nvram.c
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/*
* /dev/nvram driver for Power Macintosh.
*/
#define NVRAM_VERSION "1.0"
#include <linux/module.h>
#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>
#include <asm/nvram.h>
#define NVRAM_SIZE 8192
static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
{
switch (origin) {
case 0:
break;
case 1:
offset += file->f_pos;
break;
case 2:
offset += NVRAM_SIZE;
break;
default:
offset = -1;
}
if (offset < 0)
return -EINVAL;
file->f_pos = offset;
return file->f_pos;
}
static ssize_t read_nvram(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
unsigned int i;
char __user *p = buf;
if (!access_ok(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 __user *buf,
size_t count, loff_t *ppos)
{
unsigned int i;
const char __user *p = buf;
char c;
if (!access_ok(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 long nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch(cmd) {
case PMAC_NVRAM_GET_OFFSET:
{
int part, offset;
if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
return -EFAULT;
if (part < pmac_nvram_OF || part > pmac_nvram_NR)
return -EINVAL;
offset = pmac_get_partition(part);
if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
return -EFAULT;
break;
}
default:
return -EINVAL;
}
return 0;
}
const struct file_operations nvram_fops = {
.owner = THIS_MODULE,
.llseek = nvram_llseek,
.read = read_nvram,
.write = write_nvram,
.unlocked_ioctl = nvram_ioctl,
};
static struct miscdevice nvram_dev = {
NVRAM_MINOR,
"nvram",
&nvram_fops
};
int __init nvram_init(void)
{
printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
NVRAM_VERSION);
return misc_register(&nvram_dev);
}
void __exit nvram_cleanup(void)
{
misc_deregister( &nvram_dev );
}
module_init(nvram_init);
module_exit(nvram_cleanup);
MODULE_LICENSE("GPL");