the queue that
1053  * needs processing and if so call out to the driver to initialize hardware
1054  * and transfer each message.
1055  *
1056  * Note that it is called both from the kthread itself and also from
1057  * inside spi_sync(); the queue extraction handling at the top of the
1058  * function should deal with this safely.
1059  */
1060 static void __spi_pump_messages(struct spi_master *master, bool in_kthread,
1061                                 bool bus_locked)
1062 {
1063         unsigned long flags;
1064         bool was_busy = false;
1065         int ret;
1066
1067         /* Lock queue */
1068         spin_lock_irqsave(&master->queue_lock, flags);
1069
1070         /* Make sure we are not already running a message */
1071         if (master->cur_msg) {
1072                 spin_unlock_irqrestore(&master->queue_lock, flags);
1073                 return;
1074         }
1075
1076         /* If another context is idling the device then defer */
1077         if (master->idling) {
1078                 queue_kthread_work(&master->kworker, &master->pump_messages);
1079                 spin_unlock_irqrestore(&master->queue_lock, flags);
1080                 return;
1081         }
1082
1083         /* Check if the queue is idle */
1084         if (list_empty(&master->queue) || !master->running) {
1085                 if (!master->busy) {
1086                         spin_unlock_irqrestore(&master->queue_lock, flags);
1087                         return;
1088                 }
1089
1090                 /* Only do teardown in the thread */
1091                 if (!in_kthread) {
1092                         queue_kthread_work(&master->kworker,
1093                                            &master->pump_messages);
1094                         spin_unlock_irqrestore(&master->queue_lock, flags);
1095                         return;
1096                 }
1097
1098                 master->busy = false;
1099                 master->idling = true;
1100                 spin_unlock_irqrestore(&master->queue_lock, flags);
1101
1102                 kfree(master->dummy_rx);
1103                 master->dummy_rx = NULL;
1104                 kfree(master->dummy_tx);
1105                 master->dummy_tx = NULL;
1106                 if (master->unprepare_transfer_hardware &&
1107                     master->unprepare_transfer_hardware(master))
1108                         dev_err(&master->dev,
1109                                 "failed to unprepare transfer hardware\n");
1110                 if (master->auto_runtime_pm) {
1111                         pm_runtime_mark_last_busy(master->dev.parent);
1112                         pm_runtime_put_autosuspend(master->dev.parent);
1113                 }
1114                 trace_spi_master_idle(master);
1115
1116                 spin_lock_irqsave(&master->queue_lock, flags);
1117                 master->idling = false;
1118                 spin_unlock_irqrestore(&master->queue_lock, flags);
1119                 return;
1120         }
1121
1122         /* Extract head of queue */
1123         master->cur_msg =
1124                 list_first_entry(&master->queue, struct spi_message, queue);
1125
1126         list_del_init(&master->cur_msg->queue);
1127         if (master->busy)
1128                 was_busy = true;
1129         else
1130                 master->busy = true;
1131         spin_unlock_irqrestore(&master->queue_lock, flags);
1132
1133         if (!was_busy && master->auto_runtime_pm) {
1134                 ret = pm_runtime_get_sync(master->dev.parent);
1135                 if (ret < 0) {
1136                         dev_err(&master->dev, "Failed to power device: %d\n",
1137                                 ret);
1138                         return;
1139                 }
1140         }
1141
1142         if (!was_busy)
1143                 trace_spi_master_busy(master);
1144
1145         if (!was_busy && master->prepare_transfer_hardware) {
1146                 ret = master->prepare_transfer_hardware(master);
1147                 if (ret) {
1148                         dev_err(&master->dev,
1149                                 "failed to prepare transfer hardware\n");
1150
1151                         if (master->auto_runtime_pm)
1152                                 pm_runtime_put(master->dev.parent);
1153                         return;
1154                 }
1155         }
1156
1157         if (!bus_locked)
1158                 mutex_lock(&master->bus_lock_mutex);
1159
1160         trace_spi_message_start(master->cur_msg);
1161
1162         if (master->prepare_message) {
1163                 ret = master->prepare_message(master, master->cur_msg);
1164                 if (ret) {
1165                         dev_err(&master->dev,
1166                                 "failed to prepare message: %d\n", ret);
1167                         master->cur_msg->status = ret;
1168                         spi_finalize_current_message(master);
1169                         goto out;
1170                 }
1171                 master->cur_msg_prepared = true;
1172         }
1173
1174         ret = spi_map_msg(master, master->cur_msg);
1175         if (ret) {
1176                 master->cur_msg->status = ret;
1177                 spi_finalize_current_message(master);
1178                 goto out;
1179         }
1180
1181         ret = master->transfer_one_message(master, master->cur_msg);
1182         if (ret) {
1183                 dev_err(&master->dev,
1184                         "failed to transfer one message from queue\n");
1185                 goto out;
1186         }
1187
1188 out:
1189         if (!bus_locked)
1190                 mutex_unlock(&master->bus_lock_mutex);
1191
1192         /* Prod the scheduler in case transfer_one() was busy waiting */
1193         if (!ret)
1194                 cond_resched();
1195 }
1196
1197 /**
1198  * spi_pump_messages - kthread work function which processes spi message queue
1199  * @work: pointer to kthread work struct contained in the master struct
1200  */
1201 static void spi_pump_messages(struct kthread_work *work)
1202 {
1203         struct spi_master *master =
1204                 container_of(work, struct spi_master, pump_messages);
1205
1206         __spi_pump_messages(master, true, false);
1207 }
1208
1209 static int spi_init_queue(struct spi_master *master)
1210 {
1211         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1212
1213         master->running = false;
1214         master->busy = false;
1215
1216         init_kthread_worker(&master->kworker);
1217         master->kworker_task = kthread_run(kthread_worker_fn,
1218                                            &master->kworker, "%s",
1219                                            dev_name(&master->dev));
1220         if (IS_ERR(master->kworker_task)) {
1221                 dev_err(&master->dev, "failed to create message pump task\n");
1222                 return PTR_ERR(master->kworker_task);
1223         }
1224         init_kthread_work(&master->pump_messages, spi_pump_messages);
1225
1226         /*
1227          * Master config will indicate if this controller should run the
1228          * message pump with high (realtime) priority to reduce the transfer
1229          * latency on the bus by minimising the delay between a transfer
1230          * request and the scheduling of the message pump thread. Without this
1231          * setting the message pump thread will remain at default priority.
1232          */
1233         if (master->rt) {
1234                 dev_info(&master->dev,
1235                         "will run message pump with realtime priority\n");
1236                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1237         }
1238
1239         return 0;
1240 }
1241
1242 /**
1243  * spi_get_next_queued_message() - called by driver to check for queued
1244  * messages
1245  * @master: the master to check for queued messages
1246  *
1247  * If there are more messages in the queue, the next message is returned from
1248  * this call.
1249  *
1250  * Return: the next message in the queue, else NULL if the queue is empty.
