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