mlxsw: core: Prevent QSFP module initialization for old hardware

Old Mellanox silicons, like switchx-2, switch-ib do not support reading
QSFP modules temperature through MTMP register. Attempt to access this
register on systems equipped with the this kind of silicon will cause
initialization flow failure.
Test for hardware resource capability is added in order to distinct
between old and new silicon - old silicons do not have such capability.

Fixes: 6a79507 ("mlxsw: core: Extend thermal module with per QSFP module thermal zones")
Fixes: 5c42eaa ("mlxsw: core: Extend hwmon interface with QSFP module temperature attributes")
Reported-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Vadim Pasternak <vadimp@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

@@ -122,6 +122,12 @@ void *mlxsw_core_driver_priv(struct mlxsw_core *mlxsw_core)
 }
 EXPORT_SYMBOL(mlxsw_core_driver_priv);
 
+bool mlxsw_core_res_query_enabled(const struct mlxsw_core *mlxsw_core)
+{
+	return mlxsw_core->driver->res_query_enabled;
+}
+EXPORT_SYMBOL(mlxsw_core_res_query_enabled);
+
 struct mlxsw_rx_listener_item {
 	struct list_head list;
 	struct mlxsw_rx_listener rxl;

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

@@ -28,6 +28,8 @@ unsigned int mlxsw_core_max_ports(const struct mlxsw_core *mlxsw_core);
 
 void *mlxsw_core_driver_priv(struct mlxsw_core *mlxsw_core);
 
+bool mlxsw_core_res_query_enabled(const struct mlxsw_core *mlxsw_core);
+
 int mlxsw_core_driver_register(struct mlxsw_driver *mlxsw_driver);
 void mlxsw_core_driver_unregister(struct mlxsw_driver *mlxsw_driver);
 

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

@@ -518,6 +518,9 @@ static int mlxsw_hwmon_module_init(struct mlxsw_hwmon *mlxsw_hwmon)
 	u8 width;
 	int err;
 
+	if (!mlxsw_core_res_query_enabled(mlxsw_hwmon->core))
+		return 0;
+
 	/* Add extra attributes for module temperature. Sensor index is
 	 * assigned to sensor_count value, while all indexed before
 	 * sensor_count are already utilized by the sensors connected through

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

@@ -740,6 +740,9 @@ mlxsw_thermal_modules_init(struct device *dev, struct mlxsw_core *core,
 	struct mlxsw_thermal_module *module_tz;
 	int i, err;
 
+	if (!mlxsw_core_res_query_enabled(core))
+		return 0;
+
 	thermal->tz_module_arr = kcalloc(module_count,
 					 sizeof(*thermal->tz_module_arr),
 					 GFP_KERNEL);
@@ -776,6 +779,9 @@ mlxsw_thermal_modules_fini(struct mlxsw_thermal *thermal)
 	unsigned int module_count = mlxsw_core_max_ports(thermal->core);
 	int i;
 
+	if (!mlxsw_core_res_query_enabled(thermal->core))
+		return;
+
 	for (i = module_count - 1; i >= 0; i--)
 		mlxsw_thermal_module_fini(&thermal->tz_module_arr[i]);
 	kfree(thermal->tz_module_arr);