drivers/mtd/devices/bcm47xxsflash.c

   1 #include <linux/kernel.h>
   2 #include <linux/module.h>
   3 #include <linux/slab.h>
   4 #include <linux/delay.h>
   5 #include <linux/ioport.h>
   6 #include <linux/mtd/mtd.h>
   7 #include <linux/platform_device.h>
   8 #include <linux/bcma/bcma.h>
   9
  10 #include "bcm47xxsflash.h"
  11
  12 MODULE_LICENSE("GPL");
  13 MODULE_DESCRIPTION("Serial flash driver for BCMA bus");
  14
  15 static const char * const probes[] = { "bcm47xxpart", NULL };
  16
  17 /**************************************************
  18  * Various helpers
  19  **************************************************/
  20
  21 static void bcm47xxsflash_cmd(struct bcm47xxsflash *b47s, u32 opcode)
  22 {
  23         int i;
  24
  25         b47s->cc_write(b47s, BCMA_CC_FLASHCTL, BCMA_CC_FLASHCTL_START | opcode);
  26         for (i = 0; i < 1000; i++) {
  27                 if (!(b47s->cc_read(b47s, BCMA_CC_FLASHCTL) &
  28                       BCMA_CC_FLASHCTL_BUSY))
  29                         return;
  30                 cpu_relax();
  31         }
  32         pr_err("Control command failed (timeout)!\n");
  33 }
  34
  35 static int bcm47xxsflash_poll(struct bcm47xxsflash *b47s, int timeout)
  36 {
  37         unsigned long deadline = jiffies + timeout;
  38
  39         do {
  40                 switch (b47s->type) {
  41                 case BCM47XXSFLASH_TYPE_ST:
  42                         bcm47xxsflash_cmd(b47s, OPCODE_ST_RDSR);
  43                         if (!(b47s->cc_read(b47s, BCMA_CC_FLASHDATA) &
  44                               SR_ST_WIP))
  45                                 return 0;
  46                         break;
  47                 case BCM47XXSFLASH_TYPE_ATMEL:
  48                         bcm47xxsflash_cmd(b47s, OPCODE_AT_STATUS);
  49                         if (b47s->cc_read(b47s, BCMA_CC_FLASHDATA) &
  50                             SR_AT_READY)
  51                                 return 0;
  52                         break;
  53                 }
  54
  55                 cpu_relax();
  56                 udelay(1);
  57         } while (!time_after_eq(jiffies, deadline));
  58
  59         pr_err("Timeout waiting for flash to be ready!\n");
  60
  61         return -EBUSY;
  62 }
  63
  64 /**************************************************
  65  * MTD ops
  66  **************************************************/
  67
  68 static int bcm47xxsflash_erase(struct mtd_info *mtd, struct erase_info *erase)
  69 {
  70         struct bcm47xxsflash *b47s = mtd->priv;
  71         int err;
  72
  73         switch (b47s->type) {
  74         case BCM47XXSFLASH_TYPE_ST:
  75                 bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
  76                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, erase->addr);
  77                 /* Newer flashes have "sub-sectors" which can be erased
  78                  * independently with a new command: ST_SSE. The ST_SE command
  79                  * erases 64KB just as before.
  80                  */
  81                 if (b47s->blocksize < (64 * 1024))
  82                         bcm47xxsflash_cmd(b47s, OPCODE_ST_SSE);
  83                 else
  84                         bcm47xxsflash_cmd(b47s, OPCODE_ST_SE);
  85                 break;
  86         case BCM47XXSFLASH_TYPE_ATMEL:
  87                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, erase->addr << 1);
  88                 bcm47xxsflash_cmd(b47s, OPCODE_AT_PAGE_ERASE);
  89                 break;
  90         }
  91
  92         err = bcm47xxsflash_poll(b47s, HZ);
  93         if (err)
  94                 erase->state = MTD_ERASE_FAILED;
  95         else
  96                 erase->state = MTD_ERASE_DONE;
  97
  98         if (erase->callback)
  99                 erase->callback(erase);
 100
 101         return err;
 102 }
 103
 104 static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
 105                               size_t *retlen, u_char *buf)
 106 {
 107         struct bcm47xxsflash *b47s = mtd->priv;
 108         size_t orig_len = len;
 109
 110         /* Check address range */
 111         if ((from + len) > mtd->size)
 112                 return -EINVAL;
 113
 114         /* Read as much as possible using fast MMIO window */
 115         if (from < BCM47XXSFLASH_WINDOW_SZ) {
 116                 size_t memcpy_len;
 117
 118                 memcpy_len = min(len, (size_t)(BCM47XXSFLASH_WINDOW_SZ - from));
