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// 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 console *earlycon_console __initdata;
static const struct font_desc *font;
static u32 efi_x, efi_y;
static u64 fb_base;
static bool fb_wb;
static void *efi_fb;
/*
* EFI earlycon needs to use early_memremap() to map the framebuffer.
* But early_memremap() is not usable for 'earlycon=efifb keep_bootcon',
* memremap() should be used instead. memremap() will be available after
* paging_init() which is earlier than initcall callbacks. Thus adding this
* early initcall function early_efi_map_fb() to map the whole EFI framebuffer.
*/
static int __init efi_earlycon_remap_fb(void)
{
/* bail if there is no bootconsole or it has been disabled already */
if (!earlycon_console || !(earlycon_console->flags & CON_ENABLED))
return 0;
efi_fb = memremap(fb_base, screen_info.lfb_size,
fb_wb ? MEMREMAP_WB : MEMREMAP_WC);
return efi_fb ? 0 : -ENOMEM;
}
early_initcall(efi_earlycon_remap_fb);
static int __init efi_earlycon_unmap_fb(void)
{
/* unmap the bootconsole fb unless keep_bootcon has left it enabled */
if (efi_fb && !(earlycon_console->flags & CON_ENABLED))
memunmap(efi_fb);
return 0;
}
late_initcall(efi_earlycon_unmap_fb);
static __ref void *efi_earlycon_map(unsigned long start, unsigned long len)
{
pgprot_t fb_prot;
if (efi_fb)
return efi_fb + start;
fb_prot = fb_wb ? PAGE_KERNEL : pgprot_writecombine(PAGE_KERNEL);
return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot));
}
static __ref void efi_earlycon_unmap(void *addr, unsigned long len)
{
if (efi_fb)
return;
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;
int m, n, bytes;
u8 x;
bytes = BITS_TO_BYTES(font->width);
src = font->data + c * font->height * bytes + h * bytes;
for (m = 0; m < font->width; m++) {
n = m % 8;
x = *(src + m / 8);
if ((x >> (7 - n)) & 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;
fb_wb = opt && !strcmp(opt, "ram");
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;
earlycon_console = device->con;
return 0;
}
EARLYCON_DECLARE(efifb, efi_earlycon_setup);
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