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| 1 | +/* |
| 2 | + * Twin - A Tiny Window System |
| 3 | + * Copyright (c) 2024 National Cheng Kung University, Taiwan |
| 4 | + * All rights reserved. |
| 5 | + */ |
| 6 | + |
| 7 | +#include <fcntl.h> |
| 8 | +#include <linux/fb.h> |
| 9 | +#include <linux/kd.h> |
| 10 | +#include <linux/vt.h> |
| 11 | +#include <stdlib.h> |
| 12 | +#include <sys/ioctl.h> |
| 13 | +#include <sys/mman.h> |
| 14 | +#include <twin.h> |
| 15 | +#include <unistd.h> |
| 16 | + |
| 17 | +#include "linux_input.h" |
| 18 | +#include "twin_backend.h" |
| 19 | +#include "twin_private.h" |
| 20 | + |
| 21 | +#define FBDEV_NAME "FRAMEBUFFER" |
| 22 | +#define FBDEV_DEFAULT "/dev/fb0" |
| 23 | +#define SCREEN(x) ((twin_context_t *) x)->screen |
| 24 | +#define PRIV(x) ((twin_fbdev_t *) ((twin_context_t *) x)->priv) |
| 25 | + |
| 26 | +typedef struct { |
| 27 | + twin_screen_t *screen; |
| 28 | + |
| 29 | + /* Linux input system */ |
| 30 | + void *input; |
| 31 | + |
| 32 | + /* Linux virtual terminal (VT) */ |
| 33 | + int vt_fd; |
| 34 | + int vt_num; |
| 35 | + bool vt_active; |
| 36 | + |
| 37 | + /* Linux framebuffer */ |
| 38 | + int fb_fd; |
| 39 | + struct fb_var_screeninfo fb_var; |
| 40 | + struct fb_fix_screeninfo fb_fix; |
| 41 | + uint16_t cmap[3][256]; |
| 42 | + uint8_t *fb_base; |
| 43 | + size_t fb_len; |
| 44 | +} twin_fbdev_t; |
| 45 | + |
| 46 | +static void _twin_fbdev_put_span(twin_coord_t left, |
| 47 | + twin_coord_t top, |
| 48 | + twin_coord_t right, |
| 49 | + twin_argb32_t *pixels, |
| 50 | + void *closure) |
| 51 | +{ |
| 52 | + twin_screen_t *screen = SCREEN(closure); |
| 53 | + twin_fbdev_t *tx = PRIV(closure); |
| 54 | + |
| 55 | + if (tx->fb_base == MAP_FAILED) |
| 56 | + return; |
| 57 | + |
| 58 | + twin_coord_t width = right - left; |
| 59 | + off_t off = top * screen->width + left; |
| 60 | + uint32_t *dest = |
| 61 | + (uint32_t *) ((uintptr_t) tx->fb_base + (off * sizeof(uint32_t))); |
| 62 | + memcpy(dest, pixels, width * sizeof(uint32_t)); |
| 63 | +} |
| 64 | + |
| 65 | +static void twin_fbdev_get_screen_size(twin_fbdev_t *tx, |
| 66 | + int *width, |
| 67 | + int *height) |
| 68 | +{ |
| 69 | + struct fb_var_screeninfo info; |
| 70 | + ioctl(tx->fb_fd, FBIOGET_VSCREENINFO, &info); |
| 71 | + *width = info.xres; |
| 72 | + *height = info.yres; |
| 73 | +} |
| 74 | + |
| 75 | +static void twin_fbdev_damage(twin_screen_t *screen, twin_fbdev_t *tx) |
| 76 | +{ |
| 77 | + int width, height; |
| 78 | + twin_fbdev_get_screen_size(tx, &width, &height); |
| 79 | + twin_screen_damage(tx->screen, 0, 0, width, height); |
| 80 | +} |
| 81 | + |
| 82 | +static bool twin_fbdev_work(void *closure) |
| 83 | +{ |
| 84 | + twin_screen_t *screen = SCREEN(closure); |
| 85 | + |
| 86 | + if (twin_screen_damaged(screen)) |
| 87 | + twin_screen_update(screen); |
| 88 | + return true; |
| 89 | +} |
| 90 | + |
| 91 | +static bool twin_fbdev_apply_config(twin_fbdev_t *tx) |
| 92 | +{ |
| 93 | + /* Read changable information of the framebuffer */ |
| 94 | + if (ioctl(tx->fb_fd, FBIOGET_VSCREENINFO, &tx->fb_var) == -1) { |
| 95 | + log_error("Failed to get framebuffer information"); |
| 96 | + return false; |
