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
nvram_llseek(struct file * file,loff_t offset,int origin)22 static 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
read_nvram(struct file * file,char __user * buf,size_t count,loff_t * ppos)42 static 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
write_nvram(struct file * file,const char __user * buf,size_t count,loff_t * ppos)59 static 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
nvram_ioctl(struct inode * inode,struct file * file,unsigned int cmd,unsigned long arg)79 static 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
103 const 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
111 static struct miscdevice nvram_dev = {
112 NVRAM_MINOR,
113 "nvram",
114 &nvram_fops
115 };
116
nvram_init(void)117 int __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
nvram_cleanup(void)124 void __exit nvram_cleanup(void)
125 {
126 misc_deregister( &nvram_dev );
127 }
128
129 module_init(nvram_init);
130 module_exit(nvram_cleanup);
131 MODULE_LICENSE("GPL");
132