1251  */
1252 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1253 {
1254         struct spi_message *next;
1255         unsigned long flags;
1256
1257         /* get a pointer to the next message, if any */
1258         spin_lock_irqsave(&master->queue_lock, flags);
1259         next = list_first_entry_or_null(&master->queue, struct spi_message,
1260                                         queue);
1261         spin_unlock_irqrestore(&master->queue_lock, flags);
1262
1263         return next;
1264 }
1265 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1266
1267 /**
1268  * spi_finalize_current_message() - the current message is complete
1269  * @master: the master to return the message to
1270  *
1271  * Called by the driver to notify the core that the message in the front of the
1272  * queue is complete and can be removed from the queue.
1273  */
1274 void spi_finalize_current_message(struct spi_master *master)
1275 {
1276         struct spi_message *mesg;
1277         unsigned long flags;
1278         int ret;
1279
1280         spin_lock_irqsave(&master->queue_lock, flags);
1281         mesg = master->cur_msg;
1282         spin_unlock_irqrestore(&master->queue_lock, flags);
1283
1284         spi_unmap_msg(master, mesg);
1285
1286         if (master->cur_msg_prepared && master->unprepare_message) {
1287                 ret = master->unprepare_message(master, mesg);
1288                 if (ret) {
1289                         dev_err(&master->dev,
1290                                 "failed to unprepare message: %d\n", ret);
1291                 }
1292         }
1293
1294         spin_lock_irqsave(&master->queue_lock, flags);
1295         master->cur_msg = NULL;
1296         master->cur_msg_prepared = false;
1297         queue_kthread_work(&master->kworker, &master->pump_messages);
1298         spin_unlock_irqrestore(&master->queue_lock, flags);
1299
1300         trace_spi_message_done(mesg);
1301
1302         mesg->state = NULL;
1303         if (mesg->complete)
1304                 mesg->complete(mesg->context);
1305 }
1306 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1307
1308 static int spi_start_queue(struct spi_master *master)
1309 {
1310         unsigned long flags;
1311
1312         spin_lock_irqsave(&master->queue_lock, flags);
1313
1314         if (master->running || master->busy) {
1315                 spin_unlock_irqrestore(&master->queue_lock, flags);
1316                 return -EBUSY;
1317         }
1318
1319         master->running = true;
1320         master->cur_msg = NULL;
1321         spin_unlock_irqrestore(&master->queue_lock, flags);
1322
1323         queue_kthread_work(&master->kworker, &master->pump_messages);
1324
1325         return 0;
1326 }
1327
1328 static int spi_stop_queue(struct spi_master *master)
1329 {
1330         unsigned long flags;
1331         unsigned limit = 500;
1332         int ret = 0;
1333
1334         spin_lock_irqsave(&master->queue_lock, flags);
1335
1336         /*
1337          * This is a bit lame, but is optimized for the common execution path.
1338          * A wait_queue on the master->busy could be used, but then the common
1339          * execution path (pump_messages) would be required to call wake_up or
1340          * friends on every SPI message. Do this instead.
1341          */
1342         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1343                 spin_unlock_irqrestore(&master->queue_lock, flags);
1344                 usleep_range(10000, 11000);
1345                 spin_lock_irqsave(&master->queue_lock, flags);
1346         }
1347
1348         if (!list_empty(&master->queue) || master->busy)
1349                 ret = -EBUSY;
1350         else
1351                 master->running = false;
1352
1353         spin_unlock_irqrestore(&master->queue_lock, flags);
1354
1355         if (ret) {
1356                 dev_warn(&master->dev,
1357                          "could not stop message queue\n");
1358                 return ret;
1359         }
1360         return ret;
1361 }
1362
1363 static int spi_destroy_queue(struct spi_master *master)
1364 {
1365         int ret;
1366
1367         ret = spi_stop_queue(master);
1368
1369         /*
1370          * flush_kthread_worker will block until all work is done.
1371          * If the reason that stop_queue timed out is that the work will never
1372          * finish, then it does no good to call flush/stop thread, so
1373          * return anyway.
1374          */
1375         if (ret) {
1376                 dev_err(&master->dev, "problem destroying queue\n");
1377                 return ret;
1378         }
1379
1380         flush_kthread_worker(&master->kworker);
1381         kthread_stop(master->kworker_task);
1382
1383         return 0;
1384 }
1385
1386 static int __spi_queued_transfer(struct spi_device *spi,
1387                                  struct spi_message *msg,
1388                                  bool need_pump)
1389 {
1390         struct spi_master *master = spi->master;
1391         unsigned long flags;
1392
1393         spin_lock_irqsave(&master->queue_lock, flags);
1394
1395         if (!master->running) {
1396                 spin_unlock_irqrestore(&master->queue_lock, flags);
1397                 return -ESHUTDOWN;
1398         }
1399         msg->actual_length = 0;
1400         msg->status = -EINPROGRESS;
1401
1402         list_add_tail(&msg->queue, &master->queue);
1403         if (!master->busy && need_pump)
1404                 queue_kthread_work(&master->kworker, &master->pump_messages);
1405
1406         spin_unlock_irqrestore(&master->queue_lock, flags);
1407         return 0;
1408 }
1409
1410 /**
1411  * spi_queued_transfer - transfer function for queued transfers
1412  * @spi: spi device which is requesting transfer
1413  * @msg: spi message which is to handled is queued to driver queue
1414  *
1415  * Return: zero on success, else a negative error code.
