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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) ST-Ericsson SA 2011
4 *
5 * Author: Lee Jones <[email protected]> for ST-Ericsson.
6 */
7
8#include <linux/err.h>
9#include <linux/glob.h>
10#include <linux/idr.h>
11#include <linux/init.h>
12#include <linux/of.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15#include <linux/stat.h>
16#include <linux/sysfs.h>
17#include <linux/sys_soc.h>
18
19static DEFINE_IDA(soc_ida);
20
21/* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */
22static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
23 char *buf);
24
25struct soc_device {
26 struct device dev;
27 struct soc_device_attribute *attr;
28 int soc_dev_num;
29};
30
31static const struct bus_type soc_bus_type = {
32 .name = "soc",
33};
34static bool soc_bus_registered;
35
36static DEVICE_ATTR(machine, 0444, soc_info_show, NULL);
37static DEVICE_ATTR(family, 0444, soc_info_show, NULL);
38static DEVICE_ATTR(serial_number, 0444, soc_info_show, NULL);
39static DEVICE_ATTR(soc_id, 0444, soc_info_show, NULL);
40static DEVICE_ATTR(revision, 0444, soc_info_show, NULL);
41
42struct device *soc_device_to_device(struct soc_device *soc_dev)
43{
44 return &soc_dev->dev;
45}
46
47static umode_t soc_attribute_mode(struct kobject *kobj,
48 struct attribute *attr,
49 int index)
50{
51 struct device *dev = kobj_to_dev(kobj);
52 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
53
54 if ((attr == &dev_attr_machine.attr) && soc_dev->attr->machine)
55 return attr->mode;
56 if ((attr == &dev_attr_family.attr) && soc_dev->attr->family)
57 return attr->mode;
58 if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision)
59 return attr->mode;
60 if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number)
61 return attr->mode;
62 if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id)
63 return attr->mode;
64
65 /* Unknown or unfilled attribute */
66 return 0;
67}
68
69static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
70 char *buf)
71{
72 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
73 const char *output;
74
75 if (attr == &dev_attr_machine)
76 output = soc_dev->attr->machine;
77 else if (attr == &dev_attr_family)
78 output = soc_dev->attr->family;
79 else if (attr == &dev_attr_revision)
80 output = soc_dev->attr->revision;
81 else if (attr == &dev_attr_serial_number)
82 output = soc_dev->attr->serial_number;
83 else if (attr == &dev_attr_soc_id)
84 output = soc_dev->attr->soc_id;
85 else
86 return -EINVAL;
87
88 return sysfs_emit(buf, "%s\n", output);
89}
90
91static struct attribute *soc_attr[] = {
92 &dev_attr_machine.attr,
93 &dev_attr_family.attr,
94 &dev_attr_serial_number.attr,
95 &dev_attr_soc_id.attr,
96 &dev_attr_revision.attr,
97 NULL,
98};
99
100static const struct attribute_group soc_attr_group = {
101 .attrs = soc_attr,
102 .is_visible = soc_attribute_mode,
103};
104
105static void soc_release(struct device *dev)
106{
107 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
108
109 ida_free(&soc_ida, soc_dev->soc_dev_num);
110 kfree(soc_dev->dev.groups);
111 kfree(soc_dev);
112}
113
114int soc_attr_read_machine(struct soc_device_attribute *soc_dev_attr)
115{
116 if (soc_dev_attr->machine)
117 return -EBUSY;
118
119 return of_machine_read_model(&soc_dev_attr->machine);
120}
121EXPORT_SYMBOL_GPL(soc_attr_read_machine);
122
123static struct soc_device_attribute *early_soc_dev_attr;
124
125struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
126{
127 struct soc_device *soc_dev;
128 const struct attribute_group **soc_attr_groups;
129 int ret;
130
131 soc_attr_read_machine(soc_dev_attr);
132
133 if (!soc_bus_registered) {
134 if (early_soc_dev_attr)
135 return ERR_PTR(-EBUSY);
136 early_soc_dev_attr = soc_dev_attr;
137 return NULL;
138 }
139
140 soc_dev = kzalloc_obj(*soc_dev);
141 if (!soc_dev) {
142 ret = -ENOMEM;
143 goto out1;
144 }
145
