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); 92 } 93 EXPORT_SYMBOL(framebuffer_release); 94 95 static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var) 96 { 97 int err; 98 99 var->activate |= FB_ACTIVATE_FORCE; 100 console_lock(); 101 lock_fb_info(fb_info); 102 err = fb_set_var(fb_info, var); 103 if (!err) 104 fbcon_update_vcs(fb_info, var->activate & FB_ACTIVATE_ALL); 105 unlock_fb_info(fb_info); 106 console_unlock(); 107 if (err) 108 return err; 109 return 0; 110 } 111 112 static int mode_string(char *buf, unsigned int offset, 113 const struct fb_videomode *mode) 114 { 115 char m = 'U'; 116 char v = 'p'; 117 118 if (mode->flag & FB_MODE_IS_DETAILED) 119 m = 'D'; 120 if (mode->flag & FB_MODE_IS_VESA) 121 m = 'V'; 122 if (mode->flag & FB_MODE_IS_STANDARD) 123 m = 'S'; 124 125 if (mode->vmode & FB_VMODE_INTERLACED) 126 v = 'i'; 127 if (mode->vmode & FB_VMODE_DOUBLE) 128 v = 'd'; 129 130 return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n", 131 m, mode->xres, mode->yres, v, mode->refresh); 132 } 133 134 static ssize_t store_mode(struct device *device, struct device_attribute *attr, 135 const char *buf, size_t count) 136 { 137 struct fb_info *fb_info = dev_get_drvdata(device); 138 char mstr[100]; 139 struct fb_var_screeninfo var; 140 struct fb_modelist *modelist; 141 struct fb_videomode *mode; 142 struct list_head *pos; 143 size_t i; 144 int err; 145 146 memset(&var, 0, sizeof(var)); 147 148 list_for_each(pos, &fb_info->modelist) { 149 modelist = list_entry(pos, struct fb_modelist, list); 150 mode = &modelist->mode; 151 i = mode_string(mstr, 0, mode); 152 if (strncmp(mstr, buf, max(count, i)) == 0) { 153 154 var = fb_info->var; 155 fb_videomode_to_var(&var, mode); 156 if ((err = activate(fb_info, &var))) 157 return err; 158 fb_info->mode = mode; 159 return count; 160 } 161 } 162 return -EINVAL; 163 } 164 165 static ssize_t show_mode(struct device *device, struct device_attribute *attr, 166 char *buf) 167 { 168 struct fb_info *fb_info = dev_get_drvdata(device); 169 170 if (!fb_info->mode) 171 return 0; 172 173 return mode_string(buf, 0, fb_info->mode); 174 } 175 176 static ssize_t store_modes(struct device *device, 177 struct device_attribute *attr, 178 const char *buf, size_t count) 179 { 180 struct fb_info *fb_info = dev_get_drvdata(device); 181 LIST_HEAD(old_list); 182 int i = count / sizeof(struct fb_videomode); 183 184 if (i * sizeof(struct fb_videomode) != count) 185 return -EINVAL; 186 187 console_lock(); 188 lock_fb_info(fb_info); 189 190 list_splice(&fb_info->modelist, &old_list); 191 fb_videomode_to_modelist((const struct fb_videomode *)buf, i, 192 &fb_info->modelist); 193 if (fb_new_modelist(fb_info)) { 194 fb_destroy_modelist(&fb_info->modelist); 195 list_splice(&old_list, &fb_info->modelist); 196 } else 197 fb_destroy_modelist(&old_list); 198 199 unlock_fb_info(fb_info); 200 console_unlock(); 201 202 return 0; 203 } 204 205 static ssize_t show_modes(struct device *device, struct device_attribute *attr, 206 char *buf) 207 { 208 struct fb_info *fb_info = dev_get_drvdata(device); 209 unsigned int i; 210 struct list_head *pos; 211 struct fb_modelist *modelist; 212 const struct fb_videomode *mode; 213 214 i = 0; 215 list_for_each(pos, &fb_info->modelist) { 216 modelist = list_entry(pos, struct fb_modelist, list); 217 mode = &modelist->mode; 218 i += mode_string(buf, i, mode); 219 } 220 return i; 221 } 222 223 static ssize_t store_bpp(struct device *device, struct device_attribute *attr, 224 const char *buf, size_t count) 225 { 226 struct fb_info *fb_info = dev_get_drvdata(device); 227 struct fb_var_screeninfo var; 228 char ** last = NULL; 229 int err; 230 231 var = fb_info->var; 232 var.bits_per_pixel = simple_strtoul(buf, last, 0); 233 if ((err = activate(fb_info, &var))) 234 return err; 235 return count; 236 } 237 238 static ssize_t show_bpp(struct device *device, struct device_attribute *attr, 239 char *buf) 240 { 241 struct fb_info *fb_info = dev_get_drvdata(device); 242 return sysfs_emit(buf, "%d\n", fb_info->var.bits_per_pixel); 243 } 244 245 static ssize_t store_rotate(struct device *device, 246 struct device_attribute *attr, 247 const char *buf, size_t count) 248 { 249 struct fb_info *fb_info = dev_get_drvdata(device); 250 struct fb_var_screeninfo var; 251 char **last = NULL; 252 int err; 253 254 var = fb_info->var; 255 var.rotate = simple_strtoul(buf, last, 0); 256 257 if ((err = activate(fb_info, &var))) 258 return err; 259 260 return count; 261 } 262 263 264 static ssize_t show_rotate(struct device *device, 265 struct