xref: /linux/drivers/gpu/drm/drm_fb_helper.c (revision b8265621f4888af9494e1d685620871ec81bc33d)
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/dma-buf.h>
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/slab.h>
37 #include <linux/sysrq.h>
38 #include <linux/vmalloc.h>
39 
40 #include <drm/drm_atomic.h>
41 #include <drm/drm_crtc.h>
42 #include <drm/drm_crtc_helper.h>
43 #include <drm/drm_drv.h>
44 #include <drm/drm_fb_helper.h>
45 #include <drm/drm_fourcc.h>
46 #include <drm/drm_print.h>
47 #include <drm/drm_vblank.h>
48 
49 #include "drm_crtc_helper_internal.h"
50 #include "drm_internal.h"
51 
52 static bool drm_fbdev_emulation = true;
53 module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600);
54 MODULE_PARM_DESC(fbdev_emulation,
55 		 "Enable legacy fbdev emulation [default=true]");
56 
57 static int drm_fbdev_overalloc = CONFIG_DRM_FBDEV_OVERALLOC;
58 module_param(drm_fbdev_overalloc, int, 0444);
59 MODULE_PARM_DESC(drm_fbdev_overalloc,
60 		 "Overallocation of the fbdev buffer (%) [default="
61 		 __MODULE_STRING(CONFIG_DRM_FBDEV_OVERALLOC) "]");
62 
63 /*
64  * In order to keep user-space compatibility, we want in certain use-cases
65  * to keep leaking the fbdev physical address to the user-space program
66  * handling the fbdev buffer.
67  * This is a bad habit essentially kept into closed source opengl driver
68  * that should really be moved into open-source upstream projects instead
69  * of using legacy physical addresses in user space to communicate with
70  * other out-of-tree kernel modules.
71  *
72  * This module_param *should* be removed as soon as possible and be
73  * considered as a broken and legacy behaviour from a modern fbdev device.
74  */
75 #if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
76 static bool drm_leak_fbdev_smem = false;
77 module_param_unsafe(drm_leak_fbdev_smem, bool, 0600);
78 MODULE_PARM_DESC(drm_leak_fbdev_smem,
79 		 "Allow unsafe leaking fbdev physical smem address [default=false]");
80 #endif
81 
82 static LIST_HEAD(kernel_fb_helper_list);
83 static DEFINE_MUTEX(kernel_fb_helper_lock);
84 
85 /**
86  * DOC: fbdev helpers
87  *
88  * The fb helper functions are useful to provide an fbdev on top of a drm kernel
89  * mode setting driver. They can be used mostly independently from the crtc
90  * helper functions used by many drivers to implement the kernel mode setting
91  * interfaces.
92  *
93  * Drivers that support a dumb buffer with a virtual address and mmap support,
94  * should try out the generic fbdev emulation using drm_fbdev_generic_setup().
95  * It will automatically set up deferred I/O if the driver requires a shadow
96  * buffer.
97  *
98  * At runtime drivers should restore the fbdev console by using
99  * drm_fb_helper_lastclose() as their &drm_driver.lastclose callback.
100  * They should also notify the fb helper code from updates to the output
101  * configuration by using drm_fb_helper_output_poll_changed() as their
102  * &drm_mode_config_funcs.output_poll_changed callback.
103  *
104  * For suspend/resume consider using drm_mode_config_helper_suspend() and
105  * drm_mode_config_helper_resume() which takes care of fbdev as well.
106  *
107  * All other functions exported by the fb helper library can be used to
108  * implement the fbdev driver interface by the driver.
109  *
110  * It is possible, though perhaps somewhat tricky, to implement race-free
111  * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
112  * helper must be called first to initialize the minimum required to make
113  * hotplug detection work. Drivers also need to make sure to properly set up
114  * the &drm_mode_config.funcs member. After calling drm_kms_helper_poll_init()
115  * it is safe to enable interrupts and start processing hotplug events. At the
116  * same time, drivers should initialize all modeset objects such as CRTCs,
117  * encoders and connectors. To finish up the fbdev helper initialization, the
118  * drm_fb_helper_init() function is called. To probe for all attached displays
119  * and set up an initial configuration using the detected hardware, drivers
120  * should call drm_fb_helper_initial_config().
121  *
122  * If &drm_framebuffer_funcs.dirty is set, the
123  * drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} functions will
124  * accumulate changes and schedule &drm_fb_helper.dirty_work to run right
125  * away. This worker then calls the dirty() function ensuring that it will
126  * always run in process context since the fb_*() function could be running in
127  * atomic context. If drm_fb_helper_deferred_io() is used as the deferred_io
128  * callback it will also schedule dirty_work with the damage collected from the
129  * mmap page writes.
130  *
131  * Deferred I/O is not compatible with SHMEM. Such drivers should request an
132  * fbdev shadow buffer and call drm_fbdev_generic_setup() instead.
133  */
134 
135 static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
136 {
137 	uint16_t *r_base, *g_base, *b_base;
138 
139 	if (crtc->funcs->gamma_set == NULL)
140 		return;
141 
142 	r_base = crtc->gamma_store;
143 	g_base = r_base + crtc->gamma_size;
144 	b_base = g_base + crtc->gamma_size;
145 
146 	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base,
147 			       crtc->gamma_size, NULL);
148 }
149 
150 /**
151  * drm_fb_helper_debug_enter - implementation for &fb_ops.fb_debug_enter
152  * @info: fbdev registered by the helper
153  */
154 int drm_fb_helper_debug_enter(struct fb_info *info)
155 {
156 	struct drm_fb_helper *helper = info->par;
157 	const struct drm_crtc_helper_funcs *funcs;
158 	struct drm_mode_set *mode_set;
159 
160 	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
161 		mutex_lock(&helper->client.modeset_mutex);
162 		drm_client_for_each_modeset(mode_set, &helper->client) {
163 			if (!mode_set->crtc->enabled)
164 				continue;
165 
166 			funcs =	mode_set->crtc->helper_private;
167 			if (funcs->mode_set_base_atomic == NULL)
168 				continue;
169 
170 			if (drm_drv_uses_atomic_modeset(mode_set->crtc->dev))
171 				continue;
172 
173 			funcs->mode_set_base_atomic(mode_set->crtc,
174 						    mode_set->fb,
175 						    mode_set->x,
176 						    mode_set->y,
177 						    ENTER_ATOMIC_MODE_SET);
178 		}
179 		mutex_unlock(&helper->client.modeset_mutex);
180 	}
181 
182 	return 0;
183 }
184 EXPORT_SYMBOL(drm_fb_helper_debug_enter);
185 
186 /**
187  * drm_fb_helper_debug_leave - implementation for &fb_ops.fb_debug_leave
188  * @info: fbdev registered by the helper
189  */
190 int drm_fb_helper_debug_leave(struct fb_info *info)
191 {
192 	struct drm_fb_helper *helper = info->par;
193 	struct drm_client_dev *client = &helper->client;
194 	struct drm_device *dev = helper->dev;
195 	struct drm_crtc *crtc;
196 	const struct drm_crtc_helper_funcs *funcs;
197 	struct drm_mode_set *mode_set;
198 	struct drm_framebuffer *fb;
199 
200 	mutex_lock(&client->modeset_mutex);
201 	drm_client_for_each_modeset(mode_set, client) {
202 		crtc = mode_set->crtc;
203 		if (drm_drv_uses_atomic_modeset(crtc->dev))
204 			continue;
205 
206 		funcs = crtc->helper_private;
207 		fb = crtc->primary->fb;
208 
209 		if (!crtc->enabled)
210 			continue;
211 
212 		if (!fb) {
213 			drm_err(dev, "no fb to restore?\n");
214 			continue;
215 		}
216 
217 		if (funcs->mode_set_base_atomic == NULL)
218 			continue;
219 
220 		drm_fb_helper_restore_lut_atomic(mode_set->crtc);
221 		funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
222 					    crtc->y, LEAVE_ATOMIC_MODE_SET);
223 	}
224 	mutex_unlock(&client->modeset_mutex);
225 
226 	return 0;
227 }
228 EXPORT_SYMBOL(drm_fb_helper_debug_leave);
229 
230 static int
231 __drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
232 					    bool force)
233 {
234 	bool do_delayed;
235 	int ret;
236 
237 	if (!drm_fbdev_emulation || !fb_helper)
238 		return -ENODEV;
239 
240 	if (READ_ONCE(fb_helper->deferred_setup))
241 		return 0;
242 
243 	mutex_lock(&fb_helper->lock);
244 	if (force) {
245 		/*
246 		 * Yes this is the _locked version which expects the master lock
247 		 * to be held. But for forced restores we're intentionally
248 		 * racing here, see drm_fb_helper_set_par().
249 		 */
250 		ret = drm_client_modeset_commit_locked(&fb_helper->client);
251 	} else {
252 		ret = drm_client_modeset_commit(&fb_helper->client);
253 	}
254 
255 	do_delayed = fb_helper->delayed_hotplug;
256 	if (do_delayed)
257 		fb_helper->delayed_hotplug = false;
258 	mutex_unlock(&fb_helper->lock);
259 
260 	if (do_delayed)
261 		drm_fb_helper_hotplug_event(fb_helper);
262 
263 	return ret;
264 }
265 
266 /**
267  * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
268  * @fb_helper: driver-allocated fbdev helper, can be NULL
269  *
270  * This should be called from driver's drm &drm_driver.lastclose callback
271  * when implementing an fbcon on top of kms using this helper. This ensures that
272  * the user isn't greeted with a black screen when e.g. X dies.
273  *
274  * RETURNS:
275  * Zero if everything went ok, negative error code otherwise.
276  */
277 int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
278 {
279 	return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, false);
280 }
281 EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
282 
283 #ifdef CONFIG_MAGIC_SYSRQ
284 /*
285  * restore fbcon display for all kms driver's using this helper, used for sysrq
286  * and panic handling.
