devlink: Add a 'num_doorbells' driverinit param

This parameter can be used by drivers to configure a different number of
doorbells.

Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/networking/devlink/devlink-params.rst

@@ -148,3 +148,6 @@ own name.
      - The max number of Virtual Functions (VFs) exposed by the PF.
        after reboot/pci reset, 'sriov_totalvfs' entry under the device's sysfs
        directory will report this value.
+   * - ``num_doorbells``
+     - u32
+     - Controls the number of doorbells used by the device.

include/net/devlink.h

@@ -531,6 +531,7 @@ enum devlink_param_generic_id {
 	DEVLINK_PARAM_GENERIC_ID_ENABLE_PHC,
 	DEVLINK_PARAM_GENERIC_ID_CLOCK_ID,
 	DEVLINK_PARAM_GENERIC_ID_TOTAL_VFS,
+	DEVLINK_PARAM_GENERIC_ID_NUM_DOORBELLS,
 
 	/* add new param generic ids above here*/
 	__DEVLINK_PARAM_GENERIC_ID_MAX,
@@ -598,6 +599,9 @@ enum devlink_param_generic_id {
 #define DEVLINK_PARAM_GENERIC_TOTAL_VFS_NAME "total_vfs"
 #define DEVLINK_PARAM_GENERIC_TOTAL_VFS_TYPE DEVLINK_PARAM_TYPE_U32
 
+#define DEVLINK_PARAM_GENERIC_NUM_DOORBELLS_NAME "num_doorbells"
+#define DEVLINK_PARAM_GENERIC_NUM_DOORBELLS_TYPE DEVLINK_PARAM_TYPE_U32
+
 #define DEVLINK_PARAM_GENERIC(_id, _cmodes, _get, _set, _validate)	\
 {									\
 	.id = DEVLINK_PARAM_GENERIC_ID_##_id,				\

net/devlink/param.c

@@ -107,6 +107,11 @@ static const struct devlink_param devlink_param_generic[] = {
 		.name = DEVLINK_PARAM_GENERIC_TOTAL_VFS_NAME,
 		.type = DEVLINK_PARAM_GENERIC_TOTAL_VFS_TYPE,
 	},
+	{
+		.id = DEVLINK_PARAM_GENERIC_ID_NUM_DOORBELLS,
+		.name = DEVLINK_PARAM_GENERIC_NUM_DOORBELLS_NAME,
+		.type = DEVLINK_PARAM_GENERIC_NUM_DOORBELLS_TYPE,
+	},
 };
 
 static int devlink_param_generic_verify(const struct devlink_param *param)