net: hns3: fix interrupt clearing error for VF

Currently, VF driver has two kinds of interrupts, reset & CMDQ RX.
For revision 0x21, according to the UM, each interrupt should be
cleared by write 0 to the corresponding bit, but the implementation
writes 0 to the whole register in fact, it will clear other
interrupt at the same time, then the VF will loss the interrupt.
But for revision 0x20, this interrupt clear register is a read &
write register, for compatible, we just keep the old implementation
for 0x20.

This patch fixes it, also, adds a new register for reading the interrupt
status according to hardware user manual.

Fixes: e2cb1dec ("net: hns3: Add HNS3 VF HCL(Hardware Compatibility Layer) Support")
Fixes: b90fcc5b ("net: hns3: add reset handling for VF when doing Core/Global/IMP reset")
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Reviewed-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.c

@@ -1889,21 +1889,20 @@ static void hclgevf_clear_event_cause(struct hclgevf_dev *hdev, u32 regclr)
 static enum hclgevf_evt_cause hclgevf_check_evt_cause(struct hclgevf_dev *hdev,
 						      u32 *clearval)
 {
-	u32 val, cmdq_src_reg, rst_ing_reg;
+	u32 val, cmdq_stat_reg, rst_ing_reg;
 
 	/* fetch the events from their corresponding regs */
-	cmdq_src_reg = hclgevf_read_dev(&hdev->hw,
-					HCLGEVF_VECTOR0_CMDQ_SRC_REG);
+	cmdq_stat_reg = hclgevf_read_dev(&hdev->hw,
+					 HCLGEVF_VECTOR0_CMDQ_STAT_REG);
 
-	if (BIT(HCLGEVF_VECTOR0_RST_INT_B) & cmdq_src_reg) {
+	if (BIT(HCLGEVF_VECTOR0_RST_INT_B) & cmdq_stat_reg) {
 		rst_ing_reg = hclgevf_read_dev(&hdev->hw, HCLGEVF_RST_ING);
 		dev_info(&hdev->pdev->dev,
 			 "receive reset interrupt 0x%x!\n", rst_ing_reg);
 		set_bit(HNAE3_VF_RESET, &hdev->reset_pending);
 		set_bit(HCLGEVF_RESET_PENDING, &hdev->reset_state);
 		set_bit(HCLGEVF_STATE_CMD_DISABLE, &hdev->state);
-		cmdq_src_reg &= ~BIT(HCLGEVF_VECTOR0_RST_INT_B);
-		*clearval = cmdq_src_reg;
+		*clearval = ~(1U << HCLGEVF_VECTOR0_RST_INT_B);
 		hdev->rst_stats.vf_rst_cnt++;
 		/* set up VF hardware reset status, its PF will clear
 		 * this status when PF has initialized done.
@@ -1915,9 +1914,20 @@ static enum hclgevf_evt_cause hclgevf_check_evt_cause(struct hclgevf_dev *hdev,
 	}
 
 	/* check for vector0 mailbox(=CMDQ RX) event source */
-	if (BIT(HCLGEVF_VECTOR0_RX_CMDQ_INT_B) & cmdq_src_reg) {
-		cmdq_src_reg &= ~BIT(HCLGEVF_VECTOR0_RX_CMDQ_INT_B);
-		*clearval = cmdq_src_reg;
+	if (BIT(HCLGEVF_VECTOR0_RX_CMDQ_INT_B) & cmdq_stat_reg) {
+		/* for revision 0x21, clearing interrupt is writing bit 0
+		 * to the clear register, writing bit 1 means to keep the
+		 * old value.
+		 * for revision 0x20, the clear register is a read & write
+		 * register, so we should just write 0 to the bit we are
+		 * handling, and keep other bits as cmdq_stat_reg.
+		 */
+		if (hdev->pdev->revision >= 0x21)
+			*clearval = ~(1U << HCLGEVF_VECTOR0_RX_CMDQ_INT_B);
+		else
+			*clearval = cmdq_stat_reg &
+				    ~BIT(HCLGEVF_VECTOR0_RX_CMDQ_INT_B);
+
 		return HCLGEVF_VECTOR0_EVENT_MBX;
 	}
 

drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_main.h

@@ -87,6 +87,8 @@
 
 /* Vector0 interrupt CMDQ event source register(RW) */
 #define HCLGEVF_VECTOR0_CMDQ_SRC_REG	0x27100
+/* Vector0 interrupt CMDQ event status register(RO) */
+#define HCLGEVF_VECTOR0_CMDQ_STAT_REG	0x27104
 /* CMDQ register bits for RX event(=MBX event) */
 #define HCLGEVF_VECTOR0_RX_CMDQ_INT_B	1
 /* RST register bits for RESET event */