drivers/mtd/devices/at91_dataflash26.c

   1 /*
   2  * Atmel DataFlash driver for Atmel AT91RM9200 (Thunder)
   3  * This is a largely modified version of at91_dataflash.c that
   4  * supports AT26xxx dataflash chips. The original driver supports
   5  * AT45xxx chips.
   6  *
   7  * Note: This driver was only tested with an AT26F004. It should be
   8  * easy to make it work with other AT26xxx dataflash devices, though.
   9  *
  10  * Copyright (C) 2007 Hans J. Koch <hjk@linutronix.de>
  11  * original Copyright (C) SAN People (Pty) Ltd
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * version 2 as published by the Free Software Foundation.
  16 */
  17
  18 #include <linux/config.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/mtd/mtd.h>
  22
  23 #include <asm/arch/at91_spi.h>
  24
  25 #define DATAFLASH_MAX_DEVICES   4       /* max number of dataflash devices */
  26
  27 #define MANUFACTURER_ID_ATMEL           0x1F
  28
  29 /* command codes */
  30
  31 #define AT26_OP_READ_STATUS             0x05
  32 #define AT26_OP_READ_DEV_ID             0x9F
  33 #define AT26_OP_ERASE_PAGE_4K           0x20
  34 #define AT26_OP_READ_ARRAY_FAST         0x0B
  35 #define AT26_OP_SEQUENTIAL_WRITE        0xAF
  36 #define AT26_OP_WRITE_ENABLE            0x06
  37 #define AT26_OP_WRITE_DISABLE           0x04
  38 #define AT26_OP_SECTOR_PROTECT          0x36
  39 #define AT26_OP_SECTOR_UNPROTECT        0x39
  40
  41 /* status register bits */
  42
  43 #define AT26_STATUS_BUSY                0x01
  44 #define AT26_STATUS_WRITE_ENABLE        0x02
  45
  46 struct dataflash_local
  47 {
  48         int spi;                        /* SPI chip-select number */
  49         unsigned int page_size;         /* number of bytes per page */
  50 };
  51
  52
  53 /* Detected DataFlash devices */
  54 static struct mtd_info* mtd_devices[DATAFLASH_MAX_DEVICES];
  55 static int nr_devices = 0;
  56
  57 /* Allocate a single SPI transfer descriptor.  We're assuming that if multiple
  58    SPI transfers occur at the same time, spi_access_bus() will serialize them.
  59    If this is not valid, then either (i) each dataflash 'priv' structure
  60    needs it's own transfer descriptor, (ii) we lock this one, or (iii) use
  61    another mechanism.   */
  62 static struct spi_transfer_list* spi_transfer_desc;
  63
  64 /*
  65  * Perform a SPI transfer to access the DataFlash device.
  66  */
  67 static int do_spi_transfer(int nr, char* tx, int tx_len, char* rx, int rx_len,
  68                 char* txnext, int txnext_len, char* rxnext, int rxnext_len)
  69 {
  70         struct spi_transfer_list* list = spi_transfer_desc;
  71
  72         list->tx[0] = tx;       list->txlen[0] = tx_len;
  73         list->rx[0] = rx;       list->rxlen[0] = rx_len;
  74
  75         list->tx[1] = txnext;   list->txlen[1] = txnext_len;
  76         list->rx[1] = rxnext;   list->rxlen[1] = rxnext_len;
  77
  78         list->nr_transfers = nr;
  79         /* Note: spi_transfer() always returns 0, there are no error checks */
  80         return spi_transfer(list);
  81 }
  82
  83 /*
  84  * Return the status of the DataFlash device.
  85  */
  86 static unsigned char at91_dataflash26_status(void)
  87 {
  88         unsigned char command[2];
  89
  90         command[0] = AT26_OP_READ_STATUS;
  91         command[1] = 0;
  92
  93         do_spi_transfer(1, command, 2, command, 2, NULL, 0, NULL, 0);
  94
  95         return command[1];
  96 }
  97
  98 /*
  99  * Poll the DataFlash device until it is READY.
