arch/arm/kernel/atags.c

   1 #include <linux/slab.h>
   2 #include <linux/proc_fs.h>
   3 #include <asm/setup.h>
   4 #include <asm/types.h>
   5 #include <asm/page.h>
   6
   7 struct buffer {
   8         size_t size;
   9         char *data;
  10 };
  11 static struct buffer tags_buffer;
  12
  13 static int
  14 read_buffer(char* page, char** start, off_t off, int count,
  15         int* eof, void* data)
  16 {
  17         struct buffer *buffer = (struct buffer *)data;
  18
  19         if (off >= buffer->size) {
  20                 *eof = 1;
  21                 return 0;
  22         }
  23
  24         count = min((int) (buffer->size - off), count);
  25
  26         memcpy(page, &buffer->data[off], count);
  27
  28         return count;
  29 }
  30
  31
  32 static int
  33 create_proc_entries(void)
  34 {
  35         struct proc_dir_entry* tags_entry;
  36
  37         tags_entry = create_proc_read_entry("atags", 0400, NULL, read_buffer, &tags_buffer);
  38         if (!tags_entry)
  39                 return -ENOMEM;
  40
  41         return 0;
  42 }
  43
  44 #define BOOT_PARAMS_SIZE 1536
  45 static char __initdata atags_copy_buf[BOOT_PARAMS_SIZE];
  46 static char __initdata *atags_copy;
  47
  48 void __init save_atags(const struct tag *tags)
  49 {
  50         atags_copy = atags_copy_buf;
  51         memcpy(atags_copy, tags, sizeof(atags_copy_buf));
  52 }
  53
  54
  55 static int __init init_atags_procfs(void)
  56 {
  57         struct tag *tag;
  58         int error;
  59
  60         if (!atags_copy) {
  61                 printk(KERN_WARNING "Exporting ATAGs: No saved tags found\n");
  62                 return -EIO;
  63         }
  64
  65         for (tag = (struct tag *) atags_copy; tag->hdr.size; tag = tag_next(tag))
  66                 ;
  67
  68         tags_buffer.size = ((char *) tag - atags_copy) + sizeof(tag->hdr);
  69         tags_buffer.data = kmalloc(tags_buffer.size, GFP_KERNEL);
  70         if (tags_buffer.data == NULL)
  71                 return -ENOMEM;
  72         memcpy(tags_buffer.data, atags_copy, tags_buffer.size);
  73
  74         error = create_proc_entries();
  75         if (error) {
  76                 printk(KERN_ERR "Exporting ATAGs: not enough memory\n");
  77                 kfree(tags_buffer.data);
  78                 tags_buffer.size = 0;
  79                 tags_buffer.data = NULL;
  80         }
  81
  82         return error;
  83 }
  84
  85 arch_initcall(init_atags_procfs);