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/console.h> 18 #include <linux/module.h> 19 20 #define FB_SYSFS_FLAG_ATTR 1 21 22 /** 23 * framebuffer_alloc - creates a new frame buffer info structure 24 * 25 * @size: size of driver private data, can be zero 26 * @dev: pointer to the device for this fb, this can be NULL 27 * 28 * Creates a new frame buffer info structure. Also reserves @size bytes 29 * for driver private data (info->par). info->par (if any) will be 30 * aligned to sizeof(long). 31 * 32 * Returns the new structure, or NULL if an error occurred. 33 * 34 */ 35 struct fb_info *framebuffer_alloc(size_t size, struct device *dev) 36 { 37 #define BYTES_PER_LONG (BITS_PER_LONG/8) 38 #define PADDING (BYTES_PER_LONG - (sizeof(struct fb_info) % BYTES_PER_LONG)) 39 int fb_info_size = sizeof(struct fb_info); 40 struct fb_info *info; 41 char *p; 42 43 if (size) 44 fb_info_size += PADDING; 45 46 p = kzalloc(fb_info_size + size, GFP_KERNEL); 47 48 if (!p) 49 return NULL; 50 51 info = (struct fb_info *) p; 52 53 if (size) 54 info->par = p + fb_info_size; 55 56 info->device = dev; 57 info->fbcon_rotate_hint = -1; 58 59 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 60 mutex_init(&info->bl_curve_mutex); 61 #endif 62 63 return info; 64 #undef PADDING 65 #undef BYTES_PER_LONG 66 } 67 EXPORT_SYMBOL(framebuffer_alloc); 68 69 /** 70 * framebuffer_release - marks the structure available for freeing 71 * 72 * @info: frame buffer info structure 73 * 74 * Drop the reference count of the device embedded in the 75 * framebuffer info structure. 76 * 77 */ 78 void framebuffer_release(struct fb_info *info) 79 { 80 if (!info) 81 return; 82 kfree(info->apertures); 83 kfree(info); 84 } 85 EXPORT_SYMBOL(framebuffer_release); 86 87 static int activate(struct fb_info *fb_info, struct fb_var_screeninfo *var) 88 { 89 int err; 90 91 var->activate |= FB_ACTIVATE_FORCE; 92 console_lock(); 93 fb_info->flags |= FBINFO_MISC_USEREVENT; 94 err = fb_set_var(fb_info, var); 95 fb_info->flags &= ~FBINFO_MISC_USEREVENT; 96 console_unlock(); 97 if (err) 98 return err; 99 return 0; 100 } 101 102 static int mode_string(char *buf, unsigned int offset, 103 const struct fb_videomode *mode) 104 { 105 char m = 'U'; 106 char v = 'p'; 107 108 if (mode->flag & FB_MODE_IS_DETAILED) 109 m = 'D'; 110 if (mode->flag & FB_MODE_IS_VESA) 111 m = 'V'; 112 if (mode->flag & FB_MODE_IS_STANDARD) 113 m = 'S'; 114 115 if (mode->vmode & FB_VMODE_INTERLACED) 116 v = 'i'; 117 if (mode->vmode & FB_VMODE_DOUBLE) 118 v = 'd'; 119 120 return snprintf(&buf[offset], PAGE_SIZE - offset, "%c:%dx%d%c-%d\n", 121 m, mode->xres, mode->yres, v, mode->refresh); 122 } 123 124 static ssize_t store_mode(struct device *device, struct device_attribute *attr, 125 const char *buf, size_t count) 126 { 127 struct fb_info *fb_info = dev_get_drvdata(device); 128 char mstr[100]; 129 struct fb_var_screeninfo var; 130 struct fb_modelist *modelist; 131 struct fb_videomode *mode; 132 struct list_head *pos; 133 size_t i; 134 int err; 135 136 memset(&var, 0, sizeof(var)); 137 138 list_for_each(pos, &fb_info->modelist) { 139 modelist = list_entry(pos, struct fb_modelist, list); 140 mode = &modelist->mode; 141 i = mode_string(mstr, 0, mode); 142 if (strncmp(mstr, buf, max(count, i)) == 0) { 143 144 var = fb_info->var; 145 fb_videomode_to_var(&var, mode); 146 if ((err = activate(fb_info, &var))) 147 return err; 148 fb_info->mode = mode; 149 return count; 150 } 151 } 152 return -EINVAL; 153 } 154 155 static ssize_t show_mode(struct device *device, struct device_attribute *attr, 156 char *buf) 157 { 158 struct fb_info *fb_info = dev_get_drvdata(device); 159 160 if (!fb_info->mode) 161 return 0; 162 163 return mode_string(buf, 0, fb_info->mode); 164 } 165 166 static ssize_t store_modes(struct device *device, 167 struct device_attribute *attr, 168 const char *buf, size_t count) 169 { 170 struct fb_info *fb_info = dev_get_drvdata(device); 171 LIST_HEAD(old_list); 172 int i = count / sizeof(struct fb_videomode); 173 174 if (i * sizeof(struct fb_videomode) != count) 175 return -EINVAL; 176 