287  */
288 static bool drm_fb_helper_force_kernel_mode(void)
289 {
290 	bool ret, error = false;
291 	struct drm_fb_helper *helper;
292 
293 	if (list_empty(&kernel_fb_helper_list))
294 		return false;
295 
296 	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
297 		struct drm_device *dev = helper->dev;
298 
299 		if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
300 			continue;
301 
302 		mutex_lock(&helper->lock);
303 		ret = drm_client_modeset_commit_locked(&helper->client);
304 		if (ret)
305 			error = true;
306 		mutex_unlock(&helper->lock);
307 	}
308 	return error;
309 }
310 
311 static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
312 {
313 	bool ret;
314 
315 	ret = drm_fb_helper_force_kernel_mode();
316 	if (ret == true)
317 		DRM_ERROR("Failed to restore crtc configuration\n");
318 }
319 static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);
320 
321 static void drm_fb_helper_sysrq(int dummy1)
322 {
323 	schedule_work(&drm_fb_helper_restore_work);
324 }
325 
326 static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {
327 	.handler = drm_fb_helper_sysrq,
328 	.help_msg = "force-fb(V)",
329 	.action_msg = "Restore framebuffer console",
330 };
331 #else
332 static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };
333 #endif
334 
335 static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
336 {
337 	struct drm_fb_helper *fb_helper = info->par;
338 
339 	mutex_lock(&fb_helper->lock);
340 	drm_client_modeset_dpms(&fb_helper->client, dpms_mode);
341 	mutex_unlock(&fb_helper->lock);
342 }
343 
344 /**
345  * drm_fb_helper_blank - implementation for &fb_ops.fb_blank
346  * @blank: desired blanking state
347  * @info: fbdev registered by the helper
348  */
349 int drm_fb_helper_blank(int blank, struct fb_info *info)
350 {
351 	if (oops_in_progress)
352 		return -EBUSY;
353 
354 	switch (blank) {
355 	/* Display: On; HSync: On, VSync: On */
356 	case FB_BLANK_UNBLANK:
357 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
358 		break;
359 	/* Display: Off; HSync: On, VSync: On */
360 	case FB_BLANK_NORMAL:
361 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
362 		break;
363 	/* Display: Off; HSync: Off, VSync: On */
364 	case FB_BLANK_HSYNC_SUSPEND:
365 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
366 		break;
367 	/* Display: Off; HSync: On, VSync: Off */
368 	case FB_BLANK_VSYNC_SUSPEND:
369 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
370 		break;
371 	/* Display: Off; HSync: Off, VSync: Off */
372 	case FB_BLANK_POWERDOWN:
373 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
374 		break;
375 	}
376 	return 0;
377 }
378 EXPORT_SYMBOL(drm_fb_helper_blank);
379 
380 static void drm_fb_helper_resume_worker(struct work_struct *work)
381 {
382 	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper,
383 						    resume_work);
384 
385 	console_lock();
386 	fb_set_suspend(helper->fbdev, 0);
387 	console_unlock();
388 }
389 
390 static void drm_fb_helper_dirty_blit_real(struct drm_fb_helper *fb_helper,
391 					  struct drm_clip_rect *clip)
392 {
393 	struct drm_framebuffer *fb = fb_helper->fb;
394 	unsigned int cpp = fb->format->cpp[0];
395 	size_t offset = clip->y1 * fb->pitches[0] + clip->x1 * cpp;
396 	void *src = fb_helper->fbdev->screen_buffer + offset;
397 	void *dst = fb_helper->buffer->vaddr + offset;
398 	size_t len = (clip->x2 - clip->x1) * cpp;
399 	unsigned int y;
400 
401 	for (y = clip->y1; y < clip->y2; y++) {
402 		memcpy(dst, src, len);
403 		src += fb->pitches[0];
404 		dst += fb->pitches[0];
405 	}
406 }
407 
408 static void drm_fb_helper_dirty_work(struct work_struct *work)
409 {
410 	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper,
411 						    dirty_work);
412 	struct drm_clip_rect *clip = &helper->dirty_clip;
413 	struct drm_clip_rect clip_copy;
414 	unsigned long flags;
415 	void *vaddr;
416 
417 	spin_lock_irqsave(&helper->dirty_lock, flags);
418 	clip_copy = *clip;
419 	clip->x1 = clip->y1 = ~0;
420 	clip->x2 = clip->y2 = 0;
421 	spin_unlock_irqrestore(&helper->dirty_lock, flags);
422 
423 	/* call dirty callback only when it has been really touched */
424 	if (clip_copy.x1 < clip_copy.x2 && clip_copy.y1 < clip_copy.y2) {
425 
426 		/* Generic fbdev uses a shadow buffer */
427 		if (helper->buffer) {
428 			vaddr = drm_client_buffer_vmap(helper->buffer);
429 			if (IS_ERR(vaddr))
430 				return;
431 			drm_fb_helper_dirty_blit_real(helper, &clip_copy);
432 		}
433 		if (helper->fb->funcs->dirty)
434 			helper->fb->funcs->dirty(helper->fb, NULL, 0, 0,
435 						 &clip_copy, 1);
436 
437 		if (helper->buffer)
438 			drm_client_buffer_vunmap(helper->buffer);
439 	}
440 }
441 
442 /**
443  * drm_fb_helper_prepare - setup a drm_fb_helper structure
444  * @dev: DRM device
445  * @helper: driver-allocated fbdev helper structure to set up
446  * @funcs: pointer to structure of functions associate with this helper
447  *
448  * Sets up the bare minimum to make the framebuffer helper usable. This is
449  * useful to implement race-free initialization of the polling helpers.
450  */
451 void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
452 			   const struct drm_fb_helper_funcs *funcs)
453 {
454 	INIT_LIST_HEAD(&helper->kernel_fb_list);
455 	spin_lock_init(&helper->dirty_lock);
456 	INIT_WORK(&helper->resume_work, drm_fb_helper_resume_worker);
457 	INIT_WORK(&helper->dirty_work, drm_fb_helper_dirty_work);
458 	helper->dirty_clip.x1 = helper->dirty_clip.y1 = ~0;
459 	mutex_init(&helper->lock);
460 	helper->funcs = funcs;
461 	helper->dev = dev;
462 }
463 EXPORT_SYMBOL(drm_fb_helper_prepare);
464 
465 /**
466  * drm_fb_helper_init - initialize a &struct drm_fb_helper
467  * @dev: drm device
468  * @fb_helper: driver-allocated fbdev helper structure to initialize
469  *
470  * This allocates the structures for the fbdev helper with the given limits.
471  * Note that this won't yet touch the hardware (through the driver interfaces)
472  * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
473  * to allow driver writes more control over the exact init sequence.
474  *
475  * Drivers must call drm_fb_helper_prepare() before calling this function.
476  *
477  * RETURNS:
478  * Zero if everything went ok, nonzero otherwise.
479  */
480 int drm_fb_helper_init(struct drm_device *dev,
481 		       struct drm_fb_helper *fb_helper)
482 {
483 	int ret;
484 
485 	if (!drm_fbdev_emulation) {
486 		dev->fb_helper = fb_helper;
487 		return 0;
488 	}
489 
490 	/*
491 	 * If this is not the generic fbdev client, initialize a drm_client
492 	 * without callbacks so we can use the modesets.
493 	 */
494 	if (!fb_helper->client.funcs) {
495 		ret = drm_client_init(dev, &fb_helper->client, "drm_fb_helper", NULL);
496 		if (ret)
497 			return ret;
498 	}
499 
500 	dev->fb_helper = fb_helper;
501 
502 	return 0;
503 }
504 EXPORT_SYMBOL(drm_fb_helper_init);
505 
506 /**
507  * drm_fb_helper_alloc_fbi - allocate fb_info and some of its members
508  * @fb_helper: driver-allocated fbdev helper
509  *
510  * A helper to alloc fb_info and the members cmap and apertures. Called
511  * by the driver within the fb_probe fb_helper callback function. Drivers do not
512  * need to release the allocated fb_info structure themselves, this is
513  * automatically done when calling drm_fb_helper_fini().
514  *
515  * RETURNS:
516  * fb_info pointer if things went okay, pointer containing error code
517  * otherwise
518  */
519 struct fb_info *drm_fb_helper_alloc_fbi(struct drm_fb_helper *fb_helper)
520 {
521 	struct device *dev = fb_helper->dev->dev;
522 	struct fb_info *info;
523 	int ret;
524 
525 	info = framebuffer_alloc(0, dev);
526 	if (!info)
527 		return ERR_PTR(-ENOMEM);
528 
529 	ret = fb_alloc_cmap(&info->cmap, 256, 0);
530 	if (ret)
531 		goto err_release;
532 
533 	/*
534 	 * TODO: We really should be smarter here and alloc an apperture
535 	 * for each IORESOURCE_MEM resource helper->dev->dev has and also
536 	 * init the ranges of the appertures based on the resources.
537 	 * Note some drivers currently count on there being only 1 empty
538 	 * aperture and fill this themselves, these will need to be dealt
539 	 * with somehow when fixing this.
540 	 */
541 	info->apertures = alloc_apertures(1);
542 	if (!info->apertures) {
543 		ret = -ENOMEM;
544 		goto err_free_cmap;
545 	}
546 
547 	fb_helper->fbdev = info;
548 	info->skip_vt_switch = true;
549 
550 	return info;
551 
552 err_free_cmap:
553 	fb_dealloc_cmap(&info->cmap);
554 err_release:
555 	framebuffer_release(info);
556 	return ERR_PTR(ret);
557 }
558 EXPORT_SYMBOL(drm_fb_helper_alloc_fbi);
559 
560 /**
561  * drm_fb_helper_unregister_fbi - unregister fb_info framebuffer device
562  * @fb_helper: driver-allocated fbdev helper, can be NULL
563  *
564  * A wrapper around unregister_framebuffer, to release the fb_info
565  * framebuffer device. This must be called before releasing all resources for
566  * @fb_helper by calling drm_fb_helper_fini().
567  */
568 void drm_fb_helper_unregister_fbi(struct drm_fb_helper *fb_helper)
569 {
570 	if (fb_helper && fb_helper->fbdev)
571 		unregister_framebuffer(fb_helper->fbdev);
572 }
573 EXPORT_SYMBOL(drm_fb_helper_unregister_fbi);
574 
575 /**
576  * drm_fb_helper_fini - finialize a &struct drm_fb_helper
577  * @fb_helper: driver-allocated fbdev helper, can be NULL
578  *
579  * This cleans up all remaining resources associated with @fb_helper.