1416  */
1417 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1418 {
1419         return __spi_queued_transfer(spi, msg, true);
1420 }
1421
1422 static int spi_master_initialize_queue(struct spi_master *master)
1423 {
1424         int ret;
1425
1426         master->transfer = spi_queued_transfer;
1427         if (!master->transfer_one_message)
1428                 master->transfer_one_message = spi_transfer_one_message;
1429
1430         /* Initialize and start queue */
1431         ret = spi_init_queue(master);
1432         if (ret) {
1433                 dev_err(&master->dev, "problem initializing queue\n");
1434                 goto err_init_queue;
1435         }
1436         master->queued = true;
1437         ret = spi_start_queue(master);
1438         if (ret) {
1439                 dev_err(&master->dev, "problem starting queue\n");
1440                 goto err_start_queue;
1441         }
1442
1443         return 0;
1444
1445 err_start_queue:
1446         spi_destroy_queue(master);
1447 err_init_queue:
1448         return ret;
1449 }
1450
1451 /*-------------------------------------------------------------------------*/
1452
1453 #if defined(CONFIG_OF)
1454 static struct spi_device *
1455 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1456 {
1457         struct spi_device *spi;
1458         int rc;
1459         u32 value;
1460
1461         /* Alloc an spi_device */
1462         spi = spi_alloc_device(master);
1463         if (!spi) {
1464                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1465                         nc->full_name);
1466                 rc = -ENOMEM;
1467                 goto err_out;
1468         }
1469
1470         /* Select device driver */
1471         rc = of_modalias_node(nc, spi->modalias,
1472                                 sizeof(spi->modalias));
1473         if (rc < 0) {
1474                 dev_err(&master->dev, "cannot find modalias for %s\n",
1475                         nc->full_name);
1476                 goto err_out;
1477         }
1478
1479         /* Device address */
1480         rc = of_property_read_u32(nc, "reg", &value);
1481         if (rc) {
1482                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1483                         nc->full_name, rc);
1484                 goto err_out;
1485         }
1486         spi->chip_select = value;
1487
1488         /* Mode (clock phase/polarity/etc.) */
1489         if (of_find_property(nc, "spi-cpha", NULL))
1490                 spi->mode |= SPI_CPHA;
1491         if (of_find_property(nc, "spi-cpol", NULL))
1492                 spi->mode |= SPI_CPOL;
1493         if (of_find_property(nc, "spi-cs-high", NULL))
1494                 spi->mode |= SPI_CS_HIGH;
1495         if (of_find_property(nc, "spi-3wire", NULL))
1496                 spi->mode |= SPI_3WIRE;
1497         if (of_find_property(nc, "spi-lsb-first", NULL))
1498                 spi->mode |= SPI_LSB_FIRST;
1499
1500         /* Device DUAL/QUAD mode */
1501         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1502                 switch (value) {
1503                 case 1:
1504                         break;
1505                 case 2:
1506                         spi->mode |= SPI_TX_DUAL;
1507                         break;
1508                 case 4:
1509                         spi->mode |= SPI_TX_QUAD;
1510                         break;
1511                 default:
1512                         dev_warn(&master->dev,
1513                                 "spi-tx-bus-width %d not supported\n",
1514                                 value);
1515                         break;
1516                 }
1517         }
1518
1519         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1520                 switch (value) {
1521                 case 1:
1522                         break;
1523                 case 2:
1524                         spi->mode |= SPI_RX_DUAL;
1525                         break;
1526                 case 4:
1527                         spi->mode |= SPI_RX_QUAD;
1528                         break;
1529                 default:
1530                         dev_warn(&master->dev,
1531                                 "spi-rx-bus-width %d not supported\n",
1532                                 value);
1533                         break;
1534                 }
1535         }
1536
1537         /* Device speed */
1538         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1539         if (rc) {
1540                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1541                         nc->full_name, rc);
1542                 goto err_out;
1543         }
1544         spi->max_speed_hz = value;
1545
1546         /* Store a pointer to the node in the device structure */
1547         of_node_get(nc);
1548         spi->dev.of_node = nc;
1549
1550         /* Register the new device */
1551         rc = spi_add_device(spi);
1552         if (rc) {
1553                 dev_err(&master->dev, "spi_device register error %s\n",
1554                         nc->full_name);
1555                 goto err_out;
1556         }
1557
1558         return spi;
1559
1560 err_out:
1561         spi_dev_put(spi);
1562         return ERR_PTR(rc);
1563 }
1564
1565 /**
1566  * of_register_spi_devices() - Register child devices onto the SPI bus
1567  * @master:     Pointer to spi_master device
1568  *
1569  * Registers an spi_device for each child node of master node which has a 'reg'
1570  * property.
1571  */
1572 static void of_register_spi_devices(struct spi_master *master)
1573 {
1574         struct spi_device *spi;
1575         struct device_node *nc;
1576
1577         if (!master->dev.of_node)
1578                 return;
1579
1580         for_each_available_child_of_node(master->dev.of_node, nc) {
1581                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1582                         continue;
1583                 spi = of_register_spi_device(master, nc);
1584                 if (IS_ERR(spi))
1585                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1586                                 nc->full_name);
1587         }
1588 }
1589 #else
1590 static void of_register_spi_devices(struct spi_master *master) { }
1591 #endif
1592
1593 #ifdef CONFIG_ACPI
1594 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1595 {
1596         struct spi_device *spi = data;
1597         struct spi_master *master = spi->master;
1598
1599         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1600                 struct acpi_resource_spi_serialbus *sb;
1601
1602                 sb = &ares->data.spi_serial_bus;
1603                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1604                         /*
1605                          * ACPI DeviceSelection numbering is handled by the
1606                          * host controller driver in Windows and can vary
1607                          * from driver to driver. In Linux we always expect
1608                          * 0 .. max - 1 so we need to ask the driver to
1609                          * translate between the two schemes.
1610                          */
1611                         if (master->fw_translate_cs) {
1612                                 int cs = master->fw_translate_cs(master,
1613                                                 sb->device_selection);
1614                                 if (cs < 0)
1615                                         return cs;
1616                                 spi->chip_select = cs;
1617                         } else {
1618                                 spi->chip_select = sb->device_selection;
1619                         }
1620
1621                         spi->max_speed_hz = sb->connection_speed;
1622
1623                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1624                                 spi->mode |= SPI_CPHA;
1625                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1626                                 spi->mode |= SPI_CPOL;
1627                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1628                                 spi->mode |= SPI_CS_HIGH;
1629                 }
1630         } else if (spi->irq < 0) {
1631                 struct resource r;
1632
1633                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1634                         spi->irq = r.start;
1635         }
1636
1637         /* Always tell the ACPI core to skip this resource */
1638         return 1;
1639 }
1640
1641 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1642                                        void *data, void **return_value)
1643 {
1644         struct spi_master *master = data;
1645         struct list_head resource_list;
1646         struct acpi_device *adev;
1647         struct spi_device *spi;
1648         int ret;
1649
1650         if (acpi_bus_get_device(handle, &adev))
1651                 return AE_OK;
1652         if (acpi_bus_get_status(adev) || !adev->status.present)
1653                 return AE_OK;
1654
1655         spi = spi_alloc_device(master);
1656         if (!spi) {
1657                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1658                         dev_name(&adev->dev));
1659                 return AE_NO_MEMORY;
1660         }
1661
1662         ACPI_COMPANION_SET(&spi->dev, adev);
1663         spi->irq = -1;
1664
1665         INIT_LIST_HEAD(&resource_list);
1666         ret = acpi_dev_get_resources(adev, &resource_list,
1667                                      acpi_spi_add_resource, spi);
1668         acpi_dev_free_resource_list(&resource_list);
1669
1670         if (ret < 0 || !spi->max_speed_hz) {
1671                 spi_dev_put(spi);
1672                 return AE_OK;
1673         }
1674
1675         if (spi->irq < 0)
1676                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1677
1678         adev->power.flags.ignore_parent = true;
1679         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1680         if (spi_add_device(spi)) {
1681                 adev->power.flags.ignore_parent = false;
1682                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1683                         dev_name(&adev->dev));
1684                 spi_dev_put(spi);
1685         }
1686
1687         return AE_OK;
1688 }
1689
1690 static void acpi_register_spi_devices(struct spi_master *master)
1691 {
1692         acpi_status status;
1693         acpi_handle handle;
1694
1695         handle = ACPI_HANDLE(master->dev.parent);
1696         if (!handle)
1697                 return;
1698
1699         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1700                                      acpi_spi_add_device, NULL,
1701                                      master, NULL);
1702         if (ACPI_FAILURE(status))
1703                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1704 }
1705 #else
1706 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1707 #endif /* CONFIG_ACPI */
1708
1709 static void spi_master_release(struct device *dev)
1710 {
1711         struct spi_master *master;
1712
1713         master = container_of(dev, struct spi_master, dev);
1714         kfree(master);
1715 }
1716
1717 static struct class spi_master_class = {
1718         .name           = "spi_master",
1719         .owner          = THIS_MODULE,
1720         .dev_release    = spi_master_release,
1721         .dev_groups     = spi_master_groups,
1722 };
1723
1724
1725 /**
1726  * spi_alloc_master - allocate SPI master controller
1727  * @dev: the controller, possibly using the platform_bus
1728  * @size: how much zeroed driver-private data to allocate; the pointer to this
1729  *      memory is in the driver_data field of the returned device,
1730  *      accessible with spi_master_get_devdata().
