path: root/drivers/firmware/efi/libstub/gop.c

// SPDX-License-Identifier: GPL-2.0
/* -----------------------------------------------------------------------
 *
 *   Copyright 2011 Intel Corporation; author Matt Fleming
 *
 * ----------------------------------------------------------------------- */

#include <linux/bitops.h>
#include <linux/efi.h>
#include <linux/screen_info.h>
#include <linux/string.h>
#include <asm/efi.h>
#include <asm/setup.h>

#include "efistub.h"

enum efi_cmdline_option {
	EFI_CMDLINE_NONE,
	EFI_CMDLINE_MODE_NUM,
};

static struct {
	enum efi_cmdline_option option;
	u32 mode;
} cmdline __efistub_global = { .option = EFI_CMDLINE_NONE };

static bool parse_modenum(char *option, char **next)
{
	u32 m;

	if (!strstarts(option, "mode="))
		return false;
	option += strlen("mode=");
	m = simple_strtoull(option, &option, 0);
	if (*option && *option++ != ',')
		return false;
	cmdline.option = EFI_CMDLINE_MODE_NUM;
	cmdline.mode   = m;

	*next = option;
	return true;
}

void efi_parse_option_graphics(char *option)
{
	while (*option) {
		if (parse_modenum(option, &option))
			continue;

		while (*option && *option++ != ',')
			;
	}
}

static u32 choose_mode_modenum(efi_graphics_output_protocol_t *gop)
{
	efi_status_t status;

	efi_graphics_output_protocol_mode_t *mode;
	efi_graphics_output_mode_info_t *info;
	unsigned long info_size;

	u32 max_mode, cur_mode;
	int pf;

	mode = efi_table_attr(gop, mode);

	cur_mode = efi_table_attr(mode, mode);
	if (cmdline.mode == cur_mode)
		return cur_mode;

	max_mode = efi_table_attr(mode, max_mode);
	if (cmdline.mode >= max_mode) {
		efi_printk("Requested mode is invalid\n");
		return cur_mode;
	}

	status = efi_call_proto(gop, query_mode, cmdline.mode,
				&info_size, &info);
	if (status != EFI_SUCCESS) {
		efi_printk("Couldn't get mode information\n");
		return cur_mode;
	}

	pf = info->pixel_format;

	efi_bs_call(free_pool, info);

	if (pf == PIXEL_BLT_ONLY || pf >= PIXEL_FORMAT_MAX) {
		efi_printk("Invalid PixelFormat\n");
		return cur_mode;
	}

	return cmdline.mode;
}

static void set_mode(efi_graphics_output_protocol_t *gop)
{
	efi_graphics_output_protocol_mode_t *mode;
	u32 cur_mode, new_mode;

	switch (cmdline.option) {
	case EFI_CMDLINE_MODE_NUM:
		new_mode = choose_mode_modenum(gop);
		break;
	default:
		return;
	}

	mode = efi_table_attr(gop, mode);
	cur_mode = efi_table_attr(mode, mode);

	if (new_mode == cur_mode)
		return;

	if (efi_call_proto(gop, set_mode, new_mode) != EFI_SUCCESS)
		efi_printk("Failed to set requested mode\n");
}

static void find_bits(u32 mask, u8 *pos, u8 *size)
{
	if (!mask) {
		*pos = *size = 0;
		return;
	}

	/* UEFI spec guarantees that the set bits are contiguous */
	*pos  = __ffs(mask);
	*size = __fls(mask) - *pos + 1;
}

static void
setup_pixel_info(struct screen_info *si, u32 pixels_per_scan_line,
		 efi_pixel_bitmask_t pixel_info, int pixel_format)
{
	if (pixel_format == PIXEL_BIT_MASK) {
		find_bits(pixel_info.red_mask,
			  &si->red_pos, &si->red_size);
		find_bits(pixel_info.green_mask,
			  &si->green_pos, &si->green_size);
		find_bits(pixel_info.blue_mask,
			  &si->blue_pos, &si->blue_size);
		find_bits(pixel_info.reserved_mask,
			  &si->rsvd_pos, &si->rsvd_size);
		si->lfb_depth = si->red_size + si->green_size +
			si->blue_size + si->rsvd_size;
		si->lfb_linelength = (pixels_per_scan_line * si->lfb_depth) / 8;
	} else {
		if (pixel_format == PIXEL_RGB_RESERVED_8BIT_PER_COLOR) {
			si->red_pos   = 0;
			si->blue_pos  = 16;
		} else /* PIXEL_BGR_RESERVED_8BIT_PER_COLOR */ {
			si->blue_pos  = 0;
			si->red_pos   = 16;
		}

