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/mtd/mtd.h>
   6 #include <linux/platform_device.h>
   7 #include <linux/bcma/bcma.h>
   8
   9 #include "bcm47xxsflash.h"
  10
  11 MODULE_LICENSE("GPL");
  12 MODULE_DESCRIPTION("Serial flash driver for BCMA bus");
  13
  14 static const char * const probes[] = { "bcm47xxpart", NULL };
  15
  16 /**************************************************
  17  * Various helpers
  18  **************************************************/
  19
  20 static void bcm47xxsflash_cmd(struct bcm47xxsflash *b47s, u32 opcode)
  21 {
  22         int i;
  23
  24         b47s->cc_write(b47s, BCMA_CC_FLASHCTL, BCMA_CC_FLASHCTL_START | opcode);
  25         for (i = 0; i < 1000; i++) {
  26                 if (!(b47s->cc_read(b47s, BCMA_CC_FLASHCTL) &
  27                       BCMA_CC_FLASHCTL_BUSY))
  28                         return;
  29                 cpu_relax();
  30         }
  31         pr_err("Control command failed (timeout)!\n");
  32 }
  33
  34 static int bcm47xxsflash_poll(struct bcm47xxsflash *b47s, int timeout)
  35 {
  36         unsigned long deadline = jiffies + timeout;
  37
  38         do {
  39                 switch (b47s->type) {
  40                 case BCM47XXSFLASH_TYPE_ST:
  41                         bcm47xxsflash_cmd(b47s, OPCODE_ST_RDSR);
  42                         if (!(b47s->cc_read(b47s, BCMA_CC_FLASHDATA) &
  43                               SR_ST_WIP))
  44                                 return 0;
  45                         break;
  46                 case BCM47XXSFLASH_TYPE_ATMEL:
  47                         bcm47xxsflash_cmd(b47s, OPCODE_AT_STATUS);
  48                         if (b47s->cc_read(b47s, BCMA_CC_FLASHDATA) &
  49                             SR_AT_READY)
  50                                 return 0;
  51                         break;
  52                 }
  53
  54                 cpu_relax();
  55                 udelay(1);
  56         } while (!time_after_eq(jiffies, deadline));
  57
  58         pr_err("Timeout waiting for flash to be ready!\n");
  59
  60         return -EBUSY;
  61 }
  62
  63 /**************************************************
  64  * MTD ops
  65  **************************************************/
  66
  67 static int bcm47xxsflash_erase(struct mtd_info *mtd, struct erase_info *erase)
  68 {
  69         struct bcm47xxsflash *b47s = mtd->priv;
  70         int err;
  71
  72         switch (b47s->type) {
  73         case BCM47XXSFLASH_TYPE_ST:
  74                 bcm47xxsflash_cmd(b47s, OPCODE_ST_WREN);
  75                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, erase->addr);
  76                 /* Newer flashes have "sub-sectors" which can be erased
  77                  * independently with a new command: ST_SSE. The ST_SE command
  78                  * erases 64KB just as before.
