net: hns3: refactor the procedure of VF FLR

Currently, the actual work of VF FLR is handled in the reset task,
which is asynchronous. So in some case, if the preparing and
rebuilding are not done, then the VF FLR will trigger some problems,
for example, makes hardware go into chaos.

So this patch separates the process of VF FLR from reset task, and
adds a semaphore to serialize this reset and others.

When FLR's preparing fails, if there has other higher level reset
pending or failing times less than the HCLGE_FLR_RETRY_CNT, this
preparing should be retried, otherwise it will get into a wrong state.

BTW, while the hardware reports misc interrupt during pcie_flr(),
the driver can not receive this interrupt anymore, so disable it
when hclgevf_flr_prepare() return, and re-enable it when enter
hclgevf_flr_done().

Avoid declaring internal function hclgevf_enable_vector(), this patch
also moves its definition forward, and removes unused enum
hnae3_flr_state.
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hnae3.h

@@ -167,11 +167,6 @@ enum hnae3_reset_type {
 	HNAE3_MAX_RESET,
 };
 
-enum hnae3_flr_state {
-	HNAE3_FLR_DOWN,
-	HNAE3_FLR_DONE,
-};
-
 enum hnae3_port_base_vlan_state {
 	HNAE3_PORT_BASE_VLAN_DISABLE,
 	HNAE3_PORT_BASE_VLAN_ENABLE,

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

@@ -1411,32 +1411,6 @@ static int hclgevf_notify_client(struct hclgevf_dev *hdev,
 	return ret;
 }
 
-static void hclgevf_flr_done(struct hnae3_ae_dev *ae_dev)
-{
-	struct hclgevf_dev *hdev = ae_dev->priv;
-
-	set_bit(HNAE3_FLR_DONE, &hdev->flr_state);
-}
-
-static int hclgevf_flr_poll_timeout(struct hclgevf_dev *hdev,
-				    unsigned long delay_us,
-				    unsigned long wait_cnt)
-{
-	unsigned long cnt = 0;
-
-	while (!test_bit(HNAE3_FLR_DONE, &hdev->flr_state) &&
-	       cnt++ < wait_cnt)
-		usleep_range(delay_us, delay_us * 2);
-
-	if (!test_bit(HNAE3_FLR_DONE, &hdev->flr_state)) {
-		dev_err(&hdev->pdev->dev,
-			"flr wait timeout\n");
-		return -ETIMEDOUT;
-	}
-
-	return 0;
-}
-
 static int hclgevf_reset_wait(struct hclgevf_dev *hdev)
 {
 #define HCLGEVF_RESET_WAIT_US	20000
@@ -1447,11 +1421,7 @@ static int hclgevf_reset_wait(struct hclgevf_dev *hdev)
 	u32 val;
 	int ret;
 
-	if (hdev->reset_type == HNAE3_FLR_RESET)
-		return hclgevf_flr_poll_timeout(hdev,
-						HCLGEVF_RESET_WAIT_US,
-						HCLGEVF_RESET_WAIT_CNT);
-	else if (hdev->reset_type == HNAE3_VF_RESET)
+	if (hdev->reset_type == HNAE3_VF_RESET)
 		ret = readl_poll_timeout(hdev->hw.io_base +
 					 HCLGEVF_VF_RST_ING, val,
 					 !(val & HCLGEVF_VF_RST_ING_BIT),
@@ -1533,18 +1503,10 @@ static int hclgevf_reset_prepare_wait(struct hclgevf_dev *hdev)
 
 	int ret = 0;
 
-	switch (hdev->reset_type) {
-	case HNAE3_VF_FUNC_RESET:
+	if (hdev->reset_type == HNAE3_VF_FUNC_RESET) {
 		ret = hclgevf_send_mbx_msg(hdev, HCLGE_MBX_RESET, 0, NULL,
 					   0, true, NULL, sizeof(u8));
 		hdev->rst_stats.vf_func_rst_cnt++;
-		break;
-	case HNAE3_FLR_RESET:
-		set_bit(HNAE3_FLR_DOWN, &hdev->flr_state);
-		hdev->rst_stats.flr_rst_cnt++;
-		break;
-	default:
-		break;
 	}
 
 	set_bit(HCLGEVF_STATE_CMD_DISABLE, &hdev->state);
@@ -1734,25 +1696,60 @@ static void hclgevf_set_def_reset_request(struct hnae3_ae_dev *ae_dev,
 	set_bit(rst_type, &hdev->default_reset_request);
 }
 
+static void hclgevf_enable_vector(struct hclgevf_misc_vector *vector, bool en)
+{
+	writel(en ? 1 : 0, vector->addr);
+}
+
 static void hclgevf_flr_prepare(struct hnae3_ae_dev *ae_dev)
 {
-#define HCLGEVF_FLR_WAIT_MS	100
-#define HCLGEVF_FLR_WAIT_CNT	50
+#define HCLGEVF_FLR_RETRY_WAIT_MS	500
+#define HCLGEVF_FLR_RETRY_CNT		5
+
 	struct hclgevf_dev *hdev = ae_dev->priv;
-	int cnt = 0;
+	int retry_cnt = 0;
+	int ret;
 
