net/mlx5: Issue SW reset on FW assert

If a FW assert is considered fatal, indicated by a new bit in the health
buffer, reset the FW. After the reset go through the normal recovery
flow. Only one PF needs to issue the reset, so an attempt is made to
prevent the 2nd function from also issuing the reset.
It's not an error if that happens, it just slows recovery.
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/diag/crdump.c

@@ -51,14 +51,23 @@ int mlx5_crdump_collect(struct mlx5_core_dev *dev, u32 *cr_data)
 			       ret);
 		return ret;
 	}
+	/* Verify no other PF is running cr-dump or sw reset */
+	ret = mlx5_vsc_sem_set_space(dev, MLX5_SEMAPHORE_SW_RESET,
+				     MLX5_VSC_LOCK);
+	if (ret) {
+		mlx5_core_warn(dev, "Failed to lock SW reset semaphore\n");
+		goto unlock_gw;
+	}
 
 	ret = mlx5_vsc_gw_set_space(dev, MLX5_VSC_SPACE_SCAN_CRSPACE, NULL);
 	if (ret)
-		goto unlock;
+		goto unlock_sem;
 
 	ret = mlx5_crdump_fill(dev, cr_data);
 
-unlock:
+unlock_sem:
+	mlx5_vsc_sem_set_space(dev, MLX5_SEMAPHORE_SW_RESET, MLX5_VSC_UNLOCK);
+unlock_gw:
 	mlx5_vsc_gw_unlock(dev);
 	return ret;
 }

drivers/net/ethernet/mellanox/mlx5/core/health.c

@@ -40,6 +40,7 @@
 #include "mlx5_core.h"
 #include "lib/eq.h"
 #include "lib/mlx5.h"
+#include "lib/pci_vsc.h"
 
 enum {
 	MLX5_HEALTH_POLL_INTERVAL	= 2 * HZ,
@@ -67,8 +68,10 @@ enum {
 enum  {
 	MLX5_SENSOR_NO_ERR		= 0,
 	MLX5_SENSOR_PCI_COMM_ERR	= 1,
-	MLX5_SENSOR_NIC_DISABLED	= 2,
-	MLX5_SENSOR_NIC_SW_RESET	= 3,
+	MLX5_SENSOR_PCI_ERR		= 2,
+	MLX5_SENSOR_NIC_DISABLED	= 3,
+	MLX5_SENSOR_NIC_SW_RESET	= 4,
+	MLX5_SENSOR_FW_SYND_RFR		= 5,
 };
 
 u8 mlx5_get_nic_state(struct mlx5_core_dev *dev)
@@ -95,32 +98,162 @@ static bool sensor_pci_not_working(struct mlx5_core_dev *dev)
 	return (ioread32be(&h->fw_ver) == 0xffffffff);
 }
 
+static bool sensor_fw_synd_rfr(struct mlx5_core_dev *dev)
+{
+	struct mlx5_core_health *health = &dev->priv.health;
+	struct health_buffer __iomem *h = health->health;
+	u32 rfr = ioread32be(&h->rfr) >> MLX5_RFR_OFFSET;
+	u8 synd = ioread8(&h->synd);
+
+	if (rfr && synd)
+		mlx5_core_dbg(dev, "FW requests reset, synd: %d\n", synd);
+	return rfr && synd;
+}
+
 static u32 check_fatal_sensors(struct mlx5_core_dev *dev)
 {
 	if (sensor_pci_not_working(dev))
 		return MLX5_SENSOR_PCI_COMM_ERR;
+	if (pci_channel_offline(dev->pdev))
+		return MLX5_SENSOR_PCI_ERR;
 	if (mlx5_get_nic_state(dev) == MLX5_NIC_IFC_DISABLED)
 		return MLX5_SENSOR_NIC_DISABLED;
 	if (mlx5_get_nic_state(dev) == MLX5_NIC_IFC_SW_RESET)
 		return MLX5_SENSOR_NIC_SW_RESET;
+	if (sensor_fw_synd_rfr(dev))
+		return MLX5_SENSOR_FW_SYND_RFR;
 