580  */
581 void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
582 {
583 	struct fb_info *info;
584 
585 	if (!fb_helper)
586 		return;
587 
588 	fb_helper->dev->fb_helper = NULL;
589 
590 	if (!drm_fbdev_emulation)
591 		return;
592 
593 	cancel_work_sync(&fb_helper->resume_work);
594 	cancel_work_sync(&fb_helper->dirty_work);
595 
596 	info = fb_helper->fbdev;
597 	if (info) {
598 		if (info->cmap.len)
599 			fb_dealloc_cmap(&info->cmap);
600 		framebuffer_release(info);
601 	}
602 	fb_helper->fbdev = NULL;
603 
604 	mutex_lock(&kernel_fb_helper_lock);
605 	if (!list_empty(&fb_helper->kernel_fb_list)) {
606 		list_del(&fb_helper->kernel_fb_list);
607 		if (list_empty(&kernel_fb_helper_list))
608 			unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
609 	}
610 	mutex_unlock(&kernel_fb_helper_lock);
611 
612 	mutex_destroy(&fb_helper->lock);
613 
614 	if (!fb_helper->client.funcs)
615 		drm_client_release(&fb_helper->client);
616 }
617 EXPORT_SYMBOL(drm_fb_helper_fini);
618 
619 static bool drm_fbdev_use_shadow_fb(struct drm_fb_helper *fb_helper)
620 {
621 	struct drm_device *dev = fb_helper->dev;
622 	struct drm_framebuffer *fb = fb_helper->fb;
623 
624 	return dev->mode_config.prefer_shadow_fbdev ||
625 	       dev->mode_config.prefer_shadow ||
626 	       fb->funcs->dirty;
627 }
628 
629 static void drm_fb_helper_dirty(struct fb_info *info, u32 x, u32 y,
630 				u32 width, u32 height)
631 {
632 	struct drm_fb_helper *helper = info->par;
633 	struct drm_clip_rect *clip = &helper->dirty_clip;
634 	unsigned long flags;
635 
636 	if (!drm_fbdev_use_shadow_fb(helper))
637 		return;
638 
639 	spin_lock_irqsave(&helper->dirty_lock, flags);
640 	clip->x1 = min_t(u32, clip->x1, x);
641 	clip->y1 = min_t(u32, clip->y1, y);
642 	clip->x2 = max_t(u32, clip->x2, x + width);
643 	clip->y2 = max_t(u32, clip->y2, y + height);
644 	spin_unlock_irqrestore(&helper->dirty_lock, flags);
645 
646 	schedule_work(&helper->dirty_work);
647 }
648 
649 /**
650  * drm_fb_helper_deferred_io() - fbdev deferred_io callback function
651  * @info: fb_info struct pointer
652  * @pagelist: list of dirty mmap framebuffer pages
653  *
654  * This function is used as the &fb_deferred_io.deferred_io
655  * callback function for flushing the fbdev mmap writes.
656  */
657 void drm_fb_helper_deferred_io(struct fb_info *info,
658 			       struct list_head *pagelist)
659 {
660 	unsigned long start, end, min, max;
661 	struct page *page;
662 	u32 y1, y2;
663 
664 	min = ULONG_MAX;
665 	max = 0;
666 	list_for_each_entry(page, pagelist, lru) {
667 		start = page->index << PAGE_SHIFT;
668 		end = start + PAGE_SIZE - 1;
669 		min = min(min, start);
670 		max = max(max, end);
671 	}
672 
673 	if (min < max) {
674 		y1 = min / info->fix.line_length;
675 		y2 = min_t(u32, DIV_ROUND_UP(max, info->fix.line_length),
676 			   info->var.yres);
677 		drm_fb_helper_dirty(info, 0, y1, info->var.xres, y2 - y1);
678 	}
679 }
680 EXPORT_SYMBOL(drm_fb_helper_deferred_io);
681 
682 /**
683  * drm_fb_helper_sys_read - wrapper around fb_sys_read
684  * @info: fb_info struct pointer
685  * @buf: userspace buffer to read from framebuffer memory
686  * @count: number of bytes to read from framebuffer memory
687  * @ppos: read offset within framebuffer memory
688  *
689  * A wrapper around fb_sys_read implemented by fbdev core
690  */
691 ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
692 			       size_t count, loff_t *ppos)
693 {
694 	return fb_sys_read(info, buf, count, ppos);
695 }
696 EXPORT_SYMBOL(drm_fb_helper_sys_read);
697 
698 /**
699  * drm_fb_helper_sys_write - wrapper around fb_sys_write
700  * @info: fb_info struct pointer
701  * @buf: userspace buffer to write to framebuffer memory
702  * @count: number of bytes to write to framebuffer memory
703  * @ppos: write offset within framebuffer memory
704  *
705  * A wrapper around fb_sys_write implemented by fbdev core
706  */
707 ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char __user *buf,
708 				size_t count, loff_t *ppos)
709 {
710 	ssize_t ret;
711 
712 	ret = fb_sys_write(info, buf, count, ppos);
713 	if (ret > 0)
714 		drm_fb_helper_dirty(info, 0, 0, info->var.xres,
715 				    info->var.yres);
716 
717 	return ret;
718 }
719 EXPORT_SYMBOL(drm_fb_helper_sys_write);
720 
721 /**
722  * drm_fb_helper_sys_fillrect - wrapper around sys_fillrect
723  * @info: fbdev registered by the helper
724  * @rect: info about rectangle to fill
725  *
726  * A wrapper around sys_fillrect implemented by fbdev core
727  */
728 void drm_fb_helper_sys_fillrect(struct fb_info *info,
729 				const struct fb_fillrect *rect)
730 {
731 	sys_fillrect(info, rect);
732 	drm_fb_helper_dirty(info, rect->dx, rect->dy,
733 			    rect->width, rect->height);
734 }
735 EXPORT_SYMBOL(drm_fb_helper_sys_fillrect);
736 
737 /**
738  * drm_fb_helper_sys_copyarea - wrapper around sys_copyarea
739  * @info: fbdev registered by the helper
740  * @area: info about area to copy
741  *
742  * A wrapper around sys_copyarea implemented by fbdev core
743  */
744 void drm_fb_helper_sys_copyarea(struct fb_info *info,
745 				const struct fb_copyarea *area)
746 {
747 	sys_copyarea(info, area);
748 	drm_fb_helper_dirty(info, area->dx, area->dy,
749 			    area->width, area->height);
750 }
751 EXPORT_SYMBOL(drm_fb_helper_sys_copyarea);
752 
753 /**
754  * drm_fb_helper_sys_imageblit - wrapper around sys_imageblit
755  * @info: fbdev registered by the helper
756  * @image: info about image to blit
757  *
758  * A wrapper around sys_imageblit implemented by fbdev core
759  */
760 void drm_fb_helper_sys_imageblit(struct fb_info *info,
761 				 const struct fb_image *image)
762 {
763 	sys_imageblit(info, image);
764 	drm_fb_helper_dirty(info, image->dx, image->dy,
765 			    image->width, image->height);
766 }
767 EXPORT_SYMBOL(drm_fb_helper_sys_imageblit);
768 
769 /**
770  * drm_fb_helper_cfb_fillrect - wrapper around cfb_fillrect
771  * @info: fbdev registered by the helper
772  * @rect: info about rectangle to fill
773  *
774  * A wrapper around cfb_fillrect implemented by fbdev core
775  */
776 void drm_fb_helper_cfb_fillrect(struct fb_info *info,
777 				const struct fb_fillrect *rect)
778 {
779 	cfb_fillrect(info, rect);
780 	drm_fb_helper_dirty(info, rect->dx, rect->dy,
781 			    rect->width, rect->height);
782 }
783 EXPORT_SYMBOL(drm_fb_helper_cfb_fillrect);
784 
785 /**
786  * drm_fb_helper_cfb_copyarea - wrapper around cfb_copyarea
787  * @info: fbdev registered by the helper
788  * @area: info about area to copy
789  *
790  * A wrapper around cfb_copyarea implemented by fbdev core
791  */
792 void drm_fb_helper_cfb_copyarea(struct fb_info *info,
793 				const struct fb_copyarea *area)
794 {
795 	cfb_copyarea(info, area);
796 	drm_fb_helper_dirty(info, area->dx, area->dy,
797 			    area->width, area->height);
798 }
799 EXPORT_SYMBOL(drm_fb_helper_cfb_copyarea);
800 
801 /**
802  * drm_fb_helper_cfb_imageblit - wrapper around cfb_imageblit
803  * @info: fbdev registered by the helper
804  * @image: info about image to blit
805  *
806  * A wrapper around cfb_imageblit implemented by fbdev core
807  */
808 void drm_fb_helper_cfb_imageblit(struct fb_info *info,
809 				 const struct fb_image *image)
810 {
811 	cfb_imageblit(info, image);
812 	drm_fb_helper_dirty(info, image->dx, image->dy,
813 			    image->width, image->height);
814 }
815 EXPORT_SYMBOL(drm_fb_helper_cfb_imageblit);
816 
817 /**
818  * drm_fb_helper_set_suspend - wrapper around fb_set_suspend
819  * @fb_helper: driver-allocated fbdev helper, can be NULL
820  * @suspend: whether to suspend or resume
821  *
822  * A wrapper around fb_set_suspend implemented by fbdev core.
823  * Use drm_fb_helper_set_suspend_unlocked() if you don't need to take
824  * the lock yourself
825  */
826 void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, bool suspend)
827 {
828 	if (fb_helper && fb_helper->fbdev)
829 		fb_set_suspend(fb_helper->fbdev, suspend);
830 }
831 EXPORT_SYMBOL(drm_fb_helper_set_suspend);
832 
833 /**
834  * drm_fb_helper_set_suspend_unlocked - wrapper around fb_set_suspend that also
835  *                                      takes the console lock
836  * @fb_helper: driver-allocated fbdev helper, can be NULL
837  * @suspend: whether to suspend or resume
838  *
839  * A wrapper around fb_set_suspend() that takes the console lock. If the lock
840  * isn't available on resume, a worker is tasked with waiting for the lock
841  * to become available. The console lock can be pretty contented on resume
842  * due to all the printk activity.
843  *
844  * This function can be called multiple times with the same state since
845  * &fb_info.state is checked to see if fbdev is running or not before locking.
846  *
847  * Use drm_fb_helper_set_suspend() if you need to take the lock yourself.
