[PATCH] drivers/char/pc8736x_gpio.c: unexport a static struct
[linux-2.6.git] / drivers / char / generic_nvram.c
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
31 static 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
51 static 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
68 static 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
88 static 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
120 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
128 static struct miscdevice nvram_dev = {
129         NVRAM_MINOR,
130         "nvram",
131         &nvram_fops
132 };
133
134 int __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
141 void __exit nvram_cleanup(void)
142 {
143         misc_deregister( &nvram_dev );
144 }
145
146 module_init(nvram_init);
147 module_exit(nvram_cleanup);
148 MODULE_LICENSE("GPL");