146 soc_attr_groups = kzalloc_objs(*soc_attr_groups, 3);
147 if (!soc_attr_groups) {
148 ret = -ENOMEM;
149 goto out2;
150 }
151 soc_attr_groups[0] = &soc_attr_group;
152 soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
153
154 /* Fetch a unique (reclaimable) SOC ID. */
155 ret = ida_alloc(&soc_ida, GFP_KERNEL);
156 if (ret < 0)
157 goto out3;
158 soc_dev->soc_dev_num = ret;
159
160 soc_dev->attr = soc_dev_attr;
161 soc_dev->dev.bus = &soc_bus_type;
162 soc_dev->dev.groups = soc_attr_groups;
163 soc_dev->dev.release = soc_release;
164
165 dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
166
167 ret = device_register(&soc_dev->dev);
168 if (ret) {
169 put_device(&soc_dev->dev);
170 return ERR_PTR(ret);
171 }
172
173 return soc_dev;
174
175out3:
176 kfree(soc_attr_groups);
177out2:
178 kfree(soc_dev);
179out1:
180 return ERR_PTR(ret);
181}
182EXPORT_SYMBOL_GPL(soc_device_register);
183
184/* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
185void soc_device_unregister(struct soc_device *soc_dev)
186{
187 device_unregister(&soc_dev->dev);
188 early_soc_dev_attr = NULL;
189}
190EXPORT_SYMBOL_GPL(soc_device_unregister);
191
192static int __init soc_bus_register(void)
193{
194 struct soc_device *soc_dev;
195 int ret;
196
197 ret = bus_register(&soc_bus_type);
198 if (ret)
199 return ret;
200 soc_bus_registered = true;
201
202 if (early_soc_dev_attr) {
203 soc_dev = soc_device_register(early_soc_dev_attr);
204 if (IS_ERR(soc_dev)) {
205 ret = PTR_ERR(soc_dev);
206 goto err_unregister_bus;
207 }
208 }
209
210 return 0;
211
212err_unregister_bus:
213 soc_bus_registered = false;
214 bus_unregister(&soc_bus_type);
215 return ret;
216}
217core_initcall(soc_bus_register);
218
219static int soc_device_match_attr(const struct soc_device_attribute *attr,
220 const struct soc_device_attribute *match)
221{
222 if (match->machine &&
223 (!attr->machine || !glob_match(match->machine, attr->machine)))
224 return 0;
225
226 if (match->family &&
227 (!attr->family || !glob_match(match->family, attr->family)))
228 return 0;
229
230 if (match->revision &&
231 (!attr->revision || !glob_match(match->revision, attr->revision)))
232 return 0;
233
234 if (match->soc_id &&
235 (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
236 return 0;
237
238 return 1;
239}
240
241static int soc_device_match_one(struct device *dev, void *arg)
242{
243 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
244
245 return soc_device_match_attr(soc_dev->attr, arg);
246}
247
248/*
249 * soc_device_match - identify the SoC in the machine
250 * @matches: zero-terminated array of possible matches
251 *
252 * returns the first matching entry of the argument array, or NULL
253 * if none of them match.
254 *
255 * This function is meant as a helper in place of of_match_node()
256 * in cases where either no device tree is available or the information
257 * in a device node is insufficient to identify a particular variant
258 * by its compatible strings or other properties. For new devices,
259 * the DT binding should always provide unique compatible strings
260 * that allow the use of of_match_node() instead.
261 *
262 * The calling function can use the .data entry of the
263 * soc_device_attribute to pass a structure or function pointer for
264 * each entry.
265 */
266const struct soc_device_attribute *soc_device_match(
267 const struct soc_device_attribute *matches)
268{
269 int ret;
270
271 if (!matches)
272 return NULL;
273
274 while (matches->machine || matches->family || matches->revision ||
275 matches->soc_id) {
276 ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
277 soc_device_match_one);
278 if (ret < 0 && early_soc_dev_attr)
279 ret = soc_device_match_attr(early_soc_dev_attr,
280 matches);
281 if (ret < 0)
282 return NULL;
283 if (ret)
284 return matches;
285
286 matches++;
287 }
288 return NULL;
289}
290EXPORT_SYMBOL_GPL(soc_device_match);