		si->green_pos = 8;
		si->rsvd_pos  = 24;
		si->red_size = si->green_size =
			si->blue_size = si->rsvd_size = 8;

		si->lfb_depth = 32;
		si->lfb_linelength = pixels_per_scan_line * 4;
	}
}

static efi_graphics_output_protocol_t *
find_gop(efi_guid_t *proto, unsigned long size, void **handles)
{
	efi_graphics_output_protocol_t *first_gop;
	efi_handle_t h;
	int i;

	first_gop = NULL;

	for_each_efi_handle(h, handles, size, i) {
		efi_status_t status;

		efi_graphics_output_protocol_t *gop;
		efi_graphics_output_protocol_mode_t *mode;
		efi_graphics_output_mode_info_t *info;

		efi_guid_t conout_proto = EFI_CONSOLE_OUT_DEVICE_GUID;
		void *dummy = NULL;

		status = efi_bs_call(handle_protocol, h, proto, (void **)&gop);
		if (status != EFI_SUCCESS)
			continue;

		mode = efi_table_attr(gop, mode);
		info = efi_table_attr(mode, info);
		if (info->pixel_format == PIXEL_BLT_ONLY ||
		    info->pixel_format >= PIXEL_FORMAT_MAX)
			continue;

		/*
		 * Systems that use the UEFI Console Splitter may
		 * provide multiple GOP devices, not all of which are
		 * backed by real hardware. The workaround is to search
		 * for a GOP implementing the ConOut protocol, and if
		 * one isn't found, to just fall back to the first GOP.
		 *
		 * Once we've found a GOP supporting ConOut,
		 * don't bother looking any further.
		 */
		status = efi_bs_call(handle_protocol, h, &conout_proto, &dummy);
		if (status == EFI_SUCCESS)
			return gop;

		if (!first_gop)
			first_gop = gop;
	}

	return first_gop;
}

static efi_status_t setup_gop(struct screen_info *si, efi_guid_t *proto,
			      unsigned long size, void **handles)
{
	efi_graphics_output_protocol_t *gop;
	efi_graphics_output_protocol_mode_t *mode;
	efi_graphics_output_mode_info_t *info;
	efi_physical_addr_t fb_base;

	gop = find_gop(proto, size, handles);

	/* Did we find any GOPs? */
	if (!gop)
		return EFI_NOT_FOUND;

	/* Change mode if requested */
	set_mode(gop);

	/* EFI framebuffer */
	mode = efi_table_attr(gop, mode);
	info = efi_table_attr(mode, info);

	si->orig_video_isVGA = VIDEO_TYPE_EFI;

	si->lfb_width  = info->horizontal_resolution;
	si->lfb_height = info->vertical_resolution;

	fb_base		 = efi_table_attr(mode, frame_buffer_base);
	si->lfb_base	 = lower_32_bits(fb_base);
	si->ext_lfb_base = upper_32_bits(fb_base);
	if (si->ext_lfb_base)
		si->capabilities |= VIDEO_CAPABILITY_64BIT_BASE;

	si->pages = 1;

	setup_pixel_info(si, info->pixels_per_scan_line,
			     info->pixel_information, info->pixel_format);

	si->lfb_size = si->lfb_linelength * si->lfb_height;

	si->capabilities |= VIDEO_CAPABILITY_SKIP_QUIRKS;

	return EFI_SUCCESS;
}

/*
 * See if we have Graphics Output Protocol
 */
efi_status_t efi_setup_gop(struct screen_info *si, efi_guid_t *proto,
			   unsigned long size)
{
	efi_status_t status;
	void **gop_handle = NULL;

	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
			     (void **)&gop_handle);
	if (status != EFI_SUCCESS)
		return status;

	status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, proto, NULL,
			     &size, gop_handle);
	if (status != EFI_SUCCESS)
		goto free_handle;

	status = setup_gop(si, proto, size, gop_handle);

free_handle:
	efi_bs_call(free_pool, gop_handle);
	return status;
}