net/mlx5: Ack on sync_reset_request only if PF can do reset_now

Verify at reset_request stage that PF is capable to do reset_now. In
case PF is not capable, notify the firmware that the sync reset can not
happen and so firmware will abort the sync reset at early stage and will
not send reset_now event to any PF.
Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

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

@@ -276,6 +276,44 @@ static void mlx5_fw_live_patch_event(struct work_struct *work)
 		mlx5_core_err(dev, "Failed to reload FW tracer\n");
 }
 
+static int mlx5_check_dev_ids(struct mlx5_core_dev *dev, u16 dev_id)
+{
+	struct pci_bus *bridge_bus = dev->pdev->bus;
+	struct pci_dev *sdev;
+	u16 sdev_id;
+	int err;
+
+	/* Check that all functions under the pci bridge are PFs of
+	 * this device otherwise fail this function.
+	 */
+	list_for_each_entry(sdev, &bridge_bus->devices, bus_list) {
+		err = pci_read_config_word(sdev, PCI_DEVICE_ID, &sdev_id);
+		if (err)
+			return err;
+		if (sdev_id != dev_id) {
+			mlx5_core_warn(dev, "unrecognized dev_id (0x%x)\n", sdev_id);
+			return -EPERM;
+		}
+	}
+	return 0;
+}
+
+static bool mlx5_is_reset_now_capable(struct mlx5_core_dev *dev)
+{
+	u16 dev_id;
+	int err;
+
+	if (!MLX5_CAP_GEN(dev, fast_teardown)) {
+		mlx5_core_warn(dev, "fast teardown is not supported by firmware\n");
+		return -EOPNOTSUPP;
+	}
+
+	err = pci_read_config_word(dev->pdev, PCI_DEVICE_ID, &dev_id);
+	if (err)
+		return false;
+	return (!mlx5_check_dev_ids(dev, dev_id));
+}
+
 static void mlx5_sync_reset_request_event(struct work_struct *work)
 {
 	struct mlx5_fw_reset *fw_reset = container_of(work, struct mlx5_fw_reset,
@@ -283,7 +321,8 @@ static void mlx5_sync_reset_request_event(struct work_struct *work)
 	struct mlx5_core_dev *dev = fw_reset->dev;
 	int err;
 
-	if (test_bit(MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST, &fw_reset->reset_flags)) {
+	if (test_bit(MLX5_FW_RESET_FLAGS_NACK_RESET_REQUEST, &fw_reset->reset_flags) ||
+	    !mlx5_is_reset_now_capable(dev)) {
 		err = mlx5_fw_reset_set_reset_sync_nack(dev);
 		mlx5_core_warn(dev, "PCI Sync FW Update Reset Nack %s",
 			       err ? "Failed" : "Sent");
@@ -303,26 +342,18 @@ static int mlx5_pci_link_toggle(struct mlx5_core_dev *dev)
 {
 	struct pci_bus *bridge_bus = dev->pdev->bus;
 	struct pci_dev *bridge = bridge_bus->self;
-	u16 reg16, dev_id, sdev_id;
 	unsigned long timeout;
 	struct pci_dev *sdev;
+	u16 reg16, dev_id;
 	int cap, err;
 	u32 reg32;
 
-	/* Check that all functions under the pci bridge are PFs of
-	 * this device otherwise fail this function.
-	 */
 	err = pci_read_config_word(dev->pdev, PCI_DEVICE_ID, &dev_id);
 	if (err)
 		return err;
-	list_for_each_entry(sdev, &bridge_bus->devices, bus_list) {
-		err = pci_read_config_word(sdev, PCI_DEVICE_ID, &sdev_id);
-		if (err)
-			return err;
-		if (sdev_id != dev_id)
-			return -EPERM;
-	}
-
+	err = mlx5_check_dev_ids(dev, dev_id);
+	if (err)
+		return err;
 	cap = pci_find_capability(bridge, PCI_CAP_ID_EXP);
 	if (!cap)
 		return -EOPNOTSUPP;