net/mlx4_core: Enhance the catas flow to support device reset

This includes:

- resetting the chip when a fatal error is detected (the current code
  does not do this).

- exposing the ability to enter error state from outside the catas code
  by calling its functionality. (E.g. FW Command timeout, AER error).

- managing a persistent device state. This is needed to sync between
  reset flow cases.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/catas.c

@@ -48,6 +48,83 @@ MODULE_PARM_DESC(internal_err_reset,
 		 "Reset device on internal errors if non-zero"
 		 " (default 1, in SRIOV mode default is 0)");
 
+static int read_vendor_id(struct mlx4_dev *dev)
+{
+	u16 vendor_id = 0;
+	int ret;
+
+	ret = pci_read_config_word(dev->persist->pdev, 0, &vendor_id);
+	if (ret) {
+		mlx4_err(dev, "Failed to read vendor ID, ret=%d\n", ret);
+		return ret;
+	}
+
+	if (vendor_id == 0xffff) {
+		mlx4_err(dev, "PCI can't be accessed to read vendor id\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int mlx4_reset_master(struct mlx4_dev *dev)
+{
+	int err = 0;
+
+	if (!pci_channel_offline(dev->persist->pdev)) {
+		err = read_vendor_id(dev);
+		/* If PCI can't be accessed to read vendor ID we assume that its
+		 * link was disabled and chip was already reset.
+		 */
+		if (err)
+			return 0;
+
+		err = mlx4_reset(dev);
+		if (err)
+			mlx4_err(dev, "Fail to reset HCA\n");
+	}
+
+	return err;
+}
+
+void mlx4_enter_error_state(struct mlx4_dev_persistent *persist)
+{
+	int err;
+	struct mlx4_dev *dev;
+
+	if (!internal_err_reset)
+		return;
+
+	mutex_lock(&persist->device_state_mutex);
+	if (persist->state & MLX4_DEVICE_STATE_INTERNAL_ERROR)
+		goto out;
+
+	dev = persist->dev;
+	mlx4_err(dev, "device is going to be reset\n");
+	err = mlx4_reset_master(dev);
+	BUG_ON(err != 0);
+
+	dev->persist->state |= MLX4_DEVICE_STATE_INTERNAL_ERROR;
+	mlx4_err(dev, "device was reset successfully\n");
+	mutex_unlock(&persist->device_state_mutex);
+
+	/* At that step HW was already reset, now notify clients */
+	mlx4_dispatch_event(dev, MLX4_DEV_EVENT_CATASTROPHIC_ERROR, 0);
+	return;
+
+out:
+	mutex_unlock(&persist->device_state_mutex);
+}
+
+static void mlx4_handle_error_state(struct mlx4_dev_persistent *persist)
+{
+	int err = 0;
+
+	mlx4_enter_error_state(persist);
+	err = mlx4_restart_one(persist->pdev);
+	mlx4_info(persist->dev, "mlx4_restart_one was ended, ret=%d\n", err);
+}
+
 static void dump_err_buf(struct mlx4_dev *dev)
 {
 	struct mlx4_priv *priv = mlx4_priv(dev);
@@ -66,21 +143,22 @@ static void poll_catas(unsigned long dev_ptr)
 	struct mlx4_priv *priv = mlx4_priv(dev);
 
 	if (readl(priv->catas_err.map)) {
-		/* If the device is off-line, we cannot try to recover it */
-		if (pci_channel_offline(dev->persist->pdev))
-			mod_timer(&priv->catas_err.timer,
-				  round_jiffies(jiffies + MLX4_CATAS_POLL_INTERVAL));
-		else {
 		dump_err_buf(dev);
-			mlx4_dispatch_event(dev, MLX4_DEV_EVENT_CATASTROPHIC_ERROR, 0);
-
-			if (internal_err_reset)
-				queue_work(dev->persist->catas_wq,
-					   &dev->persist->catas_work);
+		goto internal_err;
 	}
-	} else
+
+	if (dev->persist->state & MLX4_DEVICE_STATE_INTERNAL_ERROR) {
+		mlx4_warn(dev, "Internal error mark was detected on device\n");
+		goto internal_err;
+	}
+
 	mod_timer(&priv->catas_err.timer,
 		  round_jiffies(jiffies + MLX4_CATAS_POLL_INTERVAL));
+	return;
+
+internal_err:
+	if (internal_err_reset)
+		queue_work(dev->persist->catas_wq, &dev->persist->catas_work);
 }
 