848  */
849 void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
850 					bool suspend)
851 {
852 	if (!fb_helper || !fb_helper->fbdev)
853 		return;
854 
855 	/* make sure there's no pending/ongoing resume */
856 	flush_work(&fb_helper->resume_work);
857 
858 	if (suspend) {
859 		if (fb_helper->fbdev->state != FBINFO_STATE_RUNNING)
860 			return;
861 
862 		console_lock();
863 
864 	} else {
865 		if (fb_helper->fbdev->state == FBINFO_STATE_RUNNING)
866 			return;
867 
868 		if (!console_trylock()) {
869 			schedule_work(&fb_helper->resume_work);
870 			return;
871 		}
872 	}
873 
874 	fb_set_suspend(fb_helper->fbdev, suspend);
875 	console_unlock();
876 }
877 EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);
878 
879 static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
880 {
881 	u32 *palette = (u32 *)info->pseudo_palette;
882 	int i;
883 
884 	if (cmap->start + cmap->len > 16)
885 		return -EINVAL;
886 
887 	for (i = 0; i < cmap->len; ++i) {
888 		u16 red = cmap->red[i];
889 		u16 green = cmap->green[i];
890 		u16 blue = cmap->blue[i];
891 		u32 value;
892 
893 		red >>= 16 - info->var.red.length;
894 		green >>= 16 - info->var.green.length;
895 		blue >>= 16 - info->var.blue.length;
896 		value = (red << info->var.red.offset) |
897 			(green << info->var.green.offset) |
898 			(blue << info->var.blue.offset);
899 		if (info->var.transp.length > 0) {
900 			u32 mask = (1 << info->var.transp.length) - 1;
901 
902 			mask <<= info->var.transp.offset;
903 			value |= mask;
904 		}
905 		palette[cmap->start + i] = value;
906 	}
907 
908 	return 0;
909 }
910 
911 static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
912 {
913 	struct drm_fb_helper *fb_helper = info->par;
914 	struct drm_mode_set *modeset;
915 	struct drm_crtc *crtc;
916 	u16 *r, *g, *b;
917 	int ret = 0;
918 
919 	drm_modeset_lock_all(fb_helper->dev);
920 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
921 		crtc = modeset->crtc;
922 		if (!crtc->funcs->gamma_set || !crtc->gamma_size)
923 			return -EINVAL;
924 
925 		if (cmap->start + cmap->len > crtc->gamma_size)
926 			return -EINVAL;
927 
928 		r = crtc->gamma_store;
929 		g = r + crtc->gamma_size;
930 		b = g + crtc->gamma_size;
931 
932 		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
933 		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
934 		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
935 
936 		ret = crtc->funcs->gamma_set(crtc, r, g, b,
937 					     crtc->gamma_size, NULL);
938 		if (ret)
939 			return ret;
940 	}
941 	drm_modeset_unlock_all(fb_helper->dev);
942 
943 	return ret;
944 }
945 
946 static struct drm_property_blob *setcmap_new_gamma_lut(struct drm_crtc *crtc,
947 						       struct fb_cmap *cmap)
948 {
949 	struct drm_device *dev = crtc->dev;
950 	struct drm_property_blob *gamma_lut;
951 	struct drm_color_lut *lut;
952 	int size = crtc->gamma_size;
953 	int i;
954 
955 	if (!size || cmap->start + cmap->len > size)
956 		return ERR_PTR(-EINVAL);
957 
958 	gamma_lut = drm_property_create_blob(dev, sizeof(*lut) * size, NULL);
959 	if (IS_ERR(gamma_lut))
960 		return gamma_lut;
961 
962 	lut = gamma_lut->data;
963 	if (cmap->start || cmap->len != size) {
964 		u16 *r = crtc->gamma_store;
965 		u16 *g = r + crtc->gamma_size;
966 		u16 *b = g + crtc->gamma_size;
967 
968 		for (i = 0; i < cmap->start; i++) {
969 			lut[i].red = r[i];
970 			lut[i].green = g[i];
971 			lut[i].blue = b[i];
972 		}
973 		for (i = cmap->start + cmap->len; i < size; i++) {
974 			lut[i].red = r[i];
975 			lut[i].green = g[i];
976 			lut[i].blue = b[i];
977 		}
978 	}
979 
980 	for (i = 0; i < cmap->len; i++) {
981 		lut[cmap->start + i].red = cmap->red[i];
982 		lut[cmap->start + i].green = cmap->green[i];
983 		lut[cmap->start + i].blue = cmap->blue[i];
984 	}
985 
986 	return gamma_lut;
987 }
988 
989 static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
990 {
991 	struct drm_fb_helper *fb_helper = info->par;
992 	struct drm_device *dev = fb_helper->dev;
993 	struct drm_property_blob *gamma_lut = NULL;
994 	struct drm_modeset_acquire_ctx ctx;
995 	struct drm_crtc_state *crtc_state;
996 	struct drm_atomic_state *state;
997 	struct drm_mode_set *modeset;
998 	struct drm_crtc *crtc;
999 	u16 *r, *g, *b;
1000 	bool replaced;
1001 	int ret = 0;
1002 
1003 	drm_modeset_acquire_init(&ctx, 0);
1004 
1005 	state = drm_atomic_state_alloc(dev);
1006 	if (!state) {
1007 		ret = -ENOMEM;
1008 		goto out_ctx;
1009 	}
1010 
1011 	state->acquire_ctx = &ctx;
1012 retry:
1013 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
1014 		crtc = modeset->crtc;
1015 
1016 		if (!gamma_lut)
1017 			gamma_lut = setcmap_new_gamma_lut(crtc, cmap);
1018 		if (IS_ERR(gamma_lut)) {
1019 			ret = PTR_ERR(gamma_lut);
1020 			gamma_lut = NULL;
1021 			goto out_state;
1022 		}
1023 
1024 		crtc_state = drm_atomic_get_crtc_state(state, crtc);
1025 		if (IS_ERR(crtc_state)) {
1026 			ret = PTR_ERR(crtc_state);
1027 			goto out_state;
1028 		}
1029 
1030 		replaced  = drm_property_replace_blob(&crtc_state->degamma_lut,
1031 						      NULL);
1032 		replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
1033 		replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
1034 						      gamma_lut);
1035 		crtc_state->color_mgmt_changed |= replaced;
1036 	}
1037 
1038 	ret = drm_atomic_commit(state);
1039 	if (ret)
1040 		goto out_state;
1041 
1042 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
1043 		crtc = modeset->crtc;
1044 
1045 		r = crtc->gamma_store;
1046 		g = r + crtc->gamma_size;
1047 		b = g + crtc->gamma_size;
1048 
1049 		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
1050 		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
1051 		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
1052 	}
1053 
1054 out_state:
1055 	if (ret == -EDEADLK)
1056 		goto backoff;
1057 
1058 	drm_property_blob_put(gamma_lut);
1059 	drm_atomic_state_put(state);
1060 out_ctx:
1061 	drm_modeset_drop_locks(&ctx);
1062 	drm_modeset_acquire_fini(&ctx);
1063 
1064 	return ret;
1065 
1066 backoff:
1067 	drm_atomic_state_clear(state);
1068 	drm_modeset_backoff(&ctx);
1069 	goto retry;
1070 }
1071 
1072 /**
1073  * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
1074  * @cmap: cmap to set
1075  * @info: fbdev registered by the helper
1076  */
1077 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
1078 {
1079 	struct drm_fb_helper *fb_helper = info->par;
1080 	struct drm_device *dev = fb_helper->dev;
1081 	int ret;
1082 
1083 	if (oops_in_progress)
1084 		return -EBUSY;
1085 
1086 	mutex_lock(&fb_helper->lock);
1087 
1088 	if (!drm_master_internal_acquire(dev)) {
1089 		ret = -EBUSY;
1090 		goto unlock;
1091 	}
1092 
1093 	mutex_lock(&fb_helper->client.modeset_mutex);
1094 	if (info->fix.visual == FB_VISUAL_TRUECOLOR)
1095 		ret = setcmap_pseudo_palette(cmap, info);
1096 	else if (drm_drv_uses_atomic_modeset(fb_helper->dev))
1097 		ret = setcmap_atomic(cmap, info);
1098 	else
1099 		ret = setcmap_legacy(cmap, info);
1100 	mutex_unlock(&fb_helper->client.modeset_mutex);
1101 
1102 	drm_master_internal_release(dev);
1103 unlock:
1104 	mutex_unlock(&fb_helper->lock);
1105 
1106 	return ret;
1107 }
1108 EXPORT_SYMBOL(drm_fb_helper_setcmap);
1109 
1110 /**
1111  * drm_fb_helper_ioctl - legacy ioctl implementation
1112  * @info: fbdev registered by the helper
1113  * @cmd: ioctl command
1114  * @arg: ioctl argument
1115  *
1116  * A helper to implement the standard fbdev ioctl. Only
1117  * FBIO_WAITFORVSYNC is implemented for now.
1118  */
1119 int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
1120 			unsigned long arg)
1121 {
1122 	struct drm_fb_helper *fb_helper = info->par;
1123 	struct drm_device *dev = fb_helper->dev;
1124 	struct drm_crtc *crtc;
1125 	int ret = 0;
1126 
1127 	mutex_lock(&fb_helper->lock);
1128 	if (!drm_master_internal_acquire(dev)) {
1129 		ret = -EBUSY;
1130 		goto unlock;
1131 	}
1132 
1133 	switch (cmd) {
1134 	case FBIO_WAITFORVSYNC:
1135 		/*
1136 		 * Only consider the first CRTC.
1137 		 *
1138 		 * This ioctl is supposed to take the CRTC number as
1139 		 * an argument, but in fbdev times, what that number
1140 		 * was supposed to be was quite unclear, different
1141 		 * drivers were passing that argument differently
1142 		 * (some by reference, some by value), and most of the
1143 		 * userspace applications were just hardcoding 0 as an
1144 		 * argument.
1145 		 *
1146 		 * The first CRTC should be the integrated panel on
1147 		 * most drivers, so this is the best choice we can
1148 		 * make. If we're not smart enough here, one should
1149 		 * just consider switch the userspace to KMS.
1150 		 */
1151 		crtc = fb_helper->client.modesets[0].crtc;
1152 
1153 		/*
1154 		 * Only wait for a vblank event if the CRTC is
1155 		 * enabled, otherwise just don't do anythintg,
1156 		 * not even report an error.
