summaryrefslogtreecommitdiff
path: root/drivers/firmware/arm_scmi/bus.c
blob: 35bb70724d44bceaa424b65a0e384c49c38ec6af (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
// SPDX-License-Identifier: GPL-2.0
/*
 * System Control and Management Interface (SCMI) Message Protocol bus layer
 *
 * Copyright (C) 2018-2021 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) {
			if (!id->name)
				return id;
			else if (!strcmp(id->name, scmi_dev->name))
				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_match_by_id_table(struct device *dev, void *data)
{
	struct scmi_device *sdev = to_scmi_dev(dev);
	struct scmi_device_id *id_table = data;

	return sdev->protocol_id == id_table->protocol_id &&
		!strcmp(sdev->name, id_table->name);
}

struct scmi_device *scmi_child_dev_find(struct device *parent,
					int prot_id, const char *name)
{
	struct scmi_device_id id_table;
	struct device *dev;

	id_table.protocol_id = prot_id;
	id_table.name = name;

	dev = device_find_child(parent, &id_table, scmi_match_by_id_table);
	if (!dev)
		return NULL;

	return to_scmi_dev(dev);
}

const struct scmi_protocol *scmi_protocol_get(int protocol_id)
{
	const struct scmi_protocol *proto;

	proto = idr_find(&scmi_protocols, protocol_id);
	if (!proto || !try_module_get(proto->owner)) {
		pr_warn("SCMI Protocol 0x%x not found!\n", protocol_id);
		return NULL;
	}

	pr_debug("Found SCMI Protocol 0x%x\n", protocol_id);

	return proto;
}

void scmi_protocol_put(int protocol_id)
{
	const struct scmi_protocol *proto;

	proto = idr_find(&scmi_protocols, protocol_id);
	if (proto)
		module_put(proto->owner);
}

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);

	if (!scmi_dev->handle)
		return -EPROBE_DEFER;

	return scmi_drv->probe(scmi_dev);
}

static void 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);
}

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;

	retval = scmi_protocol_device_request(driver->id_table);
	if (retval)
		return retval;

	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);
	scmi_protocol_device_unrequest(driver->id_table);
}
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,
		   const char *name)
{
	int id, retval;
	struct scmi_device *scmi_dev;

	scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
	if (!scmi_dev)
		return NULL;

	scmi_dev->name = kstrdup_const(name ?: "unknown", GFP_KERNEL);
	if (!scmi_dev->name) {
		kfree(scmi_dev);
		return NULL;
	}

	id = ida_alloc_min(&scmi_bus_id, 1, GFP_KERNEL);
	if (id < 0) {
		kfree_const(scmi_dev->name);
		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:
	kfree_const(scmi_dev->name);
	put_device(&scmi_dev->dev);
	ida_free(&scmi_bus_id, id);
	return NULL;
}

void scmi_device_destroy(struct scmi_device *scmi_dev)
{
	kfree_const(scmi_dev->name);
	scmi_handle_put(scmi_dev->handle);
	ida_free(&scmi_bus_id, scmi_dev->id);
	device_unregister(&scmi_dev->dev);
}

void scmi_device_link_add(struct device *consumer, struct device *supplier)
{
	struct device_link *link;

	link = device_link_add(consumer, supplier, DL_FLAG_AUTOREMOVE_CONSUMER);

	WARN_ON(!link);
}

void scmi_set_handle(struct scmi_device *scmi_dev)
{
	scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
	if (scmi_dev->handle)
		scmi_device_link_add(&scmi_dev->dev, scmi_dev->handle->dev);
}

int scmi_protocol_register(const struct scmi_protocol *proto)
{
	int ret;

	if (!proto) {
		pr_err("invalid protocol\n");
		return -EINVAL;
	}

	if (!proto->instance_init) {
		pr_err("missing init for protocol 0x%x\n", proto->id);
		return -EINVAL;
	}

	spin_lock(&protocol_lock);
	ret = idr_alloc(&scmi_protocols, (void *)proto,
			proto->id, proto->id + 1, GFP_ATOMIC);
	spin_unlock(&protocol_lock);
	if (ret != proto->id) {
		pr_err("unable to allocate SCMI idr slot for 0x%x - err %d\n",
		       proto->id, ret);
		return ret;
	}

	pr_debug("Registered SCMI Protocol 0x%x\n", proto->id);

	return 0;
}
EXPORT_SYMBOL_GPL(scmi_protocol_register);

void scmi_protocol_unregister(const struct scmi_protocol *proto)
{
	spin_lock(&protocol_lock);
	idr_remove(&scmi_protocols, proto->id);
	spin_unlock(&protocol_lock);

	pr_debug("Unregistered SCMI Protocol 0x%x\n", proto->id);

	return;
}
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);
}

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;
}

void __exit scmi_bus_exit(void)
{
	scmi_devices_unregister();
	bus_unregister(&scmi_bus_type);
	ida_destroy(&scmi_bus_id);
}