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
  21 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
  22 {
  23         switch (origin) {
  24         case 0:
  25                 break;
  26         case 1:
  27                 offset += file->f_pos;
  28                 break;
  29         case 2:
  30                 offset += NVRAM_SIZE;
  31                 break;
  32         default:
  33                 offset = -1;
  34         }
  35         if (offset < 0)
  36                 return -EINVAL;
  37
  38         file->f_pos = offset;
  39         return file->f_pos;
  40 }
  41
  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
  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
  79 static long nvram_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  80 {
  81         switch(cmd) {
  82                 case PMAC_NVRAM_GET_OFFSET:
  83                 {
  84                         int part, offset;
  85                         if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
  86                                 return -EFAULT;
  87                         if (part < pmac_nvram_OF || part > pmac_nvram_NR)
  88                                 return -EINVAL;
  89                         offset = pmac_get_partition(part);
  90                         if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
  91                                 return -EFAULT;
  92                         break;
  93                 }
  94
  95                 default:
  96                         return -EINVAL;
  97         }
  98
  99         return 0;
 100 }
 101
 102 const struct file_operations nvram_fops = {
 103         .owner          = THIS_MODULE,
 104         .llseek         = nvram_llseek,
 105         .read           = read_nvram,
 106         .write          = write_nvram,
 107         .unlocked_ioctl = nvram_ioctl,
 108 };
 109
 110 static struct miscdevice nvram_dev = {
 111         NVRAM_MINOR,
 112         "nvram",
 113         &nvram_fops
 114 };
 115
 116 int __init nvram_init(void)
 117 {
 118         printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
 119                 NVRAM_VERSION);
 120         return misc_register(&nvram_dev);
 121 }
 122
 123 void __exit nvram_cleanup(void)
 124 {
 125         misc_deregister( &nvram_dev );
 126 }
 127
 128 module_init(nvram_init);
 129 module_exit(nvram_cleanup);
 130 MODULE_LICENSE("GPL");