diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/firmware/arm_scmi/bus.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c new file mode 100644 index 000000000..66d445b14 --- /dev/null +++ b/drivers/firmware/arm_scmi/bus.c @@ -0,0 +1,231 @@ +// 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); |