drivers/mtd/devices/sst25l.c

   1 /*
   2  * sst25l.c
   3  *
   4  * Driver for SST25L SPI Flash chips
   5  *
   6  * Copyright © 2009 Bluewater Systems Ltd
   7  * Author: Andre Renaud <andre@bluewatersys.com>
   8  * Author: Ryan Mallon <ryan@bluewatersys.com>
   9  *
  10  * Based on m25p80.c
  11  *
  12  * This code is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  *
  16  */
  17
  18 #include <linux/init.h>
  19 #include <linux/module.h>
  20 #include <linux/device.h>
  21 #include <linux/mutex.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/slab.h>
  24 #include <linux/sched.h>
  25
  26 #include <linux/mtd/mtd.h>
  27 #include <linux/mtd/partitions.h>
  28
  29 #include <linux/spi/spi.h>
  30 #include <linux/spi/flash.h>
  31
  32 /* Erases can take up to 3 seconds! */
  33 #define MAX_READY_WAIT_JIFFIES  msecs_to_jiffies(3000)
  34
  35 #define SST25L_CMD_WRSR         0x01    /* Write status register */
  36 #define SST25L_CMD_WRDI         0x04    /* Write disable */
  37 #define SST25L_CMD_RDSR         0x05    /* Read status register */
  38 #define SST25L_CMD_WREN         0x06    /* Write enable */
  39 #define SST25L_CMD_READ         0x03    /* High speed read */
  40
  41 #define SST25L_CMD_EWSR         0x50    /* Enable write status register */
  42 #define SST25L_CMD_SECTOR_ERASE 0x20    /* Erase sector */
  43 #define SST25L_CMD_READ_ID      0x90    /* Read device ID */
  44 #define SST25L_CMD_AAI_PROGRAM  0xaf    /* Auto address increment */
  45
  46 #define SST25L_STATUS_BUSY      (1 << 0)        /* Chip is busy */
  47 #define SST25L_STATUS_WREN      (1 << 1)        /* Write enabled */
  48 #define SST25L_STATUS_BP0       (1 << 2)        /* Block protection 0 */
  49 #define SST25L_STATUS_BP1       (1 << 3)        /* Block protection 1 */
  50
  51 struct sst25l_flash {
  52         struct spi_device       *spi;
  53         struct mutex            lock;
  54         struct mtd_info         mtd;
  55
  56         int                     partitioned;
  57 };
  58
  59 struct flash_info {
  60         const char              *name;
  61         uint16_t                device_id;
  62         unsigned                page_size;
  63         unsigned                nr_pages;
  64         unsigned                erase_size;
  65 };
  66
  67 #define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)
  68
  69 static struct flash_info __initdata sst25l_flash_info[] = {
  70         {"sst25lf020a", 0xbf43, 256, 1024, 4096},
  71         {"sst25lf040a", 0xbf44, 256, 2048, 4096},
  72 };
  73
  74 static int sst25l_status(struct sst25l_flash *flash, int *status)
  75 {
  76         struct spi_message m;
  77         struct spi_transfer t;
  78         unsigned char cmd_resp[2];
  79         int err;
  80
  81         spi_message_init(&m);
  82         memset(&t, 0, sizeof(struct spi_transfer));
  83
  84         cmd_resp[0] = SST25L_CMD_RDSR;
  85         cmd_resp[1] = 0xff;
  86         t.tx_buf = cmd_resp;
  87         t.rx_buf = cmd_resp;
  88         t.len = sizeof(cmd_resp);
  89         spi_message_add_tail(&t, &m);
  90         err = spi_sync(flash->spi, &m);
  91         if (err < 0)
  92                 return err;
  93
  94         *status = cmd_resp[1];
  95         return 0;
  96 }
  97
  98 static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
  99 {
 100         unsigned char command[2];
 101         int status, err;
 102
 103         command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
 104         err = spi_write(flash->spi, command, 1);
 105         if (err)
 106                 return err;
 107
 108         command[0] = SST25L_CMD_EWSR;
 109         err = spi_write(flash->spi, command, 1);
 110         if (err)
 111                 return err;
 112
 113         command[0] = SST25L_CMD_WRSR;
 114         command[1] = enable ? 0 : SST25L_STATUS_BP0 | SST25L_STATUS_BP1;
 115         err = spi_write(flash->spi, command, 2);
 116         if (err)
 117                 return err;
 118
 119         if (enable) {
 120                 err = sst25l_status(flash, &status);
 121                 if (err)
 122                         return err;
 123                 if (!(status & SST25L_STATUS_WREN))
 124                         return -EROFS;
 125         }
 126
 127         return 0;
 128 }
 129
 130 static int sst25l_wait_till_ready(struct sst25l_flash *flash)
 131 {
