xref: /linux/drivers/gpu/drm/drm_fb_helper.c (revision 6dfebeee296cbb3296f06c28f3b2d053ec8374e7)
1 /*
2  * Copyright (c) 2006-2009 Red Hat Inc.
3  * Copyright (c) 2006-2008 Intel Corporation
4  * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
5  *
6  * DRM framebuffer helper functions
7  *
8  * Permission to use, copy, modify, distribute, and sell this software and its
9  * documentation for any purpose is hereby granted without fee, provided that
10  * the above copyright notice appear in all copies and that both that copyright
11  * notice and this permission notice appear in supporting documentation, and
12  * that the name of the copyright holders not be used in advertising or
13  * publicity pertaining to distribution of the software without specific,
14  * written prior permission.  The copyright holders make no representations
15  * about the suitability of this software for any purpose.  It is provided "as
16  * is" without express or implied warranty.
17  *
18  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
20  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
21  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
22  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
23  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
24  * OF THIS SOFTWARE.
25  *
26  * Authors:
27  *      Dave Airlie <airlied@linux.ie>
28  *      Jesse Barnes <jesse.barnes@intel.com>
29  */
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31 
32 #include <linux/console.h>
33 #include <linux/export.h>
34 
35 #include <drm/drm_atomic.h>
36 #include <drm/drm_drv.h>
37 #include <drm/drm_fb_helper.h>
38 #include <drm/drm_fourcc.h>
39 #include <drm/drm_framebuffer.h>
40 #include <drm/drm_modeset_helper_vtables.h>
41 #include <drm/drm_print.h>
42 #include <drm/drm_vblank.h>
43 
44 #include "drm_internal.h"
45 #include "drm_crtc_internal.h"
46 
47 static bool drm_fbdev_emulation = true;
48 module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600);
49 MODULE_PARM_DESC(fbdev_emulation,
50 		 "Enable legacy fbdev emulation [default=true]");
51 
52 static int drm_fbdev_overalloc = CONFIG_DRM_FBDEV_OVERALLOC;
53 module_param(drm_fbdev_overalloc, int, 0444);
54 MODULE_PARM_DESC(drm_fbdev_overalloc,
55 		 "Overallocation of the fbdev buffer (%) [default="
56 		 __MODULE_STRING(CONFIG_DRM_FBDEV_OVERALLOC) "]");
57 
58 /*
59  * In order to keep user-space compatibility, we want in certain use-cases
60  * to keep leaking the fbdev physical address to the user-space program
61  * handling the fbdev buffer.
62  *
63  * This is a bad habit, essentially kept to support closed-source OpenGL
64  * drivers that should really be moved into open-source upstream projects
65  * instead of using legacy physical addresses in user space to communicate
66  * with other out-of-tree kernel modules.
67  *
68  * This module_param *should* be removed as soon as possible and be
69  * considered as a broken and legacy behaviour from a modern fbdev device.
70  */
71 static bool drm_leak_fbdev_smem;
72 #if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
73 module_param_unsafe(drm_leak_fbdev_smem, bool, 0600);
74 MODULE_PARM_DESC(drm_leak_fbdev_smem,
75 		 "Allow unsafe leaking fbdev physical smem address [default=false]");
76 #endif
77 
78 /**
79  * DOC: fbdev helpers
80  *
81  * The fb helper functions are useful to provide an fbdev on top of a drm kernel
82  * mode setting driver. They can be used mostly independently from the crtc
83  * helper functions used by many drivers to implement the kernel mode setting
84  * interfaces. Drivers that use one of the shared memory managers, TTM, SHMEM,
85  * DMA, should instead use the corresponding fbdev emulation.
86  *
87  * For suspend/resume consider using drm_mode_config_helper_suspend() and
88  * drm_mode_config_helper_resume() which takes care of fbdev as well.
89  *
90  * All other functions exported by the fb helper library can be used to
91  * implement the fbdev driver interface by the driver.
92  *
93  * It is possible, though perhaps somewhat tricky, to implement race-free
94  * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
95  * helper must be called first to initialize the minimum required to make
96  * hotplug detection work. Drivers also need to make sure to properly set up
97  * the &drm_mode_config.funcs member. After calling drm_kms_helper_poll_init()
98  * it is safe to enable interrupts and start processing hotplug events. At the
99  * same time, drivers should initialize all modeset objects such as CRTCs,
100  * encoders and connectors. To finish up the fbdev helper initialization, the
101  * drm_fb_helper_init() function is called. To probe for all attached displays
102  * and set up an initial configuration using the detected hardware, drivers
103  * should call drm_fb_helper_initial_config().
104  *
105  * If &drm_framebuffer_funcs.dirty is set, the
106  * drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} functions will
107  * accumulate changes and schedule &drm_fb_helper.dirty_work to run right
108  * away. This worker then calls the dirty() function ensuring that it will
109  * always run in process context since the fb_*() function could be running in
110  * atomic context. If drm_fb_helper_deferred_io() is used as the deferred_io
111  * callback it will also schedule dirty_work with the damage collected from the
112  * mmap page writes.
113  */
114 
115 static int
116 __drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
117 					    bool force)
118 {
119 	bool do_delayed;
120 	int ret;
121 
122 	if (!drm_fbdev_emulation || !fb_helper)
123 		return -ENODEV;
124 
125 	if (READ_ONCE(fb_helper->deferred_setup))
126 		return 0;
127 
128 	mutex_lock(&fb_helper->lock);
129 	if (force) {
130 		/*
131 		 * Yes this is the _locked version which expects the master lock
132 		 * to be held. But for forced restores we're intentionally
133 		 * racing here, see drm_fb_helper_set_par().
134 		 */
135 		ret = drm_client_modeset_commit_locked(&fb_helper->client);
136 	} else {
137 		ret = drm_client_modeset_commit(&fb_helper->client);
138 	}
139 
140 	do_delayed = fb_helper->delayed_hotplug;
141 	if (do_delayed)
142 		fb_helper->delayed_hotplug = false;
143 	mutex_unlock(&fb_helper->lock);
144 
145 	if (do_delayed)
146 		drm_fb_helper_hotplug_event(fb_helper);
147 
148 	if (fb_helper->funcs->fb_restore)
149 		fb_helper->funcs->fb_restore(fb_helper);
150 
151 	return ret;
152 }
153 
154 /**
155  * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
156  * @fb_helper: driver-allocated fbdev helper, can be NULL
157  * @force: ignore present DRM master
158  *
159  * This helper should be called from fbdev emulation's &drm_client_funcs.restore
160  * callback. It ensures that the user isn't greeted with a black screen when the
161  * userspace compositor releases the display device.
162  *
163  * Returns:
164  * 0 on success, or a negative errno code otherwise.
165  */
166 int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper, bool force)
167 {
168 	return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
169 }
170 EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
171 
172 static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
173 {
174 	struct drm_fb_helper *fb_helper = info->par;
175 
176 	mutex_lock(&fb_helper->lock);
177 	drm_client_modeset_dpms(&fb_helper->client, dpms_mode);
178 	mutex_unlock(&fb_helper->lock);
179 }
180 
181 /**
182  * drm_fb_helper_blank - implementation for &fb_ops.fb_blank
183  * @blank: desired blanking state
184  * @info: fbdev registered by the helper
185  */
186 int drm_fb_helper_blank(int blank, struct fb_info *info)
187 {
188 	if (oops_in_progress)
189 		return -EBUSY;
190 
191 	switch (blank) {
192 	/* Display: On; HSync: On, VSync: On */
193 	case FB_BLANK_UNBLANK:
194 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
195 		break;
196 	/* Display: Off; HSync: On, VSync: On */
197 	case FB_BLANK_NORMAL:
198 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
199 		break;
200 	/* Display: Off; HSync: Off, VSync: On */
201 	case FB_BLANK_HSYNC_SUSPEND:
202 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
203 		break;
204 	/* Display: Off; HSync: On, VSync: Off */
205 	case FB_BLANK_VSYNC_SUSPEND:
206 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
207 		break;
208 	/* Display: Off; HSync: Off, VSync: Off */
209 	case FB_BLANK_POWERDOWN:
210 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
211 		break;
212 	}
213 	return 0;
214 }
215 EXPORT_SYMBOL(drm_fb_helper_blank);
216 
217 static void drm_fb_helper_resume_worker(struct work_struct *work)
218 {
219 	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper,
220 						    resume_work);
221 
222 	console_lock();
223 	fb_set_suspend(helper->info, 0);
224 	console_unlock();
225 }
226 
227 static void drm_fb_helper_fb_dirty(struct drm_fb_helper *helper)
228 {
229 	struct drm_device *dev = helper->dev;
230 	struct drm_clip_rect *clip = &helper->damage_clip;
231 	struct drm_clip_rect clip_copy;
232 	unsigned long flags;
233 	int ret;
234 
235 	mutex_lock(&helper->lock);
236 	drm_client_modeset_wait_for_vblank(&helper->client, 0);
237 	mutex_unlock(&helper->lock);
238 
239 	if (drm_WARN_ON_ONCE(dev, !helper->funcs->fb_dirty))
240 		return;
241 
242 	spin_lock_irqsave(&helper->damage_lock, flags);
243 	clip_copy = *clip;
244 	clip->x1 = clip->y1 = ~0;
245 	clip->x2 = clip->y2 = 0;
246 	spin_unlock_irqrestore(&helper->damage_lock, flags);
247 
248 	ret = helper->funcs->fb_dirty(helper, &clip_copy);
249 	if (ret)
250 		goto err;
251 
252 	return;
253 
254 err:
255 	/*
256 	 * Restore damage clip rectangle on errors. The next run
257 	 * of the damage worker will perform the update.
