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authorKonstantin Baidarov <kbaidarov@ru.mvista.com>2005-11-07 09:00:05 +0000
committerThomas Gleixner <tglx@mtd.linutronix.de>2005-11-07 10:47:08 +0100
commitb95f9609c761a14d1e7be1a89f2a66399b5ae343 (patch)
treed0f097e82deb18ebc0c854ac1ae627865b63a130 /drivers/mtd
parentbe30c10fd8015a00c97c9b473263fe3c581389de (diff)
downloadop-kernel-dev-b95f9609c761a14d1e7be1a89f2a66399b5ae343.zip
op-kernel-dev-b95f9609c761a14d1e7be1a89f2a66399b5ae343.tar.gz
[MTD] chips cfi_cmdset_0002: Prevent timeout race
We've noticed that sometimes "MTD do_write_buffer(): software timeout" message was printed out when writing to a Fujitsu NOR flash. It turned out that this was because of a race in the timeout handling do_write_buffer(). A small timeout of (HZ / 1000) + 1 is used there, and sometimes if the timer interrupt handling takes more than one or even two jiffies (which is 1-2 ms with HZ == 1000) and that interrupt happens just after chip_ready() call, the driver bails out from a ready polling loop despite the chip has actually become ready while all those interrupts were handled. To deal with this issue, extra check for chip ready is neccessary on timeout expiration (and the checks should better be reordered). As do_write_oneword() uses the same approach, it needs to also be changed. Signed-off-by: Konstantin Baidarov <kbaidarov@ru.mvista.com> Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'drivers/mtd')
-rw-r--r--drivers/mtd/chips/cfi_cmdset_0002.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index e3d31c7..50dd7d2 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -17,7 +17,7 @@
*
* This code is GPL
*
- * $Id: cfi_cmdset_0002.c,v 1.120 2005/07/20 21:01:13 tpoynor Exp $
+ * $Id: cfi_cmdset_0002.c,v 1.121 2005/11/07 09:00:01 gleixner Exp $
*
*/
@@ -1014,16 +1014,16 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
continue;
}
- if (chip_ready(map, adr))
- break;
-
- if (time_after(jiffies, timeo)) {
+ if (time_after(jiffies, timeo) && !chip_ready(map, adr)){
xip_enable(map, chip, adr);
printk(KERN_WARNING "MTD %s(): software timeout\n", __func__);
xip_disable(map, chip, adr);
- break;
+ break;
}
+ if (chip_ready(map, adr))
+ break;
+
/* Latency issues. Drop the lock, wait a while and retry */
UDELAY(map, chip, adr, 1);
}
@@ -1275,13 +1275,13 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
continue;
}
+ if (time_after(jiffies, timeo) && !chip_ready(map, adr))
+ break;
+
if (chip_ready(map, adr)) {
xip_enable(map, chip, adr);
goto op_done;
}
-
- if( time_after(jiffies, timeo))
- break;
/* Latency issues. Drop the lock, wait a while and retry */
UDELAY(map, chip, adr, 1);
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