scsi: hisi_sas: workaround a v3 hw hilink bug

There is an SoC bug of v3 hw development version. When hot- unplugging a
directly attached disk, the PHY down interrupt may not happen. It is
very easy to appear on some boards.

When this issue occurs, the controller will receive many invalid dword
frames, and the "alos" fields of register HILINK_ERR_DFX can indicate
that disk was unplugged.

As an workaround solution, this patch detects this issue in the channel
interrupt, and workaround it by following steps:

 - Disable the PHY
 - Clear error code and interrupt
 - Enable the PHY

Then the HW will reissue PHY down interrupt.

Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.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

@@ -106,6 +106,7 @@
 #define COMPL_Q_0_RD_PTR		0x4f0
 #define AWQOS_AWCACHE_CFG	0xc84
 #define ARQOS_ARCACHE_CFG	0xc88
+#define HILINK_ERR_DFX		0xe04
 
 /* phy registers requiring init */
 #define PORT_BASE			(0x2000)
@@ -167,6 +168,7 @@
 #define CHL_INT1_DMAC_RX_AXI_RD_ERR_OFF	22
 #define CHL_INT2			(PORT_BASE + 0x1bc)
 #define CHL_INT2_SL_IDAF_TOUT_CONF_OFF	0
+#define CHL_INT2_RX_INVLD_DW_OFF	30
 #define CHL_INT2_STP_LINK_TIMEOUT_OFF	31
 #define CHL_INT0_MSK			(PORT_BASE + 0x1c0)
 #define CHL_INT1_MSK			(PORT_BASE + 0x1c4)
@@ -1345,6 +1347,7 @@ static irqreturn_t int_chnl_int_v3_hw(int irq_no, void *p)
 {
 	struct hisi_hba *hisi_hba = p;
 	struct device *dev = hisi_hba->dev;
+	struct pci_dev *pci_dev = hisi_hba->pci_dev;
 	u32 irq_msk;
 	int phy_no = 0;
 
@@ -1410,8 +1413,28 @@ static irqreturn_t int_chnl_int_v3_hw(int irq_no, void *p)
 
 			hisi_sas_phy_write32(hisi_hba, phy_no,
 					     CHL_INT2, irq_value2);
-		}
 
+			if ((irq_value2 & BIT(CHL_INT2_RX_INVLD_DW_OFF)) &&
+			    (pci_dev->revision == 0x20)) {
+				u32 reg_value;
+				int rc;
+
+				rc = hisi_sas_read32_poll_timeout_atomic(
+					HILINK_ERR_DFX, reg_value,
+					!((reg_value >> 8) & BIT(phy_no)),
+					1000, 10000);
+				if (rc) {
+					disable_phy_v3_hw(hisi_hba, phy_no);
+					hisi_sas_phy_write32(hisi_hba, phy_no,
+						CHL_INT2,
+						BIT(CHL_INT2_RX_INVLD_DW_OFF));
+					hisi_sas_phy_read32(hisi_hba, phy_no,
+						ERR_CNT_INVLD_DW);
+					mdelay(1);
+					enable_phy_v3_hw(hisi_hba, phy_no);
+				}
+			}
+		}
 
 		if (irq_msk & (2 << (phy_no * 4)) && irq_value0) {
 			hisi_sas_phy_write32(hisi_hba, phy_no,