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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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