 132         unsigned long deadline;
 133         int status, err;
 134
 135         deadline = jiffies + MAX_READY_WAIT_JIFFIES;
 136         do {
 137                 err = sst25l_status(flash, &status);
 138                 if (err)
 139                         return err;
 140                 if (!(status & SST25L_STATUS_BUSY))
 141                         return 0;
 142
 143                 cond_resched();
 144         } while (!time_after_eq(jiffies, deadline));
 145
 146         return -ETIMEDOUT;
 147 }
 148
 149 static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
 150 {
 151         unsigned char command[4];
 152         int err;
 153
 154         err = sst25l_write_enable(flash, 1);
 155         if (err)
 156                 return err;
 157
 158         command[0] = SST25L_CMD_SECTOR_ERASE;
 159         command[1] = offset >> 16;
 160         command[2] = offset >> 8;
 161         command[3] = offset;
 162         err = spi_write(flash->spi, command, 4);
 163         if (err)
 164                 return err;
 165
 166         err = sst25l_wait_till_ready(flash);
 167         if (err)
 168                 return err;
 169
 170         return sst25l_write_enable(flash, 0);
 171 }
 172
 173 static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
 174 {
 175         struct sst25l_flash *flash = to_sst25l_flash(mtd);
 176         uint32_t addr, end;
 177         int err;
 178
 179         /* Sanity checks */
 180         if (instr->addr + instr->len > flash->mtd.size)
 181                 return -EINVAL;
 182
 183         if ((uint32_t)instr->len % mtd->erasesize)
 184                 return -EINVAL;
 185
 186         if ((uint32_t)instr->addr % mtd->erasesize)
 187                 return -EINVAL;
 188
 189         addr = instr->addr;
 190         end = addr + instr->len;
 191
 192         mutex_lock(&flash->lock);
 193
 194         err = sst25l_wait_till_ready(flash);
 195         if (err) {
 196                 mutex_unlock(&flash->lock);
 197                 return err;
 198         }
 199
 200         while (addr < end) {
 201                 err = sst25l_erase_sector(flash, addr);
 202                 if (err) {
 203                         mutex_unlock(&flash->lock);
 204                         instr->state = MTD_ERASE_FAILED;
 205                         dev_err(&flash->spi->dev, "Erase failed\n");
 206                         return err;
 207                 }
 208
 209                 addr += mtd->erasesize;
 210         }
 211
 212         mutex_unlock(&flash->lock);
 213
 214         instr->state = MTD_ERASE_DONE;
 215         mtd_erase_callback(instr);
 216         return 0;
 217 }
 218
 219 static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
 220                        size_t *retlen, unsigned char *buf)
 221 {
 222         struct sst25l_flash *flash = to_sst25l_flash(mtd);
 223         struct spi_transfer transfer[2];
 224         struct spi_message message;
 225         unsigned char command[4];
 226         int ret;
 227
 228         /* Sanity checking */
 229         if (len == 0)
 230                 return 0;
 231
 232         if (from + len > flash->mtd.size)
 233                 return -EINVAL;
 234
 235         if (retlen)
 236                 *retlen = 0;
 237
 238         spi_message_init(&message);
 239         memset(&transfer, 0, sizeof(transfer));
 240
 241         command[0] = SST25L_CMD_READ;
 242         command[1] = from >> 16;
 243         command[2] = from >> 8;
 244         command[3] = from;
 245
 246         transfer[0].tx_buf = command;
 247         transfer[0].len = sizeof(command);
 248         spi_message_add_tail(&transfer[0], &message);
 249
 250         transfer[1].rx_buf = buf;
 251         transfer[1].len = len;
 252         spi_message_add_tail(&transfer[1], &message);
 253
 254         mutex_lock(&flash->lock);
 255
 256         /* Wait for previous write/erase to complete */
 257         ret = sst25l_wait_till_ready(flash);
 258         if (ret) {
 259                 mutex_unlock(&flash->lock);
 260                 return ret;
 261         }
 262
 263         spi_sync(flash->spi, &message);
 264
 265         if (retlen && message.actual_length > sizeof(command))
 266                 *retlen += message.actual_length - sizeof(command);
 267
 268         mutex_unlock(&flash->lock);
 269         return 0;
 270 }
 271
 272 static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
