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 lock_fb_info(fb_info); 95 err = fb_set_var(fb_info, var); 96 if (!err) 97 fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL); 98 unlock_fb_info(fb_info); 99 console_unlock(); 100 if (err) 101 return err; 102 return 0; 103 } 104 105 static int mode_string(char *buf, unsigned int offset, 106 const struct fb_videomode *mode) 107 { 108 char m = 'U'; 109 char v = 'p'; 110 111 if (mode->flag & FB_MODE_IS_DETAILED) 112 m = 'D'; 113 if (mode->flag & FB_MODE_IS_VESA) 114 m = 'V'; 115 if (mode->flag & FB_MODE_IS_STANDARD) 116 m = 'S'; 117 118 if (mode->vmode & FB_VMODE_INTERLACED) 119 v = 'i'; 120 if (mode->vmode & FB_VMODE_DOUBLE) 121 v = 'd'; 122 123 return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n", 124 m, mode->xres, mode->yres, v, mode->refresh); 125 } 126 127 static ssize_t store_mode(struct device *device, struct device_attribute *attr, 128 const char *buf, size_t count) 129 { 130 struct fb_info *fb_info = dev_get_drvdata(device); 131 char mstr[100]; 132 struct fb_var_screeninfo var; 133 struct fb_modelist *modelist; 134 struct fb_videomode *mode; 135 struct list_head *pos; 136 size_t i; 137 int err; 138 139 memset(&var, 0, sizeof(var)); 140 141 list_for_each(pos, &fb_info->modelist) { 142 modelist = list_entry(pos, struct fb_modelist, list); 143 mode = &modelist->mode; 144 i = mode_string(mstr, 0, mode); 145 if (strncmp(mstr, buf, max(count, i)) == 0) { 146 147 var = fb_info->var; 148 fb_videomode_to_var(&var, mode); 149 if ((err = activate(fb_info, &var))) 150 return err; 151 fb_info->mode = mode; 152 return count; 153 } 154 } 155 return -EINVAL; 156 } 157 158 static ssize_t show_mode(struct device *device, struct device_attribute *attr, 159 char *buf) 160 { 161 struct fb_info *fb_info = dev_get_drvdata(device); 162 163 if (!fb_info->mode) 164 return 0; 165 166 return mode_string(buf, 0, fb_info->mode); 167 } 168 169 static ssize_t store_modes(struct device *device, 170 struct device_attribute *attr, 171 const char *buf, size_t count) 172 { 173 struct fb_info *fb_info = dev_get_drvdata(device); 174 LIST_HEAD(old_list); 175 int i = count / sizeof(struct fb_videomode); 176 177 if (i * sizeof(struct fb_videomode) != count) 178 return -EINVAL; 179 180 console_lock(); 181 lock_fb_info(fb_info); 182 183 list_splice(&fb_info->modelist, &old_list); 184 fb_videomode_to_modelist((const struct fb_videomode *)buf, i, 185 &fb_info->modelist); 186 if (fb_new_modelist(fb_info)) { 187 fb_destroy_modelist(&fb_info->modelist); 188 list_splice(&old_list, &fb_info->modelist); 189 } else 190 fb_destroy_modelist(&old_list); 191 192 unlock_fb_info(fb_info); 193 console_unlock(); 194 195 return 0; 196 } 197 198 static ssize_t show_modes(struct device *device, struct device_attribute *attr, 199 char *buf) 200 { 201 struct fb_info *fb_info = dev_get_drvdata(device); 202 unsigned int i; 203 struct list_head *pos; 204 struct fb_modelist *modelist; 205 const struct fb_videomode *mode; 206 207 i = 0; 208 list_for_each(pos, &fb_info->modelist) { 209 modelist = list_entry(pos, struct fb_modelist, list); 210 mode = &modelist->mode; 211 i += mode_string(buf, i, mode); 212 } 213 return i; 214 } 215 216 static ssize_t store_bpp(struct device *device, struct device_attribute *attr, 217 const char *buf, size_t count) 218 { 219 struct fb_info *fb_info = dev_get_drvdata(device); 220 struct fb_var_screeninfo var; 221 char ** last = NULL; 222 int err; 223 224 var = fb_info->var; 225 var.bits_per_pixel = simple_strtoul(buf, last, 0); 226 if ((err = activate(fb_info, &var))) 227 return err; 228 return count; 229 } 230 231 static ssize_t show_bpp(struct device *device, struct device_attribute *attr, 232 char *buf) 233 { 234 struct fb_info *fb_info = dev_get_drvdata(device); 235 return sysfs_emit(buf, "%d\n", fb_info->var.bits_per_pixel); 236 } 237 238 static ssize_t store_rotate(struct device *device, 239 struct device_attribute *attr, 240 const char *buf, size_t count) 241 { 242 struct fb_info *fb_info = dev_get_drvdata(device); 243 struct fb_var_screeninfo var; 244 char **last = NULL; 245 int err; 246 247 var = fb_info->var; 248 var.rotate = simple_strtoul(buf, last, 0); 249 250 if ((err = activate(fb_info, &var))) 251 return err; 252 253 return count; 254 } 255 256 257 static ssize_t show_rotate(struct device *device, 258 struct device_attribute *attr, char *buf) 259 { 260 struct fb_info *fb_info = dev_get_drvdata(device); 261 262 return sysfs_emit(buf, "%d\n", fb_info->var.rotate); 