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