-	clear_bit(HNAE3_FLR_DOWN, &hdev->flr_state);
-	clear_bit(HNAE3_FLR_DONE, &hdev->flr_state);
-	set_bit(HNAE3_FLR_RESET, &hdev->default_reset_request);
-	hclgevf_reset_event(hdev->pdev, NULL);
+retry:
+	down(&hdev->reset_sem);
+	set_bit(HCLGEVF_STATE_RST_HANDLING, &hdev->state);
+	hdev->reset_type = HNAE3_FLR_RESET;
+	ret = hclgevf_reset_prepare(hdev);
+	if (ret) {
+		dev_err(&hdev->pdev->dev, "fail to prepare FLR, ret=%d\n",
+			ret);
+		if (hdev->reset_pending ||
+		    retry_cnt++ < HCLGEVF_FLR_RETRY_CNT) {
+			dev_err(&hdev->pdev->dev,
+				"reset_pending:0x%lx, retry_cnt:%d\n",
+				hdev->reset_pending, retry_cnt);
+			clear_bit(HCLGEVF_STATE_RST_HANDLING, &hdev->state);
+			up(&hdev->reset_sem);
+			msleep(HCLGEVF_FLR_RETRY_WAIT_MS);
+			goto retry;
+		}
+	}
 
-	while (!test_bit(HNAE3_FLR_DOWN, &hdev->flr_state) &&
-	       cnt++ < HCLGEVF_FLR_WAIT_CNT)
-		msleep(HCLGEVF_FLR_WAIT_MS);
+	/* disable misc vector before FLR done */
+	hclgevf_enable_vector(&hdev->misc_vector, false);
+	hdev->rst_stats.flr_rst_cnt++;
+}
 
-	if (!test_bit(HNAE3_FLR_DOWN, &hdev->flr_state))
-		dev_err(&hdev->pdev->dev,
-			"flr wait down timeout: %d\n", cnt);
+static void hclgevf_flr_done(struct hnae3_ae_dev *ae_dev)
+{
+	struct hclgevf_dev *hdev = ae_dev->priv;
+	int ret;
+
+	hclgevf_enable_vector(&hdev->misc_vector, true);
+
+	ret = hclgevf_reset_rebuild(hdev);
+	if (ret)
+		dev_warn(&hdev->pdev->dev, "fail to rebuild, ret=%d\n",
+			 ret);
+
+	hdev->reset_type = HNAE3_NONE_RESET;
+	clear_bit(HCLGEVF_STATE_RST_HANDLING, &hdev->state);
+	up(&hdev->reset_sem);
 }
 
 static u32 hclgevf_get_fw_version(struct hnae3_handle *handle)
@@ -1808,8 +1805,8 @@ static void hclgevf_reset_service_task(struct hclgevf_dev *hdev)
 	if (!test_and_clear_bit(HCLGEVF_STATE_RST_SERVICE_SCHED, &hdev->state))
 		return;
 
-	if (test_and_set_bit(HCLGEVF_STATE_RST_HANDLING, &hdev->state))
-		return;
+	down(&hdev->reset_sem);
+	set_bit(HCLGEVF_STATE_RST_HANDLING, &hdev->state);
 
 	if (test_and_clear_bit(HCLGEVF_RESET_PENDING,
 			       &hdev->reset_state)) {
@@ -1866,6 +1863,7 @@ static void hclgevf_reset_service_task(struct hclgevf_dev *hdev)
 	}
 
 	clear_bit(HCLGEVF_STATE_RST_HANDLING, &hdev->state);
+	up(&hdev->reset_sem);
 }
 
 static void hclgevf_mailbox_service_task(struct hclgevf_dev *hdev)
@@ -2009,11 +2007,6 @@ static enum hclgevf_evt_cause hclgevf_check_evt_cause(struct hclgevf_dev *hdev,
 	return HCLGEVF_VECTOR0_EVENT_OTHER;
 }
 
-static void hclgevf_enable_vector(struct hclgevf_misc_vector *vector, bool en)
-{
-	writel(en ? 1 : 0, vector->addr);
-}
-
 static irqreturn_t hclgevf_misc_irq_handle(int irq, void *data)
 {
 	enum hclgevf_evt_cause event_cause;
@@ -2288,6 +2281,7 @@ static void hclgevf_state_init(struct hclgevf_dev *hdev)
 	INIT_DELAYED_WORK(&hdev->service_task, hclgevf_service_task);
 
 	mutex_init(&hdev->mbx_resp.mbx_mutex);
+	sema_init(&hdev->reset_sem, 1);
 
 	/* bring the device down */
 	set_bit(HCLGEVF_STATE_DOWN, &hdev->state);

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

@@ -253,6 +253,7 @@ struct hclgevf_dev {
 	unsigned long reset_state;	/* requested, pending */
 	struct hclgevf_rst_stats rst_stats;
 	u32 reset_attempts;
+	struct semaphore reset_sem;	/* protect reset process */
 
 	u32 fw_version;
 	u16 num_tqps;		/* num task queue pairs of this PF */