mlxsw: Register physical ports as a devlink resource

The switch ASIC has a limited capacity of physical ('flavour physical'
in devlink terminology) ports that it can support. While each system is
brought up with a different number of ports, this number can be
increased via splitting up to the ASIC's limit.

Expose physical ports as a devlink resource so that user space will have
visibility to the maximum number of ports that can be supported and the
current occupancy.

In addition, add a "Generic Resources" section in devlink-resource
documentation so the different drivers will be aligned by the same resource
name when exposing to user space.

Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/networking/devlink/devlink-resource.rst

@@ -23,6 +23,20 @@ current size and related sub resources. To access a sub resource, you
 specify the path of the resource. For example ``/IPv4/fib`` is the id for
 the ``fib`` sub-resource under the ``IPv4`` resource.
 
+Generic Resources
+=================
+
+Generic resources are used to describe resources that can be shared by multiple
+device drivers and their description must be added to the following table:
+
+.. list-table:: List of Generic Resources
+   :widths: 10 90
+
+   * - Name
+     - Description
+   * - ``physical_ports``
+     - A limited capacity of physical ports that the switch ASIC can support
+
 example usage
 -------------
 

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

@@ -84,6 +84,7 @@ struct mlxsw_core {
 	struct mlxsw_thermal *thermal;
 	struct mlxsw_core_port *ports;
 	unsigned int max_ports;
+	atomic_t active_ports_count;
 	bool fw_flash_in_progress;
 	struct {
 		struct devlink_health_reporter *fw_fatal;
@@ -96,8 +97,36 @@ struct mlxsw_core {
 
 #define MLXSW_PORT_MAX_PORTS_DEFAULT	0x40
 
-static int mlxsw_ports_init(struct mlxsw_core *mlxsw_core)
+static u64 mlxsw_ports_occ_get(void *priv)
 {
+	struct mlxsw_core *mlxsw_core = priv;
+
+	return atomic_read(&mlxsw_core->active_ports_count);
+}
+
+static int mlxsw_core_resources_ports_register(struct mlxsw_core *mlxsw_core)
+{
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
+	struct devlink_resource_size_params ports_num_params;
+	u32 max_ports;
+
+	max_ports = mlxsw_core->max_ports - 1;
+	devlink_resource_size_params_init(&ports_num_params, max_ports,
+					  max_ports, 1,
+					  DEVLINK_RESOURCE_UNIT_ENTRY);
+
+	return devlink_resource_register(devlink,
+					 DEVLINK_RESOURCE_GENERIC_NAME_PORTS,
+					 max_ports, MLXSW_CORE_RESOURCE_PORTS,
+					 DEVLINK_RESOURCE_ID_PARENT_TOP,
+					 &ports_num_params);
+}
+
+static int mlxsw_ports_init(struct mlxsw_core *mlxsw_core, bool reload)
+{
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
+	int err;
+
 	/* Switch ports are numbered from 1 to queried value */
 	if (MLXSW_CORE_RES_VALID(mlxsw_core, MAX_SYSTEM_PORT))
 		mlxsw_core->max_ports = MLXSW_CORE_RES_GET(mlxsw_core,
@@ -110,11 +139,30 @@ static int mlxsw_ports_init(struct mlxsw_core *mlxsw_core)
 	if (!mlxsw_core->ports)
 		return -ENOMEM;
 
+	if (!reload) {
+		err = mlxsw_core_resources_ports_register(mlxsw_core);
+		if (err)
+			goto err_resources_ports_register;
+	}
+	atomic_set(&mlxsw_core->active_ports_count, 0);
+	devlink_resource_occ_get_register(devlink, MLXSW_CORE_RESOURCE_PORTS,
+					  mlxsw_ports_occ_get, mlxsw_core);
+
 	return 0;
+
+err_resources_ports_register:
+	kfree(mlxsw_core->ports);
+	return err;
 }
 
-static void mlxsw_ports_fini(struct mlxsw_core *mlxsw_core)
+static void mlxsw_ports_fini(struct mlxsw_core *mlxsw_core, bool reload)
 {
+	struct devlink *devlink = priv_to_devlink(mlxsw_core);
+
+	devlink_resource_occ_get_unregister(devlink, MLXSW_CORE_RESOURCE_PORTS);
+	if (!reload)
+		devlink_resources_unregister(priv_to_devlink(mlxsw_core), NULL);
+
 	kfree(mlxsw_core->ports);
 }
 
