1/*
2 * Generic /dev/nvram driver for architectures providing some
3 * "generic" hooks, that is :
4 *
5 * nvram_read_byte, nvram_write_byte, nvram_sync
6 *
7 * Note that an additional hook is supported for PowerMac only
8 * for getting the nvram "partition" informations
9 *
10 */
11
12#define NVRAM_VERSION "1.1"
13
14#include <linux/module.h>
15
16#include <linux/types.h>
17#include <linux/errno.h>
18#include <linux/fs.h>
19#include <linux/miscdevice.h>
20#include <linux/fcntl.h>
21#include <linux/init.h>
22#include <linux/smp_lock.h>
23#include <asm/uaccess.h>
24#include <asm/nvram.h>
25#ifdef CONFIG_PPC_PMAC
26#include <asm/machdep.h>
27#endif
28
29#define NVRAM_SIZE	8192
30
31static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
32{
33	lock_kernel();
34	switch (origin) {
35	case 1:
36		offset += file->f_pos;
37		break;
38	case 2:
39		offset += NVRAM_SIZE;
40		break;
41	}
42	if (offset < 0) {
43		unlock_kernel();
44		return -EINVAL;
45	}
46	file->f_pos = offset;
47	unlock_kernel();
48	return file->f_pos;
49}
50
51static ssize_t read_nvram(struct file *file, char __user *buf,
52			  size_t count, loff_t *ppos)
53{
54	unsigned int i;
55	char __user *p = buf;
56
57	if (!access_ok(VERIFY_WRITE, buf, count))
58		return -EFAULT;
59	if (*ppos >= NVRAM_SIZE)
60		return 0;
61	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)
62		if (__put_user(nvram_read_byte(i), p))
63			return -EFAULT;
64	*ppos = i;
65	return p - buf;
66}
67
68static ssize_t write_nvram(struct file *file, const char __user *buf,
69			   size_t count, loff_t *ppos)
70{
71	unsigned int i;
72	const char __user *p = buf;
73	char c;
74
75	if (!access_ok(VERIFY_READ, buf, count))
76		return -EFAULT;
77	if (*ppos >= NVRAM_SIZE)
78		return 0;
79	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {
80		if (__get_user(c, p))
81			return -EFAULT;
82		nvram_write_byte(c, i);
83	}
84	*ppos = i;
85	return p - buf;
86}
87
88static int nvram_ioctl(struct inode *inode, struct file *file,
89	unsigned int cmd, unsigned long arg)
90{
91	switch(cmd) {
92#ifdef CONFIG_PPC_PMAC
93	case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
94		printk(KERN_WARNING "nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
95	case IOC_NVRAM_GET_OFFSET: {
96		int part, offset;
97
98		if (!machine_is(powermac))
99			return -EINVAL;
100		if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
101			return -EFAULT;
102		if (part < pmac_nvram_OF || part > pmac_nvram_NR)
103			return -EINVAL;
104		offset = pmac_get_partition(part);
105		if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
106			return -EFAULT;
107		break;
108	}
109#endif /* CONFIG_PPC_PMAC */
110	case IOC_NVRAM_SYNC:
111		nvram_sync();
112		break;
113	default:
114		return -EINVAL;
115	}
116
117	return 0;
118}
119
120const struct file_operations nvram_fops = {
121	.owner		= THIS_MODULE,
122	.llseek		= nvram_llseek,
123	.read		= read_nvram,
124	.write		= write_nvram,
125	.ioctl		= nvram_ioctl,
126};
127
128static struct miscdevice nvram_dev = {
129	NVRAM_MINOR,
130	"nvram",
131	&nvram_fops
132};
133
134int __init nvram_init(void)
135{
136	printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
137		NVRAM_VERSION);
138	return misc_register(&nvram_dev);
139}
140
141void __exit nvram_cleanup(void)
142{
143        misc_deregister( &nvram_dev );
144}
145
146module_init(nvram_init);
147module_exit(nvram_cleanup);
148MODULE_LICENSE("GPL");
149