258 	 */
259 	spin_lock_irqsave(&helper->damage_lock, flags);
260 	clip->x1 = min_t(u32, clip->x1, clip_copy.x1);
261 	clip->y1 = min_t(u32, clip->y1, clip_copy.y1);
262 	clip->x2 = max_t(u32, clip->x2, clip_copy.x2);
263 	clip->y2 = max_t(u32, clip->y2, clip_copy.y2);
264 	spin_unlock_irqrestore(&helper->damage_lock, flags);
265 }
266 
267 static void drm_fb_helper_damage_work(struct work_struct *work)
268 {
269 	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper, damage_work);
270 
271 	drm_fb_helper_fb_dirty(helper);
272 }
273 
274 /**
275  * drm_fb_helper_prepare - setup a drm_fb_helper structure
276  * @dev: DRM device
277  * @helper: driver-allocated fbdev helper structure to set up
278  * @preferred_bpp: Preferred bits per pixel for the device.
279  * @funcs: pointer to structure of functions associate with this helper
280  *
281  * Sets up the bare minimum to make the framebuffer helper usable. This is
282  * useful to implement race-free initialization of the polling helpers.
283  */
284 void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
285 			   unsigned int preferred_bpp,
286 			   const struct drm_fb_helper_funcs *funcs)
287 {
288 	/*
289 	 * Pick a preferred bpp of 32 if no value has been given. This
290 	 * will select XRGB8888 for the framebuffer formats. All drivers
291 	 * have to support XRGB8888 for backwards compatibility with legacy
292 	 * userspace, so it's the safe choice here.
293 	 *
294 	 * TODO: Replace struct drm_mode_config.preferred_depth and this
295 	 *       bpp value with a preferred format that is given as struct
296 	 *       drm_format_info. Then derive all other values from the
297 	 *       format.
298 	 */
299 	if (!preferred_bpp)
300 		preferred_bpp = 32;
301 
302 	spin_lock_init(&helper->damage_lock);
303 	INIT_WORK(&helper->resume_work, drm_fb_helper_resume_worker);
304 	INIT_WORK(&helper->damage_work, drm_fb_helper_damage_work);
305 	helper->damage_clip.x1 = helper->damage_clip.y1 = ~0;
306 	mutex_init(&helper->lock);
307 	helper->funcs = funcs;
308 	helper->dev = dev;
309 	helper->preferred_bpp = preferred_bpp;
310 }
311 EXPORT_SYMBOL(drm_fb_helper_prepare);
312 
313 /**
314  * drm_fb_helper_unprepare - clean up a drm_fb_helper structure
315  * @fb_helper: driver-allocated fbdev helper structure to set up
316  *
317  * Cleans up the framebuffer helper. Inverse of drm_fb_helper_prepare().
318  */
319 void drm_fb_helper_unprepare(struct drm_fb_helper *fb_helper)
320 {
321 	mutex_destroy(&fb_helper->lock);
322 }
323 EXPORT_SYMBOL(drm_fb_helper_unprepare);
324 
325 /**
326  * drm_fb_helper_init - initialize a &struct drm_fb_helper
327  * @dev: drm device
328  * @fb_helper: driver-allocated fbdev helper structure to initialize
329  *
330  * This allocates the structures for the fbdev helper with the given limits.
331  * Note that this won't yet touch the hardware (through the driver interfaces)
332  * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
333  * to allow driver writes more control over the exact init sequence.
334  *
335  * Drivers must call drm_fb_helper_prepare() before calling this function.
336  *
337  * RETURNS:
338  * Zero if everything went ok, nonzero otherwise.
339  */
340 int drm_fb_helper_init(struct drm_device *dev,
341 		       struct drm_fb_helper *fb_helper)
342 {
343 	int ret;
344 
345 	/*
346 	 * If this is not the generic fbdev client, initialize a drm_client
347 	 * without callbacks so we can use the modesets.
348 	 */
349 	if (!fb_helper->client.funcs) {
350 		ret = drm_client_init(dev, &fb_helper->client, "drm_fb_helper", NULL);
351 		if (ret)
352 			return ret;
353 	}
354 
355 	dev->fb_helper = fb_helper;
356 
357 	return 0;
358 }
359 EXPORT_SYMBOL(drm_fb_helper_init);
360 
361 static struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
362 {
363 	struct device *dev = fb_helper->dev->dev;
364 	struct fb_info *info;
365 	int ret;
366 
367 	info = framebuffer_alloc(0, dev);
368 	if (!info)
369 		return ERR_PTR(-ENOMEM);
370 
371 	if (!drm_leak_fbdev_smem)
372 		info->flags |= FBINFO_HIDE_SMEM_START;
373 
374 	ret = fb_alloc_cmap(&info->cmap, 256, 0);
375 	if (ret)
376 		goto err_release;
377 
378 	fb_helper->info = info;
379 	info->skip_vt_switch = true;
380 
381 	info->skip_panic = drm_panic_is_enabled(fb_helper->dev);
382 	return info;
383 
384 err_release:
385 	framebuffer_release(info);
386 	return ERR_PTR(ret);
387 }
388 
389 static void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
390 {
391 	struct fb_info *info = fb_helper->info;
392 
393 	if (!info)
394 		return;
395 
396 	fb_helper->info = NULL;
397 
398 	if (info->cmap.len)
399 		fb_dealloc_cmap(&info->cmap);
400 	framebuffer_release(info);
401 }
402 
403 /**
404  * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
405  * @fb_helper: driver-allocated fbdev helper, must not be NULL
406  *
407  * A wrapper around unregister_framebuffer, to release the fb_info
408  * framebuffer device. This must be called before releasing all resources for
409  * @fb_helper by calling drm_fb_helper_fini().
410  */
411 void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
412 {
413 	unregister_framebuffer(fb_helper->info);
414 }
415 EXPORT_SYMBOL(drm_fb_helper_unregister_info);
416 
417 /**
418  * drm_fb_helper_fini - finialize a &struct drm_fb_helper
419  * @fb_helper: driver-allocated fbdev helper, can be NULL
420  *
421  * This cleans up all remaining resources associated with @fb_helper.
422  */
423 void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
424 {
425 	if (!fb_helper)
426 		return;
427 
428 	fb_helper->dev->fb_helper = NULL;
429 
430 	if (!drm_fbdev_emulation)
431 		return;
432 
433 	cancel_work_sync(&fb_helper->resume_work);
434 	cancel_work_sync(&fb_helper->damage_work);
435 
436 	drm_fb_helper_release_info(fb_helper);
437 
438 	if (!fb_helper->client.funcs)
439 		drm_client_release(&fb_helper->client);
440 }
441 EXPORT_SYMBOL(drm_fb_helper_fini);
442 
443 static void drm_fb_helper_add_damage_clip(struct drm_fb_helper *helper, u32 x, u32 y,
444 					  u32 width, u32 height)
445 {
446 	struct drm_clip_rect *clip = &helper->damage_clip;
447 	unsigned long flags;
448 
449 	spin_lock_irqsave(&helper->damage_lock, flags);
450 	clip->x1 = min_t(u32, clip->x1, x);
451 	clip->y1 = min_t(u32, clip->y1, y);
452 	clip->x2 = max_t(u32, clip->x2, x + width);
453 	clip->y2 = max_t(u32, clip->y2, y + height);
454 	spin_unlock_irqrestore(&helper->damage_lock, flags);
455 }
456 
457 static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
458 				 u32 width, u32 height)
459 {
460 	/*
461 	 * This function may be invoked by panic() to flush the frame
462 	 * buffer, where all CPUs except the panic CPU are stopped.
