arch/x86/kernel/sysfb.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Generic System Framebuffers on x86
   4  * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
   5  */
   6
   7 /*
   8  * Simple-Framebuffer support for x86 systems
   9  * Create a platform-device for any available boot framebuffer. The
  10  * simple-framebuffer platform device is already available on DT systems, so
  11  * this module parses the global "screen_info" object and creates a suitable
  12  * platform device compatible with the "simple-framebuffer" DT object. If
  13  * the framebuffer is incompatible, we instead create a legacy
  14  * "vesa-framebuffer", "efi-framebuffer" or "platform-framebuffer" device and
  15  * pass the screen_info as platform_data. This allows legacy drivers
  16  * to pick these devices up without messing with simple-framebuffer drivers.
  17  * The global "screen_info" is still valid at all times.
  18  *
  19  * If CONFIG_X86_SYSFB is not selected, we never register "simple-framebuffer"
  20  * platform devices, but only use legacy framebuffer devices for
  21  * backwards compatibility.
  22  *
  23  * TODO: We set the dev_id field of all platform-devices to 0. This allows
  24  * other x86 OF/DT parsers to create such devices, too. However, they must
  25  * start at offset 1 for this to work.
  26  */
  27
  28 #include <linux/err.h>
  29 #include <linux/init.h>
  30 #include <linux/kernel.h>
  31 #include <linux/mm.h>
  32 #include <linux/platform_data/simplefb.h>
  33 #include <linux/platform_device.h>
  34 #include <linux/screen_info.h>
  35 #include <asm/sysfb.h>
  36
  37 static __init int sysfb_init(void)
  38 {
  39         struct screen_info *si = &screen_info;
  40         struct simplefb_platform_data mode;
  41         struct platform_device *pd;
  42         const char *name;
  43         bool compatible;
  44         int ret;
  45
  46         sysfb_apply_efi_quirks();
  47
  48         /* try to create a simple-framebuffer device */
  49         compatible = parse_mode(si, &mode);
  50         if (compatible) {
  51                 ret = create_simplefb(si, &mode);
  52                 if (!ret)
  53                         return 0;
  54         }
  55
  56         /* if the FB is incompatible, create a legacy framebuffer device */
  57         if (si->orig_video_isVGA == VIDEO_TYPE_EFI)
  58                 name = "efi-framebuffer";
  59         else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
  60                 name = "vesa-framebuffer";
  61         else
  62                 name = "platform-framebuffer";
  63
  64         pd = platform_device_register_resndata(NULL, name, 0,
  65                                                NULL, 0, si, sizeof(*si));
  66         return PTR_ERR_OR_ZERO(pd);
  67 }
  68
  69 /* must execute after PCI subsystem for EFI quirks */
  70 device_initcall(sysfb_init);