LXR linux/arch/x86/kernel/sysfb.c

   1/*
   2 * Generic System Framebuffers on x86
   3 * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License as published by the Free
   7 * Software Foundation; either version 2 of the License, or (at your option)
   8 * any later version.
   9 */
  10
  11/*
  12 * Simple-Framebuffer support for x86 systems
  13 * Create a platform-device for any available boot framebuffer. The
  14 * simple-framebuffer platform device is already available on DT systems, so
  15 * this module parses the global "screen_info" object and creates a suitable
  16 * platform device compatible with the "simple-framebuffer" DT object. If
  17 * the framebuffer is incompatible, we instead create a legacy
  18 * "vesa-framebuffer", "efi-framebuffer" or "platform-framebuffer" device and
  19 * pass the screen_info as platform_data. This allows legacy drivers
  20 * to pick these devices up without messing with simple-framebuffer drivers.
  21 * The global "screen_info" is still valid at all times.
  22 *
  23 * If CONFIG_X86_SYSFB is not selected, we never register "simple-framebuffer"
  24 * platform devices, but only use legacy framebuffer devices for
  25 * backwards compatibility.
  26 *
  27 * TODO: We set the dev_id field of all platform-devices to 0. This allows
  28 * other x86 OF/DT parsers to create such devices, too. However, they must
  29 * start at offset 1 for this to work.
  30 */
  31
  32#include <linux/err.h>
  33#include <linux/init.h>
  34#include <linux/kernel.h>
  35#include <linux/mm.h>
  36#include <linux/platform_data/simplefb.h>
  37#include <linux/platform_device.h>
  38#include <linux/screen_info.h>
  39#include <asm/sysfb.h>
  40
  41static __init int sysfb_init(void)
  42{
  43        struct screen_info *si = &screen_info;
  44        struct simplefb_platform_data mode;
  45        struct platform_device *pd;
  46        const char *name;
  47        bool compatible;
  48        int ret;
  49
  50        sysfb_apply_efi_quirks();
  51
  52        /* try to create a simple-framebuffer device */
  53        compatible = parse_mode(si, &mode);
  54        if (compatible) {
  55                ret = create_simplefb(si, &mode);
  56                if (!ret)
  57                        return 0;
  58        }
  59
  60        /* if the FB is incompatible, create a legacy framebuffer device */
  61        if (si->orig_video_isVGA == VIDEO_TYPE_EFI)
  62                name = "efi-framebuffer";
  63        else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
  64                name = "vesa-framebuffer";
  65        else
  66                name = "platform-framebuffer";
  67
  68        pd = platform_device_register_resndata(NULL, name, 0,
  69                                               NULL, 0, si, sizeof(*si));
  70        return PTR_ERR_OR_ZERO(pd);
  71}
  72
  73/* must execute after PCI subsystem for EFI quirks */
  74device_initcall(sysfb_init);
  75