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