@@ -1897,7 +1945,7 @@ __mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info,
 			goto err_register_resources;
 	}
 
-	err = mlxsw_ports_init(mlxsw_core);
+	err = mlxsw_ports_init(mlxsw_core, reload);
 	if (err)
 		goto err_ports_init;
 
@@ -1986,7 +2034,7 @@ err_devlink_register:
 err_emad_init:
 	kfree(mlxsw_core->lag.mapping);
 err_alloc_lag_mapping:
-	mlxsw_ports_fini(mlxsw_core);
+	mlxsw_ports_fini(mlxsw_core, reload);
 err_ports_init:
 	if (!reload)
 		devlink_resources_unregister(devlink, NULL);
@@ -2056,7 +2104,7 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core,
 		devlink_unregister(devlink);
 	mlxsw_emad_fini(mlxsw_core);
 	kfree(mlxsw_core->lag.mapping);
-	mlxsw_ports_fini(mlxsw_core);
+	mlxsw_ports_fini(mlxsw_core, reload);
 	if (!reload)
 		devlink_resources_unregister(devlink, NULL);
 	mlxsw_core->bus->fini(mlxsw_core->bus_priv);
@@ -2755,16 +2803,25 @@ int mlxsw_core_port_init(struct mlxsw_core *mlxsw_core, u8 local_port,
 			 const unsigned char *switch_id,
 			 unsigned char switch_id_len)
 {
-	return __mlxsw_core_port_init(mlxsw_core, local_port,
-				      DEVLINK_PORT_FLAVOUR_PHYSICAL,
-				      port_number, split, split_port_subnumber,
-				      splittable, lanes,
-				      switch_id, switch_id_len);
+	int err;
+
+	err = __mlxsw_core_port_init(mlxsw_core, local_port,
+				     DEVLINK_PORT_FLAVOUR_PHYSICAL,
+				     port_number, split, split_port_subnumber,
+				     splittable, lanes,
+				     switch_id, switch_id_len);
+	if (err)
+		return err;
+
+	atomic_inc(&mlxsw_core->active_ports_count);
+	return 0;
 }
 EXPORT_SYMBOL(mlxsw_core_port_init);
 
 void mlxsw_core_port_fini(struct mlxsw_core *mlxsw_core, u8 local_port)
 {
+	atomic_dec(&mlxsw_core->active_ports_count);
+
 	__mlxsw_core_port_fini(mlxsw_core, local_port);
 }
 EXPORT_SYMBOL(mlxsw_core_port_fini);

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

@@ -19,6 +19,11 @@
 #include "cmd.h"
 #include "resources.h"
 
+enum mlxsw_core_resource_id {
+	MLXSW_CORE_RESOURCE_PORTS = 1,
+	MLXSW_CORE_RESOURCE_MAX,
+};
+
 struct mlxsw_core;
 struct mlxsw_core_port;
 struct mlxsw_driver;

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

@@ -52,7 +52,7 @@
 #define MLXSW_SP_RESOURCE_NAME_COUNTERS_RIF "rif"
 
 enum mlxsw_sp_resource_id {
-	MLXSW_SP_RESOURCE_KVD = 1,
+	MLXSW_SP_RESOURCE_KVD = MLXSW_CORE_RESOURCE_MAX,
 	MLXSW_SP_RESOURCE_KVD_LINEAR,
 	MLXSW_SP_RESOURCE_KVD_HASH_SINGLE,
 	MLXSW_SP_RESOURCE_KVD_HASH_DOUBLE,

include/net/devlink.h

@@ -380,6 +380,8 @@ struct devlink_resource {
 
 #define DEVLINK_RESOURCE_ID_PARENT_TOP 0
 
+#define DEVLINK_RESOURCE_GENERIC_NAME_PORTS "physical_ports"
+
 #define __DEVLINK_PARAM_MAX_STRING_VALUE 32
 enum devlink_param_type {
 	DEVLINK_PARAM_TYPE_U8,

net/core/devlink.c

@@ -8617,6 +8617,10 @@ EXPORT_SYMBOL_GPL(devlink_dpipe_table_unregister);
  *	@resource_id: resource's id
  *	@parent_resource_id: resource's parent id
  *	@size_params: size parameters
+ *
+ *	Generic resources should reuse the same names across drivers.
+ *	Please see the generic resources list at:
+ *	Documentation/networking/devlink/devlink-resource.rst
  */
 int devlink_resource_register(struct devlink *devlink,
 			      const char *resource_name,