scsi: hisi_sas: Disable stash for v3 hw

For v3 hw, stash is enabled to promote performance, but it does little to
improve performance according to current tests. What's more, it causes
exceptions for some situations, so disable it.
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/hisi_sas/hisi_sas_v3_hw.c

@@ -28,6 +28,7 @@
 #define ITCT_CLR_EN_MSK			(0x1 << ITCT_CLR_EN_OFF)
 #define ITCT_DEV_OFF			0
 #define ITCT_DEV_MSK			(0x7ff << ITCT_DEV_OFF)
+#define SAS_AXI_USER3			0x50
 #define IO_SATA_BROKEN_MSG_ADDR_LO	0x58
 #define IO_SATA_BROKEN_MSG_ADDR_HI	0x5c
 #define SATA_INITI_D2H_STORE_ADDR_LO	0x60
@@ -554,6 +555,7 @@ static void init_reg_v3_hw(struct hisi_hba *hisi_hba)
 	/* Global registers init */
 	hisi_sas_write32(hisi_hba, DLVRY_QUEUE_ENABLE,
 			 (u32)((1ULL << hisi_hba->queue_count) - 1));
+	hisi_sas_write32(hisi_hba, SAS_AXI_USER3, 0);
 	hisi_sas_write32(hisi_hba, CFG_MAX_TAG, 0xfff0400);
 	hisi_sas_write32(hisi_hba, HGC_SAS_TXFAIL_RETRY_CTRL, 0x108);
 	hisi_sas_write32(hisi_hba, CFG_AGING_TIME, 0x1);