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
37static __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 */
70device_initcall(sysfb_init);