drivers/video/fbsysfs.c

   1 /*
   2  * fbsysfs.c - framebuffer device class and attributes
   3  *
   4  * Copyright (c) 2004 James Simmons <jsimmons@infradead.org>
   5  *
   6  *      This program is free software you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11
  12 /*
  13  * Note:  currently there's only stubs for framebuffer_alloc and
  14  * framebuffer_release here.  The reson for that is that until all drivers
  15  * are converted to use it a sysfsification will open OOPSable races.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/fb.h>
  20
  21 /**
  22  * framebuffer_alloc - creates a new frame buffer info structure
  23  *
  24  * @size: size of driver private data, can be zero
  25  * @dev: pointer to the device for this fb, this can be NULL
  26  *
  27  * Creates a new frame buffer info structure. Also reserves @size bytes
  28  * for driver private data (info->par). info->par (if any) will be
  29  * aligned to sizeof(long).
  30  *
  31  * Returns the new structure, or NULL if an error occured.
  32  *
  33  */
  34 struct fb_info *framebuffer_alloc(size_t size, struct device *dev)
  35 {
  36 #define BYTES_PER_LONG (BITS_PER_LONG/8)
  37 #define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG))
  38         int fb_info_size = sizeof(struct fb_info);
  39         struct fb_info *info;
  40         char *p;
  41
  42         if (size)
  43                 fb_info_size += PADDING;
  44
  45         p = kmalloc(fb_info_size + size, GFP_KERNEL);
  46         if (!p)
  47                 return NULL;
  48         memset(p, 0, fb_info_size + size);
  49         info = (struct fb_info *) p;
  50
  51         if (size)
  52                 info->par = p + fb_info_size;
  53
  54         return info;
  55 #undef PADDING
  56 #undef BYTES_PER_LONG
  57 }
  58
  59 /**
  60  * framebuffer_release - marks the structure available for freeing
  61  *
  62  * @info: frame buffer info structure
  63  *
  64  * Drop the reference count of the class_device embedded in the
  65  * framebuffer info structure.
  66  *
  67  */
  68 void framebuffer_release(struct fb_info *info)
  69 {
  70         kfree(info);
  71 }
  72
  73 EXPORT_SYMBOL(framebuffer_release);
  74 EXPORT_SYMBOL(framebuffer_alloc);