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 */
framebuffer_alloc(size_t size,struct device * dev)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 */
framebuffer_release(struct fb_info * info)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
activate(struct fb_info * fb_info,struct fb_var_screeninfo * var)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
mode_string(char * buf,unsigned int offset,const struct fb_videomode * mode)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
store_mode(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_mode(struct device * device,struct device_attribute * attr,char * buf)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
store_modes(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_modes(struct device * device,struct device_attribute * attr,char * buf)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
store_bpp(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_bpp(struct device * device,struct device_attribute * attr,char * buf)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
store_rotate(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_rotate(struct device * device,struct device_attribute * attr,char * buf)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
store_virtual(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_virtual(struct device * device,struct device_attribute * attr,char * buf)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
show_stride(struct device * device,struct device_attribute * attr,char * buf)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
store_blank(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_blank(struct device * device,struct device_attribute * attr,char * buf)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
store_console(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_console(struct device * device,struct device_attribute * attr,char * buf)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
store_cursor(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_cursor(struct device * device,struct device_attribute * attr,char * buf)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
store_pan(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_pan(struct device * device,struct device_attribute * attr,char * buf)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
show_name(struct device * device,struct device_attribute * attr,char * buf)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
store_fbstate(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_fbstate(struct device * device,struct device_attribute * attr,char * buf)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)
store_bl_curve(struct device * device,struct device_attribute * attr,const char * buf,size_t count)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
show_bl_curve(struct device * device,struct device_attribute * attr,char * buf)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
fb_init_device(struct fb_info * fb_info)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
fb_cleanup_device(struct fb_info * fb_info)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 */
fb_bl_default_curve(struct fb_info * fb_info,u8 off,u8 min,u8 max)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