1731  * Context: can sleep
1732  *
1733  * This call is used only by SPI master controller drivers, which are the
1734  * only ones directly touching chip registers.  It's how they allocate
1735  * an spi_master structure, prior to calling spi_register_master().
1736  *
1737  * This must be called from context that can sleep.
1738  *
1739  * The caller is responsible for assigning the bus number and initializing
1740  * the master's methods before calling spi_register_master(); and (after errors
1741  * adding the device) calling spi_master_put() to prevent a memory leak.
1742  *
1743  * Return: the SPI master structure on success, else NULL.
1744  */
1745 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1746 {
1747         struct spi_master       *master;
1748
1749         if (!dev)
1750                 return NULL;
1751
1752         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1753         if (!master)
1754                 return NULL;
1755
1756         device_initialize(&master->dev);
1757         master->bus_num = -1;
1758         master->num_chipselect = 1;
1759         master->dev.class = &spi_master_class;
1760         master->dev.parent = dev;
1761         spi_master_set_devdata(master, &master[1]);
1762
1763         return master;
1764 }
1765 EXPORT_SYMBOL_GPL(spi_alloc_master);
1766
1767 #ifdef CONFIG_OF
1768 static int of_spi_register_master(struct spi_master *master)
1769 {
1770         int nb, i, *cs;
1771         struct device_node *np = master->dev.of_node;
1772
1773         if (!np)
1774                 return 0;
1775
1776         nb = of_gpio_named_count(np, "cs-gpios");
1777         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1778
1779         /* Return error only for an incorrectly formed cs-gpios property */
1780         if (nb == 0 || nb == -ENOENT)
1781                 return 0;
1782         else if (nb < 0)
1783                 return nb;
1784
1785         cs = devm_kzalloc(&master->dev,
1786                           sizeof(int) * master->num_chipselect,
1787                           GFP_KERNEL);
1788         master->cs_gpios = cs;
1789
1790         if (!master->cs_gpios)
1791                 return -ENOMEM;
1792
1793         for (i = 0; i < master->num_chipselect; i++)
1794                 cs[i] = -ENOENT;
1795
1796         for (i = 0; i < nb; i++)
1797                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1798
1799         return 0;
1800 }
1801 #else
1802 static int of_spi_register_master(struct spi_master *master)
1803 {
1804         return 0;
1805 }
1806 #endif
1807
1808 /**
1809  * spi_register_master - register SPI master controller
1810  * @master: initialized master, originally from spi_alloc_master()
1811  * Context: can sleep
1812  *
1813  * SPI master controllers connect to their drivers using some non-SPI bus,
1814  * such as the platform bus.  The final stage of probe() in that code
1815  * includes calling spi_register_master() to hook up to this SPI bus glue.
1816  *
1817  * SPI controllers use board specific (often SOC specific) bus numbers,
1818  * and board-specific addressing for SPI devices combines those numbers
1819  * with chip select numbers.  Since SPI does not directly support dynamic
1820  * device identification, boards need configuration tables telling which
1821  * chip is at which address.
1822  *
1823  * This must be called from context that can sleep.  It returns zero on
1824  * success, else a negative error code (dropping the master's refcount).
1825  * After a successful return, the caller is responsible for calling
1826  * spi_unregister_master().
1827  *
1828  * Return: zero on success, else a negative error code.
1829  */
1830 int spi_register_master(struct spi_master *master)
1831 {
1832         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1833         struct device           *dev = master->dev.parent;
1834         struct boardinfo        *bi;
1835         int                     status = -ENODEV;
1836         int                     dynamic = 0;
1837
1838         if (!dev)
1839                 return -ENODEV;
1840
1841         status = of_spi_register_master(master);
1842         if (status)
1843                 return status;
1844
1845         /* even if it's just one always-selected device, there must
1846          * be at least one chipselect
1847          */
1848         if (master->num_chipselect == 0)
1849                 return -EINVAL;
1850
1851         if ((master->bus_num < 0) && master->dev.of_node)
1852                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1853
1854         /* convention:  dynamically assigned bus IDs count down from the max */
1855         if (master->bus_num < 0) {
1856                 /* FIXME switch to an IDR based scheme, something like
1857                  * I2C now uses, so we can't run out of "dynamic" IDs
1858                  */
1859                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1860                 dynamic = 1;
1861         }
1862
1863         INIT_LIST_HEAD(&master->queue);
1864         spin_lock_init(&master->queue_lock);
1865         spin_lock_init(&master->bus_lock_spinlock);
1866         mutex_init(&master->bus_lock_mutex);
1867         master->bus_lock_flag = 0;
1868         init_completion(&master->xfer_completion);
1869         if (!master->max_dma_len)
1870                 master->max_dma_len = INT_MAX;
1871
1872         /* register the device, then userspace will see it.
1873          * registration fails if the bus ID is in use.
1874          */
1875         dev_set_name(&master->dev, "spi%u", master->bus_num);
1876         status = device_add(&master->dev);
1877         if (status < 0)
1878                 goto done;
1879         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1880                         dynamic ? " (dynamic)" : "");
1881
1882         /* If we're using a queued driver, start the queue */
1883         if (master->transfer)
1884                 dev_info(dev, "master is unqueued, this is deprecated\n");
1885         else {
1886                 status = spi_master_initialize_queue(master);
1887                 if (status) {
1888                         device_del(&master->dev);
1889                         goto done;
1890                 }
1891         }
1892         /* add statistics */
1893         spin_lock_init(&master->statistics.lock);
1894
1895         mutex_lock(&board_lock);
1896         list_add_tail(&master->list, &spi_master_list);
1897         list_for_each_entry(bi, &board_list, list)
1898                 spi_match_master_to_boardinfo(master, &bi->board_info);
1899         mutex_unlock(&board_lock);
1900
1901         /* Register devices from the device tree and ACPI */
1902         of_register_spi_devices(master);
1903         acpi_register_spi_devices(master);
1904 done:
1905         return status;
1906 }
1907 EXPORT_SYMBOL_GPL(spi_register_master);
1908
1909 static void devm_spi_unregister(struct device *dev, void *res)
1910 {
1911         spi_unregister_master(*(struct spi_master **)res);
1912 }
1913
1914 /**
1915  * dev_spi_register_master - register managed SPI master controller
1916  * @dev:    device managing SPI master
1917  * @master: initialized master, originally from spi_alloc_master()
1918  * Context: can sleep
1919  *
1920  * Register a SPI device as with spi_register_master() which will
1921  * automatically be unregister
1922  *
1923  * Return: zero on success, else a negative error code.