 273                         size_t *retlen, const unsigned char *buf)
 274 {
 275         struct sst25l_flash *flash = to_sst25l_flash(mtd);
 276         int i, j, ret, bytes, copied = 0;
 277         unsigned char command[5];
 278
 279         /* Sanity checks */
 280         if (!len)
 281                 return 0;
 282
 283         if (to + len > flash->mtd.size)
 284                 return -EINVAL;
 285
 286         if ((uint32_t)to % mtd->writesize)
 287                 return -EINVAL;
 288
 289         mutex_lock(&flash->lock);
 290
 291         ret = sst25l_write_enable(flash, 1);
 292         if (ret)
 293                 goto out;
 294
 295         for (i = 0; i < len; i += mtd->writesize) {
 296                 ret = sst25l_wait_till_ready(flash);
 297                 if (ret)
 298                         goto out;
 299
 300                 /* Write the first byte of the page */
 301                 command[0] = SST25L_CMD_AAI_PROGRAM;
 302                 command[1] = (to + i) >> 16;
 303                 command[2] = (to + i) >> 8;
 304                 command[3] = (to + i);
 305                 command[4] = buf[i];
 306                 ret = spi_write(flash->spi, command, 5);
 307                 if (ret < 0)
 308                         goto out;
 309                 copied++;
 310
 311                 /*
 312                  * Write the remaining bytes using auto address
 313                  * increment mode
 314                  */
 315                 bytes = min_t(uint32_t, mtd->writesize, len - i);
 316                 for (j = 1; j < bytes; j++, copied++) {
 317                         ret = sst25l_wait_till_ready(flash);
 318                         if (ret)
 319                                 goto out;
 320
 321                         command[1] = buf[i + j];
 322                         ret = spi_write(flash->spi, command, 2);
 323                         if (ret)
 324                                 goto out;
 325                 }
 326         }
 327
 328 out:
 329         ret = sst25l_write_enable(flash, 0);
 330
 331         if (retlen)
 332                 *retlen = copied;
 333
 334         mutex_unlock(&flash->lock);
 335         return ret;
 336 }
 337
 338 static struct flash_info *__init sst25l_match_device(struct spi_device *spi)
 339 {
 340         struct flash_info *flash_info = NULL;
 341         struct spi_message m;
 342         struct spi_transfer t;
 343         unsigned char cmd_resp[6];
 344         int i, err;
 345         uint16_t id;
 346
 347         spi_message_init(&m);
 348         memset(&t, 0, sizeof(struct spi_transfer));
 349
 350         cmd_resp[0] = SST25L_CMD_READ_ID;
 351         cmd_resp[1] = 0;
 352         cmd_resp[2] = 0;
 353         cmd_resp[3] = 0;
 354         cmd_resp[4] = 0xff;
 355         cmd_resp[5] = 0xff;
 356         t.tx_buf = cmd_resp;
 357         t.rx_buf = cmd_resp;
 358         t.len = sizeof(cmd_resp);
 359         spi_message_add_tail(&t, &m);
 360         err = spi_sync(spi, &m);
 361         if (err < 0) {
 362                 dev_err(&spi->dev, "error reading device id\n");
 363                 return NULL;
 364         }
 365
 366         id = (cmd_resp[4] << 8) | cmd_resp[5];
 367
 368         for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
 369                 if (sst25l_flash_info[i].device_id == id)
 370                         flash_info = &sst25l_flash_info[i];
 371
 372         if (!flash_info)
 373                 dev_err(&spi->dev, "unknown id %.4x\n", id);
 374
 375         return flash_info;
 376 }
 377
 378 static int __init sst25l_probe(struct spi_device *spi)
 379 {
 380         struct flash_info *flash_info;
 381         struct sst25l_flash *flash;
 382         struct flash_platform_data *data;
 383         int ret, i;
 384
 385         flash_info = sst25l_match_device(spi);
 386         if (!flash_info)
 387                 return -ENODEV;
 388
 389         flash = kzalloc(sizeof(struct sst25l_flash), GFP_KERNEL);
 390         if (!flash)
 391                 return -ENOMEM;
 392
 393         flash->spi = spi;
 394         mutex_init(&flash->lock);
 395         dev_set_drvdata(&spi->dev, flash);
 396
 397         data = spi->dev.platform_data;
 398         if (data && data->name)
 399                 flash->mtd.name = data->name;
 400         else
 401                 flash->mtd.name = dev_name(&spi->dev);
 402
