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firmware: arm_scmi: Introduce a new lifecycle for protocol devices

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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: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222185049.737625-9-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
This commit is contained in:
Cristian Marussi 2022-12-22 18:50:48 +00:00 committed by Sudeep Holla
parent 2c3e674465
commit ee5dcedaf7
1 changed files with 45 additions and 0 deletions
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45
drivers/firmware/arm_scmi/driver.c
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@ -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;