mlxsw: spectrum: Load firmware version based on devlink parameter

Load firmware version based on 'fw_load_policy' devlink parameter. The
driver supports these two options:
    * DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DRIVER (0)
      Default, load firmware version preferred by the driver
    * DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_FLASH (1)
      Load firmware currently stored in flash

The second option, 'flash', allow the device to run with different firmware
version than preferred by the driver for testing and/or debugging purposes.
For example, testing a firmware bug fix.

Signed-off-by: Shalom Toledo <shalomt@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core.c

@@ -1036,6 +1036,12 @@ __mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info,
 			goto err_devlink_register;
 	}
 
+	if (mlxsw_driver->params_register && !reload) {
+		err = mlxsw_driver->params_register(mlxsw_core);
+		if (err)
+			goto err_register_params;
+	}
+
 	err = mlxsw_hwmon_init(mlxsw_core, mlxsw_bus_info, &mlxsw_core->hwmon);
 	if (err)
 		goto err_hwmon_init;
@@ -1058,6 +1064,9 @@ __mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info,
 err_thermal_init:
 	mlxsw_hwmon_fini(mlxsw_core->hwmon);
 err_hwmon_init:
+	if (mlxsw_driver->params_unregister && !reload)
+		mlxsw_driver->params_unregister(mlxsw_core);
+err_register_params:
 	if (!reload)
 		devlink_unregister(devlink);
 err_devlink_register:
@@ -1121,6 +1130,8 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core,
 		mlxsw_core->driver->fini(mlxsw_core);
 	mlxsw_thermal_fini(mlxsw_core->thermal);
 	mlxsw_hwmon_fini(mlxsw_core->hwmon);
+	if (mlxsw_core->driver->params_unregister && !reload)
+		mlxsw_core->driver->params_unregister(mlxsw_core);
 	if (!reload)
 		devlink_unregister(devlink);
 	mlxsw_emad_fini(mlxsw_core);
@@ -1133,6 +1144,8 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core,
 	return;
 
 reload_fail_deinit:
+	if (mlxsw_core->driver->params_unregister)
+		mlxsw_core->driver->params_unregister(mlxsw_core);
 	devlink_unregister(devlink);
 	devlink_resources_unregister(devlink, NULL);
 	devlink_free(devlink);

drivers/net/ethernet/mellanox/mlxsw/core.h

@@ -282,6 +282,8 @@ struct mlxsw_driver {
 			     const struct mlxsw_config_profile *profile,
 			     u64 *p_single_size, u64 *p_double_size,
 			     u64 *p_linear_size);
+	int (*params_register)(struct mlxsw_core *mlxsw_core);
+	void (*params_unregister)(struct mlxsw_core *mlxsw_core);
 	u8 txhdr_len;
 	const struct mlxsw_config_profile *profile;
 	bool res_query_enabled;

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -318,13 +318,23 @@ static int mlxsw_sp_fw_rev_validate(struct mlxsw_sp *mlxsw_sp)
 	const struct mlxsw_fw_rev *rev = &mlxsw_sp->bus_info->fw_rev;
 	const struct mlxsw_fw_rev *req_rev = mlxsw_sp->req_rev;
 	const char *fw_filename = mlxsw_sp->fw_filename;
+	union devlink_param_value value;
 	const struct firmware *firmware;
 	int err;
 
 	/* Don't check if driver does not require it */
 	if (!req_rev || !fw_filename)
 		return 0;
 
+	/* Don't check if devlink 'fw_load_policy' param is 'flash' */
+	err = devlink_param_driverinit_value_get(priv_to_devlink(mlxsw_sp->core),
+						 DEVLINK_PARAM_GENERIC_ID_FW_LOAD_POLICY,
+						 &value);
+	if (err)
+		return err;
+	if (value.vu8 == DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_FLASH)
+		return 0;
+
 	/* Validate driver & FW are compatible */
 	if (rev->major != req_rev->major) {
 		WARN(1, "Mismatch in major FW version [%d:%d] is never expected; Please contact support\n",
@@ -4328,6 +4338,52 @@ static int mlxsw_sp_kvd_sizes_get(struct mlxsw_core *mlxsw_core,
 	return 0;
 }
 
+static int
+mlxsw_sp_devlink_param_fw_load_policy_validate(struct devlink *devlink, u32 id,
+					       union devlink_param_value val,
+					       struct netlink_ext_ack *extack)
+{
+	if ((val.vu8 != DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DRIVER) &&
+	    (val.vu8 != DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_FLASH)) {
+		NL_SET_ERR_MSG_MOD(extack, "'fw_load_policy' must be 'driver' or 'flash'");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct devlink_param mlxsw_sp_devlink_params[] = {
+	DEVLINK_PARAM_GENERIC(FW_LOAD_POLICY,
+			      BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
+			      NULL, NULL,
+			      mlxsw_sp_devlink_param_fw_load_policy_validate),
+};
+
+static int mlxsw_sp_params_register(struct mlxsw_core *mlxsw_core)
+{
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
+	union devlink_param_value value;
+	int err;
+
+	err = devlink_params_register(devlink, mlxsw_sp_devlink_params,
+				      ARRAY_SIZE(mlxsw_sp_devlink_params));
+	if (err)
+		return err;
+
+	value.vu8 = DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DRIVER;
+	devlink_param_driverinit_value_set(devlink,
+					   DEVLINK_PARAM_GENERIC_ID_FW_LOAD_POLICY,
+					   value);
+	return 0;
+}
+
+static void mlxsw_sp_params_unregister(struct mlxsw_core *mlxsw_core)
+{
+	devlink_params_unregister(priv_to_devlink(mlxsw_core),
+				  mlxsw_sp_devlink_params,
+				  ARRAY_SIZE(mlxsw_sp_devlink_params));
+}
+
 static struct mlxsw_driver mlxsw_sp1_driver = {
 	.kind				= mlxsw_sp1_driver_name,
 	.priv_size			= sizeof(struct mlxsw_sp),
@@ -4349,6 +4405,8 @@ static struct mlxsw_driver mlxsw_sp1_driver = {
 	.txhdr_construct		= mlxsw_sp_txhdr_construct,
 	.resources_register		= mlxsw_sp1_resources_register,
 	.kvd_sizes_get			= mlxsw_sp_kvd_sizes_get,
+	.params_register		= mlxsw_sp_params_register,
+	.params_unregister		= mlxsw_sp_params_unregister,
 	.txhdr_len			= MLXSW_TXHDR_LEN,
 	.profile			= &mlxsw_sp1_config_profile,
 	.res_query_enabled		= true,
@@ -4374,6 +4432,8 @@ static struct mlxsw_driver mlxsw_sp2_driver = {
 	.sb_occ_tc_port_bind_get	= mlxsw_sp_sb_occ_tc_port_bind_get,
 	.txhdr_construct		= mlxsw_sp_txhdr_construct,
 	.resources_register		= mlxsw_sp2_resources_register,
+	.params_register		= mlxsw_sp_params_register,
+	.params_unregister		= mlxsw_sp_params_unregister,
 	.txhdr_len			= MLXSW_TXHDR_LEN,
 	.profile			= &mlxsw_sp2_config_profile,
 	.res_query_enabled		= true,