drivers/spi/spi-dw.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Designware SPI core controller driver (refer pxa2xx_spi.c)
   4  *
   5  * Copyright (c) 2009, Intel Corporation.
   6  */
   7
   8 #include <linux/dma-mapping.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/module.h>
  11 #include <linux/highmem.h>
  12 #include <linux/delay.h>
  13 #include <linux/slab.h>
  14 #include <linux/spi/spi.h>
  15
  16 #include "spi-dw.h"
  17
  18 #ifdef CONFIG_DEBUG_FS
  19 #include <linux/debugfs.h>
  20 #endif
  21
  22 /* Slave spi_dev related */
  23 struct chip_data {
  24         u8 tmode;               /* TR/TO/RO/EEPROM */
  25         u8 type;                /* SPI/SSP/MicroWire */
  26
  27         u8 poll_mode;           /* 1 means use poll mode */
  28
  29         u16 clk_div;            /* baud rate divider */
  30         u32 speed_hz;           /* baud rate */
  31         void (*cs_control)(u32 command);
  32 };
  33
  34 #ifdef CONFIG_DEBUG_FS
  35 #define SPI_REGS_BUFSIZE        1024
  36 static ssize_t dw_spi_show_regs(struct file *file, char __user *user_buf,
  37                 size_t count, loff_t *ppos)
  38 {
  39         struct dw_spi *dws = file->private_data;
  40         char *buf;
  41         u32 len = 0;
  42         ssize_t ret;
  43
  44         buf = kzalloc(SPI_REGS_BUFSIZE, GFP_KERNEL);
  45         if (!buf)
  46                 return 0;
  47
  48         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  49                         "%s registers:\n", dev_name(&dws->master->dev));
  50         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  51                         "=================================\n");
  52         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  53                         "CTRL0: \t\t0x%08x\n", dw_readl(dws, DW_SPI_CTRL0));
  54         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  55                         "CTRL1: \t\t0x%08x\n", dw_readl(dws, DW_SPI_CTRL1));
  56         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  57                         "SSIENR: \t0x%08x\n", dw_readl(dws, DW_SPI_SSIENR));
  58         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  59                         "SER: \t\t0x%08x\n", dw_readl(dws, DW_SPI_SER));
  60         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  61                         "BAUDR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_BAUDR));
  62         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  63                         "TXFTLR: \t0x%08x\n", dw_readl(dws, DW_SPI_TXFLTR));
  64         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  65                         "RXFTLR: \t0x%08x\n", dw_readl(dws, DW_SPI_RXFLTR));
  66         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  67                         "TXFLR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_TXFLR));
  68         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  69                         "RXFLR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_RXFLR));
  70         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  71                         "SR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_SR));
  72         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  73                         "IMR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_IMR));
  74         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  75                         "ISR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_ISR));
  76         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  77                         "DMACR: \t\t0x%08x\n", dw_readl(dws, DW_SPI_DMACR));
  78         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  79                         "DMATDLR: \t0x%08x\n", dw_readl(dws, DW_SPI_DMATDLR));
  80         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  81                         "DMARDLR: \t0x%08x\n", dw_readl(dws, DW_SPI_DMARDLR));
  82         len += scnprintf(buf + len, SPI_REGS_BUFSIZE - len,
  83                         "=================================\n");
  84
  85         ret = simple_read_from_buffer(user_buf, count, ppos, buf, len);