device_attribute *attr, char *buf) 266 { 267 struct fb_info *fb_info = dev_get_drvdata(device); 268 269 return sysfs_emit(buf, "%d\n", fb_info->var.rotate); 270 } 271 272 static ssize_t store_virtual(struct device *device, 273 struct device_attribute *attr, 274 const char *buf, size_t count) 275 { 276 struct fb_info *fb_info = dev_get_drvdata(device); 277 struct fb_var_screeninfo var; 278 char *last = NULL; 279 int err; 280 281 var = fb_info->var; 282 var.xres_virtual = simple_strtoul(buf, &last, 0); 283 last++; 284 if (last - buf >= count) 285 return -EINVAL; 286 var.yres_virtual = simple_strtoul(last, &last, 0); 287 288 if ((err = activate(fb_info, &var))) 289 return err; 290 return count; 291 } 292 293 static ssize_t show_virtual(struct device *device, 294 struct device_attribute *attr, char *buf) 295 { 296 struct fb_info *fb_info = dev_get_drvdata(device); 297 return sysfs_emit(buf, "%d,%d\n", fb_info->var.xres_virtual, 298 fb_info->var.yres_virtual); 299 } 300 301 static ssize_t show_stride(struct device *device, 302 struct device_attribute *attr, char *buf) 303 { 304 struct fb_info *fb_info = dev_get_drvdata(device); 305 return sysfs_emit(buf, "%d\n", fb_info->fix.line_length); 306 } 307 308 static ssize_t store_blank(struct device *device, 309 struct device_attribute *attr, 310 const char *buf, size_t count) 311 { 312 struct fb_info *fb_info = dev_get_drvdata(device); 313 char *last = NULL; 314 int err, arg; 315 316 arg = simple_strtoul(buf, &last, 0); 317 console_lock(); 318 err = fb_blank(fb_info, arg); 319 /* might again call into fb_blank */ 320 fbcon_fb_blanked(fb_info, arg); 321 console_unlock(); 322 if (err < 0) 323 return err; 324 return count; 325 } 326 327 static ssize_t show_blank(struct device *device, 328 struct device_attribute *attr, char *buf) 329 { 330 // struct fb_info *fb_info = dev_get_drvdata(device); 331 return 0; 332 } 333 334 static ssize_t store_console(struct device *device, 335 struct device_attribute *attr, 336 const char *buf, size_t count) 337 { 338 // struct fb_info *fb_info = dev_get_drvdata(device); 339 return 0; 340 } 341 342 static ssize_t show_console(struct device *device, 343 struct device_attribute *attr, char *buf) 344 { 345 // struct fb_info *fb_info = dev_get_drvdata(device); 346 return 0; 347 } 348 349 static ssize_t store_cursor(struct device *device, 350 struct device_attribute *attr, 351 const char *buf, size_t count) 352 { 353 // struct fb_info *fb_info = dev_get_drvdata(device); 354 return 0; 355 } 356 357 static ssize_t show_cursor(struct device *device, 358 struct device_attribute *attr, char *buf) 359 { 360 // struct fb_info *fb_info = dev_get_drvdata(device); 361 return 0; 362 } 363 364 static ssize_t store_pan(struct device *device, 365 struct device_attribute *attr, 366 const char *buf, size_t count) 367 { 368 struct fb_info *fb_info = dev_get_drvdata(device); 369 struct fb_var_screeninfo var; 370 char *last = NULL; 371 int err; 372 373 var = fb_info->var; 374 var.xoffset = simple_strtoul(buf, &last, 0); 375 last++; 376 if (last - buf >= count) 377 return -EINVAL; 378 var.yoffset = simple_strtoul(last, &last, 0); 379 380 console_lock(); 381 err = fb_pan_display(fb_info, &var); 382 console_unlock(); 383 384 if (err < 0) 385 return err; 386 return count; 387 } 388 389 static ssize_t show_pan(struct device *device, 390 struct device_attribute *attr, char *buf) 391 { 392 struct fb_info *fb_info = dev_get_drvdata(device); 393 return sysfs_emit(buf, "%d,%d\n", fb_info->var.xoffset, 394 fb_info->var.yoffset); 395 } 396 397 static ssize_t show_name(struct device *device, 398 struct device_attribute *attr, char *buf) 399 { 400 struct fb_info *fb_info = dev_get_drvdata(device); 401 402 return sysfs_emit(buf, "%s\n", fb_info->fix.id); 403 } 404 405 static ssize_t store_fbstate(struct device *device, 406 struct device_attribute *attr, 407 const char *buf, size_t count) 408 { 409 struct fb_info *fb_info = dev_get_drvdata(device); 410 u32 state; 411 char *last = NULL; 412 413 state = simple_strtoul(buf, &last, 0); 414 415 console_lock(); 416 lock_fb_info(fb_info); 417 418 fb_set_suspend(fb_info, (int)state); 419 420 unlock_fb_info(fb_info); 421 console_unlock(); 422 423 return count; 424 } 425 426 static ssize_t show_fbstate(struct device *device, 427 struct device_attribute *attr, char *buf) 428 { 429 struct fb_info *fb_info = dev_get_drvdata(device); 430 return sysfs_emit(buf, "%d\n", fb_info->state); 431 } 432 433 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 434 static ssize_t store_bl_curve(struct device *device, 435 struct device_attribute *attr, 436 const char *buf, size_t count) 437 { 438 struct fb_info *fb_info = dev_get_drvdata(device); 439 u8 tmp_curve[FB_BACKLIGHT_LEVELS]; 440 unsigned int i; 441 442 /* Some drivers don't use framebuffer_alloc(), but those also 443 * don't have backlights. 