1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * fbsysfs.c - framebuffer device class and attributes 4 * 5 * Copyright (c) 2004 James Simmons <jsimmons@infradead.org> 6 */ 7 8 /* 9 * Note: currently there's only stubs for framebuffer_alloc and 10 * framebuffer_release here. The reson for that is that until all drivers 11 * are converted to use it a sysfsification will open OOPSable races. 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/slab.h> 16 #include <linux/fb.h> 17 #include <linux/fbcon.h> 18 #include <linux/console.h> 19 #include <linux/module.h> 20 21 #define FB_SYSFS_FLAG_ATTR 1 22 23 /** 24 * framebuffer_alloc - creates a new frame buffer info structure 25 * 26 * @size: size of driver private data, can be zero 27 * @dev: pointer to the device for this fb, this can be NULL 28 * 29 * Creates a new frame buffer info structure. Also reserves @size bytes 30 * for driver private data (info->par). info->par (if any) will be 31 * aligned to sizeof(long). 32 * 33 * Returns the new structure, or NULL if an error occurred. 34 * 35 */ 36 struct fb_info *framebuffer_alloc(size_t size, struct device *dev) 37 { 38 #define BYTES_PER_LONG (BITS_PER_LONG/8) 39 #define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG)) 40 int fb_info_size = sizeof(struct fb_info); 41 struct fb_info *info; 42 char *p; 43 44 if (size) 45 fb_info_size += PADDING; 46 47 p = kzalloc(fb_info_size + size, GFP_KERNEL); 48 49 if (!p) 50 return NULL; 51 52 info = (struct fb_info *) p; 53 54 if (size) 55 info->par = p + fb_info_size; 56 57 info->device = dev; 58 info->fbcon_rotate_hint = -1; 59 60 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 61 mutex_init(&info->bl_curve_mutex); 62 #endif 63 64 return info; 65 #undef PADDING 66 #undef BYTES_PER_LONG 67 } 68 EXPORT_SYMBOL(framebuffer_alloc); 69 70 /** 71 * framebuffer_release - marks the structure available for freeing 72 * 73 * @info: frame buffer info structure 74 * 75 * Drop the reference count of the device embedded in the 76 * framebuffer info structure. 77 * 78 */ 79 void framebuffer_release(struct fb_info *info) 80 { 81 if (!info) 82 return; 83 kfree(info->apertures); 84 kfree(info); 85 } 86 EXPORT_SYMBOL(framebuffer_release); 87 88 static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var) 89 { 90 int err; 91 92 var->activate |= FB_ACTIVATE_FORCE; 93 console_lock(); 94 fb_info->flags |= FBINFO_MISC_USEREVENT; 95 err = fb_set_var(fb_info, var); 96 fb_info->flags &= ~FBINFO_MISC_USEREVENT; 97 console_unlock(); 98 if (err) 99 return err; 100 return 0; 101 } 102 103 static int mode_string(char *buf, unsigned int offset, 104 const struct fb_videomode *mode) 105 { 106 char m = 'U'; 107 char v = 'p'; 108 109 if (mode->flag & FB_MODE_IS_DETAILED) 110 m = 'D'; 111 if (mode->flag & FB_MODE_IS_VESA) 112 m = 'V'; 113 if (mode->flag & FB_MODE_IS_STANDARD) 114 m = 'S'; 115 116 if (mode->vmode & FB_VMODE_INTERLACED) 117 v = 'i'; 118 if (mode->vmode & FB_VMODE_DOUBLE) 119 v = 'd'; 120 121 return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n", 122 m, mode->xres, mode->yres, v, mode->refresh); 123 } 124 125 static ssize_t store_mode(struct device *device, struct device_attribute *attr, 126 const char *buf, size_t count) 127 { 128 struct fb_info *fb_info = dev_get_drvdata(device); 129 char mstr[100]; 130 struct fb_var_screeninfo var; 131 struct fb_modelist *modelist; 132 struct fb_videomode *mode; 133 struct list_head *pos; 134 size_t i; 135 int err; 136 137 memset(&var, 0, sizeof(var)); 138 139 list_for_each(pos, &fb_info->modelist) { 140 modelist = list_entry(pos, struct fb_modelist, list); 141 mode = &modelist->mode; 142 i = mode_string(mstr, 0, mode); 143 if (strncmp(mstr, buf, max(count, i)) == 0) { 144 145 var = fb_info->var; 146 fb_videomode_to_var(&var, mode); 147 if ((err = activate(fb_info, &var))) 148 return err; 149 fb_info->mode = mode; 150 return count; 151 } 152 } 153 return -EINVAL; 154 } 155 156 static ssize_t show_mode(struct