  86         kfree(buf);
  87         return ret;
  88 }
  89
  90 static const struct file_operations dw_spi_regs_ops = {
  91         .owner          = THIS_MODULE,
  92         .open           = simple_open,
  93         .read           = dw_spi_show_regs,
  94         .llseek         = default_llseek,
  95 };
  96
  97 static int dw_spi_debugfs_init(struct dw_spi *dws)
  98 {
  99         char name[32];
 100
 101         snprintf(name, 32, "dw_spi%d", dws->master->bus_num);
 102         dws->debugfs = debugfs_create_dir(name, NULL);
 103         if (!dws->debugfs)
 104                 return -ENOMEM;
 105
 106         debugfs_create_file("registers", S_IFREG | S_IRUGO,
 107                 dws->debugfs, (void *)dws, &dw_spi_regs_ops);
 108         return 0;
 109 }
 110
 111 static void dw_spi_debugfs_remove(struct dw_spi *dws)
 112 {
 113         debugfs_remove_recursive(dws->debugfs);
 114 }
 115
 116 #else
 117 static inline int dw_spi_debugfs_init(struct dw_spi *dws)
 118 {
 119         return 0;
 120 }
 121
 122 static inline void dw_spi_debugfs_remove(struct dw_spi *dws)
 123 {
 124 }
 125 #endif /* CONFIG_DEBUG_FS */
 126
 127 void dw_spi_set_cs(struct spi_device *spi, bool enable)
 128 {
 129         struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
 130         struct chip_data *chip = spi_get_ctldata(spi);
 131
 132         if (chip && chip->cs_control)
 133                 chip->cs_control(enable);
 134
 135         if (enable)
 136                 dw_writel(dws, DW_SPI_SER, BIT(spi->chip_select));
 137         else if (dws->cs_override)
 138                 dw_writel(dws, DW_SPI_SER, 0);
 139 }
 140 EXPORT_SYMBOL_GPL(dw_spi_set_cs);
 141
 142 /* Return the max entries we can fill into tx fifo */
 143 static inline u32 tx_max(struct dw_spi *dws)
 144 {
 145         u32 tx_left, tx_room, rxtx_gap;
 146
 147         tx_left = (dws->tx_end - dws->tx) / dws->n_bytes;
 148         tx_room = dws->fifo_len - dw_readl(dws, DW_SPI_TXFLR);
 149
 150         /*
 151          * Another concern is about the tx/rx mismatch, we
 152          * though to use (dws->fifo_len - rxflr - txflr) as
 153          * one maximum value for tx, but it doesn't cover the
 154          * data which is out of tx/rx fifo and inside the
 155          * shift registers. So a control from sw point of
 156          * view is taken.
 157          */
 158         rxtx_gap =  ((dws->rx_end - dws->rx) - (dws->tx_end - dws->tx))
 159                         / dws->n_bytes;
 160
 161         return min3(tx_left, tx_room, (u32) (dws->fifo_len - rxtx_gap));
 162 }
 163
 164 /* Return the max entries we should read out of rx fifo */
 165 static inline u32 rx_max(struct dw_spi *dws)
 166 {
 167         u32 rx_left = (dws->rx_end - dws->rx) / dws->n_bytes;
 168
 169         return min_t(u32, rx_left, dw_readl(dws, DW_SPI_RXFLR));
 170 }
 171
 172 static void dw_writer(struct dw_spi *dws)
 173 {
 174         u32 max = tx_max(dws);
 175         u16 txw = 0;
 176
 177         while (max--) {
 178                 /* Set the tx word if the transfer's original "tx" is not null */
 179                 if (dws->tx_end - dws->len) {
 180                         if (dws->n_bytes == 1)
 181                                 txw = *(u8 *)(dws->tx);
 182                         else
 183                                 txw = *(u16 *)(dws->tx);
 184                 }
 185                 dw_write_io_reg(dws, DW_SPI_DR, txw);
 186                 dws->tx += dws->n_bytes;
 187         }
 188 }
 189
 190 static void dw_reader(struct dw_spi *dws)
 191 {
 192         u32 max = rx_max(dws);
 193         u16 rxw;
 194
 195         while (max--) {
 196                 rxw = dw_read_io_reg(dws, DW_SPI_DR);
 197                 /* Care rx only if the transfer's original "rx" is not null */
 198                 if (dws->rx_end - dws->len) {
 199                         if (dws->n_bytes == 1)
 200                                 *(u8 *)(dws->rx) = rxw;
 201                         else
 202                                 *(u16 *)(dws->rx) = rxw;
 203                 }
 204                 dws->rx += dws->n_bytes;
