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 84 if (WARN_ON(refcount_read(&info->count))) 85 return; 86 87 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 88 mutex_destroy(&info->bl_curve_mutex); 89 #endif 90 91 kfree(info->apertures); 92 kfree(info); 93 } 94 EXPORT_SYMBOL(framebuffer_release); 95 96 static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var) 97 { 98 int err; 99 100 var->activate |= FB_ACTIVATE_FORCE; 101 console_lock(); 102 lock_fb_info(fb_info); 103 err = fb_set_var(fb_info, var); 104 if (!err) 105 fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL); 106 unlock_fb_info(fb_info); 107 console_unlock(); 108 if (err) 109 return err; 110 return 0; 111 } 112 113 static int mode_string(char *buf, unsigned int offset, 114 const struct fb_videomode *mode) 115 { 116 char m = 'U'; 117 char v = 'p'; 118 119 if (mode->flag & FB_MODE_IS_DETAILED) 120 m = 'D'; 121 if (mode->flag & FB_MODE_IS_VESA) 122 m = 'V'; 123 if (mode->flag & FB_MODE_IS_STANDARD) 124 m = 'S'; 125 126 if (mode->vmode & FB_VMODE_INTERLACED) 127 v = 'i'; 128 if (mode->vmode & FB_VMODE_DOUBLE) 129 v = 'd'; 130 131 return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n", 132 m, mode->xres, mode->yres, v, mode->refresh); 133 } 134 135 static ssize_t store_mode(struct device *device, struct device_attribute *attr, 136 const char *buf, size_t count) 137 { 138 struct fb_info *fb_info = dev_get_drvdata(device); 139 char mstr[100]; 140 struct fb_var_screeninfo var; 141 struct fb_modelist *modelist; 142 struct fb_videomode *mode; 143 struct list_head *pos; 144 size_t i; 145 int err; 146 147 memset(&var, 0, sizeof(var)); 148 149 list_for_each(pos, &fb_info->modelist) { 150 modelist = list_entry(pos, struct fb_modelist, list); 151 mode = &modelist->mode; 152 i = mode_string(mstr, 0, mode); 153 if (strncmp(mstr, buf, max(count, i)) == 0) { 154 155 var = fb_info->var; 156 fb_videomode_to_var(&var, mode); 157 if ((err = activate(fb_info, &var))) 158 return err; 159 fb_info->mode = mode; 160 return count; 161 } 162 } 163 return -EINVAL; 164 } 165 166 static ssize_t show_mode(struct device *device, struct device_attribute *attr, 167 char *buf) 168 { 169 struct fb_info *fb_info = dev_get_drvdata(device); 170 171 if (!fb_info->mode) 172 return 0; 173 174 return mode_string(buf, 0, fb_info->mode); 175 } 176 177 static ssize_t store_modes(struct device *device, 178 struct device_attribute *attr, 179 const char *buf, size_t count) 180 { 181 struct fb_info *fb_info = dev_get_drvdata(device); 182 LIST_HEAD(old_list); 183 int i = count / sizeof(struct fb_videomode); 184 185 if (i * sizeof(struct fb_videomode) != count) 186 return -EINVAL; 187 188 console_lock(); 189 lock_fb_info(fb_info); 190 191 list_splice(&fb_info->modelist, &old_list); 192 fb_videomode_to_modelist((const struct fb_videomode *)buf, i, 193 &fb_info->modelist); 194 if (fb_new_modelist(fb_info)) { 195 fb_destroy_modelist(&fb_info->modelist); 196 list_splice(&old_list, &fb_info->modelist); 197 } else 198 fb_destroy_modelist(&old_list); 199 200 unlock_fb_info(fb_info); 201 console_unlock(); 202 203 return 0; 204 } 205 206 static ssize_t show_modes(struct device *device, struct device_attribute *attr, 207 char *buf) 208 { 209 struct fb_info *fb_info = dev_get_drvdata(device); 210 unsigned int i; 211 struct list_head *pos; 212 struct fb_modelist *modelist; 213 const struct fb_videomode *mode; 214 215 i = 0; 216 list_for_each(pos, &fb_info->modelist) { 217 modelist = list_entry(pos, struct fb_modelist, list); 218 mode = &modelist->mode; 219 i += mode_string(buf, i, mode); 220 } 221 return i; 222 } 223 224 static ssize_t store_bpp(struct device *device, struct device_attribute *attr, 225 const char *buf, size_t count) 226 { 227 struct fb_info *fb_info = dev_get_drvdata(device); 228 struct fb_var_screeninfo var; 229 char ** last = NULL; 230 int err; 231 232 var = fb_info->var; 233 var.bits_per_pixel = simple_strtoul(buf, last, 0); 234 if ((err = activate(fb_info, &var))) 235 return err; 236 return count; 237 } 238 239 static ssize_t show_bpp(struct device *device, struct device_attribute *attr, 240 char *buf) 241 { 242 struct fb_info *fb_info = dev_get_drvdata(device); 243 return sysfs_emit(buf, "%d\n", fb_info->var.bits_per_pixel); 244 } 245 246 static ssize_t store_rotate(struct device *device, 247 struct device_attribute *attr, 248 const char *buf, size_t count) 249 { 250 struct fb_info *fb_info = dev_get_drvdata(device); 251 struct fb_var_screeninfo var; 252 char **last = NULL; 253 int err; 254 255 var = fb_info->var; 256 var.rotate = simple_strtoul(buf, last, 