diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/mtd/chips/cfi_cmdset_0002.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c index 8d70895a58d6..e2d94bb1d7c8 100644 --- a/drivers/mtd/chips/cfi_cmdset_0002.c +++ b/drivers/mtd/chips/cfi_cmdset_0002.c @@ -59,6 +59,9 @@ static void cfi_amdstd_resume (struct mtd_info *); static int cfi_amdstd_reboot(struct notifier_block *, unsigned long, void *); static int cfi_amdstd_secsi_read (struct mtd_info *, loff_t, size_t, size_t *, u_char *); +static int cfi_amdstd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, + size_t *retlen, const u_char *buf); + static void cfi_amdstd_destroy(struct mtd_info *); struct mtd_info *cfi_cmdset_0002(struct map_info *, int); @@ -443,6 +446,7 @@ struct mtd_info *cfi_cmdset_0002(struct map_info *map, int primary) pr_debug("MTD %s(): write buffer size %d\n", __func__, mtd->writebufsize); + mtd->panic_write = cfi_amdstd_panic_write; mtd->reboot_notifier.notifier_call = cfi_amdstd_reboot; if (cfi->cfi_mode==CFI_MODE_CFI){ @@ -1562,6 +1566,242 @@ static int cfi_amdstd_write_buffers(struct mtd_info *mtd, loff_t to, size_t len, return 0; } +/* + * Wait for the flash chip to become ready to write data + * + * This is only called during the panic_write() path. When panic_write() + * is called, the kernel is in the process of a panic, and will soon be + * dead. Therefore we don't take any locks, and attempt to get access + * to the chip as soon as possible. + */ +static int cfi_amdstd_panic_wait(struct map_info *map, struct flchip *chip, + unsigned long adr) +{ + struct cfi_private *cfi = map->fldrv_priv; + int retries = 10; + int i; + + /* + * If the driver thinks the chip is idle, and no toggle bits + * are changing, then the chip is actually idle for sure. + */ + if (chip->state == FL_READY && chip_ready(map, adr)) + return 0; + + /* + * Try several times to reset the chip and then wait for it + * to become idle. The upper limit of a few milliseconds of + * delay isn't a big problem: the kernel is dying anyway. It + * is more important to save the messages. + */ + while (retries > 0) { + const unsigned long timeo = (HZ / 1000) + 1; + + /* send the reset command */ + map_write(map, CMD(0xF0), chip->start); + + /* wait for the chip to become ready */ + for (i = 0; i < jiffies_to_usecs(timeo); i++) { + if (chip_ready(map, adr)) + return 0; + + udelay(1); + } + } + + /* the chip never became ready */ + return -EBUSY; +} + +/* + * Write out one word of data to a single flash chip during a kernel panic + * + * This is only called during the panic_write() path. When panic_write() + * is called, the kernel is in the process of a panic, and will soon be + * dead. Therefore we don't take any locks, and attempt to get access + * to the chip as soon as possible. + * + * The implementation of this routine is intentionally similar to + * do_write_oneword(), in order to ease code maintenance. + */ +static int do_panic_write_oneword(struct map_info *map, struct flchip *chip, + unsigned long adr, map_word datum) +{ + const unsigned long uWriteTimeout = (HZ / 1000) + 1; + struct cfi_private *cfi = map->fldrv_priv; + int retry_cnt = 0; + map_word oldd; + int ret = 0; + int i; + + adr += chip->start; + + ret = cfi_amdstd_panic_wait(map, chip, adr); + if (ret) + return ret; + + pr_debug("MTD %s(): PANIC WRITE 0x%.8lx(0x%.8lx)\n", + __func__, adr, datum.x[0]); + + /* + * Check for a NOP for the case when the datum to write is already + * present - it saves time and works around buggy chips that corrupt + * data at other locations when 0xff is written to a location that + * already contains 0xff. + */ + oldd = map_read(map, adr); + if (map_word_equal(map, oldd, datum)) { + pr_debug("MTD %s(): NOP\n", __func__); + goto op_done; + } + + ENABLE_VPP(map); + +retry: + cfi_send_gen_cmd(0xAA, cfi->addr_unlock1, chip->start, map, cfi, cfi->device_type, NULL); + cfi_send_gen_cmd(0x55, cfi->addr_unlock2, chip->start, map, cfi, cfi->device_type, NULL); + cfi_send_gen_cmd(0xA0, cfi->addr_unlock1, chip->start, map, cfi, cfi->device_type, NULL); + map_write(map, datum, adr); + + for (i = 0; i < jiffies_to_usecs(uWriteTimeout); i++) { + if (chip_ready(map, adr)) + break; + + udelay(1); + } + + if (!chip_good(map, adr, datum)) { + /* reset on all failures. */ + map_write(map, CMD(0xF0), chip->start); + /* FIXME - should have reset delay before continuing */ + + if (++retry_cnt <= MAX_WORD_RETRIES) + goto retry; + + ret = -EIO; + } + +op_done: + DISABLE_VPP(map); + return ret; +} + +/* + * Write out some data during a kernel panic + * + * This is used by the mtdoops driver to save the dying messages from a + * kernel which has panic'd. + * + * This routine ignores all of the locking used throughout the rest of the + * driver, in order to ensure that the data gets written out no matter what + * state this driver (and the flash chip itself) was in when the kernel crashed. + * + * The implementation of this routine is intentionally similar to + * cfi_amdstd_write_words(), in order to ease code maintenance. + */ +static int cfi_amdstd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, + size_t *retlen, const u_char *buf) +{ + struct map_info *map = mtd->priv; + struct cfi_private *cfi = map->fldrv_priv; + unsigned long ofs, chipstart; + int ret = 0; + int chipnum; + + *retlen = 0; + if (!len) + return 0; + + chipnum = to >> cfi->chipshift; + ofs = to - (chipnum << cfi->chipshift); + chipstart = cfi->chips[chipnum].start; + + /* If it's not bus aligned, do the first byte write */ + if (ofs & (map_bankwidth(map) - 1)) { + unsigned long bus_ofs = ofs & ~(map_bankwidth(map) - 1); + int i = ofs - bus_ofs; + int n = 0; + map_word tmp_buf; + + ret = cfi_amdstd_panic_wait(map, &cfi->chips[chipnum], bus_ofs); + if (ret) + return ret; + + /* Load 'tmp_buf' with old contents of flash */ + tmp_buf = map_read(map, bus_ofs + chipstart); + + /* Number of bytes to copy from buffer */ + n = min_t(int, len, map_bankwidth(map) - i); + + tmp_buf = map_word_load_partial(map, tmp_buf, buf, i, n); + + ret = do_panic_write_oneword(map, &cfi->chips[chipnum], + bus_ofs, tmp_buf); + if (ret) + return ret; + + ofs += n; + buf += n; + (*retlen) += n; + len -= n; + + if (ofs >> cfi->chipshift) { + chipnum++; + ofs = 0; + if (chipnum == cfi->numchips) + return 0; + } + } + + /* We are now aligned, write as much as possible */ + while (len >= map_bankwidth(map)) { + map_word datum; + + datum = map_word_load(map, buf); + + ret = do_panic_write_oneword(map, &cfi->chips[chipnum], + ofs, datum); + if (ret) + return ret; + + ofs += map_bankwidth(map); + buf += map_bankwidth(map); + (*retlen) += map_bankwidth(map); + len -= map_bankwidth(map); + + if (ofs >> cfi->chipshift) { + chipnum++; + ofs = 0; + if (chipnum == cfi->numchips) + return 0; + + chipstart = cfi->chips[chipnum].start; + } + } + + /* Write the trailing bytes if any */ + if (len & (map_bankwidth(map) - 1)) { + map_word tmp_buf; + + ret = cfi_amdstd_panic_wait(map, &cfi->chips[chipnum], ofs); + if (ret) + return ret; + + tmp_buf = map_read(map, ofs + chipstart); + + tmp_buf = map_word_load_partial(map, tmp_buf, buf, 0, len); + + ret = do_panic_write_oneword(map, &cfi->chips[chipnum], + ofs, tmp_buf); + if (ret) + return ret; + + (*retlen) += len; + } + + return 0; +} + /* * Handle devices with one erase region, that only implement |