444 */ 445 if (!fb_info || !fb_info->bl_dev) 446 return -ENODEV; 447 448 if (count != (FB_BACKLIGHT_LEVELS / 8 * 24)) 449 return -EINVAL; 450 451 for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i) 452 if (sscanf(&buf[i * 24], 453 "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n", 454 &tmp_curve[i * 8 + 0], 455 &tmp_curve[i * 8 + 1], 456 &tmp_curve[i * 8 + 2], 457 &tmp_curve[i * 8 + 3], 458 &tmp_curve[i * 8 + 4], 459 &tmp_curve[i * 8 + 5], 460 &tmp_curve[i * 8 + 6], 461 &tmp_curve[i * 8 + 7]) != 8) 462 return -EINVAL; 463 464 /* If there has been an error in the input data, we won't 465 * reach this loop. 466 */ 467 mutex_lock(&fb_info->bl_curve_mutex); 468 for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i) 469 fb_info->bl_curve[i] = tmp_curve[i]; 470 mutex_unlock(&fb_info->bl_curve_mutex); 471 472 return count; 473 } 474 475 static ssize_t show_bl_curve(struct device *device, 476 struct device_attribute *attr, char *buf) 477 { 478 struct fb_info *fb_info = dev_get_drvdata(device); 479 ssize_t len = 0; 480 unsigned int i; 481 482 /* Some drivers don't use framebuffer_alloc(), but those also 483 * don't have backlights. 484 */ 485 if (!fb_info || !fb_info->bl_dev) 486 return -ENODEV; 487 488 mutex_lock(&fb_info->bl_curve_mutex); 489 for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8) 490 len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n", 491 fb_info->bl_curve + i); 492 mutex_unlock(&fb_info->bl_curve_mutex); 493 494 return len; 495 } 496 #endif 497 498 /* When cmap is added back in it should be a binary attribute 499 * not a text one. Consideration should also be given to converting 500 * fbdev to use configfs instead of sysfs */ 501 static struct device_attribute device_attrs[] = { 502 __ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp), 503 __ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank), 504 __ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console), 505 __ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor), 506 __ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode), 507 __ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes), 508 __ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan), 509 __ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual), 510 __ATTR(name, S_IRUGO, show_name, NULL), 511 __ATTR(stride, S_IRUGO, show_stride, NULL), 512 __ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate), 513 __ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate), 514 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 515 __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve), 516 #endif 517 }; 518 519 int fb_init_device(struct fb_info *fb_info) 520 { 521 int i, error = 0; 522 523 dev_set_drvdata(fb_info->dev, fb_info); 524 525 fb_info->class_flag |= FB_SYSFS_FLAG_ATTR; 526 527 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) { 528 error = device_create_file(fb_info->dev, &device_attrs[i]); 529 530 if (error) 531 break; 532 } 533 534 if (error) { 535 while (--i >= 0) 536 device_remove_file(fb_info->dev, &device_attrs[i]); 537 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 538 } 539 540 return 0; 541 } 542 543 void fb_cleanup_device(struct fb_info *fb_info) 544 { 545 unsigned int i; 546 547 if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) { 548 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) 549 device_remove_file(fb_info->dev, &device_attrs[i]); 550 551 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 552 } 553 } 554 555 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 556 /* This function generates a linear backlight curve 557 * 558 * 0: off 559 * 1-7: min 560 * 8-127: linear from min to max 561 */ 562 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max) 563 { 564 unsigned int i, flat, count, range = (max - min); 565 566 mutex_lock(&fb_info->bl_curve_mutex); 567 568 fb_info->bl_curve[0] = off; 569 570 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) 571 fb_info->bl_curve[flat] = min; 572 573 count = FB_BACKLIGHT_LEVELS * 15 / 16; 574 for (i = 0; i < count; ++i) 575 fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count); 576 577 mutex_unlock(&fb_info->bl_curve_mutex); 578 } 579 EXPORT_SYMBOL_GPL(fb_bl_default_curve); 580 #endif 581