[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>

diff --git a/drivers/mtd/onenand/omap2.c b/drivers/mtd/onenand/omap2.c
index 34b42533f4bbc9b3b809a622e3c89beebce911ce..8387e05daae2186ec32627407f9ee28eda757bd8 100644 (file)
--- 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;
+                       }
                }
        }