1157 		 */
1158 		ret = drm_crtc_vblank_get(crtc);
1159 		if (!ret) {
1160 			drm_crtc_wait_one_vblank(crtc);
1161 			drm_crtc_vblank_put(crtc);
1162 		}
1163 
1164 		ret = 0;
1165 		break;
1166 	default:
1167 		ret = -ENOTTY;
1168 	}
1169 
1170 	drm_master_internal_release(dev);
1171 unlock:
1172 	mutex_unlock(&fb_helper->lock);
1173 	return ret;
1174 }
1175 EXPORT_SYMBOL(drm_fb_helper_ioctl);
1176 
1177 static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
1178 				      const struct fb_var_screeninfo *var_2)
1179 {
1180 	return var_1->bits_per_pixel == var_2->bits_per_pixel &&
1181 	       var_1->grayscale == var_2->grayscale &&
1182 	       var_1->red.offset == var_2->red.offset &&
1183 	       var_1->red.length == var_2->red.length &&
1184 	       var_1->red.msb_right == var_2->red.msb_right &&
1185 	       var_1->green.offset == var_2->green.offset &&
1186 	       var_1->green.length == var_2->green.length &&
1187 	       var_1->green.msb_right == var_2->green.msb_right &&
1188 	       var_1->blue.offset == var_2->blue.offset &&
1189 	       var_1->blue.length == var_2->blue.length &&
1190 	       var_1->blue.msb_right == var_2->blue.msb_right &&
1191 	       var_1->transp.offset == var_2->transp.offset &&
1192 	       var_1->transp.length == var_2->transp.length &&
1193 	       var_1->transp.msb_right == var_2->transp.msb_right;
1194 }
1195 
1196 static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
1197 					 u8 depth)
1198 {
1199 	switch (depth) {
1200 	case 8:
1201 		var->red.offset = 0;
1202 		var->green.offset = 0;
1203 		var->blue.offset = 0;
1204 		var->red.length = 8; /* 8bit DAC */
1205 		var->green.length = 8;
1206 		var->blue.length = 8;
1207 		var->transp.offset = 0;
1208 		var->transp.length = 0;
1209 		break;
1210 	case 15:
1211 		var->red.offset = 10;
1212 		var->green.offset = 5;
1213 		var->blue.offset = 0;
1214 		var->red.length = 5;
1215 		var->green.length = 5;
1216 		var->blue.length = 5;
1217 		var->transp.offset = 15;
1218 		var->transp.length = 1;
1219 		break;
1220 	case 16:
1221 		var->red.offset = 11;
1222 		var->green.offset = 5;
1223 		var->blue.offset = 0;
1224 		var->red.length = 5;
1225 		var->green.length = 6;
1226 		var->blue.length = 5;
1227 		var->transp.offset = 0;
1228 		break;
1229 	case 24:
1230 		var->red.offset = 16;
1231 		var->green.offset = 8;
1232 		var->blue.offset = 0;
1233 		var->red.length = 8;
1234 		var->green.length = 8;
1235 		var->blue.length = 8;
1236 		var->transp.offset = 0;
1237 		var->transp.length = 0;
1238 		break;
1239 	case 32:
1240 		var->red.offset = 16;
1241 		var->green.offset = 8;
1242 		var->blue.offset = 0;
1243 		var->red.length = 8;
1244 		var->green.length = 8;
1245 		var->blue.length = 8;
1246 		var->transp.offset = 24;
1247 		var->transp.length = 8;
1248 		break;
1249 	default:
1250 		break;
1251 	}
1252 }
1253 
1254 /**
1255  * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
1256  * @var: screeninfo to check
1257  * @info: fbdev registered by the helper
1258  */
1259 int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
1260 			    struct fb_info *info)
1261 {
1262 	struct drm_fb_helper *fb_helper = info->par;
1263 	struct drm_framebuffer *fb = fb_helper->fb;
1264 	struct drm_device *dev = fb_helper->dev;
1265 
1266 	if (in_dbg_master())
1267 		return -EINVAL;
1268 
1269 	if (var->pixclock != 0) {
1270 		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel clock, value of pixclock is ignored\n");
1271 		var->pixclock = 0;
1272 	}
1273 
1274 	if ((drm_format_info_block_width(fb->format, 0) > 1) ||
1275 	    (drm_format_info_block_height(fb->format, 0) > 1))
1276 		return -EINVAL;
1277 
1278 	/*
1279 	 * Changes struct fb_var_screeninfo are currently not pushed back
1280 	 * to KMS, hence fail if different settings are requested.
1281 	 */
1282 	if (var->bits_per_pixel > fb->format->cpp[0] * 8 ||
1283 	    var->xres > fb->width || var->yres > fb->height ||
1284 	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
1285 		drm_dbg_kms(dev, "fb requested width/height/bpp can't fit in current fb "
1286 			  "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
1287 			  var->xres, var->yres, var->bits_per_pixel,
1288 			  var->xres_virtual, var->yres_virtual,
1289 			  fb->width, fb->height, fb->format->cpp[0] * 8);
1290 		return -EINVAL;
1291 	}
1292 
1293 	/*
1294 	 * Workaround for SDL 1.2, which is known to be setting all pixel format
1295 	 * fields values to zero in some cases. We treat this situation as a
1296 	 * kind of "use some reasonable autodetected values".
1297 	 */
1298 	if (!var->red.offset     && !var->green.offset    &&
1299 	    !var->blue.offset    && !var->transp.offset   &&
1300 	    !var->red.length     && !var->green.length    &&
1301 	    !var->blue.length    && !var->transp.length   &&
1302 	    !var->red.msb_right  && !var->green.msb_right &&
1303 	    !var->blue.msb_right && !var->transp.msb_right) {
1304 		drm_fb_helper_fill_pixel_fmt(var, fb->format->depth);
1305 	}
1306 
1307 	/*
1308 	 * Likewise, bits_per_pixel should be rounded up to a supported value.
1309 	 */
1310 	var->bits_per_pixel = fb->format->cpp[0] * 8;
1311 
1312 	/*
1313 	 * drm fbdev emulation doesn't support changing the pixel format at all,
1314 	 * so reject all pixel format changing requests.
1315 	 */
1316 	if (!drm_fb_pixel_format_equal(var, &info->var)) {
1317 		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel format\n");
1318 		return -EINVAL;
1319 	}
1320 
1321 	return 0;
1322 }
1323 EXPORT_SYMBOL(drm_fb_helper_check_var);
1324 
1325 /**
1326  * drm_fb_helper_set_par - implementation for &fb_ops.fb_set_par
1327  * @info: fbdev registered by the helper
1328  *
1329  * This will let fbcon do the mode init and is called at initialization time by
1330  * the fbdev core when registering the driver, and later on through the hotplug
1331  * callback.
1332  */
1333 int drm_fb_helper_set_par(struct fb_info *info)
1334 {
1335 	struct drm_fb_helper *fb_helper = info->par;
1336 	struct fb_var_screeninfo *var = &info->var;
1337 	bool force;
1338 
1339 	if (oops_in_progress)
1340 		return -EBUSY;
1341 
1342 	if (var->pixclock != 0) {
1343 		drm_err(fb_helper->dev, "PIXEL CLOCK SET\n");
1344 		return -EINVAL;
1345 	}
1346 
1347 	/*
1348 	 * Normally we want to make sure that a kms master takes precedence over
1349 	 * fbdev, to avoid fbdev flickering and occasionally stealing the
1350 	 * display status. But Xorg first sets the vt back to text mode using
1351 	 * the KDSET IOCTL with KD_TEXT, and only after that drops the master
1352 	 * status when exiting.
1353 	 *
1354 	 * In the past this was caught by drm_fb_helper_lastclose(), but on
1355 	 * modern systems where logind always keeps a drm fd open to orchestrate
1356 	 * the vt switching, this doesn't work.
1357 	 *
1358 	 * To not break the userspace ABI we have this special case here, which
1359 	 * is only used for the above case. Everything else uses the normal
1360 	 * commit function, which ensures that we never steal the display from
1361 	 * an active drm master.
1362 	 */
1363 	force = var->activate & FB_ACTIVATE_KD_TEXT;
1364 
1365 	__drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
1366 
1367 	return 0;
1368 }
1369 EXPORT_SYMBOL(drm_fb_helper_set_par);
1370 
1371 static void pan_set(struct drm_fb_helper *fb_helper, int x, int y)
1372 {
1373 	struct drm_mode_set *mode_set;
1374 
1375 	mutex_lock(&fb_helper->client.modeset_mutex);
1376 	drm_client_for_each_modeset(mode_set, &fb_helper->client) {
1377 		mode_set->x = x;
1378 		mode_set->y = y;
1379 	}
1380 	mutex_unlock(&fb_helper->client.modeset_mutex);
1381 }
1382 
1383 static int pan_display_atomic(struct fb_var_screeninfo *var,
1384 			      struct fb_info *info)
1385 {
1386 	struct drm_fb_helper *fb_helper = info->par;
1387 	int ret;
1388 
1389 	pan_set(fb_helper, var->xoffset, var->yoffset);
1390 
1391 	ret = drm_client_modeset_commit_locked(&fb_helper->client);
1392 	if (!ret) {
1393 		info->var.xoffset = var->xoffset;
1394 		info->var.yoffset = var->yoffset;
1395 	} else
1396 		pan_set(fb_helper, info->var.xoffset, info->var.yoffset);
1397 
1398 	return ret;
1399 }
1400 
1401 static int pan_display_legacy(struct fb_var_screeninfo *var,
1402 			      struct fb_info *info)
1403 {
1404 	struct drm_fb_helper *fb_helper = info->par;
1405 	struct drm_client_dev *client = &fb_helper->client;
1406 	struct drm_mode_set *modeset;
1407 	int ret = 0;
1408 
1409 	mutex_lock(&client->modeset_mutex);
1410 	drm_modeset_lock_all(fb_helper->dev);
1411 	drm_client_for_each_modeset(modeset, client) {
1412 		modeset->x = var->xoffset;
1413 		modeset->y = var->yoffset;
1414 
1415 		if (modeset->num_connectors) {
1416 			ret = drm_mode_set_config_internal(modeset);
1417 			if (!ret) {
1418 				info->var.xoffset = var->xoffset;
1419 				info->var.yoffset = var->yoffset;
1420 			}
1421 		}
1422 	}
1423 	drm_modeset_unlock_all(fb_helper->dev);
1424 	mutex_unlock(&client->modeset_mutex);
1425 
1426 	return ret;
1427 }
1428 
1429 /**
1430  * drm_fb_helper_pan_display - implementation for &fb_ops.fb_pan_display
1431  * @var: updated screen information
1432  * @info: fbdev registered by the helper
1433  */
1434 int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
1435 			      struct fb_info *info)
1436 {
1437 	struct drm_fb_helper *fb_helper = info->par;
1438 	struct drm_device *dev = fb_helper->dev;
1439 	int ret;
1440 
1441 	if (oops_in_progress)
1442 		return -EBUSY;
1443 
1444 	mutex_lock(&fb_helper->lock);
1445 	if (!drm_master_internal_acquire(dev)) {
1446 		ret = -EBUSY;
1447 		goto unlock;
1448 	}
1449 
1450 	if (drm_drv_uses_atomic_modeset(dev))
1451 		ret = pan_display_atomic(var, info);
1452 	else
1453 		ret = pan_display_legacy(var, info);
1454 
1455 	drm_master_internal_release(dev);
1456 unlock:
1457 	mutex_unlock(&fb_helper->lock);
1458 
1459 	return ret;
1460 }
1461 EXPORT_SYMBOL(drm_fb_helper_pan_display);
1462 
1463 /*
1464  * Allocates the backing storage and sets up the fbdev info structure through
1465  * the ->fb_probe callback.
