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);