276 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2013 Intel Corporation; author Matt Fleming4 */5 6#include <linux/console.h>7#include <linux/efi.h>8#include <linux/font.h>9#include <linux/io.h>10#include <linux/kernel.h>11#include <linux/serial_core.h>12#include <linux/screen_info.h>13#include <linux/string.h>14 15#include <asm/early_ioremap.h>16 17static const struct console *earlycon_console __initdata;18static const struct font_desc *font;19static u16 cur_line_y, max_line_y;20static u32 efi_x_array[1024];21static u32 efi_x, efi_y;22static u64 fb_base;23static bool fb_wb;24static void *efi_fb;25 26/*27 * EFI earlycon needs to use early_memremap() to map the framebuffer.28 * But early_memremap() is not usable for 'earlycon=efifb keep_bootcon',29 * memremap() should be used instead. memremap() will be available after30 * paging_init() which is earlier than initcall callbacks. Thus adding this31 * early initcall function early_efi_map_fb() to map the whole EFI framebuffer.32 */33static int __init efi_earlycon_remap_fb(void)34{35 /* bail if there is no bootconsole or it was unregistered already */36 if (!earlycon_console || !console_is_registered(earlycon_console))37 return 0;38 39 efi_fb = memremap(fb_base, screen_info.lfb_size,40 fb_wb ? MEMREMAP_WB : MEMREMAP_WC);41 42 return efi_fb ? 0 : -ENOMEM;43}44early_initcall(efi_earlycon_remap_fb);45 46static int __init efi_earlycon_unmap_fb(void)47{48 /* unmap the bootconsole fb unless keep_bootcon left it registered */49 if (efi_fb && !console_is_registered(earlycon_console))50 memunmap(efi_fb);51 return 0;52}53late_initcall(efi_earlycon_unmap_fb);54 55static __ref void *efi_earlycon_map(unsigned long start, unsigned long len)56{57 pgprot_t fb_prot;58 59 if (efi_fb)60 return efi_fb + start;61 62 fb_prot = fb_wb ? PAGE_KERNEL : pgprot_writecombine(PAGE_KERNEL);63 return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot));64}65 66static __ref void efi_earlycon_unmap(void *addr, unsigned long len)67{68 if (efi_fb)69 return;70 71 early_memunmap(addr, len);72}73 74static void efi_earlycon_clear_scanline(unsigned int y)75{76 unsigned long *dst;77 u16 len;78 79 len = screen_info.lfb_linelength;80 dst = efi_earlycon_map(y*len, len);81 if (!dst)82 return;83 84 memset(dst, 0, len);85 efi_earlycon_unmap(dst, len);86}87 88static void efi_earlycon_scroll_up(void)89{90 unsigned long *dst, *src;91 u16 maxlen = 0;92 u16 len;93 u32 i, height;94 95 /* Find the cached maximum x coordinate */96 for (i = 0; i < max_line_y; i++) {97 if (efi_x_array[i] > maxlen)98 maxlen = efi_x_array[i];99 }100 maxlen *= 4;101 102 len = screen_info.lfb_linelength;103 height = screen_info.lfb_height;104 105 for (i = 0; i < height - font->height; i++) {106 dst = efi_earlycon_map(i*len, len);107 if (!dst)108 return;109 110 src = efi_earlycon_map((i + font->height) * len, len);111 if (!src) {112 efi_earlycon_unmap(dst, len);113 return;114 }115 116 memmove(dst, src, maxlen);117 118 efi_earlycon_unmap(src, len);119 efi_earlycon_unmap(dst, len);120 }121}122 123static void efi_earlycon_write_char(u32 *dst, unsigned char c, unsigned int h)124{125 const u32 color_black = 0x00000000;126 const u32 color_white = 0x00ffffff;127 const u8 *src;128 int m, n, bytes;129 u8 x;130 131 bytes = BITS_TO_BYTES(font->width);132 src = font->data + c * font->height * bytes + h * bytes;133 134 for (m = 0; m < font->width; m++) {135 n = m % 8;136 x = *(src + m / 8);137 if ((x >> (7 - n)) & 1)138 *dst = color_white;139 else140 *dst = color_black;141 dst++;142 }143}144 145static void146efi_earlycon_write(struct console *con, const char *str, unsigned int num)147{148 struct screen_info *si;149 u32 cur_efi_x = efi_x;150 unsigned int len;151 const char *s;152 void *dst;153 154 si = &screen_info;155 len = si->lfb_linelength;156 157 while (num) {158 unsigned int linemax = (si->lfb_width - efi_x) / font->width;159 unsigned int h, count;160 161 count = strnchrnul(str, num, '\n') - str;162 if (count > linemax)163 count = linemax;164 165 for (h = 0; h < font->height; h++) {166 unsigned int n, x;167 168 dst = efi_earlycon_map((efi_y + h) * len, len);169 if (!dst)170 return;171 172 s = str;173 n = count;174 x = efi_x;175 176 while (n-- > 0) {177 efi_earlycon_write_char(dst + x*4, *s, h);178 x += font->width;179 s++;180 }181 182 efi_earlycon_unmap(dst, len);183 }184 185 num -= count;186 efi_x += count * font->width;187 str += count;188 189 if (num > 0 && *s == '\n') {190 cur_efi_x = efi_x;191 efi_x = 0;192 efi_y += font->height;193 str++;194 num--;195 }196 197 if (efi_x + font->width > si->lfb_width) {198 cur_efi_x = efi_x;199 efi_x = 0;200 efi_y += font->height;201 }202 203 if (efi_y + font->height > si->lfb_height) {204 u32 i;205 206 efi_x_array[cur_line_y] = cur_efi_x;207 cur_line_y = (cur_line_y + 1) % max_line_y;208 209 efi_y -= font->height;210 efi_earlycon_scroll_up();211 212 for (i = 0; i < font->height; i++)213 efi_earlycon_clear_scanline(efi_y + i);214 }215 }216}217 218static bool __initdata fb_probed;219 220void __init efi_earlycon_reprobe(void)221{222 if (fb_probed)223 setup_earlycon("efifb");224}225 226static int __init efi_earlycon_setup(struct earlycon_device *device,227 const char *opt)228{229 struct screen_info *si;230 u16 xres, yres;231 u32 i;232 233 fb_wb = opt && !strcmp(opt, "ram");234 235 if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI) {236 fb_probed = true;237 return -ENODEV;238 }239 240 fb_base = screen_info.lfb_base;241 if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)242 fb_base |= (u64)screen_info.ext_lfb_base << 32;243 244 si = &screen_info;245 xres = si->lfb_width;246 yres = si->lfb_height;247 248 /*249 * efi_earlycon_write_char() implicitly assumes a framebuffer with250 * 32 bits per pixel.251 */252 if (si->lfb_depth != 32)253 return -ENODEV;254 255 font = get_default_font(xres, yres, NULL, NULL);256 if (!font)257 return -ENODEV;258 259 /* Fill the cache with maximum possible value of x coordinate */260 memset32(efi_x_array, rounddown(xres, font->width), ARRAY_SIZE(efi_x_array));261 efi_y = rounddown(yres, font->height);262 263 /* Make sure we have cache for the x coordinate for the full screen */264 max_line_y = efi_y / font->height + 1;265 cur_line_y = 0;266 267 efi_y -= font->height;268 for (i = 0; i < (yres - efi_y) / font->height; i++)269 efi_earlycon_scroll_up();270 271 device->con->write = efi_earlycon_write;272 earlycon_console = device->con;273 return 0;274}275EARLYCON_DECLARE(efifb, efi_earlycon_setup);276