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