1924  */
1925 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1926 {
1927         struct spi_master **ptr;
1928         int ret;
1929
1930         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1931         if (!ptr)
1932                 return -ENOMEM;
1933
1934         ret = spi_register_master(master);
1935         if (!ret) {
1936                 *ptr = master;
1937                 devres_add(dev, ptr);
1938         } else {
1939                 devres_free(ptr);
1940         }
1941
1942         return ret;
1943 }
1944 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1945
1946 static int __unregister(struct device *dev, void *null)
1947 {
1948         spi_unregister_device(to_spi_device(dev));
1949         return 0;
1950 }
1951
1952 /**
1953  * spi_unregister_master - unregister SPI master controller
1954  * @master: the master being unregistered
1955  * Context: can sleep
1956  *
1957  * This call is used only by SPI master controller drivers, which are the
1958  * only ones directly touching chip registers.
1959  *
1960  * This must be called from context that can sleep.
1961  */
1962 void spi_unregister_master(struct spi_master *master)
1963 {
1964         int dummy;
1965
1966         if (master->queued) {
1967                 if (spi_destroy_queue(master))
1968                         dev_err(&master->dev, "queue remove failed\n");
1969         }
1970
1971         mutex_lock(&board_lock);
1972         list_del(&master->list);
1973         mutex_unlock(&board_lock);
1974
1975         dummy = device_for_each_child(&master->dev, NULL, __unregister);
1976         device_unregister(&master->dev);
1977 }
1978 EXPORT_SYMBOL_GPL(spi_unregister_master);
1979
1980 int spi_master_suspend(struct spi_master *master)
1981 {
1982         int ret;
1983
1984         /* Basically no-ops for non-queued masters */
1985         if (!master->queued)
1986                 return 0;
1987
1988         ret = spi_stop_queue(master);
1989         if (ret)
1990                 dev_err(&master->dev, "queue stop failed\n");
1991
1992         return ret;
1993 }
1994 EXPORT_SYMBOL_GPL(spi_master_suspend);
1995
1996 int spi_master_resume(struct spi_master *master)
1997 {
1998         int ret;
1999
2000         if (!master->queued)
2001                 return 0;
2002
2003         ret = spi_start_queue(master);
2004         if (ret)
2005                 dev_err(&master->dev, "queue restart failed\n");
2006
2007         return ret;
2008 }
2009 EXPORT_SYMBOL_GPL(spi_master_resume);
2010
2011 static int __spi_master_match(struct device *dev, const void *data)
2012 {
2013         struct spi_master *m;
2014         const u16 *bus_num = data;
2015
2016         m = container_of(dev, struct spi_master, dev);
2017         return m->bus_num == *bus_num;
2018 }
2019
2020 /**
2021  * spi_busnum_to_master - look up master associated with bus_num
2022  * @bus_num: the master's bus number
2023  * Context: can sleep
2024  *
2025  * This call may be used with devices that are registered after
2026  * arch init time.  It returns a refcounted pointer to the relevant
2027  * spi_master (which the caller must release), or NULL if there is
2028  * no such master registered.
2029  *
2030  * Return: the SPI master structure on success, else NULL.
2031  */
2032 struct spi_master *spi_busnum_to_master(u16 bus_num)
2033 {
2034         struct device           *dev;
2035         struct spi_master       *master = NULL;
2036
2037         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2038                                 __spi_master_match);
2039         if (dev)
2040                 master = container_of(dev, struct spi_master, dev);
2041         /* reference got in class_find_device */
2042         return master;
2043 }
2044 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2045
2046
2047 /*-------------------------------------------------------------------------*/
2048
2049 /* Core methods for SPI master protocol drivers.  Some of the
2050  * other core methods are currently defined as inline functions.
2051  */
2052
2053 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2054 {
2055         if (master->bits_per_word_mask) {
2056                 /* Only 32 bits fit in the mask */
2057                 if (bits_per_word > 32)
2058                         return -EINVAL;
2059                 if (!(master->bits_per_word_mask &
2060                                 SPI_BPW_MASK(bits_per_word)))
2061                         return -EINVAL;
2062         }
2063
2064         return 0;
2065 }
2066
2067 /**
2068  * spi_setup - setup SPI mode and clock rate
2069  * @spi: the device whose settings are being modified
2070  * Context: can sleep, and no requests are queued to the device
2071  *
2072  * SPI protocol drivers may need to update the transfer mode if the
2073  * device doesn't work with its default.  They may likewise need
2074  * to update clock rates or word sizes from initial values.  This function
2075  * changes those settings, and must be called from a context that can sleep.
2076  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2077  * effect the next time the device is selected and data is transferred to
2078  * or from it.  When this function returns, the spi device is deselected.
2079  *
2080  * Note that this call will fail if the protocol driver specifies an option
2081  * that the underlying controller or its driver does not support.  For
2082  * example, not all hardware supports wire transfers using nine bit words,
2083  * LSB-first wire encoding, or active-high chipselects.
2084  *
2085  * Return: zero on success, else a negative error code.
2086  */
2087 int spi_setup(struct spi_device *spi)
2088 {
2089         unsigned        bad_bits, ugly_bits;
2090         int             status;
2091
2092         /* check mode to prevent that DUAL and QUAD set at the same time
2093          */
2094         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2095                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2096                 dev_err(&spi->dev,
2097                 "setup: can not select dual and quad at the same time\n");
2098                 return -EINVAL;
2099         }
2100         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2101          */
2102         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2103                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2104                 return -EINVAL;
2105         /* help drivers fail *cleanly* when they need options
2106          * that aren't supported with their current master
2107          */
2108         bad_bits = spi->mode & ~spi->master->mode_bits;
2109         ugly_bits = bad_bits &
2110                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2111         if (ugly_bits) {
2112                 dev_warn(&spi->dev,
2113                          "setup: ignoring unsupported mode bits %x\n",
2114                          ugly_bits);
2115                 spi->mode &= ~ugly_bits;
2116                 bad_bits &= ~ugly_bits;
2117         }
2118         if (bad_bits) {
2119                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2120                         bad_bits);
2121                 return -EINVAL;
2122         }
2123
2124         if (!spi->bits_per_word)
2125                 spi->bits_per_word = 8;
2126
2127         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2128         if (status)
2129                 return status;
2130
2131         if (!spi->max_speed_hz)
2132                 spi->max_speed_hz = spi->master->max_speed_hz;
2133
2134         if (spi->master->setup)
2135                 status = spi->master->setup(spi);
2136
2137         spi_set_cs(spi, false);
2138
2139         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2140                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2141                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2142                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2143                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2144                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2145                         spi->bits_per_word, spi->max_speed_hz,
2146                         status);
2147
2148         return status;
2149 }
2150 EXPORT_SYMBOL_GPL(spi_setup);
2151
2152 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2153 {
2154         struct spi_master *master = spi->master;
2155         struct spi_transfer *xfer;
2156         int w_size;
2157
2158         if (list_empty(&message->transfers))
2159                 return -EINVAL;
2160
2161         /* Half-duplex links include original MicroWire, and ones with
2162          * only one data pin like SPI_3WIRE (switches direction) or where
2163          * either MOSI or MISO is missing.  They can also be caused by
2164          * software limitations.