 205         }
 206 }
 207
 208 static void int_error_stop(struct dw_spi *dws, const char *msg)
 209 {
 210         spi_reset_chip(dws);
 211
 212         dev_err(&dws->master->dev, "%s\n", msg);
 213         dws->master->cur_msg->status = -EIO;
 214         spi_finalize_current_transfer(dws->master);
 215 }
 216
 217 static irqreturn_t interrupt_transfer(struct dw_spi *dws)
 218 {
 219         u16 irq_status = dw_readl(dws, DW_SPI_ISR);
 220
 221         /* Error handling */
 222         if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
 223                 dw_readl(dws, DW_SPI_ICR);
 224                 int_error_stop(dws, "interrupt_transfer: fifo overrun/underrun");
 225                 return IRQ_HANDLED;
 226         }
 227
 228         dw_reader(dws);
 229         if (dws->rx_end == dws->rx) {
 230                 spi_mask_intr(dws, SPI_INT_TXEI);
 231                 spi_finalize_current_transfer(dws->master);
 232                 return IRQ_HANDLED;
 233         }
 234         if (irq_status & SPI_INT_TXEI) {
 235                 spi_mask_intr(dws, SPI_INT_TXEI);
 236                 dw_writer(dws);
 237                 /* Enable TX irq always, it will be disabled when RX finished */
 238                 spi_umask_intr(dws, SPI_INT_TXEI);
 239         }
 240
 241         return IRQ_HANDLED;
 242 }
 243
 244 static irqreturn_t dw_spi_irq(int irq, void *dev_id)
 245 {
 246         struct spi_controller *master = dev_id;
 247         struct dw_spi *dws = spi_controller_get_devdata(master);
 248         u16 irq_status = dw_readl(dws, DW_SPI_ISR) & 0x3f;
 249
 250         if (!irq_status)
 251                 return IRQ_NONE;
 252
 253         if (!master->cur_msg) {
 254                 spi_mask_intr(dws, SPI_INT_TXEI);
 255                 return IRQ_HANDLED;
 256         }
 257
 258         return dws->transfer_handler(dws);
 259 }
 260
 261 /* Must be called inside pump_transfers() */
 262 static int poll_transfer(struct dw_spi *dws)
 263 {
 264         do {
 265                 dw_writer(dws);
 266                 dw_reader(dws);
 267                 cpu_relax();
 268         } while (dws->rx_end > dws->rx);
 269
 270         return 0;
 271 }
 272
 273 static int dw_spi_transfer_one(struct spi_controller *master,
 274                 struct spi_device *spi, struct spi_transfer *transfer)
 275 {
 276         struct dw_spi *dws = spi_controller_get_devdata(master);
 277         struct chip_data *chip = spi_get_ctldata(spi);
 278         u8 imask = 0;
 279         u16 txlevel = 0;
 280         u32 cr0;
 281         int ret;
 282
 283         dws->dma_mapped = 0;
 284
 285         dws->tx = (void *)transfer->tx_buf;
 286         dws->tx_end = dws->tx + transfer->len;
 287         dws->rx = transfer->rx_buf;
 288         dws->rx_end = dws->rx + transfer->len;
 289         dws->len = transfer->len;
 290
 291         spi_enable_chip(dws, 0);
 292
 293         /* Handle per transfer options for bpw and speed */
 294         if (transfer->speed_hz != dws->current_freq) {
 295                 if (transfer->speed_hz != chip->speed_hz) {
 296                         /* clk_div doesn't support odd number */
 297                         chip->clk_div = (DIV_ROUND_UP(dws->max_freq, transfer->speed_hz) + 1) & 0xfffe;
 298                         chip->speed_hz = transfer->speed_hz;
 299                 }
 300                 dws->current_freq = transfer->speed_hz;
 301                 spi_set_clk(dws, chip->clk_div);
 302         }
 303
 304         dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
 305         dws->dma_width = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
 306
 307         /* Default SPI mode is SCPOL = 0, SCPH = 0 */
 308         cr0 = (transfer->bits_per_word - 1)
 309                 | (chip->type << SPI_FRF_OFFSET)
 310                 | ((((spi->mode & SPI_CPOL) ? 1 : 0) << SPI_SCOL_OFFSET) |
 311                         (((spi->mode & SPI_CPHA) ? 1 : 0) << SPI_SCPH_OFFSET))
 312                 | (chip->tmode << SPI_TMOD_OFFSET);
 313
 314         /*
 315          * Adjust transfer mode if necessary. Requires platform dependent
 316          * chipselect mechanism.
