[PATCH 7/8] rsxx: Adding EEH check inside cregs timeout.

[PATCH 7/8] rsxx: Adding EEH check inside cregs timeout.

[Philip J. Kelleher]

From: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>

Unfortunaly, our CPU register path does not do any kind of
EEH error checking. So to fix this issue, an ioread32 was
added to the CPU register timeout code. This way, the
driver can check to see if the timeout was caused by an EEH
error or not.

Signed-off-by: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
-------------------------------------------------------------------------------



diff -uprN -X linux-block-vanilla/Documentation/dontdiff linux-block-vanilla/drivers/block/rsxx/cregs.c linux-block/drivers/block/rsxx/cregs.c
--- linux-block-vanilla/drivers/block/rsxx/cregs.c	2013-05-01 18:36:44.693307317 -0500
+++ linux-block/drivers/block/rsxx/cregs.c	2013-05-01 18:59:57.596197150 -0500
@@ -431,6 +431,15 @@ static int __issue_creg_rw(struct rsxx_c
 	*hw_stat = completion.creg_status;
 
 	if (completion.st) {
+		/*
+		 * This read is needed to verify that there has not been any
+		 * extreme errors that might have occurred, i.e. EEH. The
+		 * function iowrite32 will not detect EEH errors, so it is
+		 * necessary that we recover if such an error is the reason
+		 * for the timeout.
+		 */
+		ioread32(card->regmap + SCRATCH);
+
 		dev_warn(CARD_TO_DEV(card),
 			"creg command failed(%d x%08x)\n",
 			completion.st, addr);

Re: [PATCH 7/8] rsxx: Adding EEH check inside cregs timeout.

[Andy Shevchenko]

On Wed, May 29, 2013 at 12:14 AM, Philip J. Kelleher
<pjk1939@linux.vnet.ibm.com> wrote:
> From: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
>
> Unfortunaly, our CPU register path does not do any kind of
> EEH error checking. So to fix this issue, an ioread32 was
> added to the CPU register timeout code. This way, the
> driver can check to see if the timeout was caused by an EEH
> error or not.


> +++ linux-block/drivers/block/rsxx/cregs.c      2013-05-01 18:59:57.596197150 -0500
> @@ -431,6 +431,15 @@ static int __issue_creg_rw(struct rsxx_c
>         *hw_stat = completion.creg_status;
>
>         if (completion.st) {
> +               /*
> +                * This read is needed to verify that there has not been any
> +                * extreme errors that might have occurred, i.e. EEH. The
> +                * function iowrite32 will not detect EEH errors, so it is
> +                * necessary that we recover if such an error is the reason
> +                * for the timeout.
> +                */
> +               ioread32(card->regmap + SCRATCH);

This is just a dummy read, right? Perhaps you may add this word to the
explanation.

--
With Best Regards,
Andy Shevchenko

[PATCH 7/8] rsxx: Adding EEH check inside cregs timeout.

[Philip J. Kelleher]

From: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>

Unfortunaly, our CPU register path does not do any kind of
EEH error checking. So to fix this issue, an ioread32 was
added to the CPU register timeout code. This way, the
driver can check to see if the timeout was caused by an EEH
error or not.

Signed-off-by: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
-------------------------------------------------------------------------------


diff -uprN -X linux-block-vanilla/Documentation/dontdiff linux-block-vanilla/drivers/block/rsxx/cregs.c linux-block/drivers/block/rsxx/cregs.c
--- linux-block-vanilla/drivers/block/rsxx/cregs.c	2013-05-01 18:36:44.693307317 -0500
+++ linux-block/drivers/block/rsxx/cregs.c	2013-05-01 18:59:57.596197150 -0500
@@ -431,6 +431,15 @@ static int __issue_creg_rw(struct rsxx_c
 	*hw_stat = completion.creg_status;
 
 	if (completion.st) {
+		/*
+		 * This read is needed to verify that there has not been any
+		 * extreme errors that might have occurred, i.e. EEH. The
+		 * function iowrite32 will not detect EEH errors, so it is
+		 * necessary that we recover if such an error is the reason
+		 * for the timeout.
+		 */
+		ioread32(card->regmap + SCRATCH);
+
 		dev_warn(CARD_TO_DEV(card),
 			"creg command failed(%d x%08x)\n",
 			completion.st, addr);