linux/linux-5.18.11/drivers/firmware/arm_scmi/bus.c

296 lines
6.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Management Interface (SCMI) Message Protocol bus layer
*
* Copyright (C) 2018-2021 ARM Ltd.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/types.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include "common.h"
static DEFINE_IDA(scmi_bus_id);
static DEFINE_IDR(scmi_protocols);
static DEFINE_SPINLOCK(protocol_lock);
static const struct scmi_device_id *
scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv)
{
const struct scmi_device_id *id = scmi_drv->id_table;
if (!id)
return NULL;
for (; id->protocol_id; id++)
if (id->protocol_id == scmi_dev->protocol_id) {
if (!id->name)
return id;
else if (!strcmp(id->name, scmi_dev->name))
return id;
}
return NULL;
}
static int scmi_dev_match(struct device *dev, struct device_driver *drv)
{
struct scmi_driver *scmi_drv = to_scmi_driver(drv);
struct scmi_device *scmi_dev = to_scmi_dev(dev);
const struct scmi_device_id *id;
id = scmi_dev_match_id(scmi_dev, scmi_drv);
if (id)
return 1;
return 0;
}
static int scmi_match_by_id_table(struct device *dev, void *data)
{
struct scmi_device *sdev = to_scmi_dev(dev);
struct scmi_device_id *id_table = data;
return sdev->protocol_id == id_table->protocol_id &&
!strcmp(sdev->name, id_table->name);
}
struct scmi_device *scmi_child_dev_find(struct device *parent,
int prot_id, const char *name)
{
struct scmi_device_id id_table;
struct device *dev;
id_table.protocol_id = prot_id;
id_table.name = name;
dev = device_find_child(parent, &id_table, scmi_match_by_id_table);
if (!dev)
return NULL;
return to_scmi_dev(dev);
}
const struct scmi_protocol *scmi_protocol_get(int protocol_id)
{
const struct scmi_protocol *proto;
proto = idr_find(&scmi_protocols, protocol_id);
if (!proto || !try_module_get(proto->owner)) {
pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
return NULL;
}
pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);
return proto;
}
void scmi_protocol_put(int protocol_id)
{
const struct scmi_protocol *proto;
proto = idr_find(&scmi_protocols, protocol_id);
if (proto)
module_put(proto->owner);
}
static int scmi_dev_probe(struct device *dev)
{
struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
struct scmi_device *scmi_dev = to_scmi_dev(dev);
if (!scmi_dev->handle)
return -EPROBE_DEFER;
return scmi_drv->probe(scmi_dev);
}
static void scmi_dev_remove(struct device *dev)
{
struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
struct scmi_device *scmi_dev = to_scmi_dev(dev);
if (scmi_drv->remove)
scmi_drv->remove(scmi_dev);
}
static struct bus_type scmi_bus_type = {
.name = "scmi_protocol",
.match = scmi_dev_match,
.probe = scmi_dev_probe,
.remove = scmi_dev_remove,
};
int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
const char *mod_name)
{
int retval;
if (!driver->probe)
return -EINVAL;
retval = scmi_protocol_device_request(driver->id_table);
if (retval)
return retval;
driver->driver.bus = &scmi_bus_type;
driver->driver.name = driver->name;
driver->driver.owner = owner;
driver->driver.mod_name = mod_name;
retval = driver_register(&driver->driver);
if (!retval)
pr_debug("registered new scmi driver %s\n", driver->name);
return retval;
}
EXPORT_SYMBOL_GPL(scmi_driver_register);
void scmi_driver_unregister(struct scmi_driver *driver)
{
driver_unregister(&driver->driver);
scmi_protocol_device_unrequest(driver->id_table);
}
EXPORT_SYMBOL_GPL(scmi_driver_unregister);
static void scmi_device_release(struct device *dev)
{
kfree(to_scmi_dev(dev));
}
struct scmi_device *
scmi_device_create(struct device_node *np, struct device *parent, int protocol,
const char *name)
{
int id, retval;
struct scmi_device *scmi_dev;
scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
if (!scmi_dev)
return NULL;
scmi_dev->name = kstrdup_const(name ?: "unknown", GFP_KERNEL);
if (!scmi_dev->name) {
kfree(scmi_dev);
return NULL;
}
id = ida_simple_get(&scmi_bus_id, 1, 0, GFP_KERNEL);
if (id < 0) {
kfree_const(scmi_dev->name);
kfree(scmi_dev);
return NULL;
}
scmi_dev->id = id;
scmi_dev->protocol_id = protocol;
scmi_dev->dev.parent = parent;
scmi_dev->dev.of_node = np;
scmi_dev->dev.bus = &scmi_bus_type;
scmi_dev->dev.release = scmi_device_release;
dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id);
retval = device_register(&scmi_dev->dev);
if (retval)
goto put_dev;
return scmi_dev;
put_dev:
kfree_const(scmi_dev->name);
put_device(&scmi_dev->dev);
ida_simple_remove(&scmi_bus_id, id);
return NULL;
}
void scmi_device_destroy(struct scmi_device *scmi_dev)
{
kfree_const(scmi_dev->name);
scmi_handle_put(scmi_dev->handle);
ida_simple_remove(&scmi_bus_id, scmi_dev->id);
device_unregister(&scmi_dev->dev);
}
void scmi_set_handle(struct scmi_device *scmi_dev)
{
scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
}
int scmi_protocol_register(const struct scmi_protocol *proto)
{
int ret;
if (!proto) {
pr_err("invalid protocol\n");
return -EINVAL;
}
if (!proto->instance_init) {
pr_err("missing init for protocol 0x%x\n", proto->id);
return -EINVAL;
}
spin_lock(&protocol_lock);
ret = idr_alloc(&scmi_protocols, (void *)proto,
proto->id, proto->id + 1, GFP_ATOMIC);
spin_unlock(&protocol_lock);
if (ret != proto->id) {
pr_err("unable to allocate SCMI idr slot for 0x%x - err %d\n",
proto->id, ret);
return ret;
}
pr_debug("Registered SCMI Protocol 0x%x\n", proto->id);
return 0;
}
EXPORT_SYMBOL_GPL(scmi_protocol_register);
void scmi_protocol_unregister(const struct scmi_protocol *proto)
{
spin_lock(&protocol_lock);
idr_remove(&scmi_protocols, proto->id);
spin_unlock(&protocol_lock);
pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);
return;
}
EXPORT_SYMBOL_GPL(scmi_protocol_unregister);
static int __scmi_devices_unregister(struct device *dev, void *data)
{
struct scmi_device *scmi_dev = to_scmi_dev(dev);
scmi_device_destroy(scmi_dev);
return 0;
}
static void scmi_devices_unregister(void)
{
bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister);
}
int __init scmi_bus_init(void)
{
int retval;
retval = bus_register(&scmi_bus_type);
if (retval)
pr_err("scmi protocol bus register failed (%d)\n", retval);
return retval;
}
void __exit scmi_bus_exit(void)
{
scmi_devices_unregister();
bus_unregister(&scmi_bus_type);
ida_destroy(&scmi_bus_id);
}