tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * System Control and Management Interface (SCMI) Message Protocol bus layer
4 *
5 * Copyright (C) 2018 ARM Ltd.
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
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>
15
16#include "common.h"
17
18static DEFINE_IDA(scmi_bus_id);
19static DEFINE_IDR(scmi_protocols);
20static DEFINE_SPINLOCK(protocol_lock);
21
22static const struct scmi_device_id *
23scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv)
24{
25 const struct scmi_device_id *id = scmi_drv->id_table;
26
27 if (!id)
28 return NULL;
29
30 for (; id->protocol_id; id++)
31 if (id->protocol_id == scmi_dev->protocol_id)
32 return id;
33
34 return NULL;
35}
36
37static int scmi_dev_match(struct device *dev, struct device_driver *drv)
38{
39 struct scmi_driver *scmi_drv = to_scmi_driver(drv);
40 struct scmi_device *scmi_dev = to_scmi_dev(dev);
41 const struct scmi_device_id *id;
42
43 id = scmi_dev_match_id(scmi_dev, scmi_drv);
44 if (id)
45 return 1;
46
47 return 0;
48}
49
50static int scmi_protocol_init(int protocol_id, struct scmi_handle *handle)
51{
52 scmi_prot_init_fn_t fn = idr_find(&scmi_protocols, protocol_id);
53
54 if (unlikely(!fn))
55 return -EINVAL;
56 return fn(handle);
57}
58
59static int scmi_dev_probe(struct device *dev)
60{
61 struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
62 struct scmi_device *scmi_dev = to_scmi_dev(dev);
63 const struct scmi_device_id *id;
64 int ret;
65
66 id = scmi_dev_match_id(scmi_dev, scmi_drv);
67 if (!id)
68 return -ENODEV;
69
70 if (!scmi_dev->handle)
71 return -EPROBE_DEFER;
72
73 ret = scmi_protocol_init(scmi_dev->protocol_id, scmi_dev->handle);
74 if (ret)
75 return ret;
76
77 return scmi_drv->probe(scmi_dev);
78}
79
80static int scmi_dev_remove(struct device *dev)
81{
82 struct scmi_driver *scmi_drv = to_scmi_driver(dev->driver);
83 struct scmi_device *scmi_dev = to_scmi_dev(dev);
84
85 if (scmi_drv->remove)
86 scmi_drv->remove(scmi_dev);
87
88 return 0;
89}
90
91static struct bus_type scmi_bus_type = {
92 .name = "scmi_protocol",
93 .match = scmi_dev_match,
94 .probe = scmi_dev_probe,
95 .remove = scmi_dev_remove,
96};
97
98int scmi_driver_register(struct scmi_driver *driver, struct module *owner,
99 const char *mod_name)
100{
101 int retval;
102
103 driver->driver.bus = &scmi_bus_type;
104 driver->driver.name = driver->name;
105 driver->driver.owner = owner;
106 driver->driver.mod_name = mod_name;
107
108 retval = driver_register(&driver->driver);
109 if (!retval)
110 pr_debug("registered new scmi driver %s\n", driver->name);
111
112 return retval;
113}
114EXPORT_SYMBOL_GPL(scmi_driver_register);
115
116void scmi_driver_unregister(struct scmi_driver *driver)
117{
118 driver_unregister(&driver->driver);
119}
120EXPORT_SYMBOL_GPL(scmi_driver_unregister);
121
122static void scmi_device_release(struct device *dev)
123{
124 kfree(to_scmi_dev(dev));
125}
126
127struct scmi_device *
128scmi_device_create(struct device_node *np, struct device *parent, int protocol)
129{
130 int id, retval;
131 struct scmi_device *scmi_dev;
132
133 scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
134 if (!scmi_dev)
135 return NULL;
136
137 id = ida_simple_get(&scmi_bus_id, 1, 0, GFP_KERNEL);
138 if (id < 0)
139 goto free_mem;
140
141 scmi_dev->id = id;
142 scmi_dev->protocol_id = protocol;
143 scmi_dev->dev.parent = parent;
144 scmi_dev->dev.of_node = np;
145 scmi_dev->dev.bus = &scmi_bus_type;
146 scmi_dev->dev.release = scmi_device_release;
147 dev_set_name(&scmi_dev->dev, "scmi_dev.%d", id);
148
149 retval = device_register(&scmi_dev->dev);
150 if (retval)
151 goto put_dev;
152
153 return scmi_dev;
154put_dev:
155 put_device(&scmi_dev->dev);
156 ida_simple_remove(&scmi_bus_id, id);
157free_mem:
158 kfree(scmi_dev);
159 return NULL;
160}
161
162void scmi_device_destroy(struct scmi_device *scmi_dev)
163{
164 scmi_handle_put(scmi_dev->handle);
165 ida_simple_remove(&scmi_bus_id, scmi_dev->id);
166 device_unregister(&scmi_dev->dev);
167}
168
169void scmi_set_handle(struct scmi_device *scmi_dev)
170{
171 scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
172}
173
174int scmi_protocol_register(int protocol_id, scmi_prot_init_fn_t fn)
175{
176 int ret;
177
178 spin_lock(&protocol_lock);
179 ret = idr_alloc(&scmi_protocols, fn, protocol_id, protocol_id + 1,
180 GFP_ATOMIC);
181 spin_unlock(&protocol_lock);
182 if (ret != protocol_id)
183 pr_err("unable to allocate SCMI idr slot, err %d\n", ret);
184
185 return ret;
186}
187EXPORT_SYMBOL_GPL(scmi_protocol_register);
188
189void scmi_protocol_unregister(int protocol_id)
190{
191 spin_lock(&protocol_lock);
192 idr_remove(&scmi_protocols, protocol_id);
193 spin_unlock(&protocol_lock);
194}
195EXPORT_SYMBOL_GPL(scmi_protocol_unregister);
196
197static int __scmi_devices_unregister(struct device *dev, void *data)
198{
199 struct scmi_device *scmi_dev = to_scmi_dev(dev);
200
201 scmi_device_destroy(scmi_dev);
202 return 0;
203}
204
205static void scmi_devices_unregister(void)
206{
207 bus_for_each_dev(&scmi_bus_type, NULL, NULL, __scmi_devices_unregister);
208}
209
210static int __init scmi_bus_init(void)
211{
212 int retval;
213
214 retval = bus_register(&scmi_bus_type);
215 if (retval)
216 pr_err("scmi protocol bus register failed (%d)\n", retval);
217
218 return retval;
219}
220subsys_initcall(scmi_bus_init);
221
222static void __exit scmi_bus_exit(void)
223{
224 scmi_devices_unregister();
225 bus_unregister(&scmi_bus_type);
226 ida_destroy(&scmi_bus_id);
227}
228module_exit(scmi_bus_exit);