463 	 * During the following schedule_work(), the panic CPU needs
464 	 * the worker_pool lock, which might be held by a stopped CPU,
465 	 * causing schedule_work() and panic() to block. Return early on
466 	 * oops_in_progress to prevent this blocking.
467 	 */
468 	if (oops_in_progress)
469 		return;
470 
471 	drm_fb_helper_add_damage_clip(helper, x, y, width, height);
472 
473 	schedule_work(&helper->damage_work);
474 }
475 
476 /*
477  * Convert memory region into area of scanlines and pixels per
478  * scanline. The parameters off and len must not reach beyond
479  * the end of the framebuffer.
480  */
481 static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off, size_t len,
482 					       struct drm_rect *clip)
483 {
484 	u32 line_length = info->fix.line_length;
485 	u32 fb_height = info->var.yres;
486 	off_t end = off + len;
487 	u32 x1 = 0;
488 	u32 y1 = off / line_length;
489 	u32 x2 = info->var.xres;
490 	u32 y2 = DIV_ROUND_UP(end, line_length);
491 
492 	/* Don't allow any of them beyond the bottom bound of display area */
493 	if (y1 > fb_height)
494 		y1 = fb_height;
495 	if (y2 > fb_height)
496 		y2 = fb_height;
497 
498 	if ((y2 - y1) == 1) {
499 		/*
500 		 * We've only written to a single scanline. Try to reduce
501 		 * the number of horizontal pixels that need an update.
502 		 */
503 		off_t bit_off = (off % line_length) * 8;
504 		off_t bit_end = (end % line_length) * 8;
505 
506 		x1 = bit_off / info->var.bits_per_pixel;
507 		x2 = DIV_ROUND_UP(bit_end, info->var.bits_per_pixel);
508 	}
509 
510 	drm_rect_init(clip, x1, y1, x2 - x1, y2 - y1);
511 }
512 
513 /* Don't use in new code. */
514 void drm_fb_helper_damage_range(struct fb_info *info, off_t off, size_t len)
515 {
516 	struct drm_fb_helper *fb_helper = info->par;
517 	struct drm_rect damage_area;
518 
519 	drm_fb_helper_memory_range_to_clip(info, off, len, &damage_area);
520 	drm_fb_helper_damage(fb_helper, damage_area.x1, damage_area.y1,
521 			     drm_rect_width(&damage_area),
522 			     drm_rect_height(&damage_area));
523 }
524 EXPORT_SYMBOL(drm_fb_helper_damage_range);
525 
526 /* Don't use in new code. */
527 void drm_fb_helper_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
528 {
529 	struct drm_fb_helper *fb_helper = info->par;
530 
531 	drm_fb_helper_damage(fb_helper, x, y, width, height);
532 }
533 EXPORT_SYMBOL(drm_fb_helper_damage_area);
534 
535 #ifdef CONFIG_FB_DEFERRED_IO
536 /**
537  * drm_fb_helper_deferred_io() - fbdev deferred_io callback function
538  * @info: fb_info struct pointer
539  * @pagereflist: list of mmap framebuffer pages that have to be flushed
540  *
541  * This function is used as the &fb_deferred_io.deferred_io
542  * callback function for flushing the fbdev mmap writes.
543  */
544 void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist)
545 {
546 	struct drm_fb_helper *helper = info->par;
547 	unsigned long start, end, min_off, max_off, total_size;
548 	struct fb_deferred_io_pageref *pageref;
549 	struct drm_rect damage_area;
550 
551 	min_off = ULONG_MAX;
552 	max_off = 0;
553 	list_for_each_entry(pageref, pagereflist, list) {
554 		start = pageref->offset;
555 		end = start + PAGE_SIZE;
556 		min_off = min(min_off, start);
557 		max_off = max(max_off, end);
558 	}
559 
560 	/*
561 	 * As we can only track pages, we might reach beyond the end
562 	 * of the screen and account for non-existing scanlines. Hence,
563 	 * keep the covered memory area within the screen buffer.
564 	 */
565 	if (info->screen_size)
566 		total_size = info->screen_size;
567 	else
568 		total_size = info->fix.smem_len;
569 	max_off = min(max_off, total_size);
570 
571 	if (min_off < max_off) {
572 		drm_fb_helper_memory_range_to_clip(info, min_off, max_off - min_off, &damage_area);
573 		drm_fb_helper_damage(helper, damage_area.x1, damage_area.y1,
574 				     drm_rect_width(&damage_area),
575 				     drm_rect_height(&damage_area));
576 	}
577 }
578 EXPORT_SYMBOL(drm_fb_helper_deferred_io);
579 #endif
580 
581 /**
582  * drm_fb_helper_set_suspend - wrapper around fb_set_suspend
583  * @fb_helper: driver-allocated fbdev helper, can be NULL
584  * @suspend: whether to suspend or resume
585  *
586  * A wrapper around fb_set_suspend implemented by fbdev core.
587  * Use drm_fb_helper_set_suspend_unlocked() if you don't need to take
588  * the lock yourself
589  */
590 void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, bool suspend)
591 {
592 	if (!fb_helper || !fb_helper->info)
593 		return;
594 
595 	if (fb_helper->funcs->fb_set_suspend)
596 		fb_helper->funcs->fb_set_suspend(fb_helper, suspend);
597 	else
598 		fb_set_suspend(fb_helper->info, suspend);
599 }
600 EXPORT_SYMBOL(drm_fb_helper_set_suspend);
601 
602 /**
603  * drm_fb_helper_set_suspend_unlocked - wrapper around fb_set_suspend that also
604  *                                      takes the console lock
605  * @fb_helper: driver-allocated fbdev helper, can be NULL
606  * @suspend: whether to suspend or resume
607  *
608  * A wrapper around fb_set_suspend() that takes the console lock. If the lock
609  * isn't available on resume, a worker is tasked with waiting for the lock
610  * to become available. The console lock can be pretty contented on resume
611  * due to all the printk activity.
612  *
613  * This function can be called multiple times with the same state since
614  * &fb_info.state is checked to see if fbdev is running or not before locking.
615  *
616  * Use drm_fb_helper_set_suspend() if you need to take the lock yourself.
