linux/linux-5.4.31/arch/x86/kernel/sysfb.c

71 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Generic System Framebuffers on x86
* Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
*/
/*
* Simple-Framebuffer support for x86 systems
* Create a platform-device for any available boot framebuffer. The
* simple-framebuffer platform device is already available on DT systems, so
* this module parses the global "screen_info" object and creates a suitable
* platform device compatible with the "simple-framebuffer" DT object. If
* the framebuffer is incompatible, we instead create a legacy
* "vesa-framebuffer", "efi-framebuffer" or "platform-framebuffer" device and
* pass the screen_info as platform_data. This allows legacy drivers
* to pick these devices up without messing with simple-framebuffer drivers.
* The global "screen_info" is still valid at all times.
*
* If CONFIG_X86_SYSFB is not selected, we never register "simple-framebuffer"
* platform devices, but only use legacy framebuffer devices for
* backwards compatibility.
*
* TODO: We set the dev_id field of all platform-devices to 0. This allows
* other x86 OF/DT parsers to create such devices, too. However, they must
* start at offset 1 for this to work.
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/platform_data/simplefb.h>
#include <linux/platform_device.h>
#include <linux/screen_info.h>
#include <asm/sysfb.h>
static __init int sysfb_init(void)
{
struct screen_info *si = &screen_info;
struct simplefb_platform_data mode;
struct platform_device *pd;
const char *name;
bool compatible;
int ret;
sysfb_apply_efi_quirks();
/* try to create a simple-framebuffer device */
compatible = parse_mode(si, &mode);
if (compatible) {
ret = create_simplefb(si, &mode);
if (!ret)
return 0;
}
/* if the FB is incompatible, create a legacy framebuffer device */
if (si->orig_video_isVGA == VIDEO_TYPE_EFI)
name = "efi-framebuffer";
else if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
name = "vesa-framebuffer";
else
name = "platform-framebuffer";
pd = platform_device_register_resndata(NULL, name, 0,
NULL, 0, si, sizeof(*si));
return PTR_ERR_OR_ZERO(pd);
}
/* must execute after PCI subsystem for EFI quirks */
device_initcall(sysfb_init);