2165          */
2166         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2167                         || (spi->mode & SPI_3WIRE)) {
2168                 unsigned flags = master->flags;
2169
2170                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2171                         if (xfer->rx_buf && xfer->tx_buf)
2172                                 return -EINVAL;
2173                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2174                                 return -EINVAL;
2175                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2176                                 return -EINVAL;
2177                 }
2178         }
2179
2180         /**
2181          * Set transfer bits_per_word and max speed as spi device default if
2182          * it is not set for this transfer.
2183          * Set transfer tx_nbits and rx_nbits as single transfer default
2184          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2185          */
2186         message->frame_length = 0;
2187         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2188                 message->frame_length += xfer->len;
2189                 if (!xfer->bits_per_word)
2190                         xfer->bits_per_word = spi->bits_per_word;
2191
2192                 if (!xfer->speed_hz)
2193                         xfer->speed_hz = spi->max_speed_hz;
2194                 if (!xfer->speed_hz)
2195                         xfer->speed_hz = master->max_speed_hz;
2196
2197                 if (master->max_speed_hz &&
2198                     xfer->speed_hz > master->max_speed_hz)
2199                         xfer->speed_hz = master->max_speed_hz;
2200
2201                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2202                         return -EINVAL;
2203
2204                 /*
2205                  * SPI transfer length should be multiple of SPI word size
2206                  * where SPI word size should be power-of-two multiple
2207                  */
2208                 if (xfer->bits_per_word <= 8)
2209                         w_size = 1;
2210                 else if (xfer->bits_per_word <= 16)
2211                         w_size = 2;
2212                 else
2213                         w_size = 4;
2214
2215                 /* No partial transfers accepted */
2216                 if (xfer->len % w_size)
2217                         return -EINVAL;
2218
2219                 if (xfer->speed_hz && master->min_speed_hz &&
2220                     xfer->speed_hz < master->min_speed_hz)
2221                         return -EINVAL;
2222
2223                 if (xfer->tx_buf && !xfer->tx_nbits)
2224                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2225                 if (xfer->rx_buf && !xfer->rx_nbits)
2226                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2227                 /* check transfer tx/rx_nbits:
2228                  * 1. check the value matches one of single, dual and quad
2229                  * 2. check tx/rx_nbits match the mode in spi_device
2230                  */
2231                 if (xfer->tx_buf) {
2232                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2233                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2234                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2235                                 return -EINVAL;
2236                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2237                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2238                                 return -EINVAL;
2239                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2240                                 !(spi->mode & SPI_TX_QUAD))
2241                                 return -EINVAL;
2242                 }
2243                 /* check transfer rx_nbits */
2244                 if (xfer->rx_buf) {
2245                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2246                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2247                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2248                                 return -EINVAL;
2249                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2250                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2251                                 return -EINVAL;
2252                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2253                                 !(spi->mode & SPI_RX_QUAD))
2254                                 return -EINVAL;
2255                 }
2256         }
2257
2258         message->status = -EINPROGRESS;
2259
2260         return 0;
2261 }
2262
2263 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2264 {
2265         struct spi_master *master = spi->master;
2266
2267         message->spi = spi;
2268
2269         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2270         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2271
2272         trace_spi_message_submit(message);
2273
2274         return master->transfer(spi, message);
2275 }
2276
2277 /**
2278  * spi_async - asynchronous SPI transfer
2279  * @spi: device with which data will be exchanged
2280  * @message: describes the data transfers, including completion callback
2281  * Context: any (irqs may be blocked, etc)
2282  *
2283  * This call may be used in_irq and other contexts which can't sleep,
2284  * as well as from task contexts which can sleep.
2285  *
2286  * The completion callback is invoked in a context which can't sleep.
2287  * Before that invocation, the value of message->status is undefined.
2288  * When the callback is issued, message->status holds either zero (to
2289  * indicate complete success) or a negative error code.  After that
2290  * callback returns, the driver which issued the transfer request may
2291  * deallocate the associated memory; it's no longer in use by any SPI
2292  * core or controller driver code.
2293  *
2294  * Note that although all messages to a spi_device are handled in
2295  * FIFO order, messages may go to different devices in other orders.
2296  * Some device might be higher priority, or have various "hard" access
2297  * time requirements, for example.
2298  *
2299  * On detection of any fault during the transfer, processing of
2300  * the entire message is aborted, and the device is deselected.
2301  * Until returning from the associated message completion callback,
2302  * no other spi_message queued to that device will be processed.
2303  * (This rule applies equally to all the synchronous transfer calls,
2304  * which are wrappers around this core asynchronous primitive.)
2305  *
2306  * Return: zero on success, else a negative error code.
2307  */
2308 int spi_async(struct spi_device *spi, struct spi_message *message)
2309 {
2310         struct spi_master *master = spi->master;
2311         int ret;
2312         unsigned long flags;
2313
2314         ret = __spi_validate(spi, message);
2315         if (ret != 0)
2316                 return ret;
2317
2318         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2319
2320         if (master->bus_lock_flag)
2321                 ret = -EBUSY;
2322         else
2323                 ret = __spi_async(spi, message);
2324
2325         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2326
2327         return ret;
2328 }
2329 EXPORT_SYMBOL_GPL(spi_async);
2330
2331 /**
2332  * spi_async_locked - version of spi_async with exclusive bus usage
2333  * @spi: device with which data will be exchanged
2334  * @message: describes the data transfers, including completion callback
2335  * Context: any (irqs may be blocked, etc)
2336  *
2337  * This call may be used in_irq and other contexts which can't sleep,
2338  * as well as from task contexts which can sleep.
2339  *
2340  * The completion callback is invoked in a context which can't sleep.
2341  * Before that invocation, the value of message->status is undefined.
2342  * When the callback is issued, message->status holds either zero (to
2343  * indicate complete success) or a negative error code.  After that
2344  * callback returns, the driver which issued the transfer request may
2345  * deallocate the associated memory; it's no longer in use by any SPI
2346  * core or controller driver code.
2347  *
2348  * Note that although all messages to a spi_device are handled in
2349  * FIFO order, messages may go to different devices in other orders.
2350  * Some device might be higher priority, or have various "hard" access
2351  * time requirements, for example.
2352  *
2353  * On detection of any fault during the transfer, processing of
2354  * the entire message is aborted, and the device is deselected.
2355  * Until returning from the associated message completion callback,
2356  * no other spi_message queued to that device will be processed.
2357  * (This rule applies equally to all the synchronous transfer calls,
2358  * which are wrappers around this core asynchronous primitive.)