617  */
618 void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
619 					bool suspend)
620 {
621 	if (!fb_helper || !fb_helper->info)
622 		return;
623 
624 	/* make sure there's no pending/ongoing resume */
625 	flush_work(&fb_helper->resume_work);
626 
627 	if (suspend) {
628 		if (fb_helper->info->state != FBINFO_STATE_RUNNING)
629 			return;
630 
631 		console_lock();
632 
633 	} else {
634 		if (fb_helper->info->state == FBINFO_STATE_RUNNING)
635 			return;
636 
637 		if (!console_trylock()) {
638 			schedule_work(&fb_helper->resume_work);
639 			return;
640 		}
641 	}
642 
643 	drm_fb_helper_set_suspend(fb_helper, suspend);
644 	console_unlock();
645 }
646 EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);
647 
648 static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
649 {
650 	u32 *palette = (u32 *)info->pseudo_palette;
651 	int i;
652 
653 	if (cmap->start + cmap->len > 16)
654 		return -EINVAL;
655 
656 	for (i = 0; i < cmap->len; ++i) {
657 		u16 red = cmap->red[i];
658 		u16 green = cmap->green[i];
659 		u16 blue = cmap->blue[i];
660 		u32 value;
661 
662 		red >>= 16 - info->var.red.length;
663 		green >>= 16 - info->var.green.length;
664 		blue >>= 16 - info->var.blue.length;
665 		value = (red << info->var.red.offset) |
666 			(green << info->var.green.offset) |
667 			(blue << info->var.blue.offset);
668 		if (info->var.transp.length > 0) {
669 			u32 mask = (1 << info->var.transp.length) - 1;
670 
671 			mask <<= info->var.transp.offset;
672 			value |= mask;
673 		}
674 		palette[cmap->start + i] = value;
675 	}
676 
677 	return 0;
678 }
679 
680 static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
681 {
682 	struct drm_fb_helper *fb_helper = info->par;
683 	struct drm_mode_set *modeset;
684 	struct drm_crtc *crtc;
685 	u16 *r, *g, *b;
686 	int ret = 0;
687 
688 	drm_modeset_lock_all(fb_helper->dev);
689 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
690 		crtc = modeset->crtc;
691 		if (!crtc->funcs->gamma_set || !crtc->gamma_size) {
692 			ret = -EINVAL;
693 			goto out;
694 		}
695 
696 		if (cmap->start + cmap->len > crtc->gamma_size) {
697 			ret = -EINVAL;
698 			goto out;
699 		}
700 
701 		r = crtc->gamma_store;
702 		g = r + crtc->gamma_size;
703 		b = g + crtc->gamma_size;
704 
705 		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
706 		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
707 		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
708 
709 		ret = crtc->funcs->gamma_set(crtc, r, g, b,
710 					     crtc->gamma_size, NULL);
711 		if (ret)
712 			goto out;
713 	}
714 out:
715 	drm_modeset_unlock_all(fb_helper->dev);
716 
717 	return ret;
718 }
719 
720 static struct drm_property_blob *setcmap_new_gamma_lut(struct drm_crtc *crtc,
721 						       struct fb_cmap *cmap)
722 {
723 	struct drm_device *dev = crtc->dev;
724 	struct drm_property_blob *gamma_lut;
725 	struct drm_color_lut *lut;
726 	int size = crtc->gamma_size;
727 	int i;
728 
729 	if (!size || cmap->start + cmap->len > size)
730 		return ERR_PTR(-EINVAL);
731 
732 	gamma_lut = drm_property_create_blob(dev, sizeof(*lut) * size, NULL);
733 	if (IS_ERR(gamma_lut))
734 		return gamma_lut;
735 
736 	lut = gamma_lut->data;
737 	if (cmap->start || cmap->len != size) {
738 		u16 *r = crtc->gamma_store;
739 		u16 *g = r + crtc->gamma_size;
740 		u16 *b = g + crtc->gamma_size;
741 
742 		for (i = 0; i < cmap->start; i++) {
743 			lut[i].red = r[i];
744 			lut[i].green = g[i];
745 			lut[i].blue = b[i];
746 		}
747 		for (i = cmap->start + cmap->len; i < size; i++) {
748 			lut[i].red = r[i];
749 			lut[i].green = g[i];
750 			lut[i].blue = b[i];
751 		}
752 	}
753 
754 	for (i = 0; i < cmap->len; i++) {
755 		lut[cmap->start + i].red = cmap->red[i];
756 		lut[cmap->start + i].green = cmap->green[i];
757 		lut[cmap->start + i].blue = cmap->blue[i];
758 	}
759 
760 	return gamma_lut;
761 }
762 
763 static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
764 {
765 	struct drm_fb_helper *fb_helper = info->par;
766 	struct drm_device *dev = fb_helper->dev;
767 	struct drm_property_blob *gamma_lut = NULL;
768 	struct drm_modeset_acquire_ctx ctx;
769 	struct drm_crtc_state *crtc_state;
770 	struct drm_atomic_state *state;
771 	struct drm_mode_set *modeset;
772 	struct drm_crtc *crtc;
773 	u16 *r, *g, *b;
774 	bool replaced;
775 	int ret = 0;
776 
777 	drm_modeset_acquire_init(&ctx, 0);
778 
779 	state = drm_atomic_state_alloc(dev);
780 	if (!state) {
781 		ret = -ENOMEM;
782 		goto out_ctx;
783 	}
784 
785 	state->acquire_ctx = &ctx;
786 retry:
787 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
788 		crtc = modeset->crtc;
789 
790 		if (!gamma_lut)
791 			gamma_lut = setcmap_new_gamma_lut(crtc, cmap);
792 		if (IS_ERR(gamma_lut)) {
793 			ret = PTR_ERR(gamma_lut);
794 			gamma_lut = NULL;
795 			goto out_state;
796 		}
797 
798 		crtc_state = drm_atomic_get_crtc_state(state, crtc);
799 		if (IS_ERR(crtc_state)) {
800 			ret = PTR_ERR(crtc_state);
801 			goto out_state;
802 		}
803 
804 		/*
805 		 * FIXME: This always uses gamma_lut. Some HW have only
806 		 * degamma_lut, in which case we should reset gamma_lut and set
807 		 * degamma_lut. See drm_crtc_legacy_gamma_set().
808 		 */
809 		replaced  = drm_property_replace_blob(&crtc_state->degamma_lut,
810 						      NULL);
811 		replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
812 		replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
813 						      gamma_lut);
814 		crtc_state->color_mgmt_changed |= replaced;
815 	}
816 
817 	ret = drm_atomic_commit(state);
818 	if (ret)
819 		goto out_state;
820 
821 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
822 		crtc = modeset->crtc;
823 
824 		r = crtc->gamma_store;
825 		g = r + crtc->gamma_size;
826 		b = g + crtc->gamma_size;
827 
828 		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
829 		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
830 		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
831 	}
832 
833 out_state:
834 	if (ret == -EDEADLK)
835 		goto backoff;
836 
837 	drm_property_blob_put(gamma_lut);
838 	drm_atomic_state_put(state);
839 out_ctx:
840 	drm_modeset_drop_locks(&ctx);
841 	drm_modeset_acquire_fini(&ctx);
842 
843 	return ret;
844 
845 backoff:
846 	drm_atomic_state_clear(state);
847 	drm_modeset_backoff(&ctx);
848 	goto retry;
849 }
850 
851 /**
852  * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
853  * @cmap: cmap to set
854  * @info: fbdev registered by the helper
855  */
856 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
857 {
858 	struct drm_fb_helper *fb_helper = info->par;
859 	struct drm_device *dev = fb_helper->dev;
860 	int ret;
861 
862 	if (oops_in_progress)
863 		return -EBUSY;
864 
865 	mutex_lock(&fb_helper->lock);
866 
867 	if (!drm_master_internal_acquire(dev)) {
868 		ret = -EBUSY;
869 		goto unlock;
870 	}
871 
872 	mutex_lock(&fb_helper->client.modeset_mutex);
873 	if (info->fix.visual == FB_VISUAL_TRUECOLOR)
874 		ret = setcmap_pseudo_palette(cmap, info);
875 	else if (drm_drv_uses_atomic_modeset(fb_helper->dev))
876 		ret = setcmap_atomic(cmap, info);
877 	else
878 		ret = setcmap_legacy(cmap, info);
879 	mutex_unlock(&fb_helper->client.modeset_mutex);
880 
881 	drm_master_internal_release(dev);
882 unlock:
883 	mutex_unlock(&fb_helper->lock);
884 
885 	return ret;
886 }
887 EXPORT_SYMBOL(drm_fb_helper_setcmap);
888 
889 /**
890  * drm_fb_helper_ioctl - legacy ioctl implementation
891  * @info: fbdev registered by the helper
892  * @cmd: ioctl command
893  * @arg: ioctl argument
894  *
895  * A helper to implement the standard fbdev ioctl. Only
896  * FBIO_WAITFORVSYNC is implemented for now.
897  */
898 int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
899 			unsigned long arg)
900 {
901 	struct drm_fb_helper *fb_helper = info->par;
902 	int ret = 0;
903 
904 	guard(mutex)(&fb_helper->lock);
905 
906 	switch (cmd) {
907 	case FBIO_WAITFORVSYNC:
908 		/*
909 		 * Only consider the first CRTC.
910 		 *
911 		 * This ioctl is supposed to take the CRTC number as
912 		 * an argument, but in fbdev times, what that number
913 		 * was supposed to be was quite unclear, different
914 		 * drivers were passing that argument differently
915 		 * (some by reference, some by value), and most of the
916 		 * userspace applications were just hardcoding 0 as an
917 		 * argument.
918 		 *
919 		 * The first CRTC should be the integrated panel on
920 		 * most drivers, so this is the best choice we can
921 		 * make. If we're not smart enough here, one should
922 		 * just consider switch the userspace to KMS.