263 } 264 265 static ssize_t store_virtual(struct device *device, 266 struct device_attribute *attr, 267 const char *buf, size_t count) 268 { 269 struct fb_info *fb_info = dev_get_drvdata(device); 270 struct fb_var_screeninfo var; 271 char *last = NULL; 272 int err; 273 274 var = fb_info->var; 275 var.xres_virtual = simple_strtoul(buf, &last, 0); 276 last++; 277 if (last - buf >= count) 278 return -EINVAL; 279 var.yres_virtual = simple_strtoul(last, &last, 0); 280 281 if ((err = activate(fb_info, &var))) 282 return err; 283 return count; 284 } 285 286 static ssize_t show_virtual(struct device *device, 287 struct device_attribute *attr, char *buf) 288 { 289 struct fb_info *fb_info = dev_get_drvdata(device); 290 return sysfs_emit(buf, "%d,%d\n", fb_info->var.xres_virtual, 291 fb_info->var.yres_virtual); 292 } 293 294 static ssize_t show_stride(struct device *device, 295 struct device_attribute *attr, char *buf) 296 { 297 struct fb_info *fb_info = dev_get_drvdata(device); 298 return sysfs_emit(buf, "%d\n", fb_info->fix.line_length); 299 } 300 301 static ssize_t store_blank(struct device *device, 302 struct device_attribute *attr, 303 const char *buf, size_t count) 304 { 305 struct fb_info *fb_info = dev_get_drvdata(device); 306 char *last = NULL; 307 int err, arg; 308 309 arg = simple_strtoul(buf, &last, 0); 310 console_lock(); 311 err = fb_blank(fb_info, arg); 312 /* might again call into fb_blank */ 313 fbcon_fb_blanked(fb_info, arg); 314 console_unlock(); 315 if (err < 0) 316 return err; 317 return count; 318 } 319 320 static ssize_t show_blank(struct device *device, 321 struct device_attribute *attr, char *buf) 322 { 323 // struct fb_info *fb_info = dev_get_drvdata(device); 324 return 0; 325 } 326 327 static ssize_t store_console(struct device *device, 328 struct device_attribute *attr, 329 const char *buf, size_t count) 330 { 331 // struct fb_info *fb_info = dev_get_drvdata(device); 332 return 0; 333 } 334 335 static ssize_t show_console(struct device *device, 336 struct device_attribute *attr, char *buf) 337 { 338 // struct fb_info *fb_info = dev_get_drvdata(device); 339 return 0; 340 } 341 342 static ssize_t store_cursor(struct device *device, 343 struct device_attribute *attr, 344 const char *buf, size_t count) 345 { 346 // struct fb_info *fb_info = dev_get_drvdata(device); 347 return 0; 348 } 349 350 static ssize_t show_cursor(struct device *device, 351 struct device_attribute *attr, char *buf) 352 { 353 // struct fb_info *fb_info = dev_get_drvdata(device); 354 return 0; 355 } 356 357 static ssize_t store_pan(struct device *device, 358 struct device_attribute *attr, 359 const char *buf, size_t count) 360 { 361 struct fb_info *fb_info = dev_get_drvdata(device); 362 struct fb_var_screeninfo var; 363 char *last = NULL; 364 int err; 365 366 var = fb_info->var; 367 var.xoffset = simple_strtoul(buf, &last, 0); 368 last++; 369 if (last - buf >= count) 370 return -EINVAL; 371 var.yoffset = simple_strtoul(last, &last, 0); 372 373 console_lock(); 374 err = fb_pan_display(fb_info, &var); 375 console_unlock(); 376 377 if (err < 0) 378 return err; 379 return count; 380 } 381 382 static ssize_t show_pan(struct device *device, 383 struct device_attribute *attr, char *buf) 384 { 385 struct fb_info *fb_info = dev_get_drvdata(device); 386 return sysfs_emit(buf, "%d,%d\n", fb_info->var.xoffset, 387 fb_info->var.yoffset); 388 } 389 390 static ssize_t show_name(struct device *device, 391 struct device_attribute *attr, char *buf) 392 { 393 struct fb_info *fb_info = dev_get_drvdata(device); 394 395 return sysfs_emit(buf, "%s\n", fb_info->fix.id); 396 } 397 398 static ssize_t store_fbstate(struct device *device, 399 struct device_attribute *attr, 400 const char *buf, size_t count) 401 { 402 struct fb_info *fb_info = dev_get_drvdata(device); 403 u32 state; 404 char *last = NULL; 405 406 state = simple_strtoul(buf, &last, 0); 407 408 console_lock(); 409 lock_fb_info(fb_info); 410 411 fb_set_suspend(fb_info, (int)state); 412 413 unlock_fb_info(fb_info); 414 console_unlock(); 415 416 return count; 417 } 418 419 static ssize_t show_fbstate(struct device *device, 420 struct device_attribute *attr, char *buf) 421 { 422 struct fb_info *fb_info = dev_get_drvdata(device); 423 return sysfs_emit(buf, "%d\n", fb_info->state); 424 } 425 426 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 427 static ssize_t store_bl_curve(struct device *device, 428 struct device_attribute *attr, 429 const char *buf, size_t count) 430 { 431 struct fb_info *fb_info = dev_get_drvdata(device); 432 u8 tmp_curve[FB_BACKLIGHT_LEVELS]; 433 unsigned int i; 434 435 /* Some drivers don't use framebuffer_alloc(), but those also 436 * don't have backlights. 