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 <linux/smp_lock.h>
  17 #include <asm/uaccess.h>
  18 #include <asm/nvram.h>
  19
  20 #define NVRAM_SIZE      8192
  21
  22 static loff_t nvram_llseek(struct file *file, loff_t offset, int origin)
  23 {
  24         lock_kernel();
  25         switch (origin) {
  26         case 1:
  27                 offset += file->f_pos;
  28                 break;
  29         case 2:
  30                 offset += NVRAM_SIZE;
  31                 break;
  32         }
  33         if (offset < 0) {
  34                 unlock_kernel();
  35                 return -EINVAL;
  36         }
  37         file->f_pos = offset;
  38         unlock_kernel();
  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 (verify_area(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 (verify_area(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 int nvram_ioctl(struct inode *inode, struct file *file,
  80         unsigned int cmd, unsigned long arg)
  81 {
  82         switch(cmd) {
  83                 case PMAC_NVRAM_GET_OFFSET:
  84                 {
  85                         int part, offset;
  86                         if (copy_from_user(&part, (void __user*)arg, sizeof(part)) != 0)
  87                                 return -EFAULT;
  88                         if (part < pmac_nvram_OF || part > pmac_nvram_NR)
  89                                 return -EINVAL;
  90                         offset = pmac_get_partition(part);
  91                         if (copy_to_user((void __user*)arg, &offset, sizeof(offset)) != 0)
  92                                 return -EFAULT;
  93                         break;
  94                 }
  95
  96                 default:
  97                         return -EINVAL;
  98         }
  99
 100         return 0;
 101 }
 102
 103 struct file_operations nvram_fops = {
 104         .owner          = THIS_MODULE,
 105         .llseek         = nvram_llseek,
 106         .read           = read_nvram,
 107         .write          = write_nvram,
 108         .ioctl          = nvram_ioctl,
 109 };
 110
 111 static struct miscdevice nvram_dev = {
 112         NVRAM_MINOR,
 113         "nvram",
 114         &nvram_fops
 115 };
 116
 117 int __init nvram_init(void)
 118 {
 119         printk(KERN_INFO "Macintosh non-volatile memory driver v%s\n",
 120                 NVRAM_VERSION);
 121         return misc_register(&nvram_dev);
 122 }
 123
 124 void __exit nvram_cleanup(void)
 125 {
 126         misc_deregister( &nvram_dev );
 127 }
 128
 129 module_init(nvram_init);
 130 module_exit(nvram_cleanup);
 131 MODULE_LICENSE("GPL");