923 		 */
924 		ret = drm_client_modeset_wait_for_vblank(&fb_helper->client, 0);
925 		break;
926 	default:
927 		ret = -ENOTTY;
928 	}
929 
930 	return ret;
931 }
932 EXPORT_SYMBOL(drm_fb_helper_ioctl);
933 
934 static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
935 				      const struct fb_var_screeninfo *var_2)
936 {
937 	return var_1->bits_per_pixel == var_2->bits_per_pixel &&
938 	       var_1->grayscale == var_2->grayscale &&
939 	       var_1->red.offset == var_2->red.offset &&
940 	       var_1->red.length == var_2->red.length &&
941 	       var_1->red.msb_right == var_2->red.msb_right &&
942 	       var_1->green.offset == var_2->green.offset &&
943 	       var_1->green.length == var_2->green.length &&
944 	       var_1->green.msb_right == var_2->green.msb_right &&
945 	       var_1->blue.offset == var_2->blue.offset &&
946 	       var_1->blue.length == var_2->blue.length &&
947 	       var_1->blue.msb_right == var_2->blue.msb_right &&
948 	       var_1->transp.offset == var_2->transp.offset &&
949 	       var_1->transp.length == var_2->transp.length &&
950 	       var_1->transp.msb_right == var_2->transp.msb_right;
951 }
952 
953 static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
954 					 const struct drm_format_info *format)
955 {
956 	u8 depth = format->depth;
957 
958 	if (format->is_color_indexed) {
959 		var->red.offset = 0;
960 		var->green.offset = 0;
961 		var->blue.offset = 0;
962 		var->red.length = depth;
963 		var->green.length = depth;
964 		var->blue.length = depth;
965 		var->transp.offset = 0;
966 		var->transp.length = 0;
967 		return;
968 	}
969 
970 	switch (depth) {
971 	case 15:
972 		var->red.offset = 10;
973 		var->green.offset = 5;
974 		var->blue.offset = 0;
975 		var->red.length = 5;
976 		var->green.length = 5;
977 		var->blue.length = 5;
978 		var->transp.offset = 15;
979 		var->transp.length = 1;
980 		break;
981 	case 16:
982 		var->red.offset = 11;
983 		var->green.offset = 5;
984 		var->blue.offset = 0;
985 		var->red.length = 5;
986 		var->green.length = 6;
987 		var->blue.length = 5;
988 		var->transp.offset = 0;
989 		break;
990 	case 24:
991 		var->red.offset = 16;
992 		var->green.offset = 8;
993 		var->blue.offset = 0;
994 		var->red.length = 8;
995 		var->green.length = 8;
996 		var->blue.length = 8;
997 		var->transp.offset = 0;
998 		var->transp.length = 0;
999 		break;
1000 	case 32:
1001 		var->red.offset = 16;
1002 		var->green.offset = 8;
1003 		var->blue.offset = 0;
1004 		var->red.length = 8;
1005 		var->green.length = 8;
1006 		var->blue.length = 8;
1007 		var->transp.offset = 24;
1008 		var->transp.length = 8;
1009 		break;
1010 	default:
1011 		break;
1012 	}
1013 }
1014 
1015 static void __fill_var(struct fb_var_screeninfo *var, struct fb_info *info,
1016 		       struct drm_framebuffer *fb)
1017 {
1018 	int i;
1019 
1020 	var->xres_virtual = fb->width;
1021 	var->yres_virtual = fb->height;
1022 	var->accel_flags = 0;
1023 	var->bits_per_pixel = drm_format_info_bpp(fb->format, 0);
1024 
1025 	var->height = info->var.height;
1026 	var->width = info->var.width;
1027 
1028 	var->left_margin = var->right_margin = 0;
1029 	var->upper_margin = var->lower_margin = 0;
1030 	var->hsync_len = var->vsync_len = 0;
1031 	var->sync = var->vmode = 0;
1032 	var->rotate = 0;
1033 	var->colorspace = 0;
1034 	for (i = 0; i < 4; i++)
1035 		var->reserved[i] = 0;
1036 }
1037 
1038 /**
1039  * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
1040  * @var: screeninfo to check
1041  * @info: fbdev registered by the helper
1042  */
1043 int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
1044 			    struct fb_info *info)
1045 {
1046 	struct drm_fb_helper *fb_helper = info->par;
1047 	struct drm_framebuffer *fb = fb_helper->fb;
1048 	const struct drm_format_info *format = fb->format;
1049 	struct drm_device *dev = fb_helper->dev;
1050 	unsigned int bpp;
1051 
1052 	if (in_dbg_master())
1053 		return -EINVAL;
1054 
1055 	if (var->pixclock != 0) {
1056 		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel clock, value of pixclock is ignored\n");
1057 		var->pixclock = 0;
1058 	}
1059 
1060 	switch (format->format) {
1061 	case DRM_FORMAT_C1:
1062 	case DRM_FORMAT_C2:
1063 	case DRM_FORMAT_C4:
1064 		/* supported format with sub-byte pixels */
1065 		break;
1066 
1067 	default:
1068 		if ((drm_format_info_block_width(format, 0) > 1) ||
1069 		    (drm_format_info_block_height(format, 0) > 1))
1070 			return -EINVAL;
1071 		break;
1072 	}
1073 
1074 	/*
1075 	 * Changes struct fb_var_screeninfo are currently not pushed back
1076 	 * to KMS, hence fail if different settings are requested.
1077 	 */
1078 	bpp = drm_format_info_bpp(format, 0);
1079 	if (var->bits_per_pixel > bpp ||
1080 	    var->xres > fb->width || var->yres > fb->height ||
1081 	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
1082 		drm_dbg_kms(dev, "fb requested width/height/bpp can't fit in current fb "
1083 			  "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
1084 			  var->xres, var->yres, var->bits_per_pixel,
1085 			  var->xres_virtual, var->yres_virtual,
1086 			  fb->width, fb->height, bpp);
1087 		return -EINVAL;
1088 	}
1089 
1090 	__fill_var(var, info, fb);
1091 
1092 	/*
1093 	 * fb_pan_display() validates this, but fb_set_par() doesn't and just
1094 	 * falls over. Note that __fill_var above adjusts y/res_virtual.
1095 	 */
1096 	if (var->yoffset > var->yres_virtual - var->yres ||
1097 	    var->xoffset > var->xres_virtual - var->xres)
1098 		return -EINVAL;
1099 
1100 	/* We neither support grayscale nor FOURCC (also stored in here). */
1101 	if (var->grayscale > 0)
1102 		return -EINVAL;
1103 
1104 	if (var->nonstd)
1105 		return -EINVAL;
1106 
1107 	/*
1108 	 * Workaround for SDL 1.2, which is known to be setting all pixel format
1109 	 * fields values to zero in some cases. We treat this situation as a
1110 	 * kind of "use some reasonable autodetected values".
1111 	 */
1112 	if (!var->red.offset     && !var->green.offset    &&
1113 	    !var->blue.offset    && !var->transp.offset   &&
1114 	    !var->red.length     && !var->green.length    &&
1115 	    !var->blue.length    && !var->transp.length   &&
1116 	    !var->red.msb_right  && !var->green.msb_right &&
1117 	    !var->blue.msb_right && !var->transp.msb_right) {
1118 		drm_fb_helper_fill_pixel_fmt(var, format);
1119 	}
1120 
1121 	/*
1122 	 * drm fbdev emulation doesn't support changing the pixel format at all,
1123 	 * so reject all pixel format changing requests.
1124 	 */
1125 	if (!drm_fb_pixel_format_equal(var, &info->var)) {
1126 		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel format\n");
1127 		return -EINVAL;
1128 	}
1129 
1130 	return 0;
1131 }
1132 EXPORT_SYMBOL(drm_fb_helper_check_var);
1133 
1134 /**
1135  * drm_fb_helper_set_par - implementation for &fb_ops.fb_set_par
1136  * @info: fbdev registered by the helper
1137  *
1138  * This will let fbcon do the mode init and is called at initialization time by
1139  * the fbdev core when registering the driver, and later on through the hotplug
1140  * callback.
1141  */
1142 int drm_fb_helper_set_par(struct fb_info *info)
1143 {
1144 	struct drm_fb_helper *fb_helper = info->par;
1145 	struct fb_var_screeninfo *var = &info->var;
1146 	bool force;
1147 
1148 	if (oops_in_progress)
1149 		return -EBUSY;
1150 
1151 	/*
1152 	 * Normally we want to make sure that a kms master takes precedence over
1153 	 * fbdev, to avoid fbdev flickering and occasionally stealing the
1154 	 * display status. But Xorg first sets the vt back to text mode using
1155 	 * the KDSET IOCTL with KD_TEXT, and only after that drops the master
1156 	 * status when exiting.