1466  */
1467 static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
1468 					 int preferred_bpp)
1469 {
1470 	struct drm_client_dev *client = &fb_helper->client;
1471 	struct drm_device *dev = fb_helper->dev;
1472 	int ret = 0;
1473 	int crtc_count = 0;
1474 	struct drm_connector_list_iter conn_iter;
1475 	struct drm_fb_helper_surface_size sizes;
1476 	struct drm_connector *connector;
1477 	struct drm_mode_set *mode_set;
1478 	int best_depth = 0;
1479 
1480 	memset(&sizes, 0, sizeof(struct drm_fb_helper_surface_size));
1481 	sizes.surface_depth = 24;
1482 	sizes.surface_bpp = 32;
1483 	sizes.fb_width = (u32)-1;
1484 	sizes.fb_height = (u32)-1;
1485 
1486 	/*
1487 	 * If driver picks 8 or 16 by default use that for both depth/bpp
1488 	 * to begin with
1489 	 */
1490 	if (preferred_bpp != sizes.surface_bpp)
1491 		sizes.surface_depth = sizes.surface_bpp = preferred_bpp;
1492 
1493 	drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1494 	drm_client_for_each_connector_iter(connector, &conn_iter) {
1495 		struct drm_cmdline_mode *cmdline_mode;
1496 
1497 		cmdline_mode = &connector->cmdline_mode;
1498 
1499 		if (cmdline_mode->bpp_specified) {
1500 			switch (cmdline_mode->bpp) {
1501 			case 8:
1502 				sizes.surface_depth = sizes.surface_bpp = 8;
1503 				break;
1504 			case 15:
1505 				sizes.surface_depth = 15;
1506 				sizes.surface_bpp = 16;
1507 				break;
1508 			case 16:
1509 				sizes.surface_depth = sizes.surface_bpp = 16;
1510 				break;
1511 			case 24:
1512 				sizes.surface_depth = sizes.surface_bpp = 24;
1513 				break;
1514 			case 32:
1515 				sizes.surface_depth = 24;
1516 				sizes.surface_bpp = 32;
1517 				break;
1518 			}
1519 			break;
1520 		}
1521 	}
1522 	drm_connector_list_iter_end(&conn_iter);
1523 
1524 	/*
1525 	 * If we run into a situation where, for example, the primary plane
1526 	 * supports RGBA5551 (16 bpp, depth 15) but not RGB565 (16 bpp, depth
1527 	 * 16) we need to scale down the depth of the sizes we request.
1528 	 */
1529 	mutex_lock(&client->modeset_mutex);
1530 	drm_client_for_each_modeset(mode_set, client) {
1531 		struct drm_crtc *crtc = mode_set->crtc;
1532 		struct drm_plane *plane = crtc->primary;
1533 		int j;
1534 
1535 		drm_dbg_kms(dev, "test CRTC %u primary plane\n", drm_crtc_index(crtc));
1536 
1537 		for (j = 0; j < plane->format_count; j++) {
1538 			const struct drm_format_info *fmt;
1539 
1540 			fmt = drm_format_info(plane->format_types[j]);
1541 
1542 			/*
1543 			 * Do not consider YUV or other complicated formats
1544 			 * for framebuffers. This means only legacy formats
1545 			 * are supported (fmt->depth is a legacy field) but
1546 			 * the framebuffer emulation can only deal with such
1547 			 * formats, specifically RGB/BGA formats.
1548 			 */
1549 			if (fmt->depth == 0)
1550 				continue;
1551 
1552 			/* We found a perfect fit, great */
1553 			if (fmt->depth == sizes.surface_depth) {
1554 				best_depth = fmt->depth;
1555 				break;
1556 			}
1557 
1558 			/* Skip depths above what we're looking for */
1559 			if (fmt->depth > sizes.surface_depth)
1560 				continue;
1561 
1562 			/* Best depth found so far */
1563 			if (fmt->depth > best_depth)
1564 				best_depth = fmt->depth;
1565 		}
1566 	}
1567 	if (sizes.surface_depth != best_depth && best_depth) {
1568 		drm_info(dev, "requested bpp %d, scaled depth down to %d",
1569 			 sizes.surface_bpp, best_depth);
1570 		sizes.surface_depth = best_depth;
1571 	}
1572 
1573 	/* first up get a count of crtcs now in use and new min/maxes width/heights */
1574 	crtc_count = 0;
1575 	drm_client_for_each_modeset(mode_set, client) {
1576 		struct drm_display_mode *desired_mode;
1577 		int x, y, j;
1578 		/* in case of tile group, are we the last tile vert or horiz?
1579 		 * If no tile group you are always the last one both vertically
1580 		 * and horizontally
1581 		 */
1582 		bool lastv = true, lasth = true;
1583 
1584 		desired_mode = mode_set->mode;
1585 
1586 		if (!desired_mode)
1587 			continue;
1588 
1589 		crtc_count++;
1590 
1591 		x = mode_set->x;
1592 		y = mode_set->y;
1593 
1594 		sizes.surface_width  = max_t(u32, desired_mode->hdisplay + x, sizes.surface_width);
1595 		sizes.surface_height = max_t(u32, desired_mode->vdisplay + y, sizes.surface_height);
1596 
1597 		for (j = 0; j < mode_set->num_connectors; j++) {
1598 			struct drm_connector *connector = mode_set->connectors[j];
1599 
1600 			if (connector->has_tile &&
1601 			    desired_mode->hdisplay == connector->tile_h_size &&
1602 			    desired_mode->vdisplay == connector->tile_v_size) {
1603 				lasth = (connector->tile_h_loc == (connector->num_h_tile - 1));
1604 				lastv = (connector->tile_v_loc == (connector->num_v_tile - 1));
1605 				/* cloning to multiple tiles is just crazy-talk, so: */
1606 				break;
1607 			}
1608 		}
1609 
1610 		if (lasth)
1611 			sizes.fb_width  = min_t(u32, desired_mode->hdisplay + x, sizes.fb_width);
1612 		if (lastv)
1613 			sizes.fb_height = min_t(u32, desired_mode->vdisplay + y, sizes.fb_height);
1614 	}
1615 	mutex_unlock(&client->modeset_mutex);
1616 
1617 	if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
1618 		drm_info(dev, "Cannot find any crtc or sizes\n");
1619 
1620 		/* First time: disable all crtc's.. */
1621 		if (!fb_helper->deferred_setup)
1622 			drm_client_modeset_commit(client);
1623 		return -EAGAIN;
1624 	}
1625 
1626 	/* Handle our overallocation */
1627 	sizes.surface_height *= drm_fbdev_overalloc;
1628 	sizes.surface_height /= 100;
1629 
1630 	/* push down into drivers */
1631 	ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
1632 	if (ret < 0)
1633 		return ret;
1634 
1635 	strcpy(fb_helper->fb->comm, "[fbcon]");
1636 	return 0;
1637 }
1638 
1639 static void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
1640 				   uint32_t depth)
1641 {
1642 	info->fix.type = FB_TYPE_PACKED_PIXELS;
1643 	info->fix.visual = depth == 8 ? FB_VISUAL_PSEUDOCOLOR :
1644 		FB_VISUAL_TRUECOLOR;
1645 	info->fix.mmio_start = 0;
1646 	info->fix.mmio_len = 0;
1647 	info->fix.type_aux = 0;
1648 	info->fix.xpanstep = 1; /* doing it in hw */
1649 	info->fix.ypanstep = 1; /* doing it in hw */
1650 	info->fix.ywrapstep = 0;
1651 	info->fix.accel = FB_ACCEL_NONE;
1652 
1653 	info->fix.line_length = pitch;
1654 }
1655 
1656 static void drm_fb_helper_fill_var(struct fb_info *info,
1657 				   struct drm_fb_helper *fb_helper,
1658 				   uint32_t fb_width, uint32_t fb_height)
1659 {
1660 	struct drm_framebuffer *fb = fb_helper->fb;
1661 
1662 	WARN_ON((drm_format_info_block_width(fb->format, 0) > 1) ||
1663 		(drm_format_info_block_height(fb->format, 0) > 1));
1664 	info->pseudo_palette = fb_helper->pseudo_palette;
1665 	info->var.xres_virtual = fb->width;
1666 	info->var.yres_virtual = fb->height;
1667 	info->var.bits_per_pixel = fb->format->cpp[0] * 8;
1668 	info->var.accel_flags = FB_ACCELF_TEXT;
1669 	info->var.xoffset = 0;
1670 	info->var.yoffset = 0;
1671 	info->var.activate = FB_ACTIVATE_NOW;
1672 
1673 	drm_fb_helper_fill_pixel_fmt(&info->var, fb->format->depth);
1674 
1675 	info->var.xres = fb_width;
1676 	info->var.yres = fb_height;
1677 }
1678 
1679 /**
1680  * drm_fb_helper_fill_info - initializes fbdev information
1681  * @info: fbdev instance to set up
1682  * @fb_helper: fb helper instance to use as template
1683  * @sizes: describes fbdev size and scanout surface size
1684  *
1685  * Sets up the variable and fixed fbdev metainformation from the given fb helper
1686  * instance and the drm framebuffer allocated in &drm_fb_helper.fb.
1687  *
1688  * Drivers should call this (or their equivalent setup code) from their
1689  * &drm_fb_helper_funcs.fb_probe callback after having allocated the fbdev
1690  * backing storage framebuffer.
1691  */
1692 void drm_fb_helper_fill_info(struct fb_info *info,
1693 			     struct drm_fb_helper *fb_helper,
1694 			     struct drm_fb_helper_surface_size *sizes)
1695 {
1696 	struct drm_framebuffer *fb = fb_helper->fb;
1697 
1698 	drm_fb_helper_fill_fix(info, fb->pitches[0], fb->format->depth);
1699 	drm_fb_helper_fill_var(info, fb_helper,
1700 			       sizes->fb_width, sizes->fb_height);
1701 
1702 	info->par = fb_helper;
1703 	snprintf(info->fix.id, sizeof(info->fix.id), "%sdrmfb",
1704 		 fb_helper->dev->driver->name);
1705 
1706 }
1707 EXPORT_SYMBOL(drm_fb_helper_fill_info);
1708 
1709 /*
1710  * This is a continuation of drm_setup_crtcs() that sets up anything related
1711  * to the framebuffer. During initialization, drm_setup_crtcs() is called before
1712  * the framebuffer has been allocated (fb_helper->fb and fb_helper->fbdev).
1713  * So, any setup that touches those fields needs to be done here instead of in
1714  * drm_setup_crtcs().