 119                 memcpy_fromio(buf, b47s->window + from, memcpy_len);
 120                 from += memcpy_len;
 121                 len -= memcpy_len;
 122                 buf += memcpy_len;
 123         }
 124
 125         /* Use indirect access for content out of the window */
 126         for (; len; len--) {
 127                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, from++);
 128                 bcm47xxsflash_cmd(b47s, OPCODE_ST_READ4B);
 129                 *buf++ = b47s->cc_read(b47s, BCMA_CC_FLASHDATA);
 130         }
 131
 132         *retlen = orig_len;
 133
 134         return orig_len;
 135 }
 136
 137 static int bcm47xxsflash_write_st(struct mtd_info *mtd, u32 offset, size_t len,
 138                                   const u_char *buf)
 139 {
 140         struct bcm47xxsflash *b47s = mtd->priv;
 141         int written = 0;
 142
 143         /* Enable writes */
 144         bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
 145
 146         /* Write first byte */
 147         b47s->cc_write(b47s, BCMA_CC_FLASHADDR, offset);
 148         b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
 149
 150         /* Program page */
 151         if (b47s->bcma_cc->core->id.rev < 20) {
 152                 bcm47xxsflash_cmd(b47s, OPCODE_ST_PP);
 153                 return 1; /* 1B written */
 154         }
 155
 156         /* Program page and set CSA (on newer chips we can continue writing) */
 157         bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | OPCODE_ST_PP);
 158         offset++;
 159         len--;
 160         written++;
 161
 162         while (len > 0) {
 163                 /* Page boundary, another function call is needed */
 164                 if ((offset & 0xFF) == 0)
 165                         break;
 166
 167                 bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | *buf++);
 168                 offset++;
 169                 len--;
 170                 written++;
 171         }
 172
 173         /* All done, drop CSA & poll */
 174         b47s->cc_write(b47s, BCMA_CC_FLASHCTL, 0);
 175         udelay(1);
 176         if (bcm47xxsflash_poll(b47s, HZ / 10))
 177                 pr_err("Flash rejected dropping CSA\n");
 178
 179         return written;
 180 }
 181
 182 static int bcm47xxsflash_write_at(struct mtd_info *mtd, u32 offset, size_t len,
 183                                   const u_char *buf)
 184 {
 185         struct bcm47xxsflash *b47s = mtd->priv;
 186         u32 mask = b47s->blocksize - 1;
 187         u32 page = (offset & ~mask) << 1;
 188         u32 byte = offset & mask;
 189         int written = 0;
 190
 191         /* If we don't overwrite whole page, read it to the buffer first */
 192         if (byte || (len < b47s->blocksize)) {
 193                 int err;
 194
 195                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
 196                 bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_LOAD);
 197                 /* 250 us for AT45DB321B */
 198                 err = bcm47xxsflash_poll(b47s, HZ / 1000);
 199                 if (err) {
 200                         pr_err("Timeout reading page 0x%X info buffer\n", page);
 201                         return err;
 202                 }
 203         }
 204
 205         /* Change buffer content with our data */
 206         while (len > 0) {
 207                 /* Page boundary, another function call is needed */
 208                 if (byte == b47s->blocksize)
 209                         break;
 210
 211                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, byte++);
 212                 b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
 213                 bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_WRITE);
 214                 len--;
 215                 written++;
 216         }
 217
 218         /* Program page with the buffer content */
 219         b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
 220         bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_PROGRAM);
 221
 222         return written;
 223 }
 224
 225 static int bcm47xxsflash_write(struct mtd_info *mtd, loff_t to, size_t len,
 226                                size_t *retlen, const u_char *buf)
 227 {
 228         struct bcm47xxsflash *b47s = mtd->priv;
 229         int written;
 230
 231         /* Writing functions can return without writing all passed data, for
 232          * example when the hardware is too old or when we git page boundary.