1157 	 *
1158 	 * In the past this was caught by drm_fb_helper_restore_fbdev_mode_unlocked(),
1159 	 * but on modern systems where logind always keeps a drm fd open to
1160 	 * orchestrate the vt switching, this doesn't work.
1161 	 *
1162 	 * To not break the userspace ABI we have this special case here, which
1163 	 * is only used for the above case. Everything else uses the normal
1164 	 * commit function, which ensures that we never steal the display from
1165 	 * an active drm master.
1166 	 */
1167 	force = var->activate & FB_ACTIVATE_KD_TEXT;
1168 
1169 	__drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
1170 
1171 	return 0;
1172 }
1173 EXPORT_SYMBOL(drm_fb_helper_set_par);
1174 
1175 static void pan_set(struct drm_fb_helper *fb_helper, int dx, int dy)
1176 {
1177 	struct drm_mode_set *mode_set;
1178 
1179 	mutex_lock(&fb_helper->client.modeset_mutex);
1180 	drm_client_for_each_modeset(mode_set, &fb_helper->client) {
1181 		mode_set->x += dx;
1182 		mode_set->y += dy;
1183 	}
1184 	mutex_unlock(&fb_helper->client.modeset_mutex);
1185 }
1186 
1187 static int pan_display_atomic(struct fb_var_screeninfo *var,
1188 			      struct fb_info *info)
1189 {
1190 	struct drm_fb_helper *fb_helper = info->par;
1191 	int ret, dx, dy;
1192 
1193 	dx = var->xoffset - info->var.xoffset;
1194 	dy = var->yoffset - info->var.yoffset;
1195 	pan_set(fb_helper, dx, dy);
1196 
1197 	ret = drm_client_modeset_commit_locked(&fb_helper->client);
1198 	if (!ret) {
1199 		info->var.xoffset = var->xoffset;
1200 		info->var.yoffset = var->yoffset;
1201 	} else
1202 		pan_set(fb_helper, -dx, -dy);
1203 
1204 	return ret;
1205 }
1206 
1207 static int pan_display_legacy(struct fb_var_screeninfo *var,
1208 			      struct fb_info *info)
1209 {
1210 	struct drm_fb_helper *fb_helper = info->par;
1211 	struct drm_client_dev *client = &fb_helper->client;
1212 	struct drm_mode_set *modeset;
1213 	int ret = 0;
1214 
1215 	mutex_lock(&client->modeset_mutex);
1216 	drm_modeset_lock_all(fb_helper->dev);
1217 	drm_client_for_each_modeset(modeset, client) {
1218 		modeset->x = var->xoffset;
1219 		modeset->y = var->yoffset;
1220 
1221 		if (modeset->num_connectors) {
1222 			ret = drm_mode_set_config_internal(modeset);
1223 			if (!ret) {
1224 				info->var.xoffset = var->xoffset;
1225 				info->var.yoffset = var->yoffset;
1226 			}
1227 		}
1228 	}
1229 	drm_modeset_unlock_all(fb_helper->dev);
1230 	mutex_unlock(&client->modeset_mutex);
1231 
1232 	return ret;
1233 }
1234 
1235 /**
1236  * drm_fb_helper_pan_display - implementation for &fb_ops.fb_pan_display
1237  * @var: updated screen information
1238  * @info: fbdev registered by the helper
1239  */
1240 int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
1241 			      struct fb_info *info)
1242 {
1243 	struct drm_fb_helper *fb_helper = info->par;
1244 	struct drm_device *dev = fb_helper->dev;
1245 	int ret;
1246 
1247 	if (oops_in_progress)
1248 		return -EBUSY;
1249 
1250 	mutex_lock(&fb_helper->lock);
1251 	if (!drm_master_internal_acquire(dev)) {
1252 		ret = -EBUSY;
1253 		goto unlock;
1254 	}
1255 
1256 	if (drm_drv_uses_atomic_modeset(dev))
1257 		ret = pan_display_atomic(var, info);
1258 	else
1259 		ret = pan_display_legacy(var, info);
1260 
1261 	drm_master_internal_release(dev);
1262 unlock:
1263 	mutex_unlock(&fb_helper->lock);
1264 
1265 	return ret;
1266 }
1267 EXPORT_SYMBOL(drm_fb_helper_pan_display);
1268 
1269 static uint32_t drm_fb_helper_find_format(struct drm_fb_helper *fb_helper, const uint32_t *formats,
1270 					  size_t format_count, unsigned int color_mode)
1271 {
1272 	struct drm_device *dev = fb_helper->dev;
1273 	uint32_t format;
1274 	size_t i;
1275 
1276 	format = drm_driver_color_mode_format(dev, color_mode);
1277 	if (!format) {
1278 		drm_info(dev, "unsupported color mode of %d\n", color_mode);
1279 		return DRM_FORMAT_INVALID;
1280 	}
1281 
1282 	for (i = 0; i < format_count; ++i) {
1283 		if (formats[i] == format)
1284 			return format;
1285 	}
1286 	drm_warn(dev, "format %p4cc not supported\n", &format);
1287 
1288 	return DRM_FORMAT_INVALID;
1289 }
1290 
1291 static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
1292 				      struct drm_fb_helper_surface_size *sizes)
1293 {
1294 	struct drm_client_dev *client = &fb_helper->client;
1295 	struct drm_device *dev = fb_helper->dev;
1296 	int crtc_count = 0;
1297 	struct drm_connector_list_iter conn_iter;
1298 	struct drm_connector *connector;
1299 	struct drm_mode_set *mode_set;
1300 	uint32_t surface_format = DRM_FORMAT_INVALID;
1301 	const struct drm_format_info *info;
1302 
1303 	memset(sizes, 0, sizeof(*sizes));
1304 	sizes->fb_width = (u32)-1;
1305 	sizes->fb_height = (u32)-1;
1306 
1307 	drm_client_for_each_modeset(mode_set, client) {
1308 		struct drm_crtc *crtc = mode_set->crtc;
1309 		struct drm_plane *plane = crtc->primary;
1310 
1311 		drm_dbg_kms(dev, "test CRTC %u primary plane\n", drm_crtc_index(crtc));
1312 
1313 		drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1314 		drm_client_for_each_connector_iter(connector, &conn_iter) {
1315 			struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;
1316 
1317 			if (!cmdline_mode->bpp_specified)
1318 				continue;
1319 
1320 			surface_format = drm_fb_helper_find_format(fb_helper,
1321 								   plane->format_types,
1322 								   plane->format_count,
1323 								   cmdline_mode->bpp);
1324 			if (surface_format != DRM_FORMAT_INVALID)
1325 				break; /* found supported format */
1326 		}
1327 		drm_connector_list_iter_end(&conn_iter);
1328 
1329 		if (surface_format != DRM_FORMAT_INVALID)
1330 			break; /* found supported format */
1331 
1332 		/* try preferred color mode */
1333 		surface_format = drm_fb_helper_find_format(fb_helper,
1334 							   plane->format_types,
1335 							   plane->format_count,
1336 							   fb_helper->preferred_bpp);
1337 		if (surface_format != DRM_FORMAT_INVALID)
1338 			break; /* found supported format */
1339 	}
1340 
1341 	if (surface_format == DRM_FORMAT_INVALID) {
1342 		/*
1343 		 * If none of the given color modes works, fall back
1344 		 * to XRGB8888. Drivers are expected to provide this
1345 		 * format for compatibility with legacy applications.
1346 		 */
1347 		drm_warn(dev, "No compatible format found\n");
1348 		surface_format = drm_driver_legacy_fb_format(dev, 32, 24);
1349 	}
1350 
1351 	info = drm_format_info(surface_format);
1352 	sizes->surface_bpp = drm_format_info_bpp(info, 0);
1353 	sizes->surface_depth = info->depth;
1354 
1355 	/* first up get a count of crtcs now in use and new min/maxes width/heights */
1356 	crtc_count = 0;
1357 	drm_client_for_each_modeset(mode_set, client) {
1358 		struct drm_display_mode *desired_mode;
1359 		int x, y, j;
1360 		/* in case of tile group, are we the last tile vert or horiz?
