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
   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
  57 struct flash_info {
  58         const char              *name;
  59         uint16_t                device_id;
  60         unsigned                page_size;
  61         unsigned                nr_pages;
  62         unsigned                erase_size;
  63 };
  64
  65 #define to_sst25l_flash(x) container_of(x, struct sst25l_flash, mtd)
  66
  67 static struct flash_info sst25l_flash_info[] = {
  68         {"sst25lf020a", 0xbf43, 256, 1024, 4096},
  69         {"sst25lf040a", 0xbf44, 256, 2048, 4096},
  70 };
  71
  72 static int sst25l_status(struct sst25l_flash *flash, int *status)
  73 {
  74         struct spi_message m;
  75         struct spi_transfer t;
  76         unsigned char cmd_resp[2];
  77         int err;
  78
  79         spi_message_init(&m);
  80         memset(&t, 0, sizeof(struct spi_transfer));
  81
  82         cmd_resp[0] = SST25L_CMD_RDSR;
  83         cmd_resp[1] = 0xff;
  84         t.tx_buf = cmd_resp;
  85         t.rx_buf = cmd_resp;
  86         t.len = sizeof(cmd_resp);
  87         spi_message_add_tail(&t, &m);
  88         err = spi_sync(flash->spi, &m);
  89         if (err < 0)
  90                 return err;
  91
  92         *status = cmd_resp[1];
  93         return 0;
  94 }
  95
  96 static int sst25l_write_enable(struct sst25l_flash *flash, int enable)
  97 {
  98         unsigned char command[2];
  99         int status, err;
 100
 101         command[0] = enable ? SST25L_CMD_WREN : SST25L_CMD_WRDI;
 102         err = spi_write(flash->spi, command, 1);
 103         if (err)
 104                 return err;
 105
 106         command[0] = SST25L_CMD_EWSR;
 107         err = spi_write(flash->spi, command, 1);
 108         if (err)
 109                 return err;
 110
 111         command[0] = SST25L_CMD_WRSR;
 112         command[1] = enable ? 0 : SST25L_STATUS_BP0 | SST25L_STATUS_BP1;
 113         err = spi_write(flash->spi, command, 2);
 114         if (err)
 115                 return err;
 116
 117         if (enable) {
 118                 err = sst25l_status(flash, &status);
 119                 if (err)
 120                         return err;
 121                 if (!(status & SST25L_STATUS_WREN))
 122                         return -EROFS;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static int sst25l_wait_till_ready(struct sst25l_flash *flash)
 129 {
 130         unsigned long deadline;
 131         int status, err;
 132
 133         deadline = jiffies + MAX_READY_WAIT_JIFFIES;
 134         do {
 135                 err = sst25l_status(flash, &status);
 136                 if (err)
 137                         return err;
 138                 if (!(status & SST25L_STATUS_BUSY))
 139                         return 0;
 140
 141                 cond_resched();
 142         } while (!time_after_eq(jiffies, deadline));
 143
 144         return -ETIMEDOUT;
 145 }
 146
 147 static int sst25l_erase_sector(struct sst25l_flash *flash, uint32_t offset)
 148 {
 149         unsigned char command[4];
 150         int err;
 151
 152         err = sst25l_write_enable(flash, 1);
 153         if (err)
 154                 return err;
 155
 156         command[0] = SST25L_CMD_SECTOR_ERASE;
 157         command[1] = offset >> 16;
 158         command[2] = offset >> 8;
 159         command[3] = offset;
 160         err = spi_write(flash->spi, command, 4);
 161         if (err)
 162                 return err;
 163
 164         err = sst25l_wait_till_ready(flash);
 165         if (err)
 166                 return err;
 167
 168         return sst25l_write_enable(flash, 0);
 169 }
 170
 171 static int sst25l_erase(struct mtd_info *mtd, struct erase_info *instr)
 172 {
 173         struct sst25l_flash *flash = to_sst25l_flash(mtd);
 174         uint32_t addr, end;
 175         int err;
 176
 177         /* Sanity checks */
 178         if ((uint32_t)instr->len % mtd->erasesize)
 179                 return -EINVAL;
 180
 181         if ((uint32_t)instr->addr % mtd->erasesize)
 182                 return -EINVAL;
 183
 184         addr = instr->addr;
 185         end = addr + instr->len;
 186
 187         mutex_lock(&flash->lock);
 188
 189         err = sst25l_wait_till_ready(flash);