 100  */
 101 static unsigned char at91_dataflash26_waitready(void)
 102 {
 103         unsigned char status;
 104
 105         while (1) {
 106                 status = at91_dataflash26_status();
 107                 if (!(status & AT26_STATUS_BUSY))
 108                         return status;
 109         }
 110 }
 111
 112 /*
 113  * Enable/disable write access
 114  */
 115  static void at91_dataflash26_write_enable(int enable)
 116 {
 117         unsigned char cmd[2];
 118
 119         DEBUG(MTD_DEBUG_LEVEL3, "write_enable: enable=%i\n", enable);
 120
 121         if (enable)
 122                 cmd[0] = AT26_OP_WRITE_ENABLE;
 123         else
 124                 cmd[0] = AT26_OP_WRITE_DISABLE;
 125         cmd[1] = 0;
 126
 127         do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
 128 }
 129
 130 /*
 131  * Protect/unprotect sector
 132  */
 133  static void at91_dataflash26_sector_protect(loff_t addr, int protect)
 134 {
 135         unsigned char cmd[4];
 136
 137         DEBUG(MTD_DEBUG_LEVEL3, "sector_protect: addr=0x%06x prot=%d\n",
 138                addr, protect);
 139
 140         if (protect)
 141                 cmd[0] = AT26_OP_SECTOR_PROTECT;
 142         else
 143                 cmd[0] = AT26_OP_SECTOR_UNPROTECT;
 144         cmd[1] = (addr & 0x00FF0000) >> 16;
 145         cmd[2] = (addr & 0x0000FF00) >> 8;
 146         cmd[3] = (addr & 0x000000FF);
 147
 148         do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
 149 }
 150
 151 /*
 152  * Erase blocks of flash.
 153  */
 154 static int at91_dataflash26_erase(struct mtd_info *mtd,
 155                                   struct erase_info *instr)
 156 {
 157         struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
 158         unsigned char cmd[4];
 159
 160         DEBUG(MTD_DEBUG_LEVEL1, "dataflash_erase: addr=0x%06x len=%i\n",
 161                instr->addr, instr->len);
 162
 163         /* Sanity checks */
 164         if (priv->page_size != 4096)
 165                 return -EINVAL; /* Can't handle other sizes at the moment */
 166
 167         if (   ((instr->len % mtd->erasesize) != 0)
 168             || ((instr->len % priv->page_size) != 0)
 169             || ((instr->addr % priv->page_size) != 0)
 170             || ((instr->addr + instr->len) > mtd->size))
 171                 return -EINVAL;
 172
 173         spi_access_bus(priv->spi);
 174
 175         while (instr->len > 0) {
 176                 at91_dataflash26_write_enable(1);
 177                 at91_dataflash26_sector_protect(instr->addr, 0);
 178                 at91_dataflash26_write_enable(1);
 179                 cmd[0] = AT26_OP_ERASE_PAGE_4K;
 180                 cmd[1] = (instr->addr & 0x00FF0000) >> 16;
 181                 cmd[2] = (instr->addr & 0x0000FF00) >> 8;
 182                 cmd[3] = (instr->addr & 0x000000FF);
 183
 184                 DEBUG(MTD_DEBUG_LEVEL3, "ERASE: (0x%02x) 0x%02x 0x%02x"
 185                                         "0x%02x\n",
 186                         cmd[0], cmd[1], cmd[2], cmd[3]);
 187
 188                 do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
 189                 at91_dataflash26_waitready();
 190
 191                 instr->addr += priv->page_size;  /* next page */
 192                 instr->len -= priv->page_size;
 193         }
 194
 195         at91_dataflash26_write_enable(0);
 196         spi_release_bus(priv->spi);
 197
 198         /* Inform MTD subsystem that erase is complete */
 199         instr->state = MTD_ERASE_DONE;
 200         if (instr->callback)
 201                 instr->callback(instr);
 202
 203         return 0;
 204 }
 205
 206 /*
 207  * Read from the DataFlash device.
 208  *   from   : Start offset in flash device
 209  *   len    : Number of bytes to read
 210  *   retlen : Number of bytes actually read
 211  *   buf    : Buffer that will receive data
 212  */
 213 static int at91_dataflash26_read(struct mtd_info *mtd, loff_t from, size_t len,
 214                                  size_t *retlen, u_char *buf)
 215 {
 216         struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
 217         unsigned char cmd[5];
 218
 219         DEBUG(MTD_DEBUG_LEVEL1, "dataflash_read: %lli .. %lli\n",
 220               from, from+len);
 221
 222         *retlen = 0;
 223
 224         /* Sanity checks */
 225         if (!len)
 226                 return 0;
 227         if (from + len > mtd->size)
 228                 return -EINVAL;
 229
 230         cmd[0] = AT26_OP_READ_ARRAY_FAST;
 231         cmd[1] = (from & 0x00FF0000) >> 16;
 232         cmd[2] = (from & 0x0000FF00) >> 8;
 233         cmd[3] = (from & 0x000000FF);
 234         /* cmd[4] is a "Don't care" byte  */
 235
 236         DEBUG(MTD_DEBUG_LEVEL3, "READ: (0x%02x) 0x%02x 0x%02x 0x%02x\n",
 237                cmd[0], cmd[1], cmd[2], cmd[3]);
 238
 239         spi_access_bus(priv->spi);
 240         do_spi_transfer(2, cmd, 5, cmd, 5, buf, len, buf, len);
 241         spi_release_bus(priv->spi);
 242
 243         *retlen = len;
 244         return 0;
 245 }
 246
 247 /*
 248  * Write to the DataFlash device.