1361 		 * If no tile group you are always the last one both vertically
1362 		 * and horizontally
1363 		 */
1364 		bool lastv = true, lasth = true;
1365 
1366 		desired_mode = mode_set->mode;
1367 
1368 		if (!desired_mode)
1369 			continue;
1370 
1371 		crtc_count++;
1372 
1373 		x = mode_set->x;
1374 		y = mode_set->y;
1375 
1376 		sizes->surface_width  =
1377 			max_t(u32, desired_mode->hdisplay + x, sizes->surface_width);
1378 		sizes->surface_height =
1379 			max_t(u32, desired_mode->vdisplay + y, sizes->surface_height);
1380 
1381 		for (j = 0; j < mode_set->num_connectors; j++) {
1382 			struct drm_connector *connector = mode_set->connectors[j];
1383 
1384 			if (connector->has_tile &&
1385 			    desired_mode->hdisplay == connector->tile_h_size &&
1386 			    desired_mode->vdisplay == connector->tile_v_size) {
1387 				lasth = (connector->tile_h_loc == (connector->num_h_tile - 1));
1388 				lastv = (connector->tile_v_loc == (connector->num_v_tile - 1));
1389 				/* cloning to multiple tiles is just crazy-talk, so: */
1390 				break;
1391 			}
1392 		}
1393 
1394 		if (lasth)
1395 			sizes->fb_width  = min_t(u32, desired_mode->hdisplay + x, sizes->fb_width);
1396 		if (lastv)
1397 			sizes->fb_height = min_t(u32, desired_mode->vdisplay + y, sizes->fb_height);
1398 	}
1399 
1400 	if (crtc_count == 0 || sizes->fb_width == -1 || sizes->fb_height == -1) {
1401 		drm_info(dev, "Cannot find any crtc or sizes\n");
1402 		return -EAGAIN;
1403 	}
1404 
1405 	return 0;
1406 }
1407 
1408 static int drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
1409 				    struct drm_fb_helper_surface_size *sizes)
1410 {
1411 	struct drm_client_dev *client = &fb_helper->client;
1412 	struct drm_device *dev = fb_helper->dev;
1413 	struct drm_mode_config *config = &dev->mode_config;
1414 	int ret;
1415 
1416 	mutex_lock(&client->modeset_mutex);
1417 	ret = __drm_fb_helper_find_sizes(fb_helper, sizes);
1418 	mutex_unlock(&client->modeset_mutex);
1419 
1420 	if (ret)
1421 		return ret;
1422 
1423 	/* Handle our overallocation */
1424 	sizes->surface_height *= drm_fbdev_overalloc;
1425 	sizes->surface_height /= 100;
1426 	if (sizes->surface_height > config->max_height) {
1427 		drm_dbg_kms(dev, "Fbdev over-allocation too large; clamping height to %d\n",
1428 			    config->max_height);
1429 		sizes->surface_height = config->max_height;
1430 	}
1431 
1432 	return 0;
1433 }
1434 
1435 /*
1436  * Allocates the backing storage and sets up the fbdev info structure through
1437  * the ->fbdev_probe callback.
1438  */
1439 static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
1440 {
1441 	struct drm_client_dev *client = &fb_helper->client;
1442 	struct drm_device *dev = fb_helper->dev;
1443 	struct drm_fb_helper_surface_size sizes;
1444 	int ret;
1445 
1446 	if (drm_WARN_ON(dev, !dev->driver->fbdev_probe))
1447 		return -EINVAL;
1448 
1449 	ret = drm_fb_helper_find_sizes(fb_helper, &sizes);
1450 	if (ret) {
1451 		/* First time: disable all crtc's.. */
1452 		if (!fb_helper->deferred_setup)
1453 			drm_client_modeset_commit(client);
1454 		return ret;
1455 	}
1456 
1457 	/* push down into drivers */
1458 	ret = dev->driver->fbdev_probe(fb_helper, &sizes);
1459 	if (ret < 0)
1460 		return ret;
1461 
1462 	strcpy(fb_helper->fb->comm, "[fbcon]");
1463 
1464 	return 0;
1465 }
1466 
1467 static void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
1468 				   bool is_color_indexed)
1469 {
1470 	info->fix.type = FB_TYPE_PACKED_PIXELS;
1471 	info->fix.visual = is_color_indexed ? FB_VISUAL_PSEUDOCOLOR
1472 					    : FB_VISUAL_TRUECOLOR;
1473 	info->fix.mmio_start = 0;
1474 	info->fix.mmio_len = 0;
1475 	info->fix.type_aux = 0;
1476 	info->fix.xpanstep = 1; /* doing it in hw */
1477 	info->fix.ypanstep = 1; /* doing it in hw */
1478 	info->fix.ywrapstep = 0;
1479 	info->fix.accel = FB_ACCEL_NONE;
1480 
1481 	info->fix.line_length = pitch;
1482 }
1483 
1484 static void drm_fb_helper_fill_var(struct fb_info *info,
1485 				   struct drm_fb_helper *fb_helper,
1486 				   uint32_t fb_width, uint32_t fb_height)
1487 {
1488 	struct drm_framebuffer *fb = fb_helper->fb;
1489 	const struct drm_format_info *format = fb->format;
1490 
1491 	switch (format->format) {
1492 	case DRM_FORMAT_C1:
1493 	case DRM_FORMAT_C2:
1494 	case DRM_FORMAT_C4:
1495 		/* supported format with sub-byte pixels */
1496 		break;
1497 
1498 	default:
1499 		WARN_ON((drm_format_info_block_width(format, 0) > 1) ||
1500 			(drm_format_info_block_height(format, 0) > 1));
1501 		break;
1502 	}
1503 
1504 	info->pseudo_palette = fb_helper->pseudo_palette;
1505 	info->var.xoffset = 0;
1506 	info->var.yoffset = 0;
1507 	__fill_var(&info->var, info, fb);
1508 	info->var.activate = FB_ACTIVATE_NOW;
1509 
1510 	drm_fb_helper_fill_pixel_fmt(&info->var, format);
1511 
1512 	info->var.xres = fb_width;
1513 	info->var.yres = fb_height;
1514 }
1515 
1516 /**
1517  * drm_fb_helper_fill_info - initializes fbdev information
1518  * @info: fbdev instance to set up
1519  * @fb_helper: fb helper instance to use as template
1520  * @sizes: describes fbdev size and scanout surface size
1521  *
1522  * Sets up the variable and fixed fbdev metainformation from the given fb helper
1523  * instance and the drm framebuffer allocated in &drm_fb_helper.fb.
1524  *
1525  * Drivers should call this (or their equivalent setup code) from their
1526  * &drm_driver.fbdev_probe callback after having allocated the fbdev
1527  * backing storage framebuffer.
1528  */
1529 void drm_fb_helper_fill_info(struct fb_info *info,
1530 			     struct drm_fb_helper *fb_helper,
1531 			     struct drm_fb_helper_surface_size *sizes)
1532 {
1533 	struct drm_framebuffer *fb = fb_helper->fb;
1534 
1535 	drm_fb_helper_fill_fix(info, fb->pitches[0],
1536 			       fb->format->is_color_indexed);
1537 	drm_fb_helper_fill_var(info, fb_helper,
1538 			       sizes->fb_width, sizes->fb_height);
1539 
1540 	info->par = fb_helper;
1541 	/*
1542 	 * The DRM drivers fbdev emulation device name can be confusing if the
1543 	 * driver name also has a "drm" suffix on it. Leading to names such as
1544 	 * "simpledrmdrmfb" in /proc/fb. Unfortunately, it's an uAPI and can't
1545 	 * be changed due user-space tools (e.g: pm-utils) matching against it.
1546 	 */
1547 	snprintf(info->fix.id, sizeof(info->fix.id), "%sdrmfb",
1548 		 fb_helper->dev->driver->name);
1549 
1550 }
1551 EXPORT_SYMBOL(drm_fb_helper_fill_info);
1552 
1553 /*
1554  * This is a continuation of drm_setup_crtcs() that sets up anything related
1555  * to the framebuffer. During initialization, drm_setup_crtcs() is called before
1556  * the framebuffer has been allocated (fb_helper->fb and fb_helper->info).
1557  * So, any setup that touches those fields needs to be done here instead of in
1558  * drm_setup_crtcs().