 317          */
 318         if (chip->cs_control) {
 319                 if (dws->rx && dws->tx)
 320                         chip->tmode = SPI_TMOD_TR;
 321                 else if (dws->rx)
 322                         chip->tmode = SPI_TMOD_RO;
 323                 else
 324                         chip->tmode = SPI_TMOD_TO;
 325
 326                 cr0 &= ~SPI_TMOD_MASK;
 327                 cr0 |= (chip->tmode << SPI_TMOD_OFFSET);
 328         }
 329
 330         dw_writel(dws, DW_SPI_CTRL0, cr0);
 331
 332         /* Check if current transfer is a DMA transaction */
 333         if (master->can_dma && master->can_dma(master, spi, transfer))
 334                 dws->dma_mapped = master->cur_msg_mapped;
 335
 336         /* For poll mode just disable all interrupts */
 337         spi_mask_intr(dws, 0xff);
 338
 339         /*
 340          * Interrupt mode
 341          * we only need set the TXEI IRQ, as TX/RX always happen syncronizely
 342          */
 343         if (dws->dma_mapped) {
 344                 ret = dws->dma_ops->dma_setup(dws, transfer);
 345                 if (ret < 0) {
 346                         spi_enable_chip(dws, 1);
 347                         return ret;
 348                 }
 349         } else if (!chip->poll_mode) {
 350                 txlevel = min_t(u16, dws->fifo_len / 2, dws->len / dws->n_bytes);
 351                 dw_writel(dws, DW_SPI_TXFLTR, txlevel);
 352
 353                 /* Set the interrupt mask */
 354                 imask |= SPI_INT_TXEI | SPI_INT_TXOI |
 355                          SPI_INT_RXUI | SPI_INT_RXOI;
 356                 spi_umask_intr(dws, imask);
 357
 358                 dws->transfer_handler = interrupt_transfer;
 359         }
 360
 361         spi_enable_chip(dws, 1);
 362
 363         if (dws->dma_mapped) {
 364                 ret = dws->dma_ops->dma_transfer(dws, transfer);
 365                 if (ret < 0)
 366                         return ret;
 367         }
 368
 369         if (chip->poll_mode)
 370                 return poll_transfer(dws);
 371
 372         return 1;
 373 }
 374
 375 static void dw_spi_handle_err(struct spi_controller *master,
 376                 struct spi_message *msg)
 377 {
 378         struct dw_spi *dws = spi_controller_get_devdata(master);
 379
 380         if (dws->dma_mapped)
 381                 dws->dma_ops->dma_stop(dws);
 382
 383         spi_reset_chip(dws);
 384 }
 385
 386 /* This may be called twice for each spi dev */
 387 static int dw_spi_setup(struct spi_device *spi)
 388 {
 389         struct dw_spi_chip *chip_info = NULL;
 390         struct chip_data *chip;
 391
 392         /* Only alloc on first setup */
 393         chip = spi_get_ctldata(spi);
 394         if (!chip) {
 395                 chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
 396                 if (!chip)
 397                         return -ENOMEM;
 398                 spi_set_ctldata(spi, chip);
 399         }
 400
 401         /*
 402          * Protocol drivers may change the chip settings, so...
 403          * if chip_info exists, use it
 404          */
 405         chip_info = spi->controller_data;
 406
 407         /* chip_info doesn't always exist */
 408         if (chip_info) {
 409                 if (chip_info->cs_control)
 410                         chip->cs_control = chip_info->cs_control;
 411
 412                 chip->poll_mode = chip_info->poll_mode;
 413                 chip->type = chip_info->type;
 414         }
 415
 416         chip->tmode = SPI_TMOD_TR;
 417
 418         return 0;
 419 }
 420
 421 static void dw_spi_cleanup(struct spi_device *spi)
 422 {
 423         struct chip_data *chip = spi_get_ctldata(spi);
 424
 425         kfree(chip);
 426         spi_set_ctldata(spi, NULL);
 427 }
 428
 429 /* Restart the controller, disable all interrupts, clean rx fifo */
 430 static void spi_hw_init(struct device *dev, struct dw_spi *dws)
 431 {
 432         spi_reset_chip(dws);
 433
 434         /*
 435          * Try to detect the FIFO depth if not set by interface driver,
 436          * the depth could be from 2 to 256 from HW spec
 437          */
 438         if (!dws->fifo_len) {
 439                 u32 fifo;
 440
 441                 for (fifo = 1; fifo < 256; fifo++) {
 442                         dw_writel(dws, DW_SPI_TXFLTR, fifo);
