1/*
2 * /dev/nvram driver for Power Macintosh.
3 */
4
5#define NVRAM_VERSION "1.0"
6
7#include <linux/module.h>
8
9#include <linux/types.h>
10#include <linux/errno.h>
11#include <linux/fs.h>
12#include <linux/miscdevice.h>
13#include <linux/fcntl.h>
14#include <linux/nvram.h>
15#include <linux/init.h>
16#include <asm/uaccess.h>
17#include <asm/nvram.h>
18
19#define NVRAM_SIZE	8192
20
21static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
22{
23	switch (origin) {
24	case 0:
25		break;
26	case 1:
27		offset += file->f_pos;
28		break;
29	case 2:
30		offset += NVRAM_SIZE;
31		break;
32	default:
33		offset = -1;
34	}
35	if (offset < 0)
36		return -EINVAL;
37
38	file->f_pos = offset;
39	return file->f_pos;
40}
41
42static ssize_t read_nvram(struct file *file, char __user *buf,
43			  size_t count, loff_t *ppos)
44{
45	unsigned int i;
46	char __user *p = buf;
47
48	if (!access_ok(VERIFY_WRITE, buf, count))
49		return -EFAULT;
50	if (*ppos >= NVRAM_SIZE)
51		return 0;
52	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)
53		if (__put_user(nvram_read_byte(i), p))
54			return -EFAULT;
55	*ppos = i;
56	return p - buf;
57}
58
59static ssize_t write_nvram(struct file *file, const char __user *buf,
60			   size_t count, loff_t *ppos)
61{
62	unsigned int i;
63	const char __user *p = buf;
64	char c;
65
66	if (!access_ok(VERIFY_READ, buf, count))
67		return -EFAULT;
68	if (*ppos >= NVRAM_SIZE)
69		return 0;
70	for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {
71		if (__get_user(c, p))
72			return -EFAULT;
73		nvram_write_byte(c, i);
74	}
75	*ppos = i;
76	return p - buf;
77}
78
79static long nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
80{
81	switch(cmd) {
82		case PMAC_NVRAM_GET_OFFSET:
83		{
84			int part, offset;
85			if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
86				return -EFAULT;
87			if (part < pmac_nvram_OF || part > pmac_nvram_NR)
88				return -EINVAL;
89			offset = pmac_get_partition(part);
90			if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
91				return -EFAULT;
92			break;
93		}
94
95		default:
96			return -EINVAL;
97	}
98
99	return 0;
100}
101
102const struct file_operations nvram_fops = {
103	.owner		= THIS_MODULE,
104	.llseek		= nvram_llseek,
105	.read		= read_nvram,
106	.write		= write_nvram,
107	.unlocked_ioctl	= nvram_ioctl,
108};
109
110static struct miscdevice nvram_dev = {
111	NVRAM_MINOR,
112	"nvram",
113	&nvram_fops
114};
115
116int __init nvram_init(void)
117{
118	printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
119		NVRAM_VERSION);
120	return misc_register(&nvram_dev);
121}
122
123void __exit nvram_cleanup(void)
124{
125        misc_deregister( &nvram_dev );
126}
127
128module_init(nvram_init);
129module_exit(nvram_cleanup);
130MODULE_LICENSE("GPL");
131