 249  *   to     : Start offset in flash device
 250  *   len    : Number of bytes to write
 251  *   retlen : Number of bytes actually written
 252  *   buf    : Buffer containing the data
 253  */
 254 static int at91_dataflash26_write(struct mtd_info *mtd, loff_t to, size_t len,
 255                                   size_t *retlen, const u_char *buf)
 256 {
 257         struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
 258         unsigned int addr, buf_index = 0;
 259         int ret = -EIO, sector, last_sector;
 260         unsigned char status, cmd[5];
 261
 262         DEBUG(MTD_DEBUG_LEVEL1, "dataflash_write: %lli .. %lli\n", to, to+len);
 263
 264         *retlen = 0;
 265
 266         /* Sanity checks */
 267         if (!len)
 268                 return 0;
 269         if (to + len > mtd->size)
 270                 return -EINVAL;
 271
 272         spi_access_bus(priv->spi);
 273
 274         addr = to;
 275         last_sector = -1;
 276
 277         while (buf_index < len) {
 278                 sector = addr / priv->page_size;
 279                 /* Write first byte if a new sector begins */
 280                 if (sector != last_sector) {
 281                         at91_dataflash26_write_enable(1);
 282                         at91_dataflash26_sector_protect(addr, 0);
 283                         at91_dataflash26_write_enable(1);
 284
 285                         /* Program first byte of a new sector */
 286                         cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
 287                         cmd[1] = (addr & 0x00FF0000) >> 16;
 288                         cmd[2] = (addr & 0x0000FF00) >> 8;
 289                         cmd[3] = (addr & 0x000000FF);
 290                         cmd[4] = buf[buf_index++];
 291                         do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
 292                         status = at91_dataflash26_waitready();
 293                         addr++;
 294                         /* On write errors, the chip resets the write enable
 295                            flag. This also happens after the last byte of a
 296                            sector is successfully programmed. */
 297                         if (   ( !(status & AT26_STATUS_WRITE_ENABLE))
 298                             && ((addr % priv->page_size) != 0) ) {
 299                                 DEBUG(MTD_DEBUG_LEVEL1,
 300                                         "write error1: addr=0x%06x, "
 301                                         "status=0x%02x\n", addr, status);
 302                                 goto write_err;
 303                         }
 304                         (*retlen)++;
 305                         last_sector = sector;
 306                 }
 307
 308                 /* Write subsequent bytes in the same sector */
 309                 cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
 310                 cmd[1] = buf[buf_index++];
 311                 do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
 312                 status = at91_dataflash26_waitready();
 313                 addr++;
 314
 315                 if (   ( !(status & AT26_STATUS_WRITE_ENABLE))
 316                     && ((addr % priv->page_size) != 0) ) {
 317                         DEBUG(MTD_DEBUG_LEVEL1, "write error2: addr=0x%06x, "
 318                                 "status=0x%02x\n", addr, status);
 319                         goto write_err;
 320                 }
 321
 322                 (*retlen)++;
 323         }
 324
 325         ret = 0;
 326         at91_dataflash26_write_enable(0);
 327 write_err:
 328         spi_release_bus(priv->spi);
 329         return ret;
 330 }
 331
 332 /*
 333  * Initialize and register DataFlash device with MTD subsystem.