  79                  */
  80                 if (b47s->blocksize < (64 * 1024))
  81                         bcm47xxsflash_cmd(b47s, OPCODE_ST_SSE);
  82                 else
  83                         bcm47xxsflash_cmd(b47s, OPCODE_ST_SE);
  84                 break;
  85         case BCM47XXSFLASH_TYPE_ATMEL:
  86                 b47s->cc_write(b47s, BCMA_CC_FLASHADDR, erase->addr << 1);
  87                 bcm47xxsflash_cmd(b47s, OPCODE_AT_PAGE_ERASE);
  88                 break;
  89         }
  90
  91         err = bcm47xxsflash_poll(b47s, HZ);
  92         if (err)
  93                 erase->state = MTD_ERASE_FAILED;
  94         else
  95                 erase->state = MTD_ERASE_DONE;
  96
  97         if (erase->callback)
  98                 erase->callback(erase);
  99
 100         return err;
 101 }
 102
 103 static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
 104                               size_t *retlen, u_char *buf)
 105 {
 106         struct bcm47xxsflash *b47s = mtd->priv;
 107
 108         /* Check address range */
 109         if ((from + len) > mtd->size)
 110                 return -EINVAL;
 111
 112         memcpy_fromio(buf, (void __iomem *)KSEG0ADDR(b47s->window + from),
 113                       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 {
 242         struct mtd_info *mtd = &b47s->mtd;
 243
 244         mtd->priv = b47s;
 245         mtd->name = "bcm47xxsflash";
 246         mtd->owner = THIS_MODULE;
 247
 248         mtd->type = MTD_NORFLASH;
 249         mtd->flags = MTD_CAP_NORFLASH;
 250         mtd->size = b47s->size;
 251         mtd->erasesize = b47s->blocksize;
 252         mtd->writesize = 1;
 253         mtd->writebufsize = 1;
 254
 255         mtd->_erase = bcm47xxsflash_erase;
 256         mtd->_read = bcm47xxsflash_read;
 257         mtd->_write = bcm47xxsflash_write;
 258 }
 259
 260 /**************************************************
 261  * BCMA
 262  **************************************************/
 263
 264 static int bcm47xxsflash_bcma_cc_read(struct bcm47xxsflash *b47s, u16 offset)
 265 {
 266         return bcma_cc_read32(b47s->bcma_cc, offset);
 267 }
 268
 269 static void bcm47xxsflash_bcma_cc_write(struct bcm47xxsflash *b47s, u16 offset,
 270                                         u32 value)
 271 {
 272         bcma_cc_write32(b47s->bcma_cc, offset, value);
 273 }
 274
 275 static int bcm47xxsflash_bcma_probe(struct platform_device *pdev)
 276 {
 277         struct bcma_sflash *sflash = dev_get_platdata(&pdev->dev);
 278         struct bcm47xxsflash *b47s;
 279         int err;
 280
 281         b47s = devm_kzalloc(&pdev->dev, sizeof(*b47s), GFP_KERNEL);
 282         if (!b47s)
 283                 return -ENOMEM;
 284         sflash->priv = b47s;
 285
 286         b47s->bcma_cc = container_of(sflash, struct bcma_drv_cc, sflash);
 287         b47s->cc_read = bcm47xxsflash_bcma_cc_read;
 288         b47s->cc_write = bcm47xxsflash_bcma_cc_write;
 289
 290         switch (b47s->bcma_cc->capabilities & BCMA_CC_CAP_FLASHT) {
 291         case BCMA_CC_FLASHT_STSER:
 292                 b47s->type = BCM47XXSFLASH_TYPE_ST;
 293                 break;
 294         case BCMA_CC_FLASHT_ATSER:
 295                 b47s->type = BCM47XXSFLASH_TYPE_ATMEL;
 296                 break;
 297         }
 298
 299         b47s->window = sflash->window;
 300         b47s->blocksize = sflash->blocksize;
 301         b47s->numblocks = sflash->numblocks;
 302         b47s->size = sflash->size;
 303         bcm47xxsflash_fill_mtd(b47s);
 304
 305         err = mtd_device_parse_register(&b47s->mtd, probes, NULL, NULL, 0);
 306         if (err) {
 307                 pr_err("Failed to register MTD device: %d\n", err);
 308                 return err;
 309         }
 310
 311         if (bcm47xxsflash_poll(b47s, HZ / 10))
 312                 pr_warn("Serial flash busy\n");
 313
 314         return 0;
 315 }
 316
 317 static int bcm47xxsflash_bcma_remove(struct platform_device *pdev)
 318 {
 319         struct bcma_sflash *sflash = dev_get_platdata(&pdev->dev);
 320         struct bcm47xxsflash *b47s = sflash->priv;
 321
 322         mtd_device_unregister(&b47s->mtd);
 323
 324         return 0;
 325 }
 326
 327 static struct platform_driver bcma_sflash_driver = {
 328         .probe  = bcm47xxsflash_bcma_probe,
 329         .remove = bcm47xxsflash_bcma_remove,
 330         .driver = {
 331                 .name = "bcma_sflash",
 332                 .owner = THIS_MODULE,
 333         },
 334 };
 335
 336 /**************************************************
 337  * Init
 338  **************************************************/
 339
 340 module_platform_driver(bcma_sflash_driver);