 	return MLX5_SENSOR_NO_ERR;
 }
 
+static int lock_sem_sw_reset(struct mlx5_core_dev *dev, bool lock)
+{
+	enum mlx5_vsc_state state;
+	int ret;
+
+	if (!mlx5_core_is_pf(dev))
+		return -EBUSY;
+
+	/* Try to lock GW access, this stage doesn't return
+	 * EBUSY because locked GW does not mean that other PF
+	 * already started the reset.
+	 */
+	ret = mlx5_vsc_gw_lock(dev);
+	if (ret == -EBUSY)
+		return -EINVAL;
+	if (ret)
+		return ret;
+
+	state = lock ? MLX5_VSC_LOCK : MLX5_VSC_UNLOCK;
+	/* At this stage, if the return status == EBUSY, then we know
+	 * for sure that another PF started the reset, so don't allow
+	 * another reset.
+	 */
+	ret = mlx5_vsc_sem_set_space(dev, MLX5_SEMAPHORE_SW_RESET, state);
+	if (ret)
+		mlx5_core_warn(dev, "Failed to lock SW reset semaphore\n");
+
+	/* Unlock GW access */
+	mlx5_vsc_gw_unlock(dev);
+
+	return ret;
+}
+
+static bool reset_fw_if_needed(struct mlx5_core_dev *dev)
+{
+	bool supported = (ioread32be(&dev->iseg->initializing) >>
+			  MLX5_FW_RESET_SUPPORTED_OFFSET) & 1;
+	u32 fatal_error;
+
+	if (!supported)
+		return false;
+
+	/* The reset only needs to be issued by one PF. The health buffer is
+	 * shared between all functions, and will be cleared during a reset.
+	 * Check again to avoid a redundant 2nd reset. If the fatal erros was
+	 * PCI related a reset won't help.
+	 */
+	fatal_error = check_fatal_sensors(dev);
+	if (fatal_error == MLX5_SENSOR_PCI_COMM_ERR ||
+	    fatal_error == MLX5_SENSOR_NIC_DISABLED ||
+	    fatal_error == MLX5_SENSOR_NIC_SW_RESET) {
+		mlx5_core_warn(dev, "Not issuing FW reset. Either it's already done or won't help.");
+		return false;
+	}
+
+	mlx5_core_warn(dev, "Issuing FW Reset\n");
+	/* Write the NIC interface field to initiate the reset, the command
+	 * interface address also resides here, don't overwrite it.
+	 */
+	mlx5_set_nic_state(dev, MLX5_NIC_IFC_SW_RESET);
+
+	return true;
+}
+
 void mlx5_enter_error_state(struct mlx5_core_dev *dev, bool force)
 {
 	mutex_lock(&dev->intf_state_mutex);
 	if (dev->state == MLX5_DEVICE_STATE_INTERNAL_ERROR)
 		goto unlock;
+	if (dev->state == MLX5_DEVICE_STATE_UNINITIALIZED) {
+		dev->state = MLX5_DEVICE_STATE_INTERNAL_ERROR;
+		goto unlock;
+	}
 
-	mlx5_core_err(dev, "start\n");
-	if (pci_channel_offline(dev->pdev) ||
-	    dev->priv.health.fatal_error != MLX5_SENSOR_NO_ERR || force) {
+	if (check_fatal_sensors(dev) || force) {
 		dev->state = MLX5_DEVICE_STATE_INTERNAL_ERROR;
 		mlx5_cmd_flush(dev);
 	}
 
 	mlx5_notifier_call_chain(dev->priv.events, MLX5_DEV_EVENT_SYS_ERROR, (void *)1);
+unlock:
+	mutex_unlock(&dev->intf_state_mutex);
+}
+
+#define MLX5_CRDUMP_WAIT_MS	60000
+#define MLX5_FW_RESET_WAIT_MS	1000
+void mlx5_error_sw_reset(struct mlx5_core_dev *dev)
+{
+	unsigned long end, delay_ms = MLX5_FW_RESET_WAIT_MS;
+	int lock = -EBUSY;
+
+	mutex_lock(&dev->intf_state_mutex);
+	if (dev->state != MLX5_DEVICE_STATE_INTERNAL_ERROR)
+		goto unlock;
+
+	mlx5_core_err(dev, "start\n");
+
+	if (check_fatal_sensors(dev) == MLX5_SENSOR_FW_SYND_RFR) {
+		/* Get cr-dump and reset FW semaphore */
+		lock = lock_sem_sw_reset(dev, true);
+
+		if (lock == -EBUSY) {
+			delay_ms = MLX5_CRDUMP_WAIT_MS;
+			goto recover_from_sw_reset;
+		}
+		/* Execute SW reset */
+		reset_fw_if_needed(dev);
+	}
+
+recover_from_sw_reset:
+	/* Recover from SW reset */
+	end = jiffies + msecs_to_jiffies(delay_ms);
+	do {
+		if (mlx5_get_nic_state(dev) == MLX5_NIC_IFC_DISABLED)
+			break;
+
+		cond_resched();
+	} while (!time_after(jiffies, end));
+
+	if (mlx5_get_nic_state(dev) != MLX5_NIC_IFC_DISABLED) {
+		dev_err(&dev->pdev->dev, "NIC IFC still %d after %lums.\n",
+			mlx5_get_nic_state(dev), delay_ms);
+	}
+
+	/* Release FW semaphore if you are the lock owner */
+	if (!lock)
+		lock_sem_sw_reset(dev, false);
+
 	mlx5_core_err(dev, "end\n");
 
