1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2013 Intel Corporation; author Matt Fleming 4 */ 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 17 static const struct console *earlycon_console __initdata; 18 static const struct font_desc *font; 19 static u16 cur_line_y, max_line_y; 20 static u32 efi_x_array[1024]; 21 static u32 efi_x, efi_y; 22 static u64 fb_base; 23 static bool fb_wb; 24 static 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 after 30 * paging_init() which is earlier than initcall callbacks. Thus adding this 31 * early initcall function early_efi_map_fb() to map the whole EFI framebuffer. 32 */ 33 static 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 } 44 early_initcall(efi_earlycon_remap_fb); 45 46 static 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 } 53 late_initcall(efi_earlycon_unmap_fb); 54 55 static __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 66 static __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 74 static 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 88 static 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 } 122 123 static 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 else 140 *dst = color_black; 141 dst++; 142 } 143 } 144 145 static void 146 efi_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 } 217 218 static int __init efi_earlycon_setup(struct earlycon_device *device, 219 const char *opt) 220 { 221 struct screen_info *si; 222 u16 xres, yres; 223 u32 i; 224 225 if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI) 226 return -ENODEV; 227 228 fb_base = screen_info.lfb_base; 229 if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) 230 fb_base |= (u64)screen_info.ext_lfb_base << 32; 231 232 fb_wb = opt && !strcmp(opt, "ram"); 233 234 si = &screen_info; 235 xres = si->lfb_width; 236 yres = si->lfb_height; 237 238 /* 239 * efi_earlycon_write_char() implicitly assumes a framebuffer with 240 * 32 bits per pixel. 241 */ 242 if (si->lfb_depth != 32) 243 return -ENODEV; 244 245 font = get_default_font(xres, yres, -1, -1); 246 if (!font) 247 return -ENODEV; 248 249 /* Fill the cache with maximum possible value of x coordinate */ 250 memset32(efi_x_array, rounddown(xres, font->width), ARRAY_SIZE(efi_x_array)); 251 efi_y = rounddown(yres, font->height); 252 253 /* Make sure we have cache for the x coordinate for the full screen */ 254 max_line_y = efi_y / font->height + 1; 255 cur_line_y = 0; 256 257 efi_y -= font->height; 258 for (i = 0; i < (yres - efi_y) / font->height; i++) 259 efi_earlycon_scroll_up(); 260 261 device->con->write = efi_earlycon_write; 262 earlycon_console = device->con; 263 return 0; 264 } 265 EARLYCON_DECLARE(efifb, efi_earlycon_setup); 266