| 97 | + } |
| 98 | + |
| 99 | + /* Set the virtual screen size to be the same as the physical screen */ |
| 100 | + tx->fb_var.xres_virtual = tx->fb_var.xres; |
| 101 | + tx->fb_var.yres_virtual = tx->fb_var.yres; |
| 102 | + tx->fb_var.bits_per_pixel = 32; |
| 103 | + if (ioctl(tx->fb_fd, FBIOPUT_VSCREENINFO, &tx->fb_var) < 0) { |
| 104 | + log_error("Failed to set framebuffer mode"); |
| 105 | + return false; |
| 106 | + } |
| 107 | + |
| 108 | + /* Read changable information of the framebuffer again */ |
| 109 | + if (ioctl(tx->fb_fd, FBIOGET_VSCREENINFO, &tx->fb_var) < 0) { |
| 110 | + log_error("Failed to get framebuffer information"); |
| 111 | + return false; |
| 112 | + } |
| 113 | + |
| 114 | + /* Check bits per pixel */ |
| 115 | + if (tx->fb_var.bits_per_pixel != 32) { |
| 116 | + log_error("Failed to set framebuffer bpp to 32"); |
| 117 | + return false; |
| 118 | + } |
| 119 | + |
| 120 | + /* Read unchangable information of the framebuffer */ |
| 121 | + ioctl(tx->fb_fd, FBIOGET_FSCREENINFO, &tx->fb_fix); |
| 122 | + |
| 123 | + /* Align the framebuffer memory address with the page size */ |
| 124 | + off_t pgsize = getpagesize(); |
| 125 | + off_t start = (off_t) tx->fb_fix.smem_start & (pgsize - 1); |
| 126 | + |
| 127 | + /* Round up the framebuffer memory size to match the page size */ |
| 128 | + tx->fb_len = start + (size_t) tx->fb_fix.smem_len + (pgsize - 1); |
| 129 | + tx->fb_len &= ~(pgsize - 1); |
| 130 | + |
| 131 | + /* Map framebuffer device to the virtual memory */ |
| 132 | + tx->fb_base = mmap(NULL, tx->fb_len, PROT_READ | PROT_WRITE, MAP_SHARED, |
| 133 | + tx->fb_fd, 0); |
| 134 | + if (tx->fb_base == MAP_FAILED) { |
| 135 | + log_error("Failed to mmap framebuffer"); |
| 136 | + return false; |
| 137 | + } |
| 138 | + |
| 139 | + return true; |
| 140 | +} |
| 141 | + |
| 142 | +static int twin_vt_open(int vt_num) |
| 143 | +{ |
| 144 | + int fd; |
| 145 | + |
| 146 | + char vt_dev[30] = {0}; |
| 147 | + snprintf(vt_dev, 30, "/dev/tty%d", vt_num); |
| 148 | + |
| 149 | + fd = open(vt_dev, O_RDWR); |
| 150 | + if (fd < 0) { |
| 151 | + log_error("Failed to open %s", vt_dev); |
| 152 | + } |
| 153 | + |
| 154 | + return fd; |
| 155 | +} |
| 156 | + |
| 157 | +static bool twin_vt_setup(twin_fbdev_t *tx) |
| 158 | +{ |
| 159 | + /* Open VT0 to inquire information */ |
| 160 | + if ((tx->vt_fd = twin_vt_open(0)) < -1) { |
| 161 | + log_error("Failed to open VT0"); |
| 162 | + return false; |
| 163 | + } |
| 164 | + |
| 165 | + /* Inquire for current VT number */ |
| 166 | + struct vt_stat vt; |
| 167 | + if (ioctl(tx->vt_fd, VT_GETSTATE, &vt) == -1) { |
| 168 | + log_error("Failed to get VT number"); |
| 169 | + return false; |
| 170 | + } |
| 171 | + tx->vt_num = vt.v_active; |
| 172 | + |
| 173 | + /* Open the VT */ |
| 174 | + if ((tx->vt_fd = twin_vt_open(tx->vt_num)) < -1) { |
| 175 | + return false; |
| 176 | + } |
| 177 | + |
| 178 | + /* Set VT to graphics mode to inhibit command-line text */ |
| 179 | + if (ioctl(tx->vt_fd, KDSETMODE, KD_GRAPHICS) < 0) { |
| 180 | + log_error("Failed to set KD_GRAPHICS mode"); |
| 181 | + return false; |
| 182 | + } |
| 183 | + |
| 184 | + return true; |
| 185 | +} |
| 186 | + |
