Commit ee5dceda authored by Cristian Marussi's avatar Cristian Marussi Committed by Sudeep Holla
Browse files

firmware: arm_scmi: Introduce a new lifecycle for protocol devices 



Protocol devices are created or destroyed depending on the related device
request/unrequest events emitted on the scmi_requested_devices_nh
notification chain by the SCMI bus and served in the driver by the
scmi_device_request_notifier.

Signed-off-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222185049.737625-9-cristian.marussi@arm.com


Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 2c3e6744

drivers/firmware/arm_scmi/driver.c

+45 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
 * Copyright (C) 2018-2021 ARM Ltd.

 */



#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/bitmap.h>

#include <linux/device.h>

#include <linux/export.h>
@@ -140,6 +142,7 @@ struct scmi_protocol_instance { 
 * @bus_nb: A notifier to listen for device bind/unbind on the scmi bus

 * @dev_req_nb: A notifier to listen for device request/unrequest on the scmi

 *		bus

 * @devreq_mtx: A mutex to serialize device creation for this SCMI instance

 */

struct scmi_info {

	struct device *dev;
@@ -161,6 +164,8 @@ struct scmi_info { 
	int users;

	struct notifier_block bus_nb;

	struct notifier_block dev_req_nb;

	/* Serialize device creation process for this instance */

	struct mutex devreq_mtx;

};



#define handle_to_scmi_info(h)	container_of(h, struct scmi_info, handle)
@@ -255,6 +260,40 @@ void scmi_protocol_unregister(const struct scmi_protocol *proto) 
}

EXPORT_SYMBOL_GPL(scmi_protocol_unregister);



/**

 * scmi_create_protocol_devices  - Create devices for all pending requests for

 * this SCMI instance.

 *

 * @np: The device node describing the protocol

 * @info: The SCMI instance descriptor

 * @prot_id: The protocol ID

 * @name: The optional name of the device to be created: if not provided this

 *	  call will lead to the creation of all the devices currently requested

 *	  for the specified protocol.

 */

static void scmi_create_protocol_devices(struct device_node *np,

					 struct scmi_info *info,

					 int prot_id, const char *name)

{

	struct scmi_device *sdev;



	mutex_lock(&info->devreq_mtx);

	sdev = scmi_device_create(np, info->dev, prot_id, name);

	if (name && !sdev)

		dev_err(info->dev,

			"failed to create device for protocol 0x%X (%s)\n",

			prot_id, name);

	mutex_unlock(&info->devreq_mtx);

}



static void scmi_destroy_protocol_devices(struct scmi_info *info,

					  int prot_id, const char *name)

{

	mutex_lock(&info->devreq_mtx);

	scmi_device_destroy(info->dev, prot_id, name);

	mutex_unlock(&info->devreq_mtx);

}



void scmi_notification_instance_data_set(const struct scmi_handle *handle,

					 void *priv)

{
@@ -2283,8 +2322,12 @@ static int scmi_device_request_notifier(struct notifier_block *nb, 


	switch (action) {

	case SCMI_BUS_NOTIFY_DEVICE_REQUEST:

		scmi_create_protocol_devices(np, info, id_table->protocol_id,

					     id_table->name);

		break;

	case SCMI_BUS_NOTIFY_DEVICE_UNREQUEST:

		scmi_destroy_protocol_devices(info, id_table->protocol_id,

					      id_table->name);

		break;

	default:

		return NOTIFY_DONE;
@@ -2318,6 +2361,7 @@ static int scmi_probe(struct platform_device *pdev) 
	idr_init(&info->protocols);

	mutex_init(&info->protocols_mtx);

	idr_init(&info->active_protocols);

	mutex_init(&info->devreq_mtx);



	platform_set_drvdata(pdev, info);

	idr_init(&info->tx_idr);
@@ -2412,6 +2456,7 @@ static int scmi_probe(struct platform_device *pdev) 
		}



		of_node_get(child);

		scmi_create_protocol_devices(child, info, prot_id, NULL);

	}



	return 0;