2359  *
2360  * Return: zero on success, else a negative error code.
2361  */
2362 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2363 {
2364         struct spi_master *master = spi->master;
2365         int ret;
2366         unsigned long flags;
2367
2368         ret = __spi_validate(spi, message);
2369         if (ret != 0)
2370                 return ret;
2371
2372         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2373
2374         ret = __spi_async(spi, message);
2375
2376         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2377
2378         return ret;
2379
2380 }
2381 EXPORT_SYMBOL_GPL(spi_async_locked);
2382
2383
2384 int spi_flash_read(struct spi_device *spi,
2385                    struct spi_flash_read_message *msg)
2386
2387 {
2388         struct spi_master *master = spi->master;
2389         int ret;
2390
2391         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2392              msg->addr_nbits == SPI_NBITS_DUAL) &&
2393             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2394                 return -EINVAL;
2395         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2396              msg->addr_nbits == SPI_NBITS_QUAD) &&
2397             !(spi->mode & SPI_TX_QUAD))
2398                 return -EINVAL;
2399         if (msg->data_nbits == SPI_NBITS_DUAL &&
2400             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2401                 return -EINVAL;
2402         if (msg->data_nbits == SPI_NBITS_QUAD &&
2403             !(spi->mode &  SPI_RX_QUAD))
2404                 return -EINVAL;
2405
2406         if (master->auto_runtime_pm) {
2407                 ret = pm_runtime_get_sync(master->dev.parent);
2408                 if (ret < 0) {
2409                         dev_err(&master->dev, "Failed to power device: %d\n",
2410                                 ret);
2411                         return ret;
2412                 }
2413         }
2414         mutex_lock(&master->bus_lock_mutex);
2415         ret = master->spi_flash_read(spi, msg);
2416         mutex_unlock(&master->bus_lock_mutex);
2417         if (master->auto_runtime_pm)
2418                 pm_runtime_put(master->dev.parent);
2419
2420         return ret;
2421 }
2422 EXPORT_SYMBOL_GPL(spi_flash_read);
2423
2424 /*-------------------------------------------------------------------------*/
2425
2426 /* Utility methods for SPI master protocol drivers, layered on
2427  * top of the core.  Some other utility methods are defined as
2428  * inline functions.
2429  */
2430
2431 static void spi_complete(void *arg)
2432 {
2433         complete(arg);
2434 }
2435
2436 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2437                       int bus_locked)
2438 {
2439         DECLARE_COMPLETION_ONSTACK(done);
2440         int status;
2441         struct spi_master *master = spi->master;
2442         unsigned long flags;
2443
2444         status = __spi_validate(spi, message);
2445         if (status != 0)
2446                 return status;
2447
2448         message->complete = spi_complete;
2449         message->context = &done;
2450         message->spi = spi;
2451
2452         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2453         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2454
2455         if (!bus_locked)
2456                 mutex_lock(&master->bus_lock_mutex);
2457
2458         /* If we're not using the legacy transfer method then we will
2459          * try to transfer in the calling context so special case.
2460          * This code would be less tricky if we could remove the
2461          * support for driver implemented message queues.
2462          */
2463         if (master->transfer == spi_queued_transfer) {
2464                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2465
2466                 trace_spi_message_submit(message);
2467
2468                 status = __spi_queued_transfer(spi, message, false);
2469
2470                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2471         } else {
2472                 status = spi_async_locked(spi, message);
2473         }
2474
2475         if (!bus_locked)
2476                 mutex_unlock(&master->bus_lock_mutex);
2477
2478         if (status == 0) {
2479                 /* Push out the messages in the calling context if we
2480                  * can.
2481                  */
2482                 if (master->transfer == spi_queued_transfer) {
2483                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2484                                                        spi_sync_immediate);
2485                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2486                                                        spi_sync_immediate);
2487                         __spi_pump_messages(master, false, bus_locked);
2488                 }
2489
2490                 wait_for_completion(&done);
2491                 status = message->status;
2492         }
2493         message->context = NULL;
2494         return status;
2495 }
2496
2497 /**
2498  * spi_sync - blocking/synchronous SPI data transfers
2499  * @spi: device with which data will be exchanged
2500  * @message: describes the data transfers
2501  * Context: can sleep
2502  *
2503  * This call may only be used from a context that may sleep.  The sleep
2504  * is non-interruptible, and has no timeout.  Low-overhead controller
2505  * drivers may DMA directly into and out of the message buffers.
2506  *
2507  * Note that the SPI device's chip select is active during the message,
2508  * and then is normally disabled between messages.  Drivers for some
2509  * frequently-used devices may want to minimize costs of selecting a chip,
2510  * by leaving it selected in anticipation that the next message will go
2511  * to the same chip.  (That may increase power usage.)
2512  *
2513  * Also, the caller is guaranteeing that the memory associated with the
2514  * message will not be freed before this call returns.
2515  *
2516  * Return: zero on success, else a negative error code.
2517  */
2518 int spi_sync(struct spi_device *spi, struct spi_message *message)
2519 {
2520         return __spi_sync(spi, message, 0);
2521 }
2522 EXPORT_SYMBOL_GPL(spi_sync);
2523
2524 /**
2525  * spi_sync_locked - version of spi_sync with exclusive bus usage
2526  * @spi: device with which data will be exchanged
2527  * @message: describes the data transfers
2528  * Context: can sleep
2529  *
2530  * This call may only be used from a context that may sleep.  The sleep
2531  * is non-interruptible, and has no timeout.  Low-overhead controller
2532  * drivers may DMA directly into and out of the message buffers.
2533  *
2534  * This call should be used by drivers that require exclusive access to the
2535  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2536  * be released by a spi_bus_unlock call when the exclusive access is over.
2537  *
2538  * Return: zero on success, else a negative error code.
2539  */
2540 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2541 {
2542         return __spi_sync(spi, message, 1);
2543 }
2544 EXPORT_SYMBOL_GPL(spi_sync_locked);
2545
2546 /**
2547  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2548  * @master: SPI bus master that should be locked for exclusive bus access
2549  * Context: can sleep
2550  *
2551  * This call may only be used from a context that may sleep.  The sleep
2552  * is non-interruptible, and has no timeout.
2553  *
2554  * This call should be used by drivers that require exclusive access to the
2555  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2556  * exclusive access is over. Data transfer must be done by spi_sync_locked
2557  * and spi_async_locked calls when the SPI bus lock is held.
2558  *
2559  * Return: always zero.
2560  */
2561 int spi_bus_lock(struct spi_master *master)
2562 {
2563         unsigned long flags;
2564
2565         mutex_lock(&master->bus_lock_mutex);
2566
2567         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2568         master->bus_lock_flag = 1;
2569         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2570
2571         /* mutex remains locked until spi_bus_unlock is called */
2572
2573         return 0;
2574 }
2575 EXPORT_SYMBOL_GPL(spi_bus_lock);
2576
2577 /**
2578  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2579  * @master: SPI bus master that was locked for exclusive bus access
2580  * Context: can sleep
2581  *
2582  * This call may only be used from a context that may sleep.  The sleep
2583  * is non-interruptible, and has no timeout.