0); 257 258 if ((err = activate(fb_info, &var))) 259 return err; 260 261 return count; 262 } 263 264 265 static ssize_t show_rotate(struct device *device, 266 struct device_attribute *attr, char *buf) 267 { 268 struct fb_info *fb_info = dev_get_drvdata(device); 269 270 return sysfs_emit(buf, "%d\n", fb_info->var.rotate); 271 } 272 273 static ssize_t store_virtual(struct device *device, 274 struct device_attribute *attr, 275 const char *buf, size_t count) 276 { 277 struct fb_info *fb_info = dev_get_drvdata(device); 278 struct fb_var_screeninfo var; 279 char *last = NULL; 280 int err; 281 282 var = fb_info->var; 283 var.xres_virtual = simple_strtoul(buf, &last, 0); 284 last++; 285 if (last - buf >= count) 286 return -EINVAL; 287 var.yres_virtual = simple_strtoul(last, &last, 0); 288 289 if ((err = activate(fb_info, &var))) 290 return err; 291 return count; 292 } 293 294 static ssize_t show_virtual(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,%d\n", fb_info->var.xres_virtual, 299 fb_info->var.yres_virtual); 300 } 301 302 static ssize_t show_stride(struct device *device, 303 struct device_attribute *attr, char *buf) 304 { 305 struct fb_info *fb_info = dev_get_drvdata(device); 306 return sysfs_emit(buf, "%d\n", fb_info->fix.line_length); 307 } 308 309 static ssize_t store_blank(struct device *device, 310 struct device_attribute *attr, 311 const char *buf, size_t count) 312 { 313 struct fb_info *fb_info = dev_get_drvdata(device); 314 char *last = NULL; 315 int err, arg; 316 317 arg = simple_strtoul(buf, &last, 0); 318 console_lock(); 319 err = fb_blank(fb_info, arg); 320 /* might again call into fb_blank */ 321 fbcon_fb_blanked(fb_info, arg); 322 console_unlock(); 323 if (err < 0) 324 return err; 325 return count; 326 } 327 328 static ssize_t show_blank(struct device *device, 329 struct device_attribute *attr, char *buf) 330 { 331 // struct fb_info *fb_info = dev_get_drvdata(device); 332 return 0; 333 } 334 335 static ssize_t store_console(struct device *device, 336 struct device_attribute *attr, 337 const char *buf, size_t count) 338 { 339 // struct fb_info *fb_info = dev_get_drvdata(device); 340 return 0; 341 } 342 343 static ssize_t show_console(struct device *device, 344 struct device_attribute *attr, char *buf) 345 { 346 // struct fb_info *fb_info = dev_get_drvdata(device); 347 return 0; 348 } 349 350 static ssize_t store_cursor(struct device *device, 351 struct device_attribute *attr, 352 const char *buf, size_t count) 353 { 354 // struct fb_info *fb_info = dev_get_drvdata(device); 355 return 0; 356 } 357 358 static ssize_t show_cursor(struct device *device, 359 struct device_attribute *attr, char *buf) 360 { 361 // struct fb_info *fb_info = dev_get_drvdata(device); 362 return 0; 363 } 364 365 static ssize_t store_pan(struct device *device, 366 struct device_attribute *attr, 367 const char *buf, size_t count) 368 { 369 struct fb_info *fb_info = dev_get_drvdata(device); 370 struct fb_var_screeninfo var; 371 char *last = NULL; 372 int err; 373 374 var = fb_info->var; 375 var.xoffset = simple_strtoul(buf, &last, 0); 376 last++; 377 if (last - buf >= count) 378 return -EINVAL; 379 var.yoffset = simple_strtoul(last, &last, 0); 380 381 console_lock(); 382 err = fb_pan_display(fb_info, &var); 383 console_unlock(); 384 385 if (err < 0) 386 return err; 387 return count; 388 } 389 390 static ssize_t show_pan(struct device *device, 391 struct device_attribute *attr, char *buf) 392 { 393 struct fb_info *fb_info = dev_get_drvdata(device); 394 return sysfs_emit(buf, "%d,%d\n", fb_info->var.xoffset, 395 fb_info->var.yoffset); 396 } 397 398 static ssize_t show_name(struct device *device, 399 struct device_attribute *attr, char *buf) 400 { 401 struct fb_info *fb_info = dev_get_drvdata(device); 402 403 return sysfs_emit(buf, "%s\n", fb_info->fix.id); 404 } 405 406 static ssize_t store_fbstate(struct device *device, 407 struct device_attribute *attr, 408 const char *buf, size_t count) 409 { 410 struct fb_info *fb_info = dev_get_drvdata(device); 411 u32 state; 412 char *last = NULL; 413 414 state = simple_strtoul(buf, &last, 0); 415 416 console_lock(); 417 lock_fb_info(fb_info); 418 419 fb_set_suspend(fb_info, (int)state); 420 421 unlock_fb_info(fb_info); 422 console_unlock(); 423 424 return count; 425 } 426 427 static ssize_t show_fbstate(struct device *device, 428 struct device_attribute *attr, char *buf) 429 { 430 struct fb_info *fb_info = dev_get_drvdata(device); 431 return sysfs_emit(buf, "%d\n", fb_info->state); 432 } 433 434 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 435 static ssize_t store_bl_curve(struct device *device, 436 struct device_attribute *attr, 437 const char *buf, size_t count) 438 { 439 struct fb_info *fb_info = dev_get_drvdata(device); 440 u8 tmp_curve[FB_BACKLIGHT_LEVELS]; 441 unsigned int i; 442 443 /* Some drivers don't use framebuffer_alloc(), but those also 444 * don't have backlights. 