![Andy Shevchenko](/assets/img/avatar_default.png)
When commit:69c1f396f2
("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation") moved the x86 specific EFI earlyprintk implementation to a shared location, it also tweaked the behaviour. In particular, it dropped a trick with full framebuffer remapping after page initialization, leading to two regressions: 1) very slow scrolling after page initialization, 2) kernel hang when the 'keep_bootcon' command line argument is passed. Putting the tweak back fixes #2 and mitigates #1, i.e., it limits the slow behavior to the early boot stages, presumably due to eliminating heavy map()/unmap() operations per each pixel line on the screen. [ ardb: ensure efifb is unmapped again unless keep_bootcon is in effect. ] [ mingo: speling fixes. ] Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Cc: linux-efi@vger.kernel.org Fixes:69c1f396f2
("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation") Link: https://lkml.kernel.org/r/20191206165542.31469-7-ardb@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
247 lines
5.2 KiB
C
247 lines
5.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2013 Intel Corporation; author Matt Fleming
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*/
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#include <linux/console.h>
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#include <linux/efi.h>
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#include <linux/font.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/serial_core.h>
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#include <linux/screen_info.h>
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#include <asm/early_ioremap.h>
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static const struct console *earlycon_console __initdata;
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static const struct font_desc *font;
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static u32 efi_x, efi_y;
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static u64 fb_base;
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static pgprot_t fb_prot;
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static void *efi_fb;
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/*
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* EFI earlycon needs to use early_memremap() to map the framebuffer.
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* But early_memremap() is not usable for 'earlycon=efifb keep_bootcon',
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* memremap() should be used instead. memremap() will be available after
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* paging_init() which is earlier than initcall callbacks. Thus adding this
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* early initcall function early_efi_map_fb() to map the whole EFI framebuffer.
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*/
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static int __init efi_earlycon_remap_fb(void)
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{
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/* bail if there is no bootconsole or it has been disabled already */
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if (!earlycon_console || !(earlycon_console->flags & CON_ENABLED))
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return 0;
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if (pgprot_val(fb_prot) == pgprot_val(PAGE_KERNEL))
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efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WB);
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else
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efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WC);
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return efi_fb ? 0 : -ENOMEM;
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}
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early_initcall(efi_earlycon_remap_fb);
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static int __init efi_earlycon_unmap_fb(void)
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{
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/* unmap the bootconsole fb unless keep_bootcon has left it enabled */
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if (efi_fb && !(earlycon_console->flags & CON_ENABLED))
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memunmap(efi_fb);
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return 0;
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}
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late_initcall(efi_earlycon_unmap_fb);
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static __ref void *efi_earlycon_map(unsigned long start, unsigned long len)
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{
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if (efi_fb)
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return efi_fb + start;
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return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot));
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}
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static __ref void efi_earlycon_unmap(void *addr, unsigned long len)
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{
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if (efi_fb)
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return;
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early_memunmap(addr, len);
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}
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static void efi_earlycon_clear_scanline(unsigned int y)
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{
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unsigned long *dst;
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u16 len;
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len = screen_info.lfb_linelength;
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dst = efi_earlycon_map(y*len, len);
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if (!dst)
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return;
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memset(dst, 0, len);
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efi_earlycon_unmap(dst, len);
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}
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static void efi_earlycon_scroll_up(void)
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{
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unsigned long *dst, *src;
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u16 len;
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u32 i, height;
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len = screen_info.lfb_linelength;
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height = screen_info.lfb_height;
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for (i = 0; i < height - font->height; i++) {
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dst = efi_earlycon_map(i*len, len);
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if (!dst)
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return;
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src = efi_earlycon_map((i + font->height) * len, len);
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if (!src) {
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efi_earlycon_unmap(dst, len);
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return;
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}
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memmove(dst, src, len);
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efi_earlycon_unmap(src, len);
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efi_earlycon_unmap(dst, len);
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}
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}
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static void efi_earlycon_write_char(u32 *dst, unsigned char c, unsigned int h)
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{
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const u32 color_black = 0x00000000;
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const u32 color_white = 0x00ffffff;
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const u8 *src;
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u8 s8;
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int m;
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src = font->data + c * font->height;
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s8 = *(src + h);
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for (m = 0; m < 8; m++) {
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if ((s8 >> (7 - m)) & 1)
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*dst = color_white;
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else
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*dst = color_black;
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dst++;
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}
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}
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static void
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efi_earlycon_write(struct console *con, const char *str, unsigned int num)
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{
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struct screen_info *si;
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unsigned int len;
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const char *s;
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void *dst;
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si = &screen_info;
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len = si->lfb_linelength;
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while (num) {
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unsigned int linemax;
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unsigned int h, count = 0;
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for (s = str; *s && *s != '\n'; s++) {
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if (count == num)
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break;
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count++;
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}
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linemax = (si->lfb_width - efi_x) / font->width;
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if (count > linemax)
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count = linemax;
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for (h = 0; h < font->height; h++) {
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unsigned int n, x;
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dst = efi_earlycon_map((efi_y + h) * len, len);
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if (!dst)
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return;
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s = str;
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n = count;
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x = efi_x;
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while (n-- > 0) {
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efi_earlycon_write_char(dst + x*4, *s, h);
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x += font->width;
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s++;
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}
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efi_earlycon_unmap(dst, len);
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}
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num -= count;
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efi_x += count * font->width;
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str += count;
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if (num > 0 && *s == '\n') {
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efi_x = 0;
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efi_y += font->height;
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str++;
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num--;
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}
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if (efi_x + font->width > si->lfb_width) {
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efi_x = 0;
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efi_y += font->height;
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}
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if (efi_y + font->height > si->lfb_height) {
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u32 i;
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efi_y -= font->height;
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efi_earlycon_scroll_up();
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for (i = 0; i < font->height; i++)
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efi_earlycon_clear_scanline(efi_y + i);
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}
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}
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}
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static int __init efi_earlycon_setup(struct earlycon_device *device,
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const char *opt)
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{
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struct screen_info *si;
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u16 xres, yres;
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u32 i;
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if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
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return -ENODEV;
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fb_base = screen_info.lfb_base;
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if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
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fb_base |= (u64)screen_info.ext_lfb_base << 32;
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if (opt && !strcmp(opt, "ram"))
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fb_prot = PAGE_KERNEL;
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else
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fb_prot = pgprot_writecombine(PAGE_KERNEL);
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si = &screen_info;
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xres = si->lfb_width;
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yres = si->lfb_height;
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/*
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* efi_earlycon_write_char() implicitly assumes a framebuffer with
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* 32 bits per pixel.
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*/
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if (si->lfb_depth != 32)
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return -ENODEV;
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font = get_default_font(xres, yres, -1, -1);
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if (!font)
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return -ENODEV;
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efi_y = rounddown(yres, font->height) - font->height;
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for (i = 0; i < (yres - efi_y) / font->height; i++)
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efi_earlycon_scroll_up();
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device->con->write = efi_earlycon_write;
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earlycon_console = device->con;
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return 0;
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}
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EARLYCON_DECLARE(efifb, efi_earlycon_setup);
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