 403         flash->mtd.type         = MTD_NORFLASH;
 404         flash->mtd.flags        = MTD_CAP_NORFLASH;
 405         flash->mtd.erasesize    = flash_info->erase_size;
 406         flash->mtd.writesize    = flash_info->page_size;
 407         flash->mtd.size         = flash_info->page_size * flash_info->nr_pages;
 408         flash->mtd.erase        = sst25l_erase;
 409         flash->mtd.read         = sst25l_read;
 410         flash->mtd.write        = sst25l_write;
 411
 412         dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
 413                  (long long)flash->mtd.size >> 10);
 414
 415         DEBUG(MTD_DEBUG_LEVEL2,
 416               "mtd .name = %s, .size = 0x%llx (%lldMiB) "
 417               ".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
 418               flash->mtd.name,
 419               (long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
 420               flash->mtd.erasesize, flash->mtd.erasesize / 1024,
 421               flash->mtd.numeraseregions);
 422
 423         if (mtd_has_partitions()) {
 424                 struct mtd_partition *parts = NULL;
 425                 int nr_parts = 0;
 426
 427                 if (mtd_has_cmdlinepart()) {
 428                         static const char *part_probes[] =
 429                                 {"cmdlinepart", NULL};
 430
 431                         nr_parts = parse_mtd_partitions(&flash->mtd,
 432                                                         part_probes,
 433                                                         &parts, 0);
 434                 }
 435
 436                 if (nr_parts <= 0 && data && data->parts) {
 437                         parts = data->parts;
 438                         nr_parts = data->nr_parts;
 439                 }
 440
 441                 if (nr_parts > 0) {
 442                         for (i = 0; i < nr_parts; i++) {
 443                                 DEBUG(MTD_DEBUG_LEVEL2, "partitions[%d] = "
 444                                       "{.name = %s, .offset = 0x%llx, "
 445                                       ".size = 0x%llx (%lldKiB) }\n",
 446                                       i, parts[i].name,
 447                                       (long long)parts[i].offset,
 448                                       (long long)parts[i].size,
 449                                       (long long)(parts[i].size >> 10));
 450                         }
 451
 452                         flash->partitioned = 1;
 453                         return add_mtd_partitions(&flash->mtd,
 454                                                   parts, nr_parts);
 455                 }
 456
 457         } else if (data->nr_parts) {
 458                 dev_warn(&spi->dev, "ignoring %d default partitions on %s\n",
 459                          data->nr_parts, data->name);
 460         }
 461
 462         ret = add_mtd_device(&flash->mtd);
 463         if (ret == 1) {
 464                 kfree(flash);
 465                 dev_set_drvdata(&spi->dev, NULL);
 466                 return -ENODEV;
 467         }
 468
 469         return 0;
 470 }
 471
 472 static int __exit sst25l_remove(struct spi_device *spi)
 473 {
 474         struct sst25l_flash *flash = dev_get_drvdata(&spi->dev);
 475         int ret;
 476
 477         if (mtd_has_partitions() && flash->partitioned)
 478                 ret = del_mtd_partitions(&flash->mtd);
 479         else
 480                 ret = del_mtd_device(&flash->mtd);
 481         if (ret == 0)
 482                 kfree(flash);
 483         return ret;
 484 }
 485
 486 static struct spi_driver sst25l_driver = {
 487         .driver = {
 488                 .name   = "sst25l",
 489                 .bus    = &spi_bus_type,
 490                 .owner  = THIS_MODULE,
 491         },
 492         .probe          = sst25l_probe,
 493         .remove         = __exit_p(sst25l_remove),
 494 };
 495
 496 static int __init sst25l_init(void)
 497 {
 498         return spi_register_driver(&sst25l_driver);
 499 }
 500
 501 static void __exit sst25l_exit(void)
 502 {
 503         spi_unregister_driver(&sst25l_driver);
 504 }
 505
 506 module_init(sst25l_init);
 507 module_exit(sst25l_exit);
 508
 509 MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
 510 MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
 511               "Ryan Mallon <ryan@bluewatersys.com>");
 512 MODULE_LICENSE("GPL");