1559  */
1560 static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
1561 {
1562 	struct drm_client_dev *client = &fb_helper->client;
1563 	struct drm_connector_list_iter conn_iter;
1564 	struct fb_info *info = fb_helper->info;
1565 	unsigned int rotation, sw_rotations = 0;
1566 	struct drm_connector *connector;
1567 	struct drm_mode_set *modeset;
1568 
1569 	mutex_lock(&client->modeset_mutex);
1570 	drm_client_for_each_modeset(modeset, client) {
1571 		if (!modeset->num_connectors)
1572 			continue;
1573 
1574 		modeset->fb = fb_helper->fb;
1575 
1576 		if (drm_client_rotation(modeset, &rotation))
1577 			/* Rotating in hardware, fbcon should not rotate */
1578 			sw_rotations |= DRM_MODE_ROTATE_0;
1579 		else
1580 			sw_rotations |= rotation;
1581 	}
1582 	mutex_unlock(&client->modeset_mutex);
1583 
1584 	drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1585 	drm_client_for_each_connector_iter(connector, &conn_iter) {
1586 
1587 		/* use first connected connector for the physical dimensions */
1588 		if (connector->status == connector_status_connected) {
1589 			info->var.width = connector->display_info.width_mm;
1590 			info->var.height = connector->display_info.height_mm;
1591 			break;
1592 		}
1593 	}
1594 	drm_connector_list_iter_end(&conn_iter);
1595 
1596 	switch (sw_rotations) {
1597 	case DRM_MODE_ROTATE_0:
1598 		info->fbcon_rotate_hint = FB_ROTATE_UR;
1599 		break;
1600 	case DRM_MODE_ROTATE_90:
1601 		info->fbcon_rotate_hint = FB_ROTATE_CCW;
1602 		break;
1603 	case DRM_MODE_ROTATE_180:
1604 		info->fbcon_rotate_hint = FB_ROTATE_UD;
1605 		break;
1606 	case DRM_MODE_ROTATE_270:
1607 		info->fbcon_rotate_hint = FB_ROTATE_CW;
1608 		break;
1609 	default:
1610 		/*
1611 		 * Multiple bits are set / multiple rotations requested
1612 		 * fbcon cannot handle separate rotation settings per
1613 		 * output, so fallback to unrotated.
1614 		 */
1615 		info->fbcon_rotate_hint = FB_ROTATE_UR;
1616 	}
1617 }
1618 
1619 /* Note: Drops fb_helper->lock before returning. */
1620 static int
1621 __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
1622 {
1623 	struct drm_device *dev = fb_helper->dev;
1624 	struct fb_info *info;
1625 	unsigned int width, height;
1626 	int ret;
1627 
1628 	width = dev->mode_config.max_width;
1629 	height = dev->mode_config.max_height;
1630 
1631 	drm_client_modeset_probe(&fb_helper->client, width, height);
1632 
1633 	info = drm_fb_helper_alloc_info(fb_helper);
1634 	if (IS_ERR(info))
1635 		return PTR_ERR(info);
1636 
1637 	ret = drm_fb_helper_single_fb_probe(fb_helper);
1638 	if (ret < 0) {
1639 		if (ret == -EAGAIN) {
1640 			fb_helper->deferred_setup = true;
1641 			ret = 0;
1642 		}
1643 		mutex_unlock(&fb_helper->lock);
1644 
1645 		goto err_drm_fb_helper_release_info;
1646 	}
1647 	drm_setup_crtcs_fb(fb_helper);
1648 
1649 	fb_helper->deferred_setup = false;
1650 
1651 	info->var.pixclock = 0;
1652 
1653 	/* Need to drop locks to avoid recursive deadlock in
1654 	 * register_framebuffer. This is ok because the only thing left to do is
1655 	 * register the fbdev emulation instance in kernel_fb_helper_list. */
1656 	mutex_unlock(&fb_helper->lock);
1657 
1658 	ret = register_framebuffer(info);
1659 	if (ret < 0)
1660 		return ret;
1661 
1662 	drm_info(dev, "fb%d: %s frame buffer device\n",
1663 		 info->node, info->fix.id);
1664 
1665 	return 0;
1666 
1667 err_drm_fb_helper_release_info:
1668 	drm_fb_helper_release_info(fb_helper);
1669 	return ret;
1670 }
1671 
1672 /**
1673  * drm_fb_helper_initial_config - setup a sane initial connector configuration
1674  * @fb_helper: fb_helper device struct
1675  *
1676  * Scans the CRTCs and connectors and tries to put together an initial setup.
1677  * At the moment, this is a cloned configuration across all heads with
1678  * a new framebuffer object as the backing store.
1679  *
1680  * Note that this also registers the fbdev and so allows userspace to call into
1681  * the driver through the fbdev interfaces.
1682  *
1683  * This function will call down into the &drm_driver.fbdev_probe callback
1684  * to let the driver allocate and initialize the fbdev info structure and the
1685  * drm framebuffer used to back the fbdev. drm_fb_helper_fill_info() is provided
1686  * as a helper to setup simple default values for the fbdev info structure.
1687  *
1688  * HANG DEBUGGING:
1689  *
1690  * When you have fbcon support built-in or already loaded, this function will do
1691  * a full modeset to setup the fbdev console. Due to locking misdesign in the
1692  * VT/fbdev subsystem that entire modeset sequence has to be done while holding
1693  * console_lock. Until console_unlock is called no dmesg lines will be sent out
1694  * to consoles, not even serial console. This means when your driver crashes,
1695  * you will see absolutely nothing else but a system stuck in this function,
1696  * with no further output. Any kind of printk() you place within your own driver
1697  * or in the drm core modeset code will also never show up.
1698  *
1699  * Standard debug practice is to run the fbcon setup without taking the
1700  * console_lock as a hack, to be able to see backtraces and crashes on the
1701  * serial line. This can be done by setting the fb.lockless_register_fb=1 kernel
1702  * cmdline option.
1703  *
1704  * The other option is to just disable fbdev emulation since very likely the
1705  * first modeset from userspace will crash in the same way, and is even easier
1706  * to debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
1707  * kernel cmdline option.
1708  *
1709  * RETURNS:
1710  * Zero if everything went ok, nonzero otherwise.
1711  */
1712 int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper)
1713 {
1714 	int ret;
1715 
1716 	if (!drm_fbdev_emulation)
1717 		return 0;
1718 
1719 	mutex_lock(&fb_helper->lock);
1720 	ret = __drm_fb_helper_initial_config_and_unlock(fb_helper);
1721 
1722 	return ret;
1723 }
1724 EXPORT_SYMBOL(drm_fb_helper_initial_config);
1725 
1726 /**
1727  * drm_fb_helper_hotplug_event - respond to a hotplug notification by
1728  *                               probing all the outputs attached to the fb
1729  * @fb_helper: driver-allocated fbdev helper, can be NULL
1730  *
1731  * Scan the connectors attached to the fb_helper and try to put together a
1732  * setup after notification of a change in output configuration.
1733  *
1734  * Called at runtime, takes the mode config locks to be able to check/change the
1735  * modeset configuration. Must be run from process context (which usually means
1736  * either the output polling work or a work item launched from the driver's
1737  * hotplug interrupt).
1738  *
1739  * Note that drivers may call this even before calling
1740  * drm_fb_helper_initial_config but only after drm_fb_helper_init. This allows
1741  * for a race-free fbcon setup and will make sure that the fbdev emulation will
1742  * not miss any hotplug events.
1743  *
1744  * RETURNS:
1745  * 0 on success and a non-zero error code otherwise.
1746  */
1747 int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
1748 {
1749 	int err = 0;
1750 
1751 	if (!drm_fbdev_emulation || !fb_helper)
1752 		return 0;
1753 
1754 	mutex_lock(&fb_helper->lock);
1755 	if (fb_helper->deferred_setup) {
1756 		err = __drm_fb_helper_initial_config_and_unlock(fb_helper);
1757 		return err;
1758 	}
1759 
1760 	if (!fb_helper->fb || !drm_master_internal_acquire(fb_helper->dev)) {
1761 		fb_helper->delayed_hotplug = true;
1762 		mutex_unlock(&fb_helper->lock);
1763 		return err;
1764 	}
1765 
1766 	drm_master_internal_release(fb_helper->dev);
1767 
1768 	drm_dbg_kms(fb_helper->dev, "\n");
1769 
1770 	drm_client_modeset_probe(&fb_helper->client, fb_helper->fb->width, fb_helper->fb->height);
1771 	drm_setup_crtcs_fb(fb_helper);
1772 	mutex_unlock(&fb_helper->lock);
1773 
1774 	drm_fb_helper_set_par(fb_helper->info);
1775 
1776 	return 0;
1777 }
1778 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
1779