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
 109         /* Check address range */
 110         if ((from + len) > mtd->size)
 111                 return -EINVAL;
 112
 113         memcpy_fromio(buf, b47s->window + from, len);
 114         *retlen = len;
 115
 116         return len;
 117 }
 118
 119 static int bcm47xxsflash_write_st(struct mtd_info *mtd, u32 offset, size_t len,
 120                                   const u_char *buf)
 121 {
 122         struct bcm47xxsflash *b47s = mtd->priv;
 123         int written = 0;
 124
 125         /* Enable writes */
 126         bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
 127
 128         /* Write first byte */
 129         b47s->cc_write(b47s, BCMA_CC_FLASHADDR, offset);
 130         b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
 131
 132         /* Program page */
 133         if (b47s->bcma_cc->core->id.rev < 20) {
 134                 bcm47xxsflash_cmd(b47s, OPCODE_ST_PP);
 135                 return 1; /* 1B written */
 136         }
 137
 138         /* Program page and set CSA (on newer chips we can continue writing) */
 139         bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | OPCODE_ST_PP);
 140         offset++;
 141         len--;
 142         written++;
 143
 144         while (len > 0) {
 145                 /* Page boundary, another function call is needed */
 146                 if ((offset & 0xFF) == 0)
 147                         break;
 148
 149                 bcm47xxsflash_cmd(b47s, OPCODE_ST_CSA | *buf++);
 150                 offset++;
 151                 len--;
 152                 written++;
 153         }
 154
 155         /* All done, drop CSA & poll */
 156         b47s->cc_write(b47s, BCMA_CC_FLASHCTL, 0);
 157         udelay(1);
 158         if (bcm47xxsflash_poll(b47s, HZ / 10))
 159                 pr_err("Flash rejected dropping CSA\n");
 160
 161         return written;
 162 }
 163
 164 static int bcm47xxsflash_write_at(struct mtd_info *mtd, u32 offset, size_t len,
 165                                   const u_char *buf)
 166 {
 167         struct bcm47xxsflash *b47s = mtd->priv;
 168         u32 mask = b47s->blocksize - 1;
 169         u32 page = (offset & ~mask) << 1;
 170         u32 byte = offset & mask;
 171         int written = 0;
 172
 173         /* If we don't overwrite whole page, read it to the buffer first */
 174         if (byte || (len < b47s->blocksize)) {
 175                 int err;
 176
 177                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
 178                 bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_LOAD);
 179                 /* 250 us for AT45DB321B */
 180                 err = bcm47xxsflash_poll(b47s, HZ / 1000);
 181                 if (err) {
 182                         pr_err("Timeout reading page 0x%X info buffer\n", page);
 183                         return err;
 184                 }
 185         }
 186
 187         /* Change buffer content with our data */
 188         while (len > 0) {
 189                 /* Page boundary, another function call is needed */
 190                 if (byte == b47s->blocksize)
 191                         break;
 192
 193                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, byte++);
 194                 b47s->cc_write(b47s, BCMA_CC_FLASHDATA, *buf++);
 195                 bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_WRITE);
 196                 len--;
 197                 written++;
 198         }
 199
 200         /* Program page with the buffer content */
 201         b47s->cc_write(b47s, BCMA_CC_FLASHADDR, page);
 202         bcm47xxsflash_cmd(b47s, OPCODE_AT_BUF1_PROGRAM);
 203
 204         return written;
 205 }
 206
 207 static int bcm47xxsflash_write(struct mtd_info *mtd, loff_t to, size_t len,
 208                                size_t *retlen, const u_char *buf)
 209 {
 210         struct bcm47xxsflash *b47s = mtd->priv;
 211         int written;
 212
 213         /* Writing functions can return without writing all passed data, for
 214          * example when the hardware is too old or when we git page boundary.
