[MTD] [NAND] OMAP2: add retry after read timeout

Very occasionally, (about one in a million) read operations are
ongoing after the timeout has expired.  So, retry three times
while the ongoing bit remains set.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 23 insertions, 3 deletions

diff --git a/drivers/mtd/onenand/omap2.c b/drivers/mtd/onenand/omap2.c
index 34b42533f4bb..8387e05daae2 100644
--- a/drivers/mtd/onenand/omap2.c
+++ b/drivers/mtd/onenand/omap2.c
@@ -187,16 +187,36 @@ retry:
                         }
                 }
         } else {
+                int retry_cnt = 0;
+
                 /* Turn interrupts off */
                 syscfg = read_reg(c, ONENAND_REG_SYS_CFG1);
                 syscfg &= ~ONENAND_SYS_CFG1_IOBE;
                 write_reg(c, syscfg, ONENAND_REG_SYS_CFG1);
 
                 timeout = jiffies + msecs_to_jiffies(20);
-                while (time_before(jiffies, timeout)) {
-                        intr = read_reg(c, ONENAND_REG_INTERRUPT);
-                        if (intr & ONENAND_INT_MASTER)
+                while (1) {
+                        if (time_before(jiffies, timeout)) {
+                                intr = read_reg(c, ONENAND_REG_INTERRUPT);
+                                if (intr & ONENAND_INT_MASTER)
+                                        break;
+                        } else {
+                                /* Timeout after 20ms */
+                                ctrl = read_reg(c, ONENAND_REG_CTRL_STATUS);
+                                if (ctrl & ONENAND_CTRL_ONGO) {
+                                        /*
+                                         * The operation seems to be still going
+                                         * so give it some more time.
+                                         */
+                                        retry_cnt += 1;
+                                        if (retry_cnt < 3) {
+                                                timeout = jiffies +
+                                                          msecs_to_jiffies(20);
+                                                continue;
+                                        }
+                                }
                                 break;
+                        }
                 }
         }