 233          */
 234         while (len > 0) {
 235                 switch (b47s->type) {
 236                 case BCM47XXSFLASH_TYPE_ST:
 237                         written = bcm47xxsflash_write_st(mtd, to, len, buf);
 238                         break;
 239                 case BCM47XXSFLASH_TYPE_ATMEL:
 240                         written = bcm47xxsflash_write_at(mtd, to, len, buf);
 241                         break;
 242                 default:
 243                         BUG_ON(1);
 244                 }
 245                 if (written < 0) {
 246                         pr_err("Error writing at offset 0x%llX\n", to);
 247                         return written;
 248                 }
 249                 to += (loff_t)written;
 250                 len -= written;
 251                 *retlen += written;
 252                 buf += written;
 253         }
 254
 255         return 0;
 256 }
 257
 258 static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s,
 259                                    struct device *dev)
 260 {
 261         struct mtd_info *mtd = &b47s->mtd;
 262
 263         mtd->priv = b47s;
 264         mtd->dev.parent = dev;
 265         mtd->name = "bcm47xxsflash";
 266
 267         mtd->type = MTD_NORFLASH;
 268         mtd->flags = MTD_CAP_NORFLASH;
 269         mtd->size = b47s->size;
 270         mtd->erasesize = b47s->blocksize;
 271         mtd->writesize = 1;
 272         mtd->writebufsize = 1;
 273
 274         mtd->_erase = bcm47xxsflash_erase;
 275         mtd->_read = bcm47xxsflash_read;
 276         mtd->_write = bcm47xxsflash_write;
 277 }
 278
 279 /**************************************************
 280  * BCMA
 281  **************************************************/
 282
 283 static int bcm47xxsflash_bcma_cc_read(struct bcm47xxsflash *b47s, u16 offset)
 284 {
 285         return bcma_cc_read32(b47s->bcma_cc, offset);
 286 }
 287
 288 static void bcm47xxsflash_bcma_cc_write(struct bcm47xxsflash *b47s, u16 offset,
 289                                         u32 value)
 290 {
 291         bcma_cc_write32(b47s->bcma_cc, offset, value);
 292 }
 293
 294 static int bcm47xxsflash_bcma_probe(struct platform_device *pdev)
 295 {
 296         struct device *dev = &pdev->dev;
 297         struct bcma_sflash *sflash = dev_get_platdata(dev);
 298         struct bcm47xxsflash *b47s;
 299         struct resource *res;
 300         int err;
 301
 302         b47s = devm_kzalloc(dev, sizeof(*b47s), GFP_KERNEL);
 303         if (!b47s)
 304                 return -ENOMEM;
 305
 306         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 307         if (!res) {
 308                 dev_err(dev, "invalid resource\n");
 309                 return -EINVAL;
 310         }
 311         if (!devm_request_mem_region(dev, res->start, resource_size(res),
 312                                      res->name)) {
 313                 dev_err(dev, "can't request region for resource %pR\n", res);
 314                 return -EBUSY;
 315         }
 316
 317         b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);
 318         b47s->cc_read = bcm47xxsflash_bcma_cc_read;
 319         b47s->cc_write = bcm47xxsflash_bcma_cc_write;
 320
 321         /*
 322          * On old MIPS devices cache was magically invalidated when needed,
 323          * allowing us to use cached access and gain some performance. Trying
 324          * the same on ARM based BCM53573 results in flash corruptions, we need
 325          * to use uncached access for it.
 326          *
 327          * It may be arch specific, but right now there is only 1 ARM SoC using
 328          * this driver, so let's follow Broadcom's reference code and check
 329          * ChipCommon revision.
 330          */
 331         if (b47s->bcma_cc->core->id.rev == 54)
 332                 b47s->window = ioremap_nocache(res->start, resource_size(res));
 333         else
 334                 b47s->window = ioremap_cache(res->start, resource_size(res));
 335         if (!b47s->window) {
 336                 dev_err(dev, "ioremap failed for resource %pR\n", res);
 337                 return -ENOMEM;
 338         }
 339
 340         switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {
 341         case BCMA_CC_FLASHT_STSER:
 342                 b47s->type = BCM47XXSFLASH_TYPE_ST;
 343                 break;
 344         case BCMA_CC_FLASHT_ATSER:
 345                 b47s->type = BCM47XXSFLASH_TYPE_ATMEL;
 346                 break;
 347         }
 348
 349         b47s->blocksize = sflash->blocksize;
 350         b47s->numblocks = sflash->numblocks;
 351         b47s->size = sflash->size;
 352         bcm47xxsflash_fill_mtd(b47s, &pdev->dev);
 353
 354         platform_set_drvdata(pdev, b47s);
 355
 356         err = mtd_device_parse_register(&b47s->mtd, probes, NULL, NULL, 0);
 357         if (err) {
 358                 pr_err("Failed to register MTD device: %d\n", err);
 359                 iounmap(b47s->window);
 360                 return err;
 361         }
 362
 363         if (bcm47xxsflash_poll(b47s, HZ / 10))
 364                 pr_warn("Serial flash busy\n");
 365
 366         return 0;
 367 }
 368
 369 static int bcm47xxsflash_bcma_remove(struct platform_device *pdev)
 370 {
 371         struct bcm47xxsflash *b47s = platform_get_drvdata(pdev);
 372
 373         mtd_device_unregister(&b47s->mtd);
 374         iounmap(b47s->window);
 375
 376         return 0;
 377 }
 378
 379 static struct platform_driver bcma_sflash_driver = {
 380         .probe  = bcm47xxsflash_bcma_probe,
 381         .remove = bcm47xxsflash_bcma_remove,
 382         .driver = {
 383                 .name = "bcma_sflash",
 384         },
 385 };
 386
 387 /**************************************************
 388  * Init
 389  **************************************************/
 390
 391 module_platform_driver(bcma_sflash_driver);