aboutsummaryrefslogtreecommitdiff
path: root/drivers/base/soc.c
blob: 22130b5f789d9d7ef7531be5b1e05e78362a5893 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) ST-Ericsson SA 2011
 *
 * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
 */

#include <linux/sysfs.h>
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/spinlock.h>
#include <linux/sys_soc.h>
#include <linux/err.h>
#include <linux/glob.h>

static DEFINE_IDA(soc_ida);

/* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */
static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
			     char *buf);

struct soc_device {
	struct device dev;
	struct soc_device_attribute *attr;
	int soc_dev_num;
};

static struct bus_type soc_bus_type = {
	.name  = "soc",
};

static DEVICE_ATTR(machine,		0444, soc_info_show,  NULL);
static DEVICE_ATTR(family,		0444, soc_info_show,  NULL);
static DEVICE_ATTR(serial_number,	0444, soc_info_show,  NULL);
static DEVICE_ATTR(soc_id,		0444, soc_info_show,  NULL);
static DEVICE_ATTR(revision,		0444, soc_info_show,  NULL);

struct device *soc_device_to_device(struct soc_device *soc_dev)
{
	return &soc_dev->dev;
}

static umode_t soc_attribute_mode(struct kobject *kobj,
				struct attribute *attr,
				int index)
{
	struct device *dev = kobj_to_dev(kobj);
	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);

	if ((attr == &dev_attr_machine.attr) && soc_dev->attr->machine)
		return attr->mode;
	if ((attr == &dev_attr_family.attr) && soc_dev->attr->family)
		return attr->mode;
	if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision)
		return attr->mode;
	if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number)
		return attr->mode;
	if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id)
		return attr->mode;

	/* Unknown or unfilled attribute */
	return 0;
}

static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
	const char *output;

	if (attr == &dev_attr_machine)
		output = soc_dev->attr->machine;
	else if (attr == &dev_attr_family)
		output = soc_dev->attr->family;
	else if (attr == &dev_attr_revision)
		output = soc_dev->attr->revision;
	else if (attr == &dev_attr_serial_number)
		output = soc_dev->attr->serial_number;
	else if (attr == &dev_attr_soc_id)
		output = soc_dev->attr->soc_id;
	else
		return -EINVAL;

	return sysfs_emit(buf, "%s\n", output);
}

static struct attribute *soc_attr[] = {
	&dev_attr_machine.attr,
	&dev_attr_family.attr,
	&dev_attr_serial_number.attr,
	&dev_attr_soc_id.attr,
	&dev_attr_revision.attr,
	NULL,
};

static const struct attribute_group soc_attr_group = {
	.attrs = soc_attr,
	.is_visible = soc_attribute_mode,
};

static void soc_release(struct device *dev)
{
	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);

	ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
	kfree(soc_dev->dev.groups);
	kfree(soc_dev);
}

static struct soc_device_attribute *early_soc_dev_attr;

struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
{
	struct soc_device *soc_dev;
	const struct attribute_group **soc_attr_groups;
	int ret;

	if (!soc_bus_type.p) {
		if (early_soc_dev_attr)
			return ERR_PTR(-EBUSY);
		early_soc_dev_attr = soc_dev_attr;
		return NULL;
	}

	soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
	if (!soc_dev) {
		ret = -ENOMEM;
		goto out1;
	}

	soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL);
	if (!soc_attr_groups) {
		ret = -ENOMEM;
		goto out2;
	}
	soc_attr_groups[0] = &soc_attr_group;
	soc_attr_groups[1] = soc_dev_attr->custom_attr_group;

	/* Fetch a unique (reclaimable) SOC ID. */
	ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
	if (ret < 0)
		goto out3;
	soc_dev->soc_dev_num = ret;

	soc_dev->attr = soc_dev_attr;
	soc_dev->dev.bus = &soc_bus_type;
	soc_dev->dev.groups = soc_attr_groups;
	soc_dev->dev.release = soc_release;

	dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);

	ret = device_register(&soc_dev->dev);
	if (ret) {
		put_device(&soc_dev->dev);
		return ERR_PTR(ret);
	}

	return soc_dev;

out3:
	kfree(soc_attr_groups);
out2:
	kfree(soc_dev);
out1:
	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(soc_device_register);

/* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
void soc_device_unregister(struct soc_device *soc_dev)
{
	device_unregister(&soc_dev->dev);
	early_soc_dev_attr = NULL;
}
EXPORT_SYMBOL_GPL(soc_device_unregister);

static int __init soc_bus_register(void)
{
	int ret;

	ret = bus_register(&soc_bus_type);
	if (ret)
		return ret;

	if (early_soc_dev_attr)
		return PTR_ERR(soc_device_register(early_soc_dev_attr));

	return 0;
}
core_initcall(soc_bus_register);

static int soc_device_match_attr(const struct soc_device_attribute *attr,
				 const struct soc_device_attribute *match)
{
	if (match->machine &&
	    (!attr->machine || !glob_match(match->machine, attr->machine)))
		return 0;

	if (match->family &&
	    (!attr->family || !glob_match(match->family, attr->family)))
		return 0;

	if (match->revision &&
	    (!attr->revision || !glob_match(match->revision, attr->revision)))
		return 0;

	if (match->soc_id &&
	    (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
		return 0;

	return 1;
}

static int soc_device_match_one(struct device *dev, void *arg)
{
	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);

	return soc_device_match_attr(soc_dev->attr, arg);
}

/*
 * soc_device_match - identify the SoC in the machine
 * @matches: zero-terminated array of possible matches
 *
 * returns the first matching entry of the argument array, or NULL
 * if none of them match.
 *
 * This function is meant as a helper in place of of_match_node()
 * in cases where either no device tree is available or the information
 * in a device node is insufficient to identify a particular variant
 * by its compatible strings or other properties. For new devices,
 * the DT binding should always provide unique compatible strings
 * that allow the use of of_match_node() instead.
 *
 * The calling function can use the .data entry of the
 * soc_device_attribute to pass a structure or function pointer for
 * each entry.
 */
const struct soc_device_attribute *soc_device_match(
	const struct soc_device_attribute *matches)
{
	int ret;

	if (!matches)
		return NULL;

	while (matches->machine || matches->family || matches->revision ||
	       matches->soc_id) {
		ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
				       soc_device_match_one);
		if (ret < 0 && early_soc_dev_attr)
			ret = soc_device_match_attr(early_soc_dev_attr,
						    matches);
		if (ret < 0)
			return NULL;
		if (ret)
			return matches;

		matches++;
	}
	return NULL;
}
EXPORT_SYMBOL_GPL(soc_device_match);