net/mlx5: Control CR-space access by different PFs

Since the FW can be shared between different PFs/VFs it is common
that more than one health poll will detected a failure, this can
lead to multiple resets which are unneeded.

The solution is to use a FW locking mechanism using semaphore space
to provide a way to allow only one device to collect the cr-dump and
to issue a sw-reset.

Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/lib/pci_vsc.c

@@ -24,11 +24,6 @@
 	pci_write_config_dword((dev)->pdev, (dev)->vsc_addr + (offset), (val))
 #define VSC_MAX_RETRIES 2048
 
-enum mlx5_vsc_state {
-	MLX5_VSC_UNLOCK,
-	MLX5_VSC_LOCK,
-};
-
 enum {
 	VSC_CTRL_OFFSET = 0x4,
 	VSC_COUNTER_OFFSET = 0x8,
@@ -284,3 +279,38 @@ int mlx5_vsc_gw_read_block_fast(struct mlx5_core_dev *dev, u32 *data,
 	}
 	return length;
 }
+
+int mlx5_vsc_sem_set_space(struct mlx5_core_dev *dev, u16 space,
+			   enum mlx5_vsc_state state)
+{
+	u32 data, id = 0;
+	int ret;
+
+	ret = mlx5_vsc_gw_set_space(dev, MLX5_SEMAPHORE_SPACE_DOMAIN, NULL);
+	if (ret) {
+		mlx5_core_warn(dev, "Failed to set gw space %d\n", ret);
+		return ret;
+	}
+
+	if (state == MLX5_VSC_LOCK) {
+		/* Get a unique ID based on the counter */
+		ret = vsc_read(dev, VSC_COUNTER_OFFSET, &id);
+		if (ret)
+			return ret;
+	}
+
+	/* Try to modify lock */
+	ret = mlx5_vsc_gw_write(dev, space, id);
+	if (ret)
+		return ret;
+
+	/* Verify lock was modified */
+	ret = mlx5_vsc_gw_read(dev, space, &data);
+	if (ret)
+		return -EINVAL;
+
+	if (data != id)
+		return -EBUSY;
+
+	return 0;
+}

drivers/net/ethernet/mellanox/mlx5/core/lib/pci_vsc.h

@@ -4,6 +4,11 @@
 #ifndef __MLX5_PCI_VSC_H__
 #define __MLX5_PCI_VSC_H__
 
+enum mlx5_vsc_state {
+	MLX5_VSC_UNLOCK,
+	MLX5_VSC_LOCK,
+};
+
 enum {
 	MLX5_VSC_SPACE_SCAN_CRSPACE = 0x7,
 };
@@ -21,4 +26,7 @@ static inline bool mlx5_vsc_accessible(struct mlx5_core_dev *dev)
 	return !!dev->vsc_addr;
 }
 
+int mlx5_vsc_sem_set_space(struct mlx5_core_dev *dev, u16 space,
+			   enum mlx5_vsc_state state);
+
 #endif /* __MLX5_PCI_VSC_H__ */

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

@@ -111,6 +111,10 @@ enum {
 	MLX5_DRIVER_SYND = 0xbadd00de,
 };
 
+enum mlx5_semaphore_space_address {
+	MLX5_SEMAPHORE_SPACE_DOMAIN     = 0xA,
+};
+
 int mlx5_query_hca_caps(struct mlx5_core_dev *dev);
 int mlx5_query_board_id(struct mlx5_core_dev *dev);
 int mlx5_cmd_init_hca(struct mlx5_core_dev *dev, uint32_t *sw_owner_id);