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);