1715  */
1716 static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
1717 {
1718 	struct drm_client_dev *client = &fb_helper->client;
1719 	struct drm_connector_list_iter conn_iter;
1720 	struct fb_info *info = fb_helper->fbdev;
1721 	unsigned int rotation, sw_rotations = 0;
1722 	struct drm_connector *connector;
1723 	struct drm_mode_set *modeset;
1724 
1725 	mutex_lock(&client->modeset_mutex);
1726 	drm_client_for_each_modeset(modeset, client) {
1727 		if (!modeset->num_connectors)
1728 			continue;
1729 
1730 		modeset->fb = fb_helper->fb;
1731 
1732 		if (drm_client_rotation(modeset, &rotation))
1733 			/* Rotating in hardware, fbcon should not rotate */
1734 			sw_rotations |= DRM_MODE_ROTATE_0;
1735 		else
1736 			sw_rotations |= rotation;
1737 	}
1738 	mutex_unlock(&client->modeset_mutex);
1739 
1740 	drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1741 	drm_client_for_each_connector_iter(connector, &conn_iter) {
1742 
1743 		/* use first connected connector for the physical dimensions */
1744 		if (connector->status == connector_status_connected) {
1745 			info->var.width = connector->display_info.width_mm;
1746 			info->var.height = connector->display_info.height_mm;
1747 			break;
1748 		}
1749 	}
1750 	drm_connector_list_iter_end(&conn_iter);
1751 
1752 	switch (sw_rotations) {
1753 	case DRM_MODE_ROTATE_0:
1754 		info->fbcon_rotate_hint = FB_ROTATE_UR;
1755 		break;
1756 	case DRM_MODE_ROTATE_90:
1757 		info->fbcon_rotate_hint = FB_ROTATE_CCW;
1758 		break;
1759 	case DRM_MODE_ROTATE_180:
1760 		info->fbcon_rotate_hint = FB_ROTATE_UD;
1761 		break;
1762 	case DRM_MODE_ROTATE_270:
1763 		info->fbcon_rotate_hint = FB_ROTATE_CW;
1764 		break;
1765 	default:
1766 		/*
1767 		 * Multiple bits are set / multiple rotations requested
1768 		 * fbcon cannot handle separate rotation settings per
1769 		 * output, so fallback to unrotated.
1770 		 */
1771 		info->fbcon_rotate_hint = FB_ROTATE_UR;
1772 	}
1773 }
1774 
1775 /* Note: Drops fb_helper->lock before returning. */
1776 static int
1777 __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper,
1778 					  int bpp_sel)
1779 {
1780 	struct drm_device *dev = fb_helper->dev;
1781 	struct fb_info *info;
1782 	unsigned int width, height;
1783 	int ret;
1784 
1785 	width = dev->mode_config.max_width;
1786 	height = dev->mode_config.max_height;
1787 
1788 	drm_client_modeset_probe(&fb_helper->client, width, height);
1789 	ret = drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
1790 	if (ret < 0) {
1791 		if (ret == -EAGAIN) {
1792 			fb_helper->preferred_bpp = bpp_sel;
1793 			fb_helper->deferred_setup = true;
1794 			ret = 0;
1795 		}
1796 		mutex_unlock(&fb_helper->lock);
1797 
1798 		return ret;
1799 	}
1800 	drm_setup_crtcs_fb(fb_helper);
1801 
1802 	fb_helper->deferred_setup = false;
1803 
1804 	info = fb_helper->fbdev;
1805 	info->var.pixclock = 0;
1806 	/* Shamelessly allow physical address leaking to userspace */
1807 #if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
1808 	if (!drm_leak_fbdev_smem)
1809 #endif
1810 		/* don't leak any physical addresses to userspace */
1811 		info->flags |= FBINFO_HIDE_SMEM_START;
1812 
1813 	/* Need to drop locks to avoid recursive deadlock in
1814 	 * register_framebuffer. This is ok because the only thing left to do is
1815 	 * register the fbdev emulation instance in kernel_fb_helper_list. */
1816 	mutex_unlock(&fb_helper->lock);
1817 
1818 	ret = register_framebuffer(info);
1819 	if (ret < 0)
1820 		return ret;
1821 
1822 	dev_info(dev->dev, "fb%d: %s frame buffer device\n",
1823 		 info->node, info->fix.id);
1824 
1825 	mutex_lock(&kernel_fb_helper_lock);
1826 	if (list_empty(&kernel_fb_helper_list))
1827 		register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
1828 
1829 	list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
1830 	mutex_unlock(&kernel_fb_helper_lock);
1831 
1832 	return 0;
1833 }
1834 
1835 /**
1836  * drm_fb_helper_initial_config - setup a sane initial connector configuration
1837  * @fb_helper: fb_helper device struct
1838  * @bpp_sel: bpp value to use for the framebuffer configuration
1839  *
1840  * Scans the CRTCs and connectors and tries to put together an initial setup.
1841  * At the moment, this is a cloned configuration across all heads with
1842  * a new framebuffer object as the backing store.
1843  *
1844  * Note that this also registers the fbdev and so allows userspace to call into
1845  * the driver through the fbdev interfaces.
1846  *
1847  * This function will call down into the &drm_fb_helper_funcs.fb_probe callback
1848  * to let the driver allocate and initialize the fbdev info structure and the
1849  * drm framebuffer used to back the fbdev. drm_fb_helper_fill_info() is provided
1850  * as a helper to setup simple default values for the fbdev info structure.
1851  *
1852  * HANG DEBUGGING:
1853  *
1854  * When you have fbcon support built-in or already loaded, this function will do
1855  * a full modeset to setup the fbdev console. Due to locking misdesign in the
1856  * VT/fbdev subsystem that entire modeset sequence has to be done while holding
1857  * console_lock. Until console_unlock is called no dmesg lines will be sent out
1858  * to consoles, not even serial console. This means when your driver crashes,
1859  * you will see absolutely nothing else but a system stuck in this function,
1860  * with no further output. Any kind of printk() you place within your own driver
1861  * or in the drm core modeset code will also never show up.
1862  *
1863  * Standard debug practice is to run the fbcon setup without taking the
1864  * console_lock as a hack, to be able to see backtraces and crashes on the
1865  * serial line. This can be done by setting the fb.lockless_register_fb=1 kernel
1866  * cmdline option.
1867  *
1868  * The other option is to just disable fbdev emulation since very likely the
1869  * first modeset from userspace will crash in the same way, and is even easier
1870  * to debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
1871  * kernel cmdline option.
1872  *
1873  * RETURNS:
1874  * Zero if everything went ok, nonzero otherwise.
1875  */
1876 int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
1877 {
1878 	int ret;
1879 
1880 	if (!drm_fbdev_emulation)
1881 		return 0;
1882 
1883 	mutex_lock(&fb_helper->lock);
1884 	ret = __drm_fb_helper_initial_config_and_unlock(fb_helper, bpp_sel);
1885 
1886 	return ret;
1887 }
1888 EXPORT_SYMBOL(drm_fb_helper_initial_config);
1889 
1890 /**
1891  * drm_fb_helper_hotplug_event - respond to a hotplug notification by
1892  *                               probing all the outputs attached to the fb
1893  * @fb_helper: driver-allocated fbdev helper, can be NULL
1894  *
1895  * Scan the connectors attached to the fb_helper and try to put together a
1896  * setup after notification of a change in output configuration.
1897  *
1898  * Called at runtime, takes the mode config locks to be able to check/change the
1899  * modeset configuration. Must be run from process context (which usually means
1900  * either the output polling work or a work item launched from the driver's
1901  * hotplug interrupt).
1902  *
1903  * Note that drivers may call this even before calling
1904  * drm_fb_helper_initial_config but only after drm_fb_helper_init. This allows
1905  * for a race-free fbcon setup and will make sure that the fbdev emulation will
1906  * not miss any hotplug events.
1907  *
1908  * RETURNS:
1909  * 0 on success and a non-zero error code otherwise.
1910  */
1911 int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
1912 {
1913 	int err = 0;
1914 
1915 	if (!drm_fbdev_emulation || !fb_helper)
1916 		return 0;
1917 
1918 	mutex_lock(&fb_helper->lock);
1919 	if (fb_helper->deferred_setup) {
1920 		err = __drm_fb_helper_initial_config_and_unlock(fb_helper,
1921 				fb_helper->preferred_bpp);
1922 		return err;
1923 	}
1924 
1925 	if (!fb_helper->fb || !drm_master_internal_acquire(fb_helper->dev)) {
1926 		fb_helper->delayed_hotplug = true;
1927 		mutex_unlock(&fb_helper->lock);
1928 		return err;
1929 	}
1930 
1931 	drm_master_internal_release(fb_helper->dev);
1932 
1933 	drm_dbg_kms(fb_helper->dev, "\n");
1934 
1935 	drm_client_modeset_probe(&fb_helper->client, fb_helper->fb->width, fb_helper->fb->height);
1936 	drm_setup_crtcs_fb(fb_helper);
1937 	mutex_unlock(&fb_helper->lock);
1938 
1939 	drm_fb_helper_set_par(fb_helper->fbdev);
1940 
1941 	return 0;
1942 }
1943 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
1944 
1945 /**
1946  * drm_fb_helper_lastclose - DRM driver lastclose helper for fbdev emulation
1947  * @dev: DRM device
1948  *
1949  * This function can be used as the &drm_driver->lastclose callback for drivers
1950  * that only need to call drm_fb_helper_restore_fbdev_mode_unlocked().
1951  */
1952 void drm_fb_helper_lastclose(struct drm_device *dev)
1953 {
1954 	drm_fb_helper_restore_fbdev_mode_unlocked(dev->fb_helper);
1955 }
1956 EXPORT_SYMBOL(drm_fb_helper_lastclose);
1957 
1958 /**
1959  * drm_fb_helper_output_poll_changed - DRM mode config \.output_poll_changed
1960  *                                     helper for fbdev emulation
1961  * @dev: DRM device
1962  *
1963  * This function can be used as the
1964  * &drm_mode_config_funcs.output_poll_changed callback for drivers that only
1965  * need to call drm_fb_helper_hotplug_event().
1966  */
1967 void drm_fb_helper_output_poll_changed(struct drm_device *dev)
1968 {
1969 	drm_fb_helper_hotplug_event(dev->fb_helper);
1970 }
1971 EXPORT_SYMBOL(drm_fb_helper_output_poll_changed);
1972 
1973 /* @user: 1=userspace, 0=fbcon */
1974 static int drm_fbdev_fb_open(struct fb_info *info, int user)
1975 {
1976 	struct drm_fb_helper *fb_helper = info->par;
1977 
1978 	/* No need to take a ref for fbcon because it unbinds on unregister */
1979 	if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
1980 		return -ENODEV;
1981 
1982 	return 0;
1983 }
1984 
1985 static int drm_fbdev_fb_release(struct fb_info *info, int user)
1986 {
1987 	struct drm_fb_helper *fb_helper = info->par;
1988 
1989 	if (user)
1990 		module_put(fb_helper->dev->driver->fops->owner);
1991 
1992 	return 0;
1993 }
1994 
1995 static void drm_fbdev_cleanup(struct drm_fb_helper *fb_helper)
1996 {
1997 	struct fb_info *fbi = fb_helper->fbdev;
1998 	void *shadow = NULL;
1999 
2000 	if (!fb_helper->dev)
2001 		return;
2002 
2003 	if (fbi && fbi->fbdefio) {
2004 		fb_deferred_io_cleanup(fbi);
2005 		shadow = fbi->screen_buffer;
2006 	}
2007 
2008 	drm_fb_helper_fini(fb_helper);
2009 
2010 	vfree(shadow);
2011 
2012 	drm_client_framebuffer_delete(fb_helper->buffer);
2013 }
2014 
2015 static void drm_fbdev_release(struct drm_fb_helper *fb_helper)
2016 {
2017 	drm_fbdev_cleanup(fb_helper);
2018 	drm_client_release(&fb_helper->client);
2019 	kfree(fb_helper);
2020 }
2021 
2022 /*
2023  * fb_ops.fb_destroy is called by the last put_fb_info() call at the end of
2024  * unregister_framebuffer() or fb_release().
