Commit 53b8c25d authored by Cristian Marussi's avatar Cristian Marussi Committed by Sudeep Holla
Browse files

firmware: arm_scmi: Add common notifier helpers 



Add a pair of notifier chains and generic empty notifier callbacks.
Currently they are still unused but they will be used to act properly
on device request and creation events.

Signed-off-by: default avatarCristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222185049.737625-5-cristian.marussi@arm.com


Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
parent 9115c20a

drivers/firmware/arm_scmi/bus.c

+5 −1
Original line number Diff line number Diff line
@@ -15,6 +15,9 @@ 


#include "common.h"



BLOCKING_NOTIFIER_HEAD(scmi_requested_devices_nh);

EXPORT_SYMBOL_GPL(scmi_requested_devices_nh);



static DEFINE_IDA(scmi_bus_id);



static const struct scmi_device_id *
@@ -94,12 +97,13 @@ static void scmi_dev_remove(struct device *dev) 
		scmi_drv->remove(scmi_dev);

}



static struct bus_type scmi_bus_type = {

struct bus_type scmi_bus_type = {

	.name =	"scmi_protocol",

	.match = scmi_dev_match,

	.probe = scmi_dev_probe,

	.remove = scmi_dev_remove,

};

EXPORT_SYMBOL_GPL(scmi_bus_type);



int scmi_driver_register(struct scmi_driver *driver, struct module *owner,

			 const char *mod_name)

drivers/firmware/arm_scmi/common.h

+5 −0
Original line number Diff line number Diff line
@@ -105,6 +105,11 @@ void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph, 


int __init scmi_bus_init(void);

void __exit scmi_bus_exit(void);

extern struct bus_type scmi_bus_type;



#define SCMI_BUS_NOTIFY_DEVICE_REQUEST		0

#define SCMI_BUS_NOTIFY_DEVICE_UNREQUEST	1

extern struct blocking_notifier_head scmi_requested_devices_nh;



int scmi_protocol_acquire(const struct scmi_handle *handle, u8 protocol_id);

void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);

drivers/firmware/arm_scmi/driver.c

+82 −1
Original line number Diff line number Diff line
@@ -150,6 +150,9 @@ struct scmi_protocol_instance { 
 * @notify_priv: Pointer to private data structure specific to notifications.

 * @node: List head

 * @users: Number of users of this 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

 */

struct scmi_info {

	struct device *dev;
@@ -169,9 +172,13 @@ struct scmi_info { 
	void *notify_priv;

	struct list_head node;

	int users;

	struct notifier_block bus_nb;

	struct notifier_block dev_req_nb;

};



#define handle_to_scmi_info(h)	container_of(h, struct scmi_info, handle)

#define bus_nb_to_scmi_info(nb)	container_of(nb, struct scmi_info, bus_nb)

#define req_nb_to_scmi_info(nb)	container_of(nb, struct scmi_info, dev_req_nb)



static const int scmi_linux_errmap[] = {

	/* better than switch case as long as return value is continuous */
@@ -2509,6 +2516,60 @@ static void scmi_cleanup_txrx_channels(struct scmi_info *info) 
	scmi_cleanup_channels(info, &info->rx_idr);

}



static int scmi_bus_notifier(struct notifier_block *nb,

			     unsigned long action, void *data)

{

	struct scmi_info *info = bus_nb_to_scmi_info(nb);

	struct scmi_device *sdev = to_scmi_dev(data);



	/* Skip transport devices and devices of different SCMI instances */

	if (!strncmp(sdev->name, "__scmi_transport_device", 23) ||

	    sdev->dev.parent != info->dev)

		return NOTIFY_DONE;



	switch (action) {

	case BUS_NOTIFY_BIND_DRIVER:

		break;

	case BUS_NOTIFY_UNBOUND_DRIVER:

		break;

	default:

		return NOTIFY_DONE;

	}



	dev_dbg(info->dev, "Device %s (%s) is now %s\n", dev_name(&sdev->dev),

		sdev->name, action == BUS_NOTIFY_BIND_DRIVER ?

		"about to be BOUND." : "UNBOUND.");



	return NOTIFY_OK;

}



static int scmi_device_request_notifier(struct notifier_block *nb,

					unsigned long action, void *data)

{

	struct device_node *np;

	struct scmi_device_id *id_table = data;

	struct scmi_info *info = req_nb_to_scmi_info(nb);



	np = idr_find(&info->active_protocols, id_table->protocol_id);

	if (!np)

		return NOTIFY_DONE;



	dev_dbg(info->dev, "%sRequested device (%s) for protocol 0x%x\n",

		action == SCMI_BUS_NOTIFY_DEVICE_REQUEST ? "" : "UN-",

		id_table->name, id_table->protocol_id);



	switch (action) {

	case SCMI_BUS_NOTIFY_DEVICE_REQUEST:

		break;

	case SCMI_BUS_NOTIFY_DEVICE_UNREQUEST:

		break;

	default:

		return NOTIFY_DONE;

	}



	return NOTIFY_OK;

}



static int scmi_probe(struct platform_device *pdev)

{

	int ret;
@@ -2528,6 +2589,8 @@ static int scmi_probe(struct platform_device *pdev) 


	info->dev = dev;

	info->desc = desc;

	info->bus_nb.notifier_call = scmi_bus_notifier;

	info->dev_req_nb.notifier_call = scmi_device_request_notifier;

	INIT_LIST_HEAD(&info->node);

	idr_init(&info->protocols);

	mutex_init(&info->protocols_mtx);
@@ -2563,10 +2626,19 @@ static int scmi_probe(struct platform_device *pdev) 
	if (ret)

		return ret;



	ret = scmi_xfer_info_init(info);

	ret = bus_register_notifier(&scmi_bus_type, &info->bus_nb);

	if (ret)

		goto clear_txrx_setup;



	ret = blocking_notifier_chain_register(&scmi_requested_devices_nh,

					       &info->dev_req_nb);

	if (ret)

		goto clear_bus_notifier;



	ret = scmi_xfer_info_init(info);

	if (ret)

		goto clear_dev_req_notifier;



	if (scmi_notification_init(handle))

		dev_err(dev, "SCMI Notifications NOT available.\n");
@@ -2624,6 +2696,11 @@ static int scmi_probe(struct platform_device *pdev) 


notification_exit:

	scmi_notification_exit(&info->handle);

clear_dev_req_notifier:

	blocking_notifier_chain_unregister(&scmi_requested_devices_nh,

					   &info->dev_req_nb);

clear_bus_notifier:

	bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);

clear_txrx_setup:

	scmi_cleanup_txrx_channels(info);

	return ret;
@@ -2652,6 +2729,10 @@ static int scmi_remove(struct platform_device *pdev) 
		of_node_put(child);

	idr_destroy(&info->active_protocols);



	blocking_notifier_chain_unregister(&scmi_requested_devices_nh,

					   &info->dev_req_nb);

	bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);



	/* Safe to free channels since no more users */

	scmi_cleanup_txrx_channels(info);