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(serial_number, S_IRUGO, soc_info_get,  NULL);
 37static DEVICE_ATTR(soc_id,   S_IRUGO, soc_info_get,  NULL);
 38static DEVICE_ATTR(revision, S_IRUGO, soc_info_get,  NULL);
 39
 40struct device *soc_device_to_device(struct soc_device *soc_dev)
 41{
 42	return &soc_dev->dev;
 43}
 44
 45static umode_t soc_attribute_mode(struct kobject *kobj,
 46				struct attribute *attr,
 47				int index)
 48{
 49	struct device *dev = container_of(kobj, struct device, kobj);
 50	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 51
 52	if ((attr == &dev_attr_machine.attr)
 53	    && (soc_dev->attr->machine != NULL))
 54		return attr->mode;
 55	if ((attr == &dev_attr_family.attr)
 56	    && (soc_dev->attr->family != NULL))
 57		return attr->mode;
 58	if ((attr == &dev_attr_revision.attr)
 59	    && (soc_dev->attr->revision != NULL))
 60		return attr->mode;
 61	if ((attr == &dev_attr_serial_number.attr)
 62	    && (soc_dev->attr->serial_number != NULL))
 63		return attr->mode;
 64	if ((attr == &dev_attr_soc_id.attr)
 65	    && (soc_dev->attr->soc_id != NULL))
 66		return attr->mode;
 67
 68	/* Unknown or unfilled attribute. */
 69	return 0;
 70}
 71
 72static ssize_t soc_info_get(struct device *dev,
 73			    struct device_attribute *attr,
 74			    char *buf)
 75{
 76	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
 77
 78	if (attr == &dev_attr_machine)
 79		return sprintf(buf, "%s\n", soc_dev->attr->machine);
 80	if (attr == &dev_attr_family)
 81		return sprintf(buf, "%s\n", soc_dev->attr->family);
 82	if (attr == &dev_attr_revision)
 83		return sprintf(buf, "%s\n", soc_dev->attr->revision);
 84	if (attr == &dev_attr_serial_number)
 85		return sprintf(buf, "%s\n", soc_dev->attr->serial_number);
 86	if (attr == &dev_attr_soc_id)
 87		return sprintf(buf, "%s\n", soc_dev->attr->soc_id);
 88
 89	return -EINVAL;
 90
 91}
 92
 93static struct attribute *soc_attr[] = {
 94	&dev_attr_machine.attr,
 95	&dev_attr_family.attr,
 96	&dev_attr_serial_number.attr,
 97	&dev_attr_soc_id.attr,
 98	&dev_attr_revision.attr,
 99	NULL,
100};
101
102static const struct attribute_group soc_attr_group = {
103	.attrs = soc_attr,
104	.is_visible = soc_attribute_mode,
105};
106
107static const struct attribute_group *soc_attr_groups[] = {
108	&soc_attr_group,
109	NULL,
110};
111
112static void soc_release(struct device *dev)
113{
114	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
115
116	kfree(soc_dev);
117}
118
119static struct soc_device_attribute *early_soc_dev_attr;
120
121struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
122{
123	struct soc_device *soc_dev;
124	int ret;
125
126	if (!soc_bus_type.p) {
127		if (early_soc_dev_attr)
128			return ERR_PTR(-EBUSY);
129		early_soc_dev_attr = soc_dev_attr;
130		return NULL;
131	}
132
133	soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
134	if (!soc_dev) {
135		ret = -ENOMEM;
136		goto out1;
137	}
138
139	/* Fetch a unique (reclaimable) SOC ID. */
140	ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
141	if (ret < 0)
142		goto out2;
143	soc_dev->soc_dev_num = ret;
144
145	soc_dev->attr = soc_dev_attr;
146	soc_dev->dev.bus = &soc_bus_type;
147	soc_dev->dev.groups = soc_attr_groups;
148	soc_dev->dev.release = soc_release;
149
150	dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
151
152	ret = device_register(&soc_dev->dev);
153	if (ret)
154		goto out3;
155
156	return soc_dev;
157
158out3:
159	ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
160	put_device(&soc_dev->dev);
161	soc_dev = NULL;
162out2:
163	kfree(soc_dev);
164out1:
165	return ERR_PTR(ret);
166}
167EXPORT_SYMBOL_GPL(soc_device_register);
168
169/* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */
170void soc_device_unregister(struct soc_device *soc_dev)
171{
172	ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
173
174	device_unregister(&soc_dev->dev);
175	early_soc_dev_attr = NULL;
176}
177EXPORT_SYMBOL_GPL(soc_device_unregister);
178
179static 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}
192core_initcall(soc_bus_register);
193
194static 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
216static 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 */
241const 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}
267EXPORT_SYMBOL_GPL(soc_device_match);