 190         if (err) {
 191                 mutex_unlock(&flash->lock);
 192                 return err;
 193         }
 194
 195         while (addr < end) {
 196                 err = sst25l_erase_sector(flash, addr);
 197                 if (err) {
 198                         mutex_unlock(&flash->lock);
 199                         instr->state = MTD_ERASE_FAILED;
 200                         dev_err(&flash->spi->dev, "Erase failed\n");
 201                         return err;
 202                 }
 203
 204                 addr += mtd->erasesize;
 205         }
 206
 207         mutex_unlock(&flash->lock);
 208
 209         instr->state = MTD_ERASE_DONE;
 210         mtd_erase_callback(instr);
 211         return 0;
 212 }
 213
 214 static int sst25l_read(struct mtd_info *mtd, loff_t from, size_t len,
 215                        size_t *retlen, unsigned char *buf)
 216 {
 217         struct sst25l_flash *flash = to_sst25l_flash(mtd);
 218         struct spi_transfer transfer[2];
 219         struct spi_message message;
 220         unsigned char command[4];
 221         int ret;
 222
 223         spi_message_init(&message);
 224         memset(&transfer, 0, sizeof(transfer));
 225
 226         command[0] = SST25L_CMD_READ;
 227         command[1] = from >> 16;
 228         command[2] = from >> 8;
 229         command[3] = from;
 230
 231         transfer[0].tx_buf = command;
 232         transfer[0].len = sizeof(command);
 233         spi_message_add_tail(&transfer[0], &message);
 234
 235         transfer[1].rx_buf = buf;
 236         transfer[1].len = len;
 237         spi_message_add_tail(&transfer[1], &message);
 238
 239         mutex_lock(&flash->lock);
 240
 241         /* Wait for previous write/erase to complete */
 242         ret = sst25l_wait_till_ready(flash);
 243         if (ret) {
 244                 mutex_unlock(&flash->lock);
 245                 return ret;
 246         }
 247
 248         spi_sync(flash->spi, &message);
 249
 250         if (retlen && message.actual_length > sizeof(command))
 251                 *retlen += message.actual_length - sizeof(command);
 252
 253         mutex_unlock(&flash->lock);
 254         return 0;
 255 }
 256
 257 static int sst25l_write(struct mtd_info *mtd, loff_t to, size_t len,
 258                         size_t *retlen, const unsigned char *buf)
 259 {
 260         struct sst25l_flash *flash = to_sst25l_flash(mtd);
 261         int i, j, ret, bytes, copied = 0;
 262         unsigned char command[5];
 263
 264         if ((uint32_t)to % mtd->writesize)
 265                 return -EINVAL;
 266
 267         mutex_lock(&flash->lock);
 268
 269         ret = sst25l_write_enable(flash, 1);
 270         if (ret)
 271                 goto out;
 272
 273         for (i = 0; i < len; i += mtd->writesize) {
 274                 ret = sst25l_wait_till_ready(flash);
 275                 if (ret)
 276                         goto out;
 277
 278                 /* Write the first byte of the page */
 279                 command[0] = SST25L_CMD_AAI_PROGRAM;
 280                 command[1] = (to + i) >> 16;
 281                 command[2] = (to + i) >> 8;
 282                 command[3] = (to + i);
 283                 command[4] = buf[i];
 284                 ret = spi_write(flash->spi, command, 5);
 285                 if (ret < 0)
 286                         goto out;
 287                 copied++;
 288
 289                 /*
 290                  * Write the remaining bytes using auto address
 291                  * increment mode
 292                  */
 293                 bytes = min_t(uint32_t, mtd->writesize, len - i);
 294                 for (j = 1; j < bytes; j++, copied++) {
 295                         ret = sst25l_wait_till_ready(flash);
 296                         if (ret)
 297                                 goto out;
 298
 299                         command[1] = buf[i + j];
 300                         ret = spi_write(flash->spi, command, 2);
 301                         if (ret)
 302                                 goto out;
 303                 }
 304         }
 305
 306 out:
 307         ret = sst25l_write_enable(flash, 0);
 308
 309         if (retlen)
 310                 *retlen = copied;
 311
 312         mutex_unlock(&flash->lock);