device *device, struct device_attribute *attr, 157 char *buf) 158 { 159 struct fb_info *fb_info = dev_get_drvdata(device); 160 161 if (!fb_info->mode) 162 return 0; 163 164 return mode_string(buf, 0, fb_info->mode); 165 } 166 167 static ssize_t store_modes(struct device *device, 168 struct device_attribute *attr, 169 const char *buf, size_t count) 170 { 171 struct fb_info *fb_info = dev_get_drvdata(device); 172 LIST_HEAD(old_list); 173 int i = count / sizeof(struct fb_videomode); 174 175 if (i * sizeof(struct fb_videomode) != count) 176 return -EINVAL; 177 178 console_lock(); 179 lock_fb_info(fb_info); 180 181 list_splice(&fb_info->modelist, &old_list); 182 fb_videomode_to_modelist((const struct fb_videomode *)buf, i, 183 &fb_info->modelist); 184 if (fb_new_modelist(fb_info)) { 185 fb_destroy_modelist(&fb_info->modelist); 186 list_splice(&old_list, &fb_info->modelist); 187 } else 188 fb_destroy_modelist(&old_list); 189 190 unlock_fb_info(fb_info); 191 console_unlock(); 192 193 return 0; 194 } 195 196 static ssize_t show_modes(struct device *device, struct device_attribute *attr, 197 char *buf) 198 { 199 struct fb_info *fb_info = dev_get_drvdata(device); 200 unsigned int i; 201 struct list_head *pos; 202 struct fb_modelist *modelist; 203 const struct fb_videomode *mode; 204 205 i = 0; 206 list_for_each(pos, &fb_info->modelist) { 207 modelist = list_entry(pos, struct fb_modelist, list); 208 mode = &modelist->mode; 209 i += mode_string(buf, i, mode); 210 } 211 return i; 212 } 213 214 static ssize_t store_bpp(struct device *device, struct device_attribute *attr, 215 const char *buf, size_t count) 216 { 217 struct fb_info *fb_info = dev_get_drvdata(device); 218 struct fb_var_screeninfo var; 219 char ** last = NULL; 220 int err; 221 222 var = fb_info->var; 223 var.bits_per_pixel = simple_strtoul(buf, last, 0); 224 if ((err = activate(fb_info, &var))) 225 return err; 226 return count; 227 } 228 229 static ssize_t show_bpp(struct device *device, struct device_attribute *attr, 230 char *buf) 231 { 232 struct fb_info *fb_info = dev_get_drvdata(device); 233 return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->var.bits_per_pixel); 234 } 235 236 static ssize_t store_rotate(struct device *device, 237 struct device_attribute *attr, 238 const char *buf, size_t count) 239 { 240 struct fb_info *fb_info = dev_get_drvdata(device); 241 struct fb_var_screeninfo var; 242 char **last = NULL; 243 int err; 244 245 var = fb_info->var; 246 var.rotate = simple_strtoul(buf, last, 0); 247 248 if ((err = activate(fb_info, &var))) 249 return err; 250 251 return count; 252 } 253 254 255 static ssize_t show_rotate(struct device *device, 256 struct device_attribute *attr, char *buf) 257 { 258 struct fb_info *fb_info = dev_get_drvdata(device); 259 260 return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->var.rotate); 261 } 262 263 static ssize_t store_virtual(struct device *device, 264 struct device_attribute *attr, 265 const char *buf, size_t count) 266 { 267 struct fb_info *fb_info = dev_get_drvdata(device); 268 struct fb_var_screeninfo var; 269 char *last = NULL; 270 int err; 271 272 var = fb_info->var; 273 var.xres_virtual = simple_strtoul(buf, &last, 0); 274 last++; 275 if (last - buf >= count) 276 return -EINVAL; 277 var.yres_virtual = simple_strtoul(last, &last, 0); 278 279 if ((err = activate(fb_info, &var))) 280 return err; 281 return count; 282 } 283 284 static ssize_t show_virtual(struct device *device, 285 struct device_attribute *attr, char *buf) 286 { 287 struct fb_info *fb_info = dev_get_drvdata(device); 288 return snprintf(buf, PAGE_SIZE, "%d,%d\n", fb_info->var.xres_virtual, 289 fb_info->var.yres_virtual); 290 } 291 292 static ssize_t show_stride(struct device *device, 293 struct device_attribute *attr, char *buf) 294 { 295 struct fb_info *fb_info = dev_get_drvdata(device); 296 return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->fix.line_length); 297 } 298 299 static ssize_t