LXR linux/drivers/macintosh/nvram.c

   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 <asm/uaccess.h>
  17#include <asm/nvram.h>
  18
  19#define NVRAM_SIZE      8192
  20
  21static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
  22{
  23        switch (origin) {
  24        case 1:
  25                offset += file->f_pos;
  26                break;
  27        case 2:
  28                offset += NVRAM_SIZE;
  29                break;
  30        }
  31        if (offset < 0)
  32                return -EINVAL;
  33
  34        file->f_pos = offset;
  35        return file->f_pos;
  36}
  37
  38static ssize_t read_nvram(struct file *file, char __user *buf,
  39                          size_t count, loff_t *ppos)
  40{
  41        unsigned int i;
  42        char __user *p = buf;
  43
  44        if (!access_ok(VERIFY_WRITE, buf, count))
  45                return -EFAULT;
  46        if (*ppos >= NVRAM_SIZE)
  47                return 0;
  48        for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count)
  49                if (__put_user(nvram_read_byte(i), p))
  50                        return -EFAULT;
  51        *ppos = i;
  52        return p - buf;
  53}
  54
  55static ssize_t write_nvram(struct file *file, const char __user *buf,
  56                           size_t count, loff_t *ppos)
  57{
  58        unsigned int i;
  59        const char __user *p = buf;
  60        char c;
  61
  62        if (!access_ok(VERIFY_READ, buf, count))
  63                return -EFAULT;
  64        if (*ppos >= NVRAM_SIZE)
  65                return 0;
  66        for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) {
  67                if (__get_user(c, p))
  68                        return -EFAULT;
  69                nvram_write_byte(c, i);
  70        }
  71        *ppos = i;
  72        return p - buf;
  73}
  74
  75static long nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  76{
  77        switch(cmd) {
  78                case PMAC_NVRAM_GET_OFFSET:
  79                {
  80                        int part, offset;
  81                        if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
  82                                return -EFAULT;
  83                        if (part < pmac_nvram_OF || part > pmac_nvram_NR)
  84                                return -EINVAL;
  85                        offset = pmac_get_partition(part);
  86                        if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
  87                                return -EFAULT;
  88                        break;
  89                }
  90
  91                default:
  92                        return -EINVAL;
  93        }
  94
  95        return 0;
  96}
  97
  98const struct file_operations nvram_fops = {
  99        .owner          = THIS_MODULE,
 100        .llseek         = nvram_llseek,
 101        .read           = read_nvram,
 102        .write          = write_nvram,
 103        .unlocked_ioctl = nvram_ioctl,
 104};
 105
 106static struct miscdevice nvram_dev = {
 107        NVRAM_MINOR,
 108        "nvram",
 109        &nvram_fops
 110};
 111
 112int __init nvram_init(void)
 113{
 114        printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
 115                NVRAM_VERSION);
 116        return misc_register(&nvram_dev);
 117}
 118
 119void __exit nvram_cleanup(void)
 120{
 121        misc_deregister( &nvram_dev );
 122}
 123
 124module_init(nvram_init);
 125module_exit(nvram_cleanup);
 126MODULE_LICENSE("GPL");
 127