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[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>
This commit is contained in:
Adrian Hunter 2008-08-25 12:01:31 +03:00 committed by David Woodhouse
parent 34f6e15786
commit 8afbc11454
1 changed files with 23 additions and 3 deletions
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26
drivers/mtd/onenand/omap2.c
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@ -187,16 +187,36 @@ retry:
} }
} }
} else { } else {
int retry_cnt = 0;
/* Turn interrupts off */ /* Turn interrupts off */
syscfg = read_reg(c, ONENAND_REG_SYS_CFG1); syscfg = read_reg(c, ONENAND_REG_SYS_CFG1);
syscfg &= ~ONENAND_SYS_CFG1_IOBE; syscfg &= ~ONENAND_SYS_CFG1_IOBE;
write_reg(c, syscfg, ONENAND_REG_SYS_CFG1); write_reg(c, syscfg, ONENAND_REG_SYS_CFG1);
timeout = jiffies + msecs_to_jiffies(20); timeout = jiffies + msecs_to_jiffies(20);
while (time_before(jiffies, timeout)) { while (1) {
intr = read_reg(c, ONENAND_REG_INTERRUPT); if (time_before(jiffies, timeout)) {
if (intr & ONENAND_INT_MASTER) 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; break;
}
} }
} }