store_blank(struct device *device, 300 struct device_attribute *attr, 301 const char *buf, size_t count) 302 { 303 struct fb_info *fb_info = dev_get_drvdata(device); 304 char *last = NULL; 305 int err, arg; 306 307 arg = simple_strtoul(buf, &last, 0); 308 console_lock(); 309 err = fb_blank(fb_info, arg); 310 /* might again call into fb_blank */ 311 fbcon_fb_blanked(fb_info, arg); 312 console_unlock(); 313 if (err < 0) 314 return err; 315 return count; 316 } 317 318 static ssize_t show_blank(struct device *device, 319 struct device_attribute *attr, char *buf) 320 { 321 // struct fb_info *fb_info = dev_get_drvdata(device); 322 return 0; 323 } 324 325 static ssize_t store_console(struct device *device, 326 struct device_attribute *attr, 327 const char *buf, size_t count) 328 { 329 // struct fb_info *fb_info = dev_get_drvdata(device); 330 return 0; 331 } 332 333 static ssize_t show_console(struct device *device, 334 struct device_attribute *attr, char *buf) 335 { 336 // struct fb_info *fb_info = dev_get_drvdata(device); 337 return 0; 338 } 339 340 static ssize_t store_cursor(struct device *device, 341 struct device_attribute *attr, 342 const char *buf, size_t count) 343 { 344 // struct fb_info *fb_info = dev_get_drvdata(device); 345 return 0; 346 } 347 348 static ssize_t show_cursor(struct device *device, 349 struct device_attribute *attr, char *buf) 350 { 351 // struct fb_info *fb_info = dev_get_drvdata(device); 352 return 0; 353 } 354 355 static ssize_t store_pan(struct device *device, 356 struct device_attribute *attr, 357 const char *buf, size_t count) 358 { 359 struct fb_info *fb_info = dev_get_drvdata(device); 360 struct fb_var_screeninfo var; 361 char *last = NULL; 362 int err; 363 364 var = fb_info->var; 365 var.xoffset = simple_strtoul(buf, &last, 0); 366 last++; 367 if (last - buf >= count) 368 return -EINVAL; 369 var.yoffset = simple_strtoul(last, &last, 0); 370 371 console_lock(); 372 err = fb_pan_display(fb_info, &var); 373 console_unlock(); 374 375 if (err < 0) 376 return err; 377 return count; 378 } 379 380 static ssize_t show_pan(struct device *device, 381 struct device_attribute *attr, char *buf) 382 { 383 struct fb_info *fb_info = dev_get_drvdata(device); 384 return snprintf(buf, PAGE_SIZE, "%d,%d\n", fb_info->var.xoffset, 385 fb_info->var.yoffset); 386 } 387 388 static ssize_t show_name(struct device *device, 389 struct device_attribute *attr, char *buf) 390 { 391 struct fb_info *fb_info = dev_get_drvdata(device); 392 393 return snprintf(buf, PAGE_SIZE, "%s\n", fb_info->fix.id); 394 } 395 396 static ssize_t store_fbstate(struct device *device, 397 struct device_attribute *attr, 398 const char *buf, size_t count) 399 { 400 struct fb_info *fb_info = dev_get_drvdata(device); 401 u32 state; 402 char *last = NULL; 403 404 state = simple_strtoul(buf, &last, 0); 405 406 console_lock(); 407 lock_fb_info(fb_info); 408 409 fb_set_suspend(fb_info, (int)state); 410 411 unlock_fb_info(fb_info); 412 console_unlock(); 413 414 return count; 415 } 416 417 static ssize_t show_fbstate(struct device *device, 418 struct device_attribute *attr, char *buf) 419 { 420 struct fb_info *fb_info = dev_get_drvdata(device); 421 return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->state); 422 } 423 424 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 425 static ssize_t store_bl_curve(struct device *device, 426 struct device_attribute *attr, 427 const char *buf, size_t count) 428 { 429 struct fb_info *fb_info = dev_get_drvdata(device); 430 u8 tmp_curve[FB_BACKLIGHT_LEVELS]; 431 unsigned int i; 432 433 /* Some drivers don't use framebuffer_alloc(), but those also 434 * don't have backlights. 