 313         return ret;
 314 }
 315
 316 static struct flash_info *sst25l_match_device(struct spi_device *spi)
 317 {
 318         struct flash_info *flash_info = NULL;
 319         struct spi_message m;
 320         struct spi_transfer t;
 321         unsigned char cmd_resp[6];
 322         int i, err;
 323         uint16_t id;
 324
 325         spi_message_init(&m);
 326         memset(&t, 0, sizeof(struct spi_transfer));
 327
 328         cmd_resp[0] = SST25L_CMD_READ_ID;
 329         cmd_resp[1] = 0;
 330         cmd_resp[2] = 0;
 331         cmd_resp[3] = 0;
 332         cmd_resp[4] = 0xff;
 333         cmd_resp[5] = 0xff;
 334         t.tx_buf = cmd_resp;
 335         t.rx_buf = cmd_resp;
 336         t.len = sizeof(cmd_resp);
 337         spi_message_add_tail(&t, &m);
 338         err = spi_sync(spi, &m);
 339         if (err < 0) {
 340                 dev_err(&spi->dev, "error reading device id\n");
 341                 return NULL;
 342         }
 343
 344         id = (cmd_resp[4] << 8) | cmd_resp[5];
 345
 346         for (i = 0; i < ARRAY_SIZE(sst25l_flash_info); i++)
 347                 if (sst25l_flash_info[i].device_id == id)
 348                         flash_info = &sst25l_flash_info[i];
 349
 350         if (!flash_info)
 351                 dev_err(&spi->dev, "unknown id %.4x\n", id);
 352
 353         return flash_info;
 354 }
 355
 356 static int sst25l_probe(struct spi_device *spi)
 357 {
 358         struct flash_info *flash_info;
 359         struct sst25l_flash *flash;
 360         struct flash_platform_data *data;
 361         int ret;
 362
 363         flash_info = sst25l_match_device(spi);
 364         if (!flash_info)
 365                 return -ENODEV;
 366
 367         flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
 368         if (!flash)
 369                 return -ENOMEM;
 370
 371         flash->spi = spi;
 372         mutex_init(&flash->lock);
 373         spi_set_drvdata(spi, flash);
 374
 375         data = dev_get_platdata(&spi->dev);
 376         if (data && data->name)
 377                 flash->mtd.name = data->name;
 378         else
 379                 flash->mtd.name = dev_name(&spi->dev);
 380
 381         flash->mtd.type         = MTD_NORFLASH;
 382         flash->mtd.flags        = MTD_CAP_NORFLASH;
 383         flash->mtd.erasesize    = flash_info->erase_size;
 384         flash->mtd.writesize    = flash_info->page_size;
 385         flash->mtd.writebufsize = flash_info->page_size;
 386         flash->mtd.size         = flash_info->page_size * flash_info->nr_pages;
 387         flash->mtd._erase       = sst25l_erase;
 388         flash->mtd._read                = sst25l_read;
 389         flash->mtd._write       = sst25l_write;
 390
 391         dev_info(&spi->dev, "%s (%lld KiB)\n", flash_info->name,
 392                  (long long)flash->mtd.size >> 10);
 393
 394         pr_debug("mtd .name = %s, .size = 0x%llx (%lldMiB) "
 395               ".erasesize = 0x%.8x (%uKiB) .numeraseregions = %d\n",
 396               flash->mtd.name,
 397               (long long)flash->mtd.size, (long long)(flash->mtd.size >> 20),
 398               flash->mtd.erasesize, flash->mtd.erasesize / 1024,
 399               flash->mtd.numeraseregions);
 400
 401
 402         ret = mtd_device_parse_register(&flash->mtd, NULL, NULL,
 403                                         data ? data->parts : NULL,
 404                                         data ? data->nr_parts : 0);
 405         if (ret)
 406                 return -ENODEV;
 407
 408         return 0;
 409 }
 410
 411 static int sst25l_remove(struct spi_device *spi)
 412 {
 413         struct sst25l_flash *flash = spi_get_drvdata(spi);
 414
 415         return mtd_device_unregister(&flash->mtd);
 416 }
 417
 418 static struct spi_driver sst25l_driver = {
 419         .driver = {
 420                 .name   = "sst25l",
 421                 .owner  = THIS_MODULE,
 422         },
 423         .probe          = sst25l_probe,
 424         .remove         = sst25l_remove,
 425 };
 426
 427 module_spi_driver(sst25l_driver);
 428
 429 MODULE_DESCRIPTION("MTD SPI driver for SST25L Flash chips");
 430 MODULE_AUTHOR("Andre Renaud <andre@bluewatersys.com>, "
 431               "Ryan Mallon");
 432 MODULE_LICENSE("GPL");