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 <linux/smp_lock.h>
17#include <asm/uaccess.h>
18#include <asm/nvram.h>
19
20#define NVRAM_SIZE	8192
21
22static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
23{
24	lock_kernel();
25	switch (origin) {
26	case 1:
27		offset += file->f_pos;
28		break;
29	case 2:
30		offset += NVRAM_SIZE;
31		break;
32	}
33	if (offset < 0) {
34		unlock_kernel();
35		return -EINVAL;
36	}
37	file->f_pos = offset;
38	unlock_kernel();
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 int nvram_ioctl(struct inode *inode, struct file *file,
80	unsigned int cmd, unsigned long arg)
81{
82	switch(cmd) {
83		case PMAC_NVRAM_GET_OFFSET:
84		{
85			int part, offset;
86			if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
87				return -EFAULT;
88			if (part < pmac_nvram_OF || part > pmac_nvram_NR)
89				return -EINVAL;
90			offset = pmac_get_partition(part);
91			if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
92				return -EFAULT;
93			break;
94		}
95
96		default:
97			return -EINVAL;
98	}
99
100	return 0;
101}
102
103const struct file_operations nvram_fops = {
104	.owner		= THIS_MODULE,
105	.llseek		= nvram_llseek,
106	.read		= read_nvram,
107	.write		= write_nvram,
108	.ioctl		= nvram_ioctl,
109};
110
111static struct miscdevice nvram_dev = {
112	NVRAM_MINOR,
113	"nvram",
114	&nvram_fops
115};
116
117int __init nvram_init(void)
118{
119	printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
120		NVRAM_VERSION);
121	return misc_register(&nvram_dev);
122}
123
124void __exit nvram_cleanup(void)
125{
126        misc_deregister( &nvram_dev );
127}
128
129module_init(nvram_init);
130module_exit(nvram_cleanup);
131MODULE_LICENSE("GPL");
132