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
 20/* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */
 21static ssize_t soc_info_show(struct device *dev, 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,		0444, soc_info_show,  NULL);
 35static DEVICE_ATTR(family,		0444, soc_info_show,  NULL);
 36static DEVICE_ATTR(serial_number,	0444, soc_info_show,  NULL);
 37static DEVICE_ATTR(soc_id,		0444, soc_info_show,  NULL);
 38static DEVICE_ATTR(revision,		0444, soc_info_show,  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 = 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
 67static 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
 89static 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
 98static const struct attribute_group soc_attr_group = {
 99	.attrs = soc_attr,
100	.is_visible = soc_attribute_mode,
101};
102
103static 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
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	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
162out3:
163	kfree(soc_attr_groups);
164out2:
165	kfree(soc_dev);
166out1:
167	return ERR_PTR(ret);
168}
169EXPORT_SYMBOL_GPL(soc_device_register);
170
171/* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
172void soc_device_unregister(struct soc_device *soc_dev)
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;
245
246	if (!matches)
247		return NULL;
248
249	while (matches->machine || matches->family || matches->revision ||
250	       matches->soc_id) {
251		ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
252				       soc_device_match_one);
253		if (ret < 0 && early_soc_dev_attr)
254			ret = soc_device_match_attr(early_soc_dev_attr,
255						    matches);
256		if (ret < 0)
257			return NULL;
258		if (ret)
259			return matches;
260
261		matches++;
262	}
263	return NULL;
264}
265EXPORT_SYMBOL_GPL(soc_device_match);