2025  */
2026 static void drm_fbdev_fb_destroy(struct fb_info *info)
2027 {
2028 	drm_fbdev_release(info->par);
2029 }
2030 
2031 static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
2032 {
2033 	struct drm_fb_helper *fb_helper = info->par;
2034 
2035 	if (fb_helper->dev->driver->gem_prime_mmap)
2036 		return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma);
2037 	else
2038 		return -ENODEV;
2039 }
2040 
2041 static const struct fb_ops drm_fbdev_fb_ops = {
2042 	.owner		= THIS_MODULE,
2043 	DRM_FB_HELPER_DEFAULT_OPS,
2044 	.fb_open	= drm_fbdev_fb_open,
2045 	.fb_release	= drm_fbdev_fb_release,
2046 	.fb_destroy	= drm_fbdev_fb_destroy,
2047 	.fb_mmap	= drm_fbdev_fb_mmap,
2048 	.fb_read	= drm_fb_helper_sys_read,
2049 	.fb_write	= drm_fb_helper_sys_write,
2050 	.fb_fillrect	= drm_fb_helper_sys_fillrect,
2051 	.fb_copyarea	= drm_fb_helper_sys_copyarea,
2052 	.fb_imageblit	= drm_fb_helper_sys_imageblit,
2053 };
2054 
2055 static struct fb_deferred_io drm_fbdev_defio = {
2056 	.delay		= HZ / 20,
2057 	.deferred_io	= drm_fb_helper_deferred_io,
2058 };
2059 
2060 /*
2061  * This function uses the client API to create a framebuffer backed by a dumb buffer.
2062  *
2063  * The _sys_ versions are used for &fb_ops.fb_read, fb_write, fb_fillrect,
2064  * fb_copyarea, fb_imageblit.
2065  */
2066 static int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper,
2067 				       struct drm_fb_helper_surface_size *sizes)
2068 {
2069 	struct drm_client_dev *client = &fb_helper->client;
2070 	struct drm_device *dev = fb_helper->dev;
2071 	struct drm_client_buffer *buffer;
2072 	struct drm_framebuffer *fb;
2073 	struct fb_info *fbi;
2074 	u32 format;
2075 	void *vaddr;
2076 
2077 	drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
2078 		    sizes->surface_width, sizes->surface_height,
2079 		    sizes->surface_bpp);
2080 
2081 	format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
2082 	buffer = drm_client_framebuffer_create(client, sizes->surface_width,
2083 					       sizes->surface_height, format);
2084 	if (IS_ERR(buffer))
2085 		return PTR_ERR(buffer);
2086 
2087 	fb_helper->buffer = buffer;
2088 	fb_helper->fb = buffer->fb;
2089 	fb = buffer->fb;
2090 
2091 	fbi = drm_fb_helper_alloc_fbi(fb_helper);
2092 	if (IS_ERR(fbi))
2093 		return PTR_ERR(fbi);
2094 
2095 	fbi->fbops = &drm_fbdev_fb_ops;
2096 	fbi->screen_size = fb->height * fb->pitches[0];
2097 	fbi->fix.smem_len = fbi->screen_size;
2098 
2099 	drm_fb_helper_fill_info(fbi, fb_helper, sizes);
2100 
2101 	if (drm_fbdev_use_shadow_fb(fb_helper)) {
2102 		fbi->screen_buffer = vzalloc(fbi->screen_size);
2103 		if (!fbi->screen_buffer)
2104 			return -ENOMEM;
2105 
2106 		fbi->fbdefio = &drm_fbdev_defio;
2107 
2108 		fb_deferred_io_init(fbi);
2109 	} else {
2110 		/* buffer is mapped for HW framebuffer */
2111 		vaddr = drm_client_buffer_vmap(fb_helper->buffer);
2112 		if (IS_ERR(vaddr))
2113 			return PTR_ERR(vaddr);
2114 
2115 		fbi->screen_buffer = vaddr;
2116 		/* Shamelessly leak the physical address to user-space */
2117 #if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
2118 		if (drm_leak_fbdev_smem && fbi->fix.smem_start == 0)
2119 			fbi->fix.smem_start =
2120 				page_to_phys(virt_to_page(fbi->screen_buffer));
2121 #endif
2122 	}
2123 
2124 	return 0;
2125 }
2126 
2127 static const struct drm_fb_helper_funcs drm_fb_helper_generic_funcs = {
2128 	.fb_probe = drm_fb_helper_generic_probe,
2129 };
2130 
2131 static void drm_fbdev_client_unregister(struct drm_client_dev *client)
2132 {
2133 	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
2134 
2135 	if (fb_helper->fbdev)
2136 		/* drm_fbdev_fb_destroy() takes care of cleanup */
2137 		drm_fb_helper_unregister_fbi(fb_helper);
2138 	else
2139 		drm_fbdev_release(fb_helper);
2140 }
2141 
2142 static int drm_fbdev_client_restore(struct drm_client_dev *client)
2143 {
2144 	drm_fb_helper_lastclose(client->dev);
2145 
2146 	return 0;
2147 }
2148 
2149 static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
2150 {
2151 	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
2152 	struct drm_device *dev = client->dev;
2153 	int ret;
2154 
2155 	/* Setup is not retried if it has failed */
2156 	if (!fb_helper->dev && fb_helper->funcs)
2157 		return 0;
2158 
2159 	if (dev->fb_helper)
2160 		return drm_fb_helper_hotplug_event(dev->fb_helper);
2161 
2162 	if (!dev->mode_config.num_connector) {
2163 		drm_dbg_kms(dev, "No connectors found, will not create framebuffer!\n");
2164 		return 0;
2165 	}
2166 
2167 	drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);
2168 
2169 	ret = drm_fb_helper_init(dev, fb_helper);
2170 	if (ret)
2171 		goto err;
2172 
2173 	if (!drm_drv_uses_atomic_modeset(dev))
2174 		drm_helper_disable_unused_functions(dev);
2175 
2176 	ret = drm_fb_helper_initial_config(fb_helper, fb_helper->preferred_bpp);
2177 	if (ret)
2178 		goto err_cleanup;
2179 
2180 	return 0;
2181 
2182 err_cleanup:
2183 	drm_fbdev_cleanup(fb_helper);
2184 err:
2185 	fb_helper->dev = NULL;
2186 	fb_helper->fbdev = NULL;
2187 
2188 	drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret);
2189 
2190 	return ret;
2191 }
2192 
2193 static const struct drm_client_funcs drm_fbdev_client_funcs = {
2194 	.owner		= THIS_MODULE,
2195 	.unregister	= drm_fbdev_client_unregister,
2196 	.restore	= drm_fbdev_client_restore,
2197 	.hotplug	= drm_fbdev_client_hotplug,
2198 };
2199 
2200 /**
2201  * drm_fbdev_generic_setup() - Setup generic fbdev emulation
2202  * @dev: DRM device
2203  * @preferred_bpp: Preferred bits per pixel for the device.
2204  *                 @dev->mode_config.preferred_depth is used if this is zero.
2205  *
2206  * This function sets up generic fbdev emulation for drivers that supports
2207  * dumb buffers with a virtual address and that can be mmap'ed.
2208  * drm_fbdev_generic_setup() shall be called after the DRM driver registered
2209  * the new DRM device with drm_dev_register().
2210  *
2211  * Restore, hotplug events and teardown are all taken care of. Drivers that do
2212  * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
2213  * Simple drivers might use drm_mode_config_helper_suspend().
2214  *
2215  * Drivers that set the dirty callback on their framebuffer will get a shadow
2216  * fbdev buffer that is blitted onto the real buffer. This is done in order to
2217  * make deferred I/O work with all kinds of buffers. A shadow buffer can be
2218  * requested explicitly by setting struct drm_mode_config.prefer_shadow or
2219  * struct drm_mode_config.prefer_shadow_fbdev to true beforehand. This is
2220  * required to use generic fbdev emulation with SHMEM helpers.
2221  *
2222  * This function is safe to call even when there are no connectors present.
2223  * Setup will be retried on the next hotplug event.
2224  *
2225  * The fbdev is destroyed by drm_dev_unregister().
2226  */
2227 void drm_fbdev_generic_setup(struct drm_device *dev,
2228 			     unsigned int preferred_bpp)
2229 {
2230 	struct drm_fb_helper *fb_helper;
2231 	int ret;
2232 
2233 	drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
2234 	drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
2235 
2236 	if (!drm_fbdev_emulation)
2237 		return;
2238 
2239 	fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
2240 	if (!fb_helper) {
2241 		drm_err(dev, "Failed to allocate fb_helper\n");
2242 		return;
2243 	}
2244 
2245 	ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);
2246 	if (ret) {
2247 		kfree(fb_helper);
2248 		drm_err(dev, "Failed to register client: %d\n", ret);
2249 		return;
2250 	}
2251 
2252 	if (!preferred_bpp)
2253 		preferred_bpp = dev->mode_config.preferred_depth;
2254 	if (!preferred_bpp)
2255 		preferred_bpp = 32;
2256 	fb_helper->preferred_bpp = preferred_bpp;
2257 
2258 	ret = drm_fbdev_client_hotplug(&fb_helper->client);
2259 	if (ret)
2260 		drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);
2261 
2262 	drm_client_register(&fb_helper->client);
2263 }
2264 EXPORT_SYMBOL(drm_fbdev_generic_setup);
2265 
2266 /* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
2267  * but the module doesn't depend on any fb console symbols.  At least
2268  * attempt to load fbcon to avoid leaving the system without a usable console.
2269  */
2270 int __init drm_fb_helper_modinit(void)
2271 {
2272 #if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
2273 	const char name[] = "fbcon";
2274 	struct module *fbcon;
2275 
2276 	mutex_lock(&module_mutex);
2277 	fbcon = find_module(name);
2278 	mutex_unlock(&module_mutex);
2279 
2280 	if (!fbcon)
2281 		request_module_nowait(name);
2282 #endif
2283 	return 0;
2284 }
2285 EXPORT_SYMBOL(drm_fb_helper_modinit);
2286