mtd: cfi_cmdset_0001: Fix problem with unlocking timeout

Unlocking may take up to 1.4 seconds on some Intel flashes. So
lets use a max. of 1.5 seconds (1500ms) as timeout.

See "Clear Block Lock-Bits Time" on page 40 in
"3 Volt Intel StrataFlash Memory" 28F128J3,28F640J3,28F320J3 manual
from February 2003

This patch also fixes some other problems with this timeout:

- Don't use HZ in timeout "calculation"!
  While testing we noticed that an unlocking timeout occured with
  HZ=1000 and didn't occur with HZ=300. This was because the
  timeout parameter was calculated differently depending on the
  HZ value. Now a fixed value of 1500ms is used.

- The last parameter of WAIT_TIMEOUT (defined to
  inval_cache_and_wait_for_operation) has to be passed in
  micro-seconds. So multiply the ms value with 1000 and not 100
  to calculate this value.

- Use variable name "mdelay" instead of misleading "udelay".

Signed-off-by: Stefan Roese <sr@denx.de>
Tested-by: Stephan Gatzka <stephan@gatzka.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index dbbd2edfb812..77514430f1fe 100644
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -2043,7 +2043,7 @@ static int __xipram do_xxlock_oneblock(struct map_info *map, struct flchip *chip
 {
         struct cfi_private *cfi = map->fldrv_priv;
         struct cfi_pri_intelext *extp = cfi->cmdset_priv;
-        int udelay;
+        int mdelay;
         int ret;
 
         adr += chip->start;
@@ -2072,9 +2072,17 @@ static int __xipram do_xxlock_oneblock(struct map_info *map, struct flchip *chip
          * If Instant Individual Block Locking supported then no need
          * to delay.
          */
-        udelay = (!extp || !(extp->FeatureSupport & (1 << 5))) ? 1000000/HZ : 0;
+        /*
+         * Unlocking may take up to 1.4 seconds on some Intel flashes. So
+         * lets use a max of 1.5 seconds (1500ms) as timeout.
+         *
+         * See "Clear Block Lock-Bits Time" on page 40 in
+         * "3 Volt Intel StrataFlash Memory" 28F128J3,28F640J3,28F320J3 manual
+         * from February 2003
+         */
+        mdelay = (!extp || !(extp->FeatureSupport & (1 << 5))) ? 1500 : 0;
 
-        ret = WAIT_TIMEOUT(map, chip, adr, udelay, udelay * 100);
+        ret = WAIT_TIMEOUT(map, chip, adr, mdelay, mdelay * 1000);
         if (ret) {
                 map_write(map, CMD(0x70), adr);
                 chip->state = FL_STATUS;