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>

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index dfadef84c0528f9318f0c0d6fa3e2c612db65b5a..cc6369ea67dd22051eccddcf88f90ee19096c5d5 100644 (file)
--- 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;
 }