437 */ 438 if (!fb_info || !fb_info->bl_dev) 439 return -ENODEV; 440 441 if (count != (FB_BACKLIGHT_LEVELS / 8 * 24)) 442 return -EINVAL; 443 444 for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i) 445 if (sscanf(&buf[i * 24], 446 "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n", 447 &tmp_curve[i * 8 + 0], 448 &tmp_curve[i * 8 + 1], 449 &tmp_curve[i * 8 + 2], 450 &tmp_curve[i * 8 + 3], 451 &tmp_curve[i * 8 + 4], 452 &tmp_curve[i * 8 + 5], 453 &tmp_curve[i * 8 + 6], 454 &tmp_curve[i * 8 + 7]) != 8) 455 return -EINVAL; 456 457 /* If there has been an error in the input data, we won't 458 * reach this loop. 459 */ 460 mutex_lock(&fb_info->bl_curve_mutex); 461 for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i) 462 fb_info->bl_curve[i] = tmp_curve[i]; 463 mutex_unlock(&fb_info->bl_curve_mutex); 464 465 return count; 466 } 467 468 static ssize_t show_bl_curve(struct device *device, 469 struct device_attribute *attr, char *buf) 470 { 471 struct fb_info *fb_info = dev_get_drvdata(device); 472 ssize_t len = 0; 473 unsigned int i; 474 475 /* Some drivers don't use framebuffer_alloc(), but those also 476 * don't have backlights. 477 */ 478 if (!fb_info || !fb_info->bl_dev) 479 return -ENODEV; 480 481 mutex_lock(&fb_info->bl_curve_mutex); 482 for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8) 483 len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n", 484 fb_info->bl_curve + i); 485 mutex_unlock(&fb_info->bl_curve_mutex); 486 487 return len; 488 } 489 #endif 490 491 /* When cmap is added back in it should be a binary attribute 492 * not a text one. Consideration should also be given to converting 493 * fbdev to use configfs instead of sysfs */ 494 static struct device_attribute device_attrs[] = { 495 __ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp), 496 __ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank), 497 __ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console), 498 __ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor), 499 __ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode), 500 __ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes), 501 __ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan), 502 __ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual), 503 __ATTR(name, S_IRUGO, show_name, NULL), 504 __ATTR(stride, S_IRUGO, show_stride, NULL), 505 __ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate), 506 __ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate), 507 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 508 __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve), 509 #endif 510 }; 511 512 int fb_init_device(struct fb_info *fb_info) 513 { 514 int i, error = 0; 515 516 dev_set_drvdata(fb_info->dev, fb_info); 517 518 fb_info->class_flag |= FB_SYSFS_FLAG_ATTR; 519 520 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) { 521 error = device_create_file(fb_info->dev, &device_attrs[i]); 522 523 if (error) 524 break; 525 } 526 527 if (error) { 528 while (--i >= 0) 529 device_remove_file(fb_info->dev, &device_attrs[i]); 530 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 531 } 532 533 return 0; 534 } 535 536 void fb_cleanup_device(struct fb_info *fb_info) 537 { 538 unsigned int i; 539 540 if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) { 541 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) 542 device_remove_file(fb_info->dev, &device_attrs[i]); 543 544 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 545 } 546 } 547 548 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 549 /* This function generates a linear backlight curve 550 * 551 * 0: off 552 * 1-7: min 553 * 8-127: linear from min to max 554 */ 555 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max) 556 { 557 unsigned int i, flat, count, range = (max - min); 558 559 mutex_lock(&fb_info->bl_curve_mutex); 560 561 fb_info->bl_curve[0] = off; 562 563 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) 564 fb_info->bl_curve[flat] = min; 565 566 count = FB_BACKLIGHT_LEVELS * 15 / 16; 567 for (i = 0; i < count; ++i) 568 fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count); 569 570 mutex_unlock(&fb_info->bl_curve_mutex); 571 } 572 EXPORT_SYMBOL_GPL(fb_bl_default_curve); 573 #endif 574