 static void catas_reset(struct work_struct *work)
@@ -88,20 +166,8 @@ static void catas_reset(struct work_struct *work)
 	struct mlx4_dev_persistent *persist =
 		container_of(work, struct mlx4_dev_persistent,
 			     catas_work);
-	struct pci_dev *pdev = persist->pdev;
-	int ret;
 
-	/* If the device is off-line, we cannot reset it */
-	if (pci_channel_offline(pdev))
-		return;
-
-	ret = mlx4_restart_one(pdev);
-	/* 'priv' now is not valid */
-	if (ret)
-		pr_err("mlx4 %s: Reset failed (%d)\n",
-		       pci_name(pdev), ret);
-	else
-		mlx4_dbg(persist->dev, "Reset succeeded\n");
+	mlx4_handle_error_state(persist);
 }
 
 void mlx4_start_catas_poll(struct mlx4_dev *dev)

drivers/net/ethernet/mellanox/mlx4/main.c

@@ -2624,6 +2624,11 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 		}
 	}
 
+	/* on load remove any previous indication of internal error,
+	 * device is up.
+	 */
+	dev->persist->state = MLX4_DEVICE_STATE_UP;
+
 slave_start:
 	err = mlx4_cmd_init(dev);
 	if (err) {
@@ -3108,6 +3113,7 @@ static int mlx4_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 	dev->persist->dev = dev;
 	pci_set_drvdata(pdev, dev->persist);
 	priv->pci_dev_data = id->driver_data;
+	mutex_init(&dev->persist->device_state_mutex);
 
 	ret =  __mlx4_init_one(pdev, id->driver_data, priv);
 	if (ret) {

drivers/net/ethernet/mellanox/mlx4/mlx4.h

@@ -1178,7 +1178,7 @@ void mlx4_qp_event(struct mlx4_dev *dev, u32 qpn, int event_type);
 
 void mlx4_srq_event(struct mlx4_dev *dev, u32 srqn, int event_type);
 
-void mlx4_handle_catas_err(struct mlx4_dev *dev);
+void mlx4_enter_error_state(struct mlx4_dev_persistent *persist);
 
 int mlx4_SENSE_PORT(struct mlx4_dev *dev, int port,
 		    enum mlx4_port_type *type);

include/linux/mlx4/device.h

@@ -411,6 +411,11 @@ enum {
 	MLX4_EQ_PORT_INFO_MSTR_SM_SL_CHANGE_MASK	= 1 << 4,
 };
 
+enum {
+	MLX4_DEVICE_STATE_UP			= 1 << 0,
+	MLX4_DEVICE_STATE_INTERNAL_ERROR	= 1 << 1,
+};
+
 #define MSTR_SM_CHANGE_MASK (MLX4_EQ_PORT_INFO_MSTR_SM_SL_CHANGE_MASK | \
 			     MLX4_EQ_PORT_INFO_MSTR_SM_LID_CHANGE_MASK)
 
@@ -753,6 +758,8 @@ struct mlx4_dev_persistent {
 	enum mlx4_port_type curr_port_poss_type[MLX4_MAX_PORTS + 1];
 	struct work_struct      catas_work;
 	struct workqueue_struct *catas_wq;
+	struct mutex	device_state_mutex; /* protect HW state */
+	u8		state;
 };
 
 struct mlx4_dev {