1 // SPDX-License-Identifier: GPL-2.0
3 * System Control and Management Interface (SCMI) Message Protocol bus layer
5 * Copyright (C) 2018-2021 ARM Ltd.
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 #include <linux/types.h>
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/device.h>
18 static DEFINE_IDA(scmi_bus_id);
19 static DEFINE_IDR(scmi_protocols);
20 static DEFINE_SPINLOCK(protocol_lock);
22 static const struct scmi_device_id *
23 scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv)
25 const struct scmi_device_id *id = scmi_drv->id_table;
30 for (; id->protocol_id; id++)
31 if (id->protocol_id == scmi_dev->protocol_id) {
34 else if (!strcmp(id->name, scmi_dev->name))
41 static int scmi_dev_match(struct device *dev, struct device_driver *drv)
43 struct scmi_driver *scmi_drv = to_scmi_driver(drv);
44 struct scmi_device *scmi_dev = to_scmi_dev(dev);
45 const struct scmi_device_id *id;
47 id = scmi_dev_match_id(scmi_dev, scmi_drv);
54 static int scmi_match_by_id_table(struct device *dev, void *data)
56 struct scmi_device *sdev = to_scmi_dev(dev);
57 struct scmi_device_id *id_table = data;
59 return sdev->protocol_id == id_table->protocol_id &&
60 !strcmp(sdev->name, id_table->name);
63 struct scmi_device *scmi_child_dev_find(struct device *parent,
64 int prot_id, const char *name)
66 struct scmi_device_id id_table;
69 id_table.protocol_id = prot_id;
72 dev = device_find_child(parent, &id_table, scmi_match_by_id_table);
76 return to_scmi_dev(dev);
79 const struct scmi_protocol *scmi_protocol_get(int protocol_id)
81 const struct scmi_protocol *proto;
83 proto = idr_find(&scmi_protocols, protocol_id);
84 if (!proto || !try_module_get(proto->owner)) {
85 pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
89 pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);
94 void scmi_protocol_put(int protocol_id)
96 const struct scmi_protocol *proto;
98 proto = idr_find(&scmi_protocols, protocol_id);
100 module_put(proto->owner);
103 static int scmi_dev_probe(struct device *dev)
105 struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
106 struct scmi_device *scmi_dev = to_scmi_dev(dev);
108 if (!scmi_dev->handle)
109 return -EPROBE_DEFER;
111 return scmi_drv->probe(scmi_dev);
114 static void scmi_dev_remove(struct device *dev)
116 struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
117 struct scmi_device *scmi_dev = to_scmi_dev(dev);
119 if (scmi_drv->remove)
120 scmi_drv->remove(scmi_dev);
123 static struct bus_type scmi_bus_type = {
124 .name = "scmi_protocol",
125 .match = scmi_dev_match,
126 .probe = scmi_dev_probe,
127 .remove = scmi_dev_remove,
130 int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
131 const char *mod_name)
138 retval = scmi_protocol_device_request(driver->id_table);
142 driver->driver.bus = &scmi_bus_type;
143 driver->driver.name = driver->name;
144 driver->driver.owner = owner;
145 driver->driver.mod_name = mod_name;
147 retval = driver_register(&driver->driver);
149 pr_debug("registered new scmi driver %s\n", driver->name);
153 EXPORT_SYMBOL_GPL(scmi_driver_register);
155 void scmi_driver_unregister(struct scmi_driver *driver)
157 driver_unregister(&driver->driver);
158 scmi_protocol_device_unrequest(driver->id_table);
160 EXPORT_SYMBOL_GPL(scmi_driver_unregister);
162 static void scmi_device_release(struct device *dev)
164 kfree(to_scmi_dev(dev));
168 scmi_device_create(struct device_node *np, struct device *parent, int protocol,
172 struct scmi_device *scmi_dev;
174 scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
178 scmi_dev->name = kstrdup_const(name ?: "unknown", GFP_KERNEL);
179 if (!scmi_dev->name) {
184 id = ida_simple_get(&scmi_bus_id, 1, 0, GFP_KERNEL);
186 kfree_const(scmi_dev->name);
192 scmi_dev->protocol_id = protocol;
193 scmi_dev->dev.parent = parent;
194 scmi_dev->dev.of_node = np;
195 scmi_dev->dev.bus = &scmi_bus_type;
196 scmi_dev->dev.release = scmi_device_release;
197 dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id);
199 retval = device_register(&scmi_dev->dev);
205 kfree_const(scmi_dev->name);
206 put_device(&scmi_dev->dev);
207 ida_simple_remove(&scmi_bus_id, id);
211 void scmi_device_destroy(struct scmi_device *scmi_dev)
213 kfree_const(scmi_dev->name);
214 scmi_handle_put(scmi_dev->handle);
215 ida_simple_remove(&scmi_bus_id, scmi_dev->id);
216 device_unregister(&scmi_dev->dev);
219 void scmi_set_handle(struct scmi_device *scmi_dev)
221 scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
224 int scmi_protocol_register(const struct scmi_protocol *proto)
229 pr_err("invalid protocol\n");
233 if (!proto->instance_init) {
234 pr_err("missing init for protocol 0x%x\n", proto->id);
238 spin_lock(&protocol_lock);
239 ret = idr_alloc(&scmi_protocols, (void *)proto,
240 proto->id, proto->id + 1, GFP_ATOMIC);
241 spin_unlock(&protocol_lock);
242 if (ret != proto->id) {
243 pr_err("unable to allocate SCMI idr slot for 0x%x - err %d\n",
248 pr_debug("Registered SCMI Protocol 0x%x\n", proto->id);
252 EXPORT_SYMBOL_GPL(scmi_protocol_register);
254 void scmi_protocol_unregister(const struct scmi_protocol *proto)
256 spin_lock(&protocol_lock);
257 idr_remove(&scmi_protocols, proto->id);
258 spin_unlock(&protocol_lock);
260 pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);
264 EXPORT_SYMBOL_GPL(scmi_protocol_unregister);
266 static int __scmi_devices_unregister(struct device *dev, void *data)
268 struct scmi_device *scmi_dev = to_scmi_dev(dev);
270 scmi_device_destroy(scmi_dev);
274 static void scmi_devices_unregister(void)
276 bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister);
279 int __init scmi_bus_init(void)
283 retval = bus_register(&scmi_bus_type);
285 pr_err("scmi protocol bus register failed (%d)\n", retval);
290 void __exit scmi_bus_exit(void)
292 scmi_devices_unregister();
293 bus_unregister(&scmi_bus_type);
294 ida_destroy(&scmi_bus_id);