1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) ST-Ericsson SA 2011
4 *
5 * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
6 */
7
8#include <linux/sysfs.h>
9#include <linux/init.h>
10#include <linux/of.h>
11#include <linux/stat.h>
12#include <linux/slab.h>
13#include <linux/idr.h>
14#include <linux/spinlock.h>
15#include <linux/sys_soc.h>
16#include <linux/err.h>
17#include <linux/glob.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, fmt: "%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, id: soc_dev->soc_dev_num);
110 kfree(objp: soc_dev->dev.groups);
111 kfree(objp: soc_dev);
112}
113
114static void soc_device_get_machine(struct soc_device_attribute *soc_dev_attr)
115{
116 struct device_node *np;
117
118 if (soc_dev_attr->machine)
119 return;
120
121 np = of_find_node_by_path(path: "/");
122 of_property_read_string(np, propname: "model", out_string: &soc_dev_attr->machine);
123 of_node_put(node: np);
124}
125
126static struct soc_device_attribute *early_soc_dev_attr;
127
128struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
129{
130 struct soc_device *soc_dev;
131 const struct attribute_group **soc_attr_groups;
132 int ret;
133
134 soc_device_get_machine(soc_dev_attr);
135
136 if (!soc_bus_registered) {
137 if (early_soc_dev_attr)
138 return ERR_PTR(error: -EBUSY);
139 early_soc_dev_attr = soc_dev_attr;
140 return NULL;
141 }
142
143 soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
144 if (!soc_dev) {
145 ret = -ENOMEM;
146 goto out1;
147 }
148
149 soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL);
150 if (!soc_attr_groups) {
151 ret = -ENOMEM;
152 goto out2;
153 }
154 soc_attr_groups[0] = &soc_attr_group;
155 soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
156
157 /* Fetch a unique (reclaimable) SOC ID. */
158 ret = ida_alloc(ida: &soc_ida, GFP_KERNEL);
159 if (ret < 0)
160 goto out3;
161 soc_dev->soc_dev_num = ret;
162
163 soc_dev->attr = soc_dev_attr;
164 soc_dev->dev.bus = &soc_bus_type;
165 soc_dev->dev.groups = soc_attr_groups;
166 soc_dev->dev.release = soc_release;
167
168 dev_set_name(dev: &soc_dev->dev, name: "soc%d", soc_dev->soc_dev_num);
169
170 ret = device_register(dev: &soc_dev->dev);
171 if (ret) {
172 put_device(dev: &soc_dev->dev);
173 return ERR_PTR(error: ret);
174 }
175
176 return soc_dev;
177
178out3:
179 kfree(objp: soc_attr_groups);
180out2:
181 kfree(objp: soc_dev);
182out1:
183 return ERR_PTR(error: ret);
184}
185EXPORT_SYMBOL_GPL(soc_device_register);
186
187/* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
188void soc_device_unregister(struct soc_device *soc_dev)
189{
190 device_unregister(dev: &soc_dev->dev);
191 early_soc_dev_attr = NULL;
192}
193EXPORT_SYMBOL_GPL(soc_device_unregister);
194
195static int __init soc_bus_register(void)
196{
197 int ret;
198
199 ret = bus_register(bus: &soc_bus_type);
200 if (ret)
201 return ret;
202 soc_bus_registered = true;
203
204 if (early_soc_dev_attr)
205 return PTR_ERR(ptr: soc_device_register(early_soc_dev_attr));
206
207 return 0;
208}
209core_initcall(soc_bus_register);
210
211static int soc_device_match_attr(const struct soc_device_attribute *attr,
212 const struct soc_device_attribute *match)
213{
214 if (match->machine &&
215 (!attr->machine || !glob_match(pat: match->machine, str: attr->machine)))
216 return 0;
217
218 if (match->family &&
219 (!attr->family || !glob_match(pat: match->family, str: attr->family)))
220 return 0;
221
222 if (match->revision &&
223 (!attr->revision || !glob_match(pat: match->revision, str: attr->revision)))
224 return 0;
225
226 if (match->soc_id &&
227 (!attr->soc_id || !glob_match(pat: match->soc_id, str: attr->soc_id)))
228 return 0;
229
230 return 1;
231}
232
233static int soc_device_match_one(struct device *dev, void *arg)
234{
235 struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
236
237 return soc_device_match_attr(attr: soc_dev->attr, match: arg);
238}
239
240/*
241 * soc_device_match - identify the SoC in the machine
242 * @matches: zero-terminated array of possible matches
243 *
244 * returns the first matching entry of the argument array, or NULL
245 * if none of them match.
246 *
247 * This function is meant as a helper in place of of_match_node()
248 * in cases where either no device tree is available or the information
249 * in a device node is insufficient to identify a particular variant
250 * by its compatible strings or other properties. For new devices,
251 * the DT binding should always provide unique compatible strings
252 * that allow the use of of_match_node() instead.
253 *
254 * The calling function can use the .data entry of the
255 * soc_device_attribute to pass a structure or function pointer for
256 * each entry.
257 */
258const struct soc_device_attribute *soc_device_match(
259 const struct soc_device_attribute *matches)
260{
261 int ret;
262
263 if (!matches)
264 return NULL;
265
266 while (matches->machine || matches->family || matches->revision ||
267 matches->soc_id) {
268 ret = bus_for_each_dev(bus: &soc_bus_type, NULL, data: (void *)matches,
269 fn: soc_device_match_one);
270 if (ret < 0 && early_soc_dev_attr)
271 ret = soc_device_match_attr(attr: early_soc_dev_attr,
272 match: matches);
273 if (ret < 0)
274 return NULL;
275 if (ret)
276 return matches;
277
278 matches++;
279 }
280 return NULL;
281}
282EXPORT_SYMBOL_GPL(soc_device_match);
283

source code of linux/drivers/base/soc.c