445 */ 446 if (!fb_info || !fb_info->bl_dev) 447 return -ENODEV; 448 449 if (count != (FB_BACKLIGHT_LEVELS / 8 * 24)) 450 return -EINVAL; 451 452 for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i) 453 if (sscanf(&buf[i * 24], 454 "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n", 455 &tmp_curve[i * 8 + 0], 456 &tmp_curve[i * 8 + 1], 457 &tmp_curve[i * 8 + 2], 458 &tmp_curve[i * 8 + 3], 459 &tmp_curve[i * 8 + 4], 460 &tmp_curve[i * 8 + 5], 461 &tmp_curve[i * 8 + 6], 462 &tmp_curve[i * 8 + 7]) != 8) 463 return -EINVAL; 464 465 /* If there has been an error in the input data, we won't 466 * reach this loop. 467 */ 468 mutex_lock(&fb_info->bl_curve_mutex); 469 for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i) 470 fb_info->bl_curve[i] = tmp_curve[i]; 471 mutex_unlock(&fb_info->bl_curve_mutex); 472 473 return count; 474 } 475 476 static ssize_t show_bl_curve(struct device *device, 477 struct device_attribute *attr, char *buf) 478 { 479 struct fb_info *fb_info = dev_get_drvdata(device); 480 ssize_t len = 0; 481 unsigned int i; 482 483 /* Some drivers don't use framebuffer_alloc(), but those also 484 * don't have backlights. 485 */ 486 if (!fb_info || !fb_info->bl_dev) 487 return -ENODEV; 488 489 mutex_lock(&fb_info->bl_curve_mutex); 490 for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8) 491 len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n", 492 fb_info->bl_curve + i); 493 mutex_unlock(&fb_info->bl_curve_mutex); 494 495 return len; 496 } 497 #endif 498 499 /* When cmap is added back in it should be a binary attribute 500 * not a text one. Consideration should also be given to converting 501 * fbdev to use configfs instead of sysfs */ 502 static struct device_attribute device_attrs[] = { 503 __ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp), 504 __ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank), 505 __ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console), 506 __ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor), 507 __ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode), 508 __ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes), 509 __ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan), 510 __ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual), 511 __ATTR(name, S_IRUGO, show_name, NULL), 512 __ATTR(stride, S_IRUGO, show_stride, NULL), 513 __ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate), 514 __ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate), 515 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 516 __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve), 517 #endif 518 }; 519 520 int fb_init_device(struct fb_info *fb_info) 521 { 522 int i, error = 0; 523 524 dev_set_drvdata(fb_info->dev, fb_info); 525 526 fb_info->class_flag |= FB_SYSFS_FLAG_ATTR; 527 528 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) { 529 error = device_create_file(fb_info->dev, &device_attrs[i]); 530 531 if (error) 532 break; 533 } 534 535 if (error) { 536 while (--i >= 0) 537 device_remove_file(fb_info->dev, &device_attrs[i]); 538 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 539 } 540 541 return 0; 542 } 543 544 void fb_cleanup_device(struct fb_info *fb_info) 545 { 546 unsigned int i; 547 548 if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) { 549 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) 550 device_remove_file(fb_info->dev, &device_attrs[i]); 551 552 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 553 } 554 } 555 556 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 557 /* This function generates a linear backlight curve 558 * 559 * 0: off 560 * 1-7: min 561 * 8-127: linear from min to max 562 */ 563 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max) 564 { 565 unsigned int i, flat, count, range = (max - min); 566 567 mutex_lock(&fb_info->bl_curve_mutex); 568 569 fb_info->bl_curve[0] = off; 570 571 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) 572 fb_info->bl_curve[flat] = min; 573 574 count = FB_BACKLIGHT_LEVELS * 15 / 16; 575 for (i = 0; i < count; ++i) 576 fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count); 577 578 mutex_unlock(&fb_info->bl_curve_mutex); 579 } 580 EXPORT_SYMBOL_GPL(fb_bl_default_curve); 581 #endif 582