 334  */
 335 static int __init add_dataflash(int channel, char *name, int nr_pages,
 336                                 int pagesize)
 337 {
 338         struct mtd_info *device;
 339         struct dataflash_local *priv;
 340
 341         if (nr_devices >= DATAFLASH_MAX_DEVICES) {
 342                 printk(KERN_ERR "at91_dataflash26: Too many devices "
 343                                 "detected\n");
 344                 return 0;
 345         }
 346
 347         device = kzalloc(sizeof(struct mtd_info) + strlen(name) + 8,
 348                          GFP_KERNEL);
 349         if (!device)
 350                 return -ENOMEM;
 351
 352         device->name = (char *)&device[1];
 353         sprintf(device->name, "%s.spi%d", name, channel);
 354         device->size = nr_pages * pagesize;
 355         device->erasesize = pagesize;
 356         device->owner = THIS_MODULE;
 357         device->type = MTD_DATAFLASH;
 358         device->flags = MTD_CAP_NORFLASH;
 359         device->erase = at91_dataflash26_erase;
 360         device->read = at91_dataflash26_read;
 361         device->write = at91_dataflash26_write;
 362
 363         priv = (struct dataflash_local *)kzalloc(sizeof(struct dataflash_local),
 364                 GFP_KERNEL);
 365         if (!priv) {
 366                 kfree(device);
 367                 return -ENOMEM;
 368         }
 369
 370         priv->spi = channel;
 371         priv->page_size = pagesize;
 372         device->priv = priv;
 373
 374         mtd_devices[nr_devices] = device;
 375         nr_devices++;
 376         printk(KERN_INFO "at91_dataflash26: %s detected [spi%i] (%i bytes)\n",
 377                name, channel, device->size);
 378
 379         return add_mtd_device(device);
 380 }
 381
 382 /*
 383  * Detect and initialize DataFlash device connected to specified SPI channel.
 384  *
 385  */
 386
 387 struct dataflash26_types {
 388         unsigned char id0;
 389         unsigned char id1;
 390         char *name;
 391         int pagesize;
 392         int nr_pages;
 393 };
 394
 395 struct dataflash26_types df26_types[] = {
 396         {
 397                 .id0 = 0x04,
 398                 .id1 = 0x00,
 399                 .name = "AT26F004",
 400                 .pagesize = 4096,
 401                 .nr_pages = 128,
 402         },
 403         {
 404                 .id0 = 0x45,
 405                 .id1 = 0x01,
 406                 .name = "AT26DF081A", /* Not tested ! */
 407                 .pagesize = 4096,
 408                 .nr_pages = 256,
 409         },
 410 };
 411
 412 static int __init at91_dataflash26_detect(int channel)
 413 {
 414         unsigned char status, cmd[5];
 415         int i;
 416
 417         spi_access_bus(channel);
 418         status = at91_dataflash26_status();
 419
 420         if (status == 0 || status == 0xff) {
 421                 printk(KERN_ERR "at91_dataflash26_detect: status error %d\n",
 422                         status);
 423                 spi_release_bus(channel);
 424                 return -ENODEV;
 425         }
 426
 427         cmd[0] = AT26_OP_READ_DEV_ID;
 428         do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
 429         spi_release_bus(channel);
 430
 431         if (cmd[1] != MANUFACTURER_ID_ATMEL)
 432                 return -ENODEV;
 433
 434         for (i = 0; i < ARRAY_SIZE(df26_types); i++) {
 435                 if (   cmd[2] == df26_types[i].id0
 436                     && cmd[3] == df26_types[i].id1)
 437                         return add_dataflash(channel,
 438                                                 df26_types[i].name,
 439                                                 df26_types[i].nr_pages,
 440                                                 df26_types[i].pagesize);
 441         }
 442
 443         printk(KERN_ERR "at91_dataflash26_detect: Unsupported device "
 444                         "(0x%02x/0x%02x)\n", cmd[2], cmd[3]);
 445         return -ENODEV;
 446 }
 447
 448 static int __init at91_dataflash26_init(void)
 449 {
 450         spi_transfer_desc = kmalloc(sizeof(struct spi_transfer_list),
 451                                     GFP_KERNEL);
 452         if (!spi_transfer_desc)
 453                 return -ENOMEM;
 454
 455         /* DataFlash (SPI chip select 0) */
 456         at91_dataflash26_detect(0);
 457
 458 #ifdef CONFIG_MTD_AT91_DATAFLASH_CARD
 459         /* DataFlash card (SPI chip select 3) */
 460         at91_dataflash26_detect(3);
 461 #endif
 462         return 0;
 463 }
 464
 465 static void __exit at91_dataflash26_exit(void)
 466 {
 467         int i;
 468
 469         for (i = 0; i < DATAFLASH_MAX_DEVICES; i++) {
 470                 if (mtd_devices[i]) {
 471                         del_mtd_device(mtd_devices[i]);
 472                         kfree(mtd_devices[i]->priv);
 473                         kfree(mtd_devices[i]);
 474                 }
 475         }
 476         nr_devices = 0;
 477         kfree(spi_transfer_desc);
 478 }
 479
 480 module_init(at91_dataflash26_init);
 481 module_exit(at91_dataflash26_exit);
 482
 483 MODULE_LICENSE("GPL");
 484 MODULE_AUTHOR("Hans J. Koch");
 485 MODULE_DESCRIPTION("DataFlash AT26xxx driver for Atmel AT91RM9200");