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// SPDX-License-Identifier: GPL-2.0
/*
* System Control and Management Interface (SCMI) Message Protocol bus layer
*
* Copyright (C) 2018 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)
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_protocol_init(int protocol_id, struct scmi_handle *handle)
{
scmi_prot_init_fn_t fn = idr_find(&scmi_protocols, protocol_id);
if (unlikely(!fn))
return -EINVAL;
return fn(handle);
}
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);
const struct scmi_device_id *id;
int ret;
id = scmi_dev_match_id(scmi_dev, scmi_drv);
if (!id)
return -ENODEV;
if (!scmi_dev->handle)
return -EPROBE_DEFER;
ret = scmi_protocol_init(scmi_dev->protocol_id, scmi_dev->handle);
if (ret)
return ret;
return scmi_drv->probe(scmi_dev);
}
static int 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);
return 0;
}
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;
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);
}
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)
{
int id, retval;
struct scmi_device *scmi_dev;
scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
if (!scmi_dev)
return NULL;
id = ida_simple_get(&scmi_bus_id, 1, 0, GFP_KERNEL);
if (id < 0) {
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:
put_device(&scmi_dev->dev);
ida_simple_remove(&scmi_bus_id, id);
return NULL;
}
void scmi_device_destroy(struct scmi_device *scmi_dev)
{
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(int protocol_id, scmi_prot_init_fn_t fn)
{
int ret;
spin_lock(&protocol_lock);
ret = idr_alloc(&scmi_protocols, fn, protocol_id, protocol_id + 1,
GFP_ATOMIC);
spin_unlock(&protocol_lock);
if (ret != protocol_id)
pr_err("unable to allocate SCMI idr slot, err %d\n", ret);
return ret;
}
EXPORT_SYMBOL_GPL(scmi_protocol_register);
void scmi_protocol_unregister(int protocol_id)
{
spin_lock(&protocol_lock);
idr_remove(&scmi_protocols, protocol_id);
spin_unlock(&protocol_lock);
}
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);
}
static 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;
}
subsys_initcall(scmi_bus_init);
static void __exit scmi_bus_exit(void)
{
scmi_devices_unregister();
bus_unregister(&scmi_bus_type);
ida_destroy(&scmi_bus_id);
}
module_exit(scmi_bus_exit);
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