 unlock:
@@ -143,6 +276,20 @@ static void mlx5_handle_bad_state(struct mlx5_core_dev *dev)
 	case MLX5_NIC_IFC_NO_DRAM_NIC:
 		mlx5_core_warn(dev, "Expected to see disabled NIC but it is no dram nic\n");
 		break;
+
+	case MLX5_NIC_IFC_SW_RESET:
+		/* The IFC mode field is 3 bits, so it will read 0x7 in 2 cases:
+		 * 1. PCI has been disabled (ie. PCI-AER, PF driver unloaded
+		 *    and this is a VF), this is not recoverable by SW reset.
+		 *    Logging of this is handled elsewhere.
+		 * 2. FW reset has been issued by another function, driver can
+		 *    be reloaded to recover after the mode switches to
+		 *    MLX5_NIC_IFC_DISABLED.
+		 */
+		if (dev->priv.health.fatal_error != MLX5_SENSOR_PCI_COMM_ERR)
+			mlx5_core_warn(dev, "NIC SW reset in progress\n");
+		break;
+
 	default:
 		mlx5_core_warn(dev, "Expected to see disabled NIC but it is has invalid value %d\n",
 			       nic_interface);

drivers/net/ethernet/mellanox/mlx5/core/main.c

@@ -1361,6 +1361,7 @@ static pci_ers_result_t mlx5_pci_err_detected(struct pci_dev *pdev,
 	mlx5_core_info(dev, "%s was called\n", __func__);
 
 	mlx5_enter_error_state(dev, false);
+	mlx5_error_sw_reset(dev);
 	mlx5_unload_one(dev, false);
 	/* In case of kernel call drain the health wq */
 	if (state) {

drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.h

@@ -113,6 +113,7 @@ enum {
 
 enum mlx5_semaphore_space_address {
 	MLX5_SEMAPHORE_SPACE_DOMAIN     = 0xA,
+	MLX5_SEMAPHORE_SW_RESET         = 0x20,
 };
 
 int mlx5_query_hca_caps(struct mlx5_core_dev *dev);
@@ -122,6 +123,7 @@ int mlx5_cmd_teardown_hca(struct mlx5_core_dev *dev);
 int mlx5_cmd_force_teardown_hca(struct mlx5_core_dev *dev);
 int mlx5_cmd_fast_teardown_hca(struct mlx5_core_dev *dev);
 void mlx5_enter_error_state(struct mlx5_core_dev *dev, bool force);
+void mlx5_error_sw_reset(struct mlx5_core_dev *dev);
 void mlx5_disable_device(struct mlx5_core_dev *dev);
 void mlx5_recover_device(struct mlx5_core_dev *dev);
 int mlx5_sriov_init(struct mlx5_core_dev *dev);

include/linux/mlx5/device.h

@@ -510,6 +510,10 @@ struct mlx5_cmd_layout {
 	u8		status_own;
 };
 
+enum mlx5_fatal_assert_bit_offsets {
+	MLX5_RFR_OFFSET = 31,
+};
+
 struct health_buffer {
 	__be32		assert_var[5];
 	__be32		rsvd0[3];
@@ -518,12 +522,16 @@ struct health_buffer {
 	__be32		rsvd1[2];
 	__be32		fw_ver;
 	__be32		hw_id;
-	__be32		rsvd2;
+	__be32		rfr;
 	u8		irisc_index;
 	u8		synd;
 	__be16		ext_synd;
 };
 
+enum mlx5_initializing_bit_offsets {
+	MLX5_FW_RESET_SUPPORTED_OFFSET = 30,
+};
+
 enum mlx5_cmd_addr_l_sz_offset {
 	MLX5_NIC_IFC_OFFSET = 8,
 };

include/linux/mlx5/driver.h

@@ -583,6 +583,7 @@ struct mlx5_priv {
 };
 
 enum mlx5_device_state {
+	MLX5_DEVICE_STATE_UNINITIALIZED,
 	MLX5_DEVICE_STATE_UP,
 	MLX5_DEVICE_STATE_INTERNAL_ERROR,
 };