From ea38de7f97d6b503555f87f52446937e0025f7f5 Mon Sep 17 00:00:00 2001
From: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Date: Mon, 25 Apr 2016 23:32:37 -0700
Subject: [PATCH] aacraid: Fix for KDUMP driver hang

When KDUMP is triggered the driver first talks to the firmware in INTX
mode, but the adapter firmware is still in MSIX mode. Therefore the first
driver command hangs since the driver is waiting for an INTX response and
firmware gives a MSIX response. If when the OS is installed on a RAID
drive created by the adapter KDUMP will hang since the driver does not
receive a response in sync mode.

Fixed by: Change the firmware to INTX mode if it is in MSIX mode before
sending the first sync command.

Cc: stable@vger.kernel.org
Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 drivers/scsi/aacraid/aacraid.h  |  1 +
 drivers/scsi/aacraid/comminit.c | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h
index b70f3eb323f73..0ba8f6118e75a 100644
--- a/drivers/scsi/aacraid/aacraid.h
+++ b/drivers/scsi/aacraid/aacraid.h
@@ -29,6 +29,7 @@ enum {
 #define AAC_INT_MODE_MSI		(1<<1)
 #define AAC_INT_MODE_AIF		(1<<2)
 #define AAC_INT_MODE_SYNC		(1<<3)
+#define AAC_INT_MODE_MSIX		(1<<16)
 
 #define AAC_INT_ENABLE_TYPE1_INTX	0xfffffffb
 #define AAC_INT_ENABLE_TYPE1_MSIX	0xfffffffa
diff --git a/drivers/scsi/aacraid/comminit.c b/drivers/scsi/aacraid/comminit.c
index 50d521a452d2c..341ea327ae794 100644
--- a/drivers/scsi/aacraid/comminit.c
+++ b/drivers/scsi/aacraid/comminit.c
@@ -37,6 +37,7 @@
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/blkdev.h>
+#include <linux/delay.h>
 #include <linux/completion.h>
 #include <linux/mm.h>
 #include <scsi/scsi_host.h>
@@ -47,6 +48,20 @@ struct aac_common aac_config = {
 	.irq_mod = 1
 };
 
+static inline int aac_is_msix_mode(struct aac_dev *dev)
+{
+	u32 status;
+
+	status = src_readl(dev, MUnit.OMR);
+	return (status & AAC_INT_MODE_MSIX);
+}
+
+static inline void aac_change_to_intx(struct aac_dev *dev)
+{
+	aac_src_access_devreg(dev, AAC_DISABLE_MSIX);
+	aac_src_access_devreg(dev, AAC_ENABLE_INTX);
+}
+
 static int aac_alloc_comm(struct aac_dev *dev, void **commaddr, unsigned long commsize, unsigned long commalign)
 {
 	unsigned char *base;
@@ -414,6 +429,15 @@ struct aac_dev *aac_init_adapter(struct aac_dev *dev)
 	dev->comm_interface = AAC_COMM_PRODUCER;
 	dev->raw_io_interface = dev->raw_io_64 = 0;
 
+
+	/*
+	 * Enable INTX mode, if not done already Enabled
+	 */
+	if (aac_is_msix_mode(dev)) {
+		aac_change_to_intx(dev);
+		dev_info(&dev->pdev->dev, "Changed firmware to INTX mode");
+	}
+
 	if ((!aac_adapter_sync_cmd(dev, GET_ADAPTER_PROPERTIES,
 		0, 0, 0, 0, 0, 0,
 		status+0, status+1, status+2, status+3, NULL)) &&
-- 
2.39.5