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/*
* /dev/nvram driver for Power Macintosh.
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>
#include <linux/nvram.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#define NVRAM_SIZE 8192
static long long nvram_llseek(struct file *file, loff_t offset, int origin)
{
switch (origin) {
case 1:
offset += file->f_pos;
break;
case 2:
offset += NVRAM_SIZE;
break;
}
if (offset < 0)
return -EINVAL;
file->f_pos = offset;
return file->f_pos;
}
static ssize_t read_nvram(struct file *file, char *buf,
size_t count, loff_t *ppos)
{
unsigned int i;
char *p = buf;
if (verify_area(VERIFY_WRITE, buf, count))
return -EFAULT;
if (*ppos >= NVRAM_SIZE)
return 0;
for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)
if (__put_user(nvram_read_byte(i), p))
return -EFAULT;
*ppos = i;
return p - buf;
}
static ssize_t write_nvram(struct file *file, const char *buf,
size_t count, loff_t *ppos)
{
unsigned int i;
const char *p = buf;
char c;
if (verify_area(VERIFY_READ, buf, count))
return -EFAULT;
if (*ppos >= NVRAM_SIZE)
return 0;
for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {
if (__get_user(c, p))
return -EFAULT;
nvram_write_byte(c, i);
}
*ppos = i;
return p - buf;
}
static int nvram_open(struct inode *inode, struct file *file)
{
return 0;
}
struct file_operations nvram_fops = {
nvram_llseek,
read_nvram,
write_nvram,
NULL, /* nvram_readdir */
NULL, /* nvram_select */
NULL, /* nvram_ioctl */
NULL, /* nvram_mmap */
nvram_open,
NULL, /* no special release code */
NULL /* fsync */
};
static struct miscdevice nvram_dev = {
NVRAM_MINOR,
"nvram",
&nvram_fops
};
__initfunc(int nvram_init(void))
{
misc_register(&nvram_dev);
return 0;
}
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