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, "%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
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("/");
122	of_property_read_string(np, "model", &soc_dev_attr->machine);
123	of_node_put(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(-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(&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(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
169
170	ret = device_register(&soc_dev->dev);
171	if (ret) {
172		put_device(&soc_dev->dev);
173		return ERR_PTR(ret);
174	}
175
176	return soc_dev;
177
178out3:
179	kfree(soc_attr_groups);
180out2:
181	kfree(soc_dev);
182out1:
183	return ERR_PTR(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(&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(&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(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(match->machine, attr->machine)))
216		return 0;
217
218	if (match->family &&
219	    (!attr->family || !glob_match(match->family, attr->family)))
220		return 0;
221
222	if (match->revision &&
223	    (!attr->revision || !glob_match(match->revision, attr->revision)))
224		return 0;
225
226	if (match->soc_id &&
227	    (!attr->soc_id || !glob_match(match->soc_id, 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(soc_dev->attr, 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(&soc_bus_type, NULL, (void *)matches,
269				       soc_device_match_one);
270		if (ret < 0 && early_soc_dev_attr)
271			ret = soc_device_match_attr(early_soc_dev_attr,
272						    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