From: Ching Huang <ching2048@areca.com.tw>
Date: Tue, 5 Dec 2017 10:02:16 +0800
Subject: [PATCH] scsi: arcmsr: Fix clear doorbell queue on ACB_ADAPTER_TYPE_B
Git-commit: 2124c5b2cc6a4dc92f609378ecadb66e686efb5f
Patch-mainline: v4.16-rc1
References: bsc#1118139

Fix clear doorbell queue on ACB_ADAPTER_TYPE_B controller.

Signed-off-by: Ching Huang <ching2048@areca.com.tw>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/scsi/arcmsr/arcmsr_hba.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
index 716ecec0df5a..c63d6757fee5 100644
--- a/drivers/scsi/arcmsr/arcmsr_hba.c
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c
@@ -4196,10 +4196,19 @@ static void arcmsr_clear_doorbell_queue_buffer(struct AdapterControlBlock *acb)
 
 	case ACB_ADAPTER_TYPE_B: {
 		struct MessageUnit_B *reg = acb->pmuB;
-		/*clear interrupt and message state*/
-		writel(ARCMSR_MESSAGE_INT_CLEAR_PATTERN, reg->iop2drv_doorbell);
+		uint32_t outbound_doorbell, i;
+		writel(ARCMSR_DOORBELL_INT_CLEAR_PATTERN, reg->iop2drv_doorbell);
 		writel(ARCMSR_DRV2IOP_DATA_READ_OK, reg->drv2iop_doorbell);
 		/* let IOP know data has been read */
+		for(i=0; i < 200; i++) {
+			msleep(20);
+			outbound_doorbell = readl(reg->iop2drv_doorbell);
+			if( outbound_doorbell & ARCMSR_IOP2DRV_DATA_WRITE_OK) {
+				writel(ARCMSR_DOORBELL_INT_CLEAR_PATTERN, reg->iop2drv_doorbell);
+				writel(ARCMSR_DRV2IOP_DATA_READ_OK, reg->drv2iop_doorbell);
+			} else
+				break;
+		}
 		}
 		break;
 	case ACB_ADAPTER_TYPE_C: {
-- 
2.12.3