linux/drivers/firmware/efi/earlycon.c
Ard Biesheuvel 69c1f396f2 efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation
Move the x86 EFI earlyprintk implementation to a shared location under
drivers/firmware and tweak it slightly so we can expose it as an earlycon
implementation (which is generic) rather than earlyprintk (which is only
implemented for a few architectures)

This also involves switching to write-combine mappings by default (which
is required on ARM since device mappings lack memory semantics, and so
memcpy/memset may not be used on them), and adding support for shared
memory framebuffers on cache coherent non-x86 systems (which do not
tolerate mismatched attributes).

Note that 32-bit ARM does not populate its struct screen_info early
enough for earlycon=efifb to work, so it is disabled there.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190202094119.13230-10-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-04 08:27:30 +01:00

207 lines
3.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013 Intel Corporation; author Matt Fleming
*/
#include <linux/console.h>
#include <linux/efi.h>
#include <linux/font.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/serial_core.h>
#include <linux/screen_info.h>
#include <asm/early_ioremap.h>
static const struct font_desc *font;
static u32 efi_x, efi_y;
static u64 fb_base;
static pgprot_t fb_prot;
static __ref void *efi_earlycon_map(unsigned long start, unsigned long len)
{
return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot));
}
static __ref void efi_earlycon_unmap(void *addr, unsigned long len)
{
early_memunmap(addr, len);
}
static void efi_earlycon_clear_scanline(unsigned int y)
{
unsigned long *dst;
u16 len;
len = screen_info.lfb_linelength;
dst = efi_earlycon_map(y*len, len);
if (!dst)
return;
memset(dst, 0, len);
efi_earlycon_unmap(dst, len);
}
static void efi_earlycon_scroll_up(void)
{
unsigned long *dst, *src;
u16 len;
u32 i, height;
len = screen_info.lfb_linelength;
height = screen_info.lfb_height;
for (i = 0; i < height - font->height; i++) {
dst = efi_earlycon_map(i*len, len);
if (!dst)
return;
src = efi_earlycon_map((i + font->height) * len, len);
if (!src) {
efi_earlycon_unmap(dst, len);
return;
}
memmove(dst, src, len);
efi_earlycon_unmap(src, len);
efi_earlycon_unmap(dst, len);
}
}
static void efi_earlycon_write_char(u32 *dst, unsigned char c, unsigned int h)
{
const u32 color_black = 0x00000000;
const u32 color_white = 0x00ffffff;
const u8 *src;
u8 s8;
int m;
src = font->data + c * font->height;
s8 = *(src + h);
for (m = 0; m < 8; m++) {
if ((s8 >> (7 - m)) & 1)
*dst = color_white;
else
*dst = color_black;
dst++;
}
}
static void
efi_earlycon_write(struct console *con, const char *str, unsigned int num)
{
struct screen_info *si;
unsigned int len;
const char *s;
void *dst;
si = &screen_info;
len = si->lfb_linelength;
while (num) {
unsigned int linemax;
unsigned int h, count = 0;
for (s = str; *s && *s != '\n'; s++) {
if (count == num)
break;
count++;
}
linemax = (si->lfb_width - efi_x) / font->width;
if (count > linemax)
count = linemax;
for (h = 0; h < font->height; h++) {
unsigned int n, x;
dst = efi_earlycon_map((efi_y + h) * len, len);
if (!dst)
return;
s = str;
n = count;
x = efi_x;
while (n-- > 0) {
efi_earlycon_write_char(dst + x*4, *s, h);
x += font->width;
s++;
}
efi_earlycon_unmap(dst, len);
}
num -= count;
efi_x += count * font->width;
str += count;
if (num > 0 && *s == '\n') {
efi_x = 0;
efi_y += font->height;
str++;
num--;
}
if (efi_x + font->width > si->lfb_width) {
efi_x = 0;
efi_y += font->height;
}
if (efi_y + font->height > si->lfb_height) {
u32 i;
efi_y -= font->height;
efi_earlycon_scroll_up();
for (i = 0; i < font->height; i++)
efi_earlycon_clear_scanline(efi_y + i);
}
}
}
static int __init efi_earlycon_setup(struct earlycon_device *device,
const char *opt)
{
struct screen_info *si;
u16 xres, yres;
u32 i;
if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
return -ENODEV;
fb_base = screen_info.lfb_base;
if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
fb_base |= (u64)screen_info.ext_lfb_base << 32;
if (opt && !strcmp(opt, "ram"))
fb_prot = PAGE_KERNEL;
else
fb_prot = pgprot_writecombine(PAGE_KERNEL);
si = &screen_info;
xres = si->lfb_width;
yres = si->lfb_height;
/*
* efi_earlycon_write_char() implicitly assumes a framebuffer with
* 32 bits per pixel.
*/
if (si->lfb_depth != 32)
return -ENODEV;
font = get_default_font(xres, yres, -1, -1);
if (!font)
return -ENODEV;
efi_y = rounddown(yres, font->height) - font->height;
for (i = 0; i < (yres - efi_y) / font->height; i++)
efi_earlycon_scroll_up();
device->con->write = efi_earlycon_write;
return 0;
}
EARLYCON_DECLARE(efifb, efi_earlycon_setup);