| 187 | +twin_context_t *twin_fbdev_init(int width, int height) |
| 188 | +{ |
| 189 | + char *fbdev_path = getenv(FBDEV_NAME); |
| 190 | + if (!fbdev_path) { |
| 191 | + log_info("Environment variable $FRAMEBUFFER not set, use %s by default", |
| 192 | + FBDEV_DEFAULT); |
| 193 | + fbdev_path = FBDEV_DEFAULT; |
| 194 | + } |
| 195 | + |
| 196 | + twin_context_t *ctx = calloc(1, sizeof(twin_context_t)); |
| 197 | + if (!ctx) |
| 198 | + return NULL; |
| 199 | + ctx->priv = calloc(1, sizeof(twin_fbdev_t)); |
| 200 | + if (!ctx->priv) |
| 201 | + return NULL; |
| 202 | + |
| 203 | + twin_fbdev_t *tx = ctx->priv; |
| 204 | + |
| 205 | + /* Open the framebuffer device */ |
| 206 | + tx->fb_fd = open(fbdev_path, O_RDWR); |
| 207 | + if (tx->fb_fd == -1) { |
| 208 | + log_error("Failed to open %s", fbdev_path); |
| 209 | + goto bail; |
| 210 | + } |
| 211 | + |
| 212 | + /* Set up virtual terminal environment */ |
| 213 | + if (!twin_vt_setup(tx)) { |
| 214 | + goto bail_fb_fd; |
| 215 | + } |
| 216 | + |
| 217 | + /* Apply configurations to the framebuffer device */ |
| 218 | + if (!twin_fbdev_apply_config(tx)) { |
| 219 | + log_error("Failed to apply configurations to the framebuffer device"); |
| 220 | + goto bail_vt_fd; |
| 221 | + } |
| 222 | + |
| 223 | + /* Create TWIN screen */ |
| 224 | + ctx->screen = |
| 225 | + twin_screen_create(width, height, NULL, _twin_fbdev_put_span, ctx); |
| 226 | + |
| 227 | + /* Create Linux input system object */ |
| 228 | + tx->input = twin_linux_input_create(ctx->screen); |
| 229 | + if (!tx->input) { |
| 230 | + log_error("Failed to create Linux input system object"); |
| 231 | + goto bail_screen; |
| 232 | + } |
| 233 | + |
| 234 | + /* Setup file handler and work functions */ |
| 235 | + twin_set_work(twin_fbdev_work, TWIN_WORK_REDISPLAY, ctx); |
| 236 | + |
| 237 | + return ctx; |
| 238 | + |
| 239 | +bail_screen: |
| 240 | + twin_screen_destroy(ctx->screen); |
| 241 | +bail_vt_fd: |
| 242 | + close(tx->vt_fd); |
| 243 | +bail_fb_fd: |
| 244 | + close(tx->fb_fd); |
| 245 | +bail: |
| 246 | + free(ctx->priv); |
| 247 | + free(ctx); |
| 248 | + return NULL; |
| 249 | +} |
| 250 | + |
| 251 | +static void twin_fbdev_configure(twin_context_t *ctx) |
| 252 | +{ |
| 253 | + int width, height; |
| 254 | + twin_fbdev_t *tx = ctx->priv; |
| 255 | + twin_fbdev_get_screen_size(tx, &width, &height); |
| 256 | + twin_screen_resize(ctx->screen, width, height); |
| 257 | +} |
| 258 | + |
| 259 | +static void twin_fbdev_exit(twin_context_t *ctx) |
| 260 | +{ |
| 261 | + if (!ctx) |
| 262 | + return; |
| 263 | + |
| 264 | + twin_fbdev_t *tx = PRIV(ctx); |
| 265 | + ioctl(tx->vt_fd, KDSETMODE, KD_TEXT); |
| 266 | + munmap(tx->fb_base, tx->fb_len); |
| 267 | + twin_linux_input_destroy(tx->input); |
| 268 | + close(tx->vt_fd); |
| 269 | + close(tx->fb_fd); |
| 270 | + free(ctx->priv); |
| 271 | + free(ctx); |
| 272 | +} |
| 273 | + |
| 274 | +/* Register the Linux framebuffer backend */ |
| 275 | + |
| 276 | +const twin_backend_t g_twin_backend = { |
| 277 | + .init = twin_fbdev_init, |
| 278 | + .configure = twin_fbdev_configure, |
| 279 | + .exit = twin_fbdev_exit, |
| 280 | +}; |
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