 443                         if (fifo != dw_readl(dws, DW_SPI_TXFLTR))
 444                                 break;
 445                 }
 446                 dw_writel(dws, DW_SPI_TXFLTR, 0);
 447
 448                 dws->fifo_len = (fifo == 1) ? 0 : fifo;
 449                 dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len);
 450         }
 451
 452         /* enable HW fixup for explicit CS deselect for Amazon's alpine chip */
 453         if (dws->cs_override)
 454                 dw_writel(dws, DW_SPI_CS_OVERRIDE, 0xF);
 455 }
 456
 457 int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
 458 {
 459         struct spi_controller *master;
 460         int ret;
 461
 462         BUG_ON(dws == NULL);
 463
 464         master = spi_alloc_master(dev, 0);
 465         if (!master)
 466                 return -ENOMEM;
 467
 468         dws->master = master;
 469         dws->type = SSI_MOTO_SPI;
 470         dws->dma_inited = 0;
 471         dws->dma_addr = (dma_addr_t)(dws->paddr + DW_SPI_DR);
 472
 473         spi_controller_set_devdata(master, dws);
 474
 475         ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev),
 476                           master);
 477         if (ret < 0) {
 478                 dev_err(dev, "can not get IRQ\n");
 479                 goto err_free_master;
 480         }
 481
 482         master->use_gpio_descriptors = true;
 483         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP;
 484         master->bits_per_word_mask =  SPI_BPW_RANGE_MASK(4, 16);
 485         master->bus_num = dws->bus_num;
 486         master->num_chipselect = dws->num_cs;
 487         master->setup = dw_spi_setup;
 488         master->cleanup = dw_spi_cleanup;
 489         master->set_cs = dw_spi_set_cs;
 490         master->transfer_one = dw_spi_transfer_one;
 491         master->handle_err = dw_spi_handle_err;
 492         master->max_speed_hz = dws->max_freq;
 493         master->dev.of_node = dev->of_node;
 494         master->dev.fwnode = dev->fwnode;
 495         master->flags = SPI_MASTER_GPIO_SS;
 496
 497         if (dws->set_cs)
 498                 master->set_cs = dws->set_cs;
 499
 500         /* Basic HW init */
 501         spi_hw_init(dev, dws);
 502
 503         if (dws->dma_ops && dws->dma_ops->dma_init) {
 504                 ret = dws->dma_ops->dma_init(dws);
 505                 if (ret) {
 506                         dev_warn(dev, "DMA init failed\n");
 507                         dws->dma_inited = 0;
 508                 } else {
 509                         master->can_dma = dws->dma_ops->can_dma;
 510                 }
 511         }
 512
 513         ret = devm_spi_register_controller(dev, master);
 514         if (ret) {
 515                 dev_err(&master->dev, "problem registering spi master\n");
 516                 goto err_dma_exit;
 517         }
 518
 519         dw_spi_debugfs_init(dws);
 520         return 0;
 521
 522 err_dma_exit:
 523         if (dws->dma_ops && dws->dma_ops->dma_exit)
 524                 dws->dma_ops->dma_exit(dws);
 525         spi_enable_chip(dws, 0);
 526         free_irq(dws->irq, master);
 527 err_free_master:
 528         spi_controller_put(master);
 529         return ret;
 530 }
 531 EXPORT_SYMBOL_GPL(dw_spi_add_host);
 532
 533 void dw_spi_remove_host(struct dw_spi *dws)
 534 {
 535         dw_spi_debugfs_remove(dws);
 536
 537         if (dws->dma_ops && dws->dma_ops->dma_exit)
 538                 dws->dma_ops->dma_exit(dws);
 539
 540         spi_shutdown_chip(dws);
 541
 542         free_irq(dws->irq, dws->master);
 543 }
 544 EXPORT_SYMBOL_GPL(dw_spi_remove_host);
 545
 546 int dw_spi_suspend_host(struct dw_spi *dws)
 547 {
 548         int ret;
 549
 550         ret = spi_controller_suspend(dws->master);
 551         if (ret)
 552                 return ret;
 553
 554         spi_shutdown_chip(dws);
 555         return 0;
 556 }
 557 EXPORT_SYMBOL_GPL(dw_spi_suspend_host);
 558
 559 int dw_spi_resume_host(struct dw_spi *dws)
 560 {
 561         spi_hw_init(&dws->master->dev, dws);
 562         return spi_controller_resume(dws->master);
 563 }
 564 EXPORT_SYMBOL_GPL(dw_spi_resume_host);
 565
 566 MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
 567 MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
 568 MODULE_LICENSE("GPL v2");