mtd: fix timeout in M25P80 driver

Extend erase timeout in M25P80 SPI Flash driver.

The M25P80 drivers fails erasing sectors on a M25P128 because the ready
wait timeout is too short. Change the timeout from a simple loop count to a
suitable number of seconds.

Signed-off-by: Peter Horton <zero@colonel-panic.org>
Tested-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index dfadef84c052..cc6369ea67dd 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -54,7 +54,7 @@
 #define SR_SRWD                 0x80    /* SR write protect */
 
 /* Define max times to check status register before we give up. */
-#define MAX_READY_WAIT_COUNT    1000000
+#define MAX_READY_WAIT_JIFFIES  (10 * HZ)       /* eg. M25P128 specs 6s max sector erase */
 #define CMD_SIZE                4
 
 #ifdef CONFIG_M25PXX_USE_FAST_READ
@@ -139,20 +139,20 @@ static inline int write_enable(struct m25p *flash)
  */
 static int wait_till_ready(struct m25p *flash)
 {
-        int count;
+        unsigned long deadline;
         int sr;
 
-        /* one chip guarantees max 5 msec wait here after page writes,
-         * but potentially three seconds (!) after page erase.
-         */
-        for (count = 0; count < MAX_READY_WAIT_COUNT; count++) {
+        deadline = jiffies + MAX_READY_WAIT_JIFFIES;
+
+        do {
                 if ((sr = read_sr(flash)) < 0)
                         break;
                 else if (!(sr & SR_WIP))
                         return 0;
 
-                /* REVISIT sometimes sleeping would be best */
-        }
+                cond_resched();
+
+        } while (!time_after_eq(jiffies, deadline));
 
         return 1;
 }