177 console_lock(); 178 if (!lock_fb_info(fb_info)) { 179 console_unlock(); 180 return -ENODEV; 181 } 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 snprintf(buf, PAGE_SIZE, "%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 snprintf(buf, PAGE_SIZE, "%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 snprintf(buf, PAGE_SIZE, "%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 snprintf(buf, PAGE_SIZE, "%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; 308 309 console_lock(); 310 fb_info->flags |= FBINFO_MISC_USEREVENT; 311 err = fb_blank(fb_info, simple_strtoul(buf, &last, 0)); 312 fb_info->flags &= ~FBINFO_MISC_USEREVENT; 313 console_unlock(); 314 if (err < 0) 315 return err; 316 return count; 317 } 318 319 static ssize_t show_blank(struct device *device, 320 struct device_attribute *attr, char *buf) 321 { 322 // struct fb_info *fb_info = dev_get_drvdata(device); 323 return 0; 324 } 325 326 static ssize_t store_console(struct device *device, 327 struct device_attribute *attr, 328 const char *buf, size_t count) 329 { 330 // struct fb_info *fb_info = dev_get_drvdata(device); 331 return 0; 332 } 333 334 static ssize_t show_console(struct device *device, 335 struct device_attribute *attr, char *buf) 336 { 337 // struct fb_info *fb_info = dev_get_drvdata(device); 338 return 0; 339 } 340 341 static ssize_t store_cursor(struct device *device, 342 struct device_attribute *attr, 343 const char *buf, size_t count) 344 { 345 // struct fb_info *fb_info = dev_get_drvdata(device); 346 return 0; 347 } 348 349 static ssize_t show_cursor(struct device *device, 350 struct device_attribute *attr, char *buf) 351 { 352 // struct fb_info *fb_info = dev_get_drvdata(device); 353 return 0; 354 } 355 356 static ssize_t store_pan(struct device *device, 357 struct device_attribute *attr, 358 const char *buf, size_t count) 359 { 360 struct fb_info *fb_info = dev_get_drvdata(device); 361 struct fb_var_screeninfo var; 362 char *last = NULL; 363 int err; 364 365 var = fb_info->var; 366 var.xoffset = simple_strtoul(buf, &last, 0); 367 last++; 368 if (last - buf >= count) 369 return -EINVAL; 370 var.yoffset = simple_strtoul(last, &last, 0); 371 372 console_lock(); 373 err = fb_pan_display(fb_info, &var); 374 console_unlock(); 375 376 if (err < 0) 377 return err; 378 return count; 379 } 380 381 static ssize_t show_pan(struct device *device, 382 struct device_attribute *attr, char *buf) 383 { 384 struct fb_info *fb_info = dev_get_drvdata(device); 385 return snprintf(buf, PAGE_SIZE, "%d,%d\n", fb_info->var.xoffset, 386 fb_info->var.yoffset); 387 } 388 389 static ssize_t show_name(struct device *device, 390 struct device_attribute *attr, char *buf) 391 { 392 struct fb_info *fb_info = dev_get_drvdata(device); 393 394 return snprintf(buf, PAGE_SIZE, "%s\n", fb_info->fix.id); 395 } 396 397 static ssize_t store_fbstate(struct device *device, 398 struct device_attribute *attr, 399 const char *buf, size_t count) 400 { 401 struct fb_info *fb_info = dev_get_drvdata(device); 402 u32 state; 403 char *last = NULL; 404 405 state = simple_strtoul(buf, &last, 0); 406 407 console_lock(); 408 if (!lock_fb_info(fb_info)) { 409 console_unlock(); 410 return -ENODEV; 411 } 412 413 fb_set_suspend(fb_info, (int)state); 414 415 unlock_fb_info(fb_info); 416 console_unlock(); 417 418 return count; 419 } 420 421 static ssize_t show_fbstate(struct device *device, 422 struct device_attribute *attr, char *buf) 423 { 424 struct fb_info *fb_info = dev_get_drvdata(device); 425 return snprintf(buf, PAGE_SIZE, "%d\n", fb_info->state); 426 } 427 428 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 429 static ssize_t store_bl_curve(struct device *device, 430 struct device_attribute *attr, 431 const char *buf, size_t count) 432 { 433 struct fb_info *fb_info = dev_get_drvdata(device); 434 u8 tmp_curve[FB_BACKLIGHT_LEVELS]; 435 unsigned int i; 436 437 /* Some drivers don't use framebuffer_alloc(), but those also 438 * don't have backlights. 