435 */ 436 if (!fb_info || !fb_info->bl_dev) 437 return -ENODEV; 438 439 if (count != (FB_BACKLIGHT_LEVELS / 8 * 24)) 440 return -EINVAL; 441 442 for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i) 443 if (sscanf(&buf[i * 24], 444 "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n", 445 &tmp_curve[i * 8 + 0], 446 &tmp_curve[i * 8 + 1], 447 &tmp_curve[i * 8 + 2], 448 &tmp_curve[i * 8 + 3], 449 &tmp_curve[i * 8 + 4], 450 &tmp_curve[i * 8 + 5], 451 &tmp_curve[i * 8 + 6], 452 &tmp_curve[i * 8 + 7]) != 8) 453 return -EINVAL; 454 455 /* If there has been an error in the input data, we won't 456 * reach this loop. 457 */ 458 mutex_lock(&fb_info->bl_curve_mutex); 459 for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i) 460 fb_info->bl_curve[i] = tmp_curve[i]; 461 mutex_unlock(&fb_info->bl_curve_mutex); 462 463 return count; 464 } 465 466 static ssize_t show_bl_curve(struct device *device, 467 struct device_attribute *attr, char *buf) 468 { 469 struct fb_info *fb_info = dev_get_drvdata(device); 470 ssize_t len = 0; 471 unsigned int i; 472 473 /* Some drivers don't use framebuffer_alloc(), but those also 474 * don't have backlights. 475 */ 476 if (!fb_info || !fb_info->bl_dev) 477 return -ENODEV; 478 479 mutex_lock(&fb_info->bl_curve_mutex); 480 for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8) 481 len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n", 482 fb_info->bl_curve + i); 483 mutex_unlock(&fb_info->bl_curve_mutex); 484 485 return len; 486 } 487 #endif 488 489 /* When cmap is added back in it should be a binary attribute 490 * not a text one. Consideration should also be given to converting 491 * fbdev to use configfs instead of sysfs */ 492 static struct device_attribute device_attrs[] = { 493 __ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp), 494 __ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank), 495 __ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console), 496 __ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor), 497 __ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode), 498 __ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes), 499 __ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan), 500 __ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual), 501 __ATTR(name, S_IRUGO, show_name, NULL), 502 __ATTR(stride, S_IRUGO, show_stride, NULL), 503 __ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate), 504 __ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate), 505 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 506 __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve), 507 #endif 508 }; 509 510 int fb_init_device(struct fb_info *fb_info) 511 { 512 int i, error = 0; 513 514 dev_set_drvdata(fb_info->dev, fb_info); 515 516 fb_info->class_flag |= FB_SYSFS_FLAG_ATTR; 517 518 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) { 519 error = device_create_file(fb_info->dev, &device_attrs[i]); 520 521 if (error) 522 break; 523 } 524 525 if (error) { 526 while (--i >= 0) 527 device_remove_file(fb_info->dev, &device_attrs[i]); 528 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 529 } 530 531 return 0; 532 } 533 534 void fb_cleanup_device(struct fb_info *fb_info) 535 { 536 unsigned int i; 537 538 if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) { 539 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) 540 device_remove_file(fb_info->dev, &device_attrs[i]); 541 542 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 543 } 544 } 545 546 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 547 /* This function generates a linear backlight curve 548 * 549 * 0: off 550 * 1-7: min 551 * 8-127: linear from min to max 552 */ 553 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max) 554 { 555 unsigned int i, flat, count, range = (max - min); 556 557 mutex_lock(&fb_info->bl_curve_mutex); 558 559 fb_info->bl_curve[0] = off; 560 561 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) 562 fb_info->bl_curve[flat] = min; 563 564 count = FB_BACKLIGHT_LEVELS * 15 / 16; 565 for (i = 0; i < count; ++i) 566 fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count); 567 568 mutex_unlock(&fb_info->bl_curve_mutex); 569 } 570 EXPORT_SYMBOL_GPL(fb_bl_default_curve); 571 #endif 572