 215          */
 216         while (len > 0) {
 217                 switch (b47s->type) {
 218                 case BCM47XXSFLASH_TYPE_ST:
 219                         written = bcm47xxsflash_write_st(mtd, to, len, buf);
 220                         break;
 221                 case BCM47XXSFLASH_TYPE_ATMEL:
 222                         written = bcm47xxsflash_write_at(mtd, to, len, buf);
 223                         break;
 224                 default:
 225                         BUG_ON(1);
 226                 }
 227                 if (written < 0) {
 228                         pr_err("Error writing at offset 0x%llX\n", to);
 229                         return written;
 230                 }
 231                 to += (loff_t)written;
 232                 len -= written;
 233                 *retlen += written;
 234                 buf += written;
 235         }
 236
 237         return 0;
 238 }
 239
 240 static void bcm47xxsflash_fill_mtd(struct bcm47xxsflash *b47s,
 241                                    struct device *dev)
 242 {
 243         struct mtd_info *mtd = &b47s->mtd;
 244
 245         mtd->priv = b47s;
 246         mtd->dev.parent = dev;
 247         mtd->name = "bcm47xxsflash";
 248
 249         mtd->type = MTD_NORFLASH;
 250         mtd->flags = MTD_CAP_NORFLASH;
 251         mtd->size = b47s->size;
 252         mtd->erasesize = b47s->blocksize;
 253         mtd->writesize = 1;
 254         mtd->writebufsize = 1;
 255
 256         mtd->_erase = bcm47xxsflash_erase;
 257         mtd->_read = bcm47xxsflash_read;
 258         mtd->_write = bcm47xxsflash_write;
 259 }
 260
 261 /**************************************************
 262  * BCMA
 263  **************************************************/
 264
 265 static int bcm47xxsflash_bcma_cc_read(struct bcm47xxsflash *b47s, u16 offset)
 266 {
 267         return bcma_cc_read32(b47s->bcma_cc, offset);
 268 }
 269
 270 static void bcm47xxsflash_bcma_cc_write(struct bcm47xxsflash *b47s, u16 offset,
 271                                         u32 value)
 272 {
 273         bcma_cc_write32(b47s->bcma_cc, offset, value);
 274 }
 275
 276 static int bcm47xxsflash_bcma_probe(struct platform_device *pdev)
 277 {
 278         struct device *dev = &pdev->dev;
 279         struct bcma_sflash *sflash = dev_get_platdata(dev);
 280         struct bcm47xxsflash *b47s;
 281         struct resource *res;
 282         int err;
 283
 284         b47s = devm_kzalloc(dev, sizeof(*b47s), GFP_KERNEL);
 285         if (!b47s)
 286                 return -ENOMEM;
 287         sflash->priv = b47s;
 288
 289         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 290         if (!res) {
 291                 dev_err(dev, "invalid resource\n");
 292                 return -EINVAL;
 293         }
 294         if (!devm_request_mem_region(dev, res->start, resource_size(res),
 295                                      res->name)) {
 296                 dev_err(dev, "can't request region for resource %pR\n", res);
 297                 return -EBUSY;
 298         }
 299         b47s->window = ioremap_cache(res->start, resource_size(res));
 300         if (!b47s->window) {
 301                 dev_err(dev, "ioremap failed for resource %pR\n", res);
 302                 return -ENOMEM;
 303         }
 304
 305         b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);
 306         b47s->cc_read = bcm47xxsflash_bcma_cc_read;
 307         b47s->cc_write = bcm47xxsflash_bcma_cc_write;
 308
 309         switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {
 310         case BCMA_CC_FLASHT_STSER:
 311                 b47s->type = BCM47XXSFLASH_TYPE_ST;
 312                 break;
 313         case BCMA_CC_FLASHT_ATSER:
 314                 b47s->type = BCM47XXSFLASH_TYPE_ATMEL;
 315                 break;
 316         }
 317
 318         b47s->blocksize = sflash->blocksize;
 319         b47s->numblocks = sflash->numblocks;
 320         b47s->size = sflash->size;
 321         bcm47xxsflash_fill_mtd(b47s, &pdev->dev);
 322
 323         err = mtd_device_parse_register(&b47s->mtd, probes, NULL, NULL, 0);
 324         if (err) {
 325                 pr_err("Failed to register MTD device: %d\n", err);
 326                 iounmap(b47s->window);
 327                 return err;
 328         }
 329
 330         if (bcm47xxsflash_poll(b47s, HZ / 10))
 331                 pr_warn("Serial flash busy\n");
 332
 333         return 0;
 334 }
 335
 336 static int bcm47xxsflash_bcma_remove(struct platform_device *pdev)
 337 {
 338         struct bcma_sflash *sflash = dev_get_platdata(&pdev->dev);
 339         struct bcm47xxsflash *b47s = sflash->priv;
 340
 341         mtd_device_unregister(&b47s->mtd);
 342         iounmap(b47s->window);
 343
 344         return 0;
 345 }
 346
 347 static struct platform_driver bcma_sflash_driver = {
 348         .probe  = bcm47xxsflash_bcma_probe,
 349         .remove = bcm47xxsflash_bcma_remove,
 350         .driver = {
 351                 .name = "bcma_sflash",
 352         },
 353 };
 354
 355 /**************************************************
 356  * Init
 357  **************************************************/
 358
 359 module_platform_driver(bcma_sflash_driver);