439 */ 440 if (!fb_info || !fb_info->bl_dev) 441 return -ENODEV; 442 443 if (count != (FB_BACKLIGHT_LEVELS / 8 * 24)) 444 return -EINVAL; 445 446 for (i = 0; i < (FB_BACKLIGHT_LEVELS / 8); ++i) 447 if (sscanf(&buf[i * 24], 448 "%2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx %2hhx\n", 449 &tmp_curve[i * 8 + 0], 450 &tmp_curve[i * 8 + 1], 451 &tmp_curve[i * 8 + 2], 452 &tmp_curve[i * 8 + 3], 453 &tmp_curve[i * 8 + 4], 454 &tmp_curve[i * 8 + 5], 455 &tmp_curve[i * 8 + 6], 456 &tmp_curve[i * 8 + 7]) != 8) 457 return -EINVAL; 458 459 /* If there has been an error in the input data, we won't 460 * reach this loop. 461 */ 462 mutex_lock(&fb_info->bl_curve_mutex); 463 for (i = 0; i < FB_BACKLIGHT_LEVELS; ++i) 464 fb_info->bl_curve[i] = tmp_curve[i]; 465 mutex_unlock(&fb_info->bl_curve_mutex); 466 467 return count; 468 } 469 470 static ssize_t show_bl_curve(struct device *device, 471 struct device_attribute *attr, char *buf) 472 { 473 struct fb_info *fb_info = dev_get_drvdata(device); 474 ssize_t len = 0; 475 unsigned int i; 476 477 /* Some drivers don't use framebuffer_alloc(), but those also 478 * don't have backlights. 479 */ 480 if (!fb_info || !fb_info->bl_dev) 481 return -ENODEV; 482 483 mutex_lock(&fb_info->bl_curve_mutex); 484 for (i = 0; i < FB_BACKLIGHT_LEVELS; i += 8) 485 len += scnprintf(&buf[len], PAGE_SIZE - len, "%8ph\n", 486 fb_info->bl_curve + i); 487 mutex_unlock(&fb_info->bl_curve_mutex); 488 489 return len; 490 } 491 #endif 492 493 /* When cmap is added back in it should be a binary attribute 494 * not a text one. Consideration should also be given to converting 495 * fbdev to use configfs instead of sysfs */ 496 static struct device_attribute device_attrs[] = { 497 __ATTR(bits_per_pixel, S_IRUGO|S_IWUSR, show_bpp, store_bpp), 498 __ATTR(blank, S_IRUGO|S_IWUSR, show_blank, store_blank), 499 __ATTR(console, S_IRUGO|S_IWUSR, show_console, store_console), 500 __ATTR(cursor, S_IRUGO|S_IWUSR, show_cursor, store_cursor), 501 __ATTR(mode, S_IRUGO|S_IWUSR, show_mode, store_mode), 502 __ATTR(modes, S_IRUGO|S_IWUSR, show_modes, store_modes), 503 __ATTR(pan, S_IRUGO|S_IWUSR, show_pan, store_pan), 504 __ATTR(virtual_size, S_IRUGO|S_IWUSR, show_virtual, store_virtual), 505 __ATTR(name, S_IRUGO, show_name, NULL), 506 __ATTR(stride, S_IRUGO, show_stride, NULL), 507 __ATTR(rotate, S_IRUGO|S_IWUSR, show_rotate, store_rotate), 508 __ATTR(state, S_IRUGO|S_IWUSR, show_fbstate, store_fbstate), 509 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 510 __ATTR(bl_curve, S_IRUGO|S_IWUSR, show_bl_curve, store_bl_curve), 511 #endif 512 }; 513 514 int fb_init_device(struct fb_info *fb_info) 515 { 516 int i, error = 0; 517 518 dev_set_drvdata(fb_info->dev, fb_info); 519 520 fb_info->class_flag |= FB_SYSFS_FLAG_ATTR; 521 522 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) { 523 error = device_create_file(fb_info->dev, &device_attrs[i]); 524 525 if (error) 526 break; 527 } 528 529 if (error) { 530 while (--i >= 0) 531 device_remove_file(fb_info->dev, &device_attrs[i]); 532 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 533 } 534 535 return 0; 536 } 537 538 void fb_cleanup_device(struct fb_info *fb_info) 539 { 540 unsigned int i; 541 542 if (fb_info->class_flag & FB_SYSFS_FLAG_ATTR) { 543 for (i = 0; i < ARRAY_SIZE(device_attrs); i++) 544 device_remove_file(fb_info->dev, &device_attrs[i]); 545 546 fb_info->class_flag &= ~FB_SYSFS_FLAG_ATTR; 547 } 548 } 549 550 #if IS_ENABLED(CONFIG_FB_BACKLIGHT) 551 /* This function generates a linear backlight curve 552 * 553 * 0: off 554 * 1-7: min 555 * 8-127: linear from min to max 556 */ 557 void fb_bl_default_curve(struct fb_info *fb_info, u8 off, u8 min, u8 max) 558 { 559 unsigned int i, flat, count, range = (max - min); 560 561 mutex_lock(&fb_info->bl_curve_mutex); 562 563 fb_info->bl_curve[0] = off; 564 565 for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat) 566 fb_info->bl_curve[flat] = min; 567 568 count = FB_BACKLIGHT_LEVELS * 15 / 16; 569 for (i = 0; i < count; ++i) 570 fb_info->bl_curve[flat + i] = min + (range * (i + 1) / count); 571 572 mutex_unlock(&fb_info->bl_curve_mutex); 573 } 574 EXPORT_SYMBOL_GPL(fb_bl_default_curve); 575 #endif 576