2584  *
2585  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2586  * call.
2587  *
2588  * Return: always zero.
2589  */
2590 int spi_bus_unlock(struct spi_master *master)
2591 {
2592         master->bus_lock_flag = 0;
2593
2594         mutex_unlock(&master->bus_lock_mutex);
2595
2596         return 0;
2597 }
2598 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2599
2600 /* portable code must never pass more than 32 bytes */
2601 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
2602
2603 static u8       *buf;
2604
2605 /**
2606  * spi_write_then_read - SPI synchronous write followed by read
2607  * @spi: device with which data will be exchanged
2608  * @txbuf: data to be written (need not be dma-safe)
2609  * @n_tx: size of txbuf, in bytes
2610  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2611  * @n_rx: size of rxbuf, in bytes
2612  * Context: can sleep
2613  *
2614  * This performs a half duplex MicroWire style transaction with the
2615  * device, sending txbuf and then reading rxbuf.  The return value
2616  * is zero for success, else a negative errno status code.
2617  * This call may only be used from a context that may sleep.
2618  *
2619  * Parameters to this routine are always copied using a small buffer;
2620  * portable code should never use this for more than 32 bytes.
2621  * Performance-sensitive or bulk transfer code should instead use
2622  * spi_{async,sync}() calls with dma-safe buffers.
2623  *
2624  * Return: zero on success, else a negative error code.
2625  */
2626 int spi_write_then_read(struct spi_device *spi,
2627                 const void *txbuf, unsigned n_tx,
2628                 void *rxbuf, unsigned n_rx)
2629 {
2630         static DEFINE_MUTEX(lock);
2631
2632         int                     status;
2633         struct spi_message      message;
2634         struct spi_transfer     x[2];
2635         u8                      *local_buf;
2636
2637         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
2638          * copying here, (as a pure convenience thing), but we can
2639          * keep heap costs out of the hot path unless someone else is
2640          * using the pre-allocated buffer or the transfer is too large.
2641          */
2642         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2643                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2644                                     GFP_KERNEL | GFP_DMA);
2645                 if (!local_buf)
2646                         return -ENOMEM;
2647         } else {
2648                 local_buf = buf;
2649         }
2650
2651         spi_message_init(&message);
2652         memset(x, 0, sizeof(x));
2653         if (n_tx) {
2654                 x[0].len = n_tx;
2655                 spi_message_add_tail(&x[0], &message);
2656         }
2657         if (n_rx) {
2658                 x[1].len = n_rx;
2659                 spi_message_add_tail(&x[1], &message);
2660         }
2661
2662         memcpy(local_buf, txbuf, n_tx);
2663         x[0].tx_buf = local_buf;
2664         x[1].rx_buf = local_buf + n_tx;
2665
2666         /* do the i/o */
2667         status = spi_sync(spi, &message);
2668         if (status == 0)
2669                 memcpy(rxbuf, x[1].rx_buf, n_rx);
2670
2671         if (x[0].tx_buf == buf)
2672                 mutex_unlock(&lock);
2673         else
2674                 kfree(local_buf);
2675
2676         return status;
2677 }
2678 EXPORT_SYMBOL_GPL(spi_write_then_read);
2679
2680 /*-------------------------------------------------------------------------*/
2681
2682 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2683 static int __spi_of_device_match(struct device *dev, void *data)
2684 {
2685         return dev->of_node == data;
2686 }
2687
2688 /* must call put_device() when done with returned spi_device device */
2689 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2690 {
2691         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2692                                                 __spi_of_device_match);
2693         return dev ? to_spi_device(dev) : NULL;
2694 }
2695
2696 static int __spi_of_master_match(struct device *dev, const void *data)
2697 {
2698         return dev->of_node == data;
2699 }
2700
2701 /* the spi masters are not using spi_bus, so we find it with another way */
2702 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2703 {
2704         struct device *dev;
2705
2706         dev = class_find_device(&spi_master_class, NULL, node,
2707                                 __spi_of_master_match);
2708         if (!dev)
2709                 return NULL;
2710
2711         /* reference got in class_find_device */
2712         return container_of(dev, struct spi_master, dev);
2713 }
2714
2715 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2716                          void *arg)
2717 {
2718         struct of_reconfig_data *rd = arg;
2719         struct spi_master *master;
2720         struct spi_device *spi;
2721
2722         switch (of_reconfig_get_state_change(action, arg)) {
2723         case OF_RECONFIG_CHANGE_ADD:
2724                 master = of_find_spi_master_by_node(rd->dn->parent);
2725                 if (master == NULL)
2726                         return NOTIFY_OK;       /* not for us */
2727
2728                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
2729                         put_device(&master->dev);
2730                         return NOTIFY_OK;
2731                 }
2732
2733                 spi = of_register_spi_device(master, rd->dn);
2734                 put_device(&master->dev);
2735
2736                 if (IS_ERR(spi)) {
2737                         pr_err("%s: failed to create for '%s'\n",
2738                                         __func__, rd->dn->full_name);
2739                         return notifier_from_errno(PTR_ERR(spi));
2740                 }
2741                 break;
2742
2743         case OF_RECONFIG_CHANGE_REMOVE:
2744                 /* already depopulated? */
2745                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
2746                         return NOTIFY_OK;
2747
2748                 /* find our device by node */
2749                 spi = of_find_spi_device_by_node(rd->dn);
2750                 if (spi == NULL)
2751                         return NOTIFY_OK;       /* no? not meant for us */
2752
2753                 /* unregister takes one ref away */
2754                 spi_unregister_device(spi);
2755
2756                 /* and put the reference of the find */
2757                 put_device(&spi->dev);
2758                 break;
2759         }
2760
2761         return NOTIFY_OK;
2762 }
2763
2764 static struct notifier_block spi_of_notifier = {
2765         .notifier_call = of_spi_notify,
2766 };
2767 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2768 extern struct notifier_block spi_of_notifier;
2769 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2770
2771 static int __init spi_init(void)
2772 {
2773         int     status;
2774
2775         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2776         if (!buf) {
2777                 status = -ENOMEM;
2778                 goto err0;
2779         }
2780
2781         status = bus_register(&spi_bus_type);
2782         if (status < 0)
2783                 goto err1;
2784
2785         status = class_register(&spi_master_class);
2786         if (status < 0)
2787                 goto err2;
2788
2789         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2790                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2791
2792         return 0;
2793
2794 err2:
2795         bus_unregister(&spi_bus_type);
2796 err1:
2797         kfree(buf);
2798         buf = NULL;
2799 err0:
2800         return status;
2801 }
2802
2803 /* board_info is normally registered in arch_initcall(),
2804  * but even essential drivers wait till later
2805  *
2806  * REVISIT only boardinfo really needs static linking. the rest (device and
2807  * driver registration) _could_ be dynamically linked (modular) ... costs
2808  * include needing to have boardinfo data structures be much more public.
2809  */
2810 postcore_initcall(spi_init);
2811