1/*
2 * Copyright (C) ST-Ericsson SA 2011
3 *
4 * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
5 * License terms:  GNU General Public License (GPL), version 2
6 */
7
8#include <linux/sysfs.h>
9#include <linux/module.h>
10#include <linux/init.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
18static DEFINE_IDA(soc_ida);
19static DEFINE_SPINLOCK(soc_lock);
20
21static ssize_t soc_info_get(struct device *dev,
22			    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 struct bus_type soc_bus_type = {
32	.name  = "soc",
33};
34
35static DEVICE_ATTR(machine,  S_IRUGO, soc_info_get,  NULL);
36static DEVICE_ATTR(family,   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_soc_id.attr)
62	    && (soc_dev->attr->soc_id != NULL))
63		return attr->mode;
64
65	/* Unknown or unfilled attribute. */
66	return 0;
67}
68
69static ssize_t soc_info_get(struct device *dev,
70			    struct device_attribute *attr,
71			    char *buf)
72{
73	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
74
75	if (attr == &dev_attr_machine)
76		return sprintf(buf, "%s\n", soc_dev->attr->machine);
77	if (attr == &dev_attr_family)
78		return sprintf(buf, "%s\n", soc_dev->attr->family);
79	if (attr == &dev_attr_revision)
80		return sprintf(buf, "%s\n", soc_dev->attr->revision);
81	if (attr == &dev_attr_soc_id)
82		return sprintf(buf, "%s\n", soc_dev->attr->soc_id);
83
84	return -EINVAL;
85
86}
87
88static struct attribute *soc_attr[] = {
89	&dev_attr_machine.attr,
90	&dev_attr_family.attr,
91	&dev_attr_soc_id.attr,
92	&dev_attr_revision.attr,
93	NULL,
94};
95
96static const struct attribute_group soc_attr_group = {
97	.attrs = soc_attr,
98	.is_visible = soc_attribute_mode,
99};
100
101static const struct attribute_group *soc_attr_groups[] = {
102	&soc_attr_group,
103	NULL,
104};
105
106static void soc_release(struct device *dev)
107{
108	struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
109
110	kfree(soc_dev);
111}
112
113struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
114{
115	struct soc_device *soc_dev;
116	int ret;
117
118	soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
119	if (!soc_dev) {
120		ret = -ENOMEM;
121		goto out1;
122	}
123
124	/* Fetch a unique (reclaimable) SOC ID. */
125	do {
126		if (!ida_pre_get(&soc_ida, GFP_KERNEL)) {
127			ret = -ENOMEM;
128			goto out2;
129		}
130
131		spin_lock(&soc_lock);
132		ret = ida_get_new(&soc_ida, &soc_dev->soc_dev_num);
133		spin_unlock(&soc_lock);
134
135	} while (ret == -EAGAIN);
136
137	if (ret)
138		goto out2;
139
140	soc_dev->attr = soc_dev_attr;
141	soc_dev->dev.bus = &soc_bus_type;
142	soc_dev->dev.groups = soc_attr_groups;
143	soc_dev->dev.release = soc_release;
144
145	dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
146
147	ret = device_register(&soc_dev->dev);
148	if (ret)
149		goto out3;
150
151	return soc_dev;
152
153out3:
154	ida_remove(&soc_ida, soc_dev->soc_dev_num);
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_remove(&soc_ida, soc_dev->soc_dev_num);
165
166	device_unregister(&soc_dev->dev);
167}
168
169static int __init soc_bus_register(void)
170{
171	return bus_register(&soc_bus_type);
172}
173core_initcall(soc_bus_register);
174
175static void __exit soc_bus_unregister(void)
176{
177	ida_destroy(&soc_ida);
178
179	bus_unregister(&soc_bus_type);
180}
181module_exit(soc_bus_unregister);
182