ipr: Add delay to ensure coherent dumps.

Add a holding pattern prior to collecting dump data, to wait for the IOA
indication that the Mailbox register is stable and won't change without
an explicit reset.  This ensures we'll be collecting meaningful dump
data, even when dumping right after an adapter reset.

In the event of a timeout, we still force the dump, since a partial dump
still might be useful.

Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 39 insertions, 12 deletions

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index b62836d..238efab 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -8277,6 +8277,42 @@ static int ipr_reset_get_unit_check_job(struct ipr_cmnd *ipr_cmd)
 	return IPR_RC_JOB_RETURN;
 }
 
+static int ipr_dump_mailbox_wait(struct ipr_cmnd *ipr_cmd)
+{
+	struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg;
+
+	ENTER;
+
+	if (ioa_cfg->sdt_state != GET_DUMP)
+		return IPR_RC_JOB_RETURN;
+
+	if (!ioa_cfg->sis64 || !ipr_cmd->u.time_left ||
+	    (readl(ioa_cfg->regs.sense_interrupt_reg) &
+	     IPR_PCII_MAILBOX_STABLE)) {
+
+		if (!ipr_cmd->u.time_left)
+			dev_err(&ioa_cfg->pdev->dev,
+				"Timed out waiting for Mailbox register.\n");
+
+		ioa_cfg->sdt_state = READ_DUMP;
+		ioa_cfg->dump_timeout = 0;
+		if (ioa_cfg->sis64)
+			ipr_reset_start_timer(ipr_cmd, IPR_SIS64_DUMP_TIMEOUT);
+		else
+			ipr_reset_start_timer(ipr_cmd, IPR_SIS32_DUMP_TIMEOUT);
+		ipr_cmd->job_step = ipr_reset_wait_for_dump;
+		schedule_work(&ioa_cfg->work_q);
+
+	} else {
+		ipr_cmd->u.time_left -= IPR_CHECK_FOR_RESET_TIMEOUT;
+		ipr_reset_start_timer(ipr_cmd,
+				      IPR_CHECK_FOR_RESET_TIMEOUT);
+	}
+
+	LEAVE;
+	return IPR_RC_JOB_RETURN;
+}
+
 /**
  * ipr_reset_restore_cfg_space - Restore PCI config space.
  * @ipr_cmd:	ipr command struct
@@ -8326,20 +8362,11 @@ static int ipr_reset_restore_cfg_space(struct ipr_cmnd *ipr_cmd)
 
 	if (ioa_cfg->in_ioa_bringdown) {
 		ipr_cmd->job_step = ipr_ioa_bringdown_done;
+	} else if (ioa_cfg->sdt_state == GET_DUMP) {
+		ipr_cmd->job_step = ipr_dump_mailbox_wait;
+		ipr_cmd->u.time_left = IPR_WAIT_FOR_MAILBOX;
 	} else {
 		ipr_cmd->job_step = ipr_reset_enable_ioa;
-
-		if (GET_DUMP == ioa_cfg->sdt_state) {
-			ioa_cfg->sdt_state = READ_DUMP;
-			ioa_cfg->dump_timeout = 0;
-			if (ioa_cfg->sis64)
-				ipr_reset_start_timer(ipr_cmd, IPR_SIS64_DUMP_TIMEOUT);
-			else
-				ipr_reset_start_timer(ipr_cmd, IPR_SIS32_DUMP_TIMEOUT);
-			ipr_cmd->job_step = ipr_reset_wait_for_dump;
-			schedule_work(&ioa_cfg->work_q);
-			return IPR_RC_JOB_RETURN;
-		}
 	}
 
 	LEAVE;