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);
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){
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
projects / karo-tx-linux.git / blobdiff