xref: /linux/drivers/gpu/drm/drm_fb_helper.c (revision 2ba9268dd603d23e17643437b2246acb6844953b)
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/kernel.h>
33 #include <linux/sysrq.h>
34 #include <linux/slab.h>
35 #include <linux/fb.h>
36 #include <linux/module.h>
37 #include <drm/drmP.h>
38 #include <drm/drm_crtc.h>
39 #include <drm/drm_fb_helper.h>
40 #include <drm/drm_crtc_helper.h>
41 
42 static LIST_HEAD(kernel_fb_helper_list);
43 
44 /**
45  * DOC: fbdev helpers
46  *
47  * The fb helper functions are useful to provide an fbdev on top of a drm kernel
48  * mode setting driver. They can be used mostly independently from the crtc
49  * helper functions used by many drivers to implement the kernel mode setting
50  * interfaces.
51  *
52  * Initialization is done as a four-step process with drm_fb_helper_prepare(),
53  * drm_fb_helper_init(), drm_fb_helper_single_add_all_connectors() and
54  * drm_fb_helper_initial_config(). Drivers with fancier requirements than the
55  * default behaviour can override the third step with their own code.
56  * Teardown is done with drm_fb_helper_fini().
57  *
58  * At runtime drivers should restore the fbdev console by calling
59  * drm_fb_helper_restore_fbdev_mode() from their ->lastclose callback. They
60  * should also notify the fb helper code from updates to the output
61  * configuration by calling drm_fb_helper_hotplug_event(). For easier
62  * integration with the output polling code in drm_crtc_helper.c the modeset
63  * code provides a ->output_poll_changed callback.
64  *
65  * All other functions exported by the fb helper library can be used to
66  * implement the fbdev driver interface by the driver.
67  *
68  * It is possible, though perhaps somewhat tricky, to implement race-free
69  * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
70  * helper must be called first to initialize the minimum required to make
71  * hotplug detection work. Drivers also need to make sure to properly set up
72  * the dev->mode_config.funcs member. After calling drm_kms_helper_poll_init()
73  * it is safe to enable interrupts and start processing hotplug events. At the
74  * same time, drivers should initialize all modeset objects such as CRTCs,
75  * encoders and connectors. To finish up the fbdev helper initialization, the
76  * drm_fb_helper_init() function is called. To probe for all attached displays
77  * and set up an initial configuration using the detected hardware, drivers
78  * should call drm_fb_helper_single_add_all_connectors() followed by
79  * drm_fb_helper_initial_config().
80  */
81 
82 /**
83  * drm_fb_helper_single_add_all_connectors() - add all connectors to fbdev
84  * 					       emulation helper
85  * @fb_helper: fbdev initialized with drm_fb_helper_init
86  *
87  * This functions adds all the available connectors for use with the given
88  * fb_helper. This is a separate step to allow drivers to freely assign
89  * connectors to the fbdev, e.g. if some are reserved for special purposes or
90  * not adequate to be used for the fbcon.
91  *
92  * Since this is part of the initial setup before the fbdev is published, no
93  * locking is required.
94  */
95 int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
96 {
97 	struct drm_device *dev = fb_helper->dev;
98 	struct drm_connector *connector;
99 	int i;
100 
101 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
102 		struct drm_fb_helper_connector *fb_helper_connector;
103 
104 		fb_helper_connector = kzalloc(sizeof(struct drm_fb_helper_connector), GFP_KERNEL);
105 		if (!fb_helper_connector)
106 			goto fail;
107 
108 		fb_helper_connector->connector = connector;
109 		fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector;
110 	}
111 	return 0;
112 fail:
113 	for (i = 0; i < fb_helper->connector_count; i++) {
114 		kfree(fb_helper->connector_info[i]);
115 		fb_helper->connector_info[i] = NULL;
116 	}
117 	fb_helper->connector_count = 0;
118 	return -ENOMEM;
119 }
120 EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors);
121 
122 int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct drm_connector *connector)
123 {
124 	struct drm_fb_helper_connector **temp;
125 	struct drm_fb_helper_connector *fb_helper_connector;
126 
127 	WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));
128 	if (fb_helper->connector_count + 1 > fb_helper->connector_info_alloc_count) {
129 		temp = krealloc(fb_helper->connector_info, sizeof(struct drm_fb_helper_connector *) * (fb_helper->connector_count + 1), GFP_KERNEL);
130 		if (!temp)
131 			return -ENOMEM;
132 
133 		fb_helper->connector_info_alloc_count = fb_helper->connector_count + 1;
134 		fb_helper->connector_info = temp;
135 	}
136 
137 
138 	fb_helper_connector = kzalloc(sizeof(struct drm_fb_helper_connector), GFP_KERNEL);
139 	if (!fb_helper_connector)
140 		return -ENOMEM;
141 
142 	fb_helper_connector->connector = connector;
143 	fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector;
144 	return 0;
145 }
146 EXPORT_SYMBOL(drm_fb_helper_add_one_connector);
147 
148 static void remove_from_modeset(struct drm_mode_set *set,
149 		struct drm_connector *connector)
150 {
151 	int i, j;
152 
153 	for (i = 0; i < set->num_connectors; i++) {
154 		if (set->connectors[i] == connector)
155 			break;
156 	}
157 
158 	if (i == set->num_connectors)
159 		return;
160 
161 	for (j = i + 1; j < set->num_connectors; j++) {
162 		set->connectors[j - 1] = set->connectors[j];
163 	}
164 	set->num_connectors--;
165 
166 	/* because i915 is pissy about this..
167 	 * TODO maybe need to makes sure we set it back to !=NULL somewhere?
168 	 */
169 	if (set->num_connectors == 0)
170 		set->fb = NULL;
171 }
172 
173 int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
174 				       struct drm_connector *connector)
175 {
176 	struct drm_fb_helper_connector *fb_helper_connector;
177 	int i, j;
178 
179 	WARN_ON(!mutex_is_locked(&fb_helper->dev->mode_config.mutex));
180 
181 	for (i = 0; i < fb_helper->connector_count; i++) {
182 		if (fb_helper->connector_info[i]->connector == connector)
183 			break;
184 	}
185 
186 	if (i == fb_helper->connector_count)
187 		return -EINVAL;
188 	fb_helper_connector = fb_helper->connector_info[i];
189 
190 	for (j = i + 1; j < fb_helper->connector_count; j++) {
191 		fb_helper->connector_info[j - 1] = fb_helper->connector_info[j];
192 	}
193 	fb_helper->connector_count--;
194 	kfree(fb_helper_connector);
195 
196 	/* also cleanup dangling references to the connector: */
197 	for (i = 0; i < fb_helper->crtc_count; i++)
198 		remove_from_modeset(&fb_helper->crtc_info[i].mode_set, connector);
199 
200 	return 0;
201 }
202 EXPORT_SYMBOL(drm_fb_helper_remove_one_connector);
203 
204 static void drm_fb_helper_save_lut_atomic(struct drm_crtc *crtc, struct drm_fb_helper *helper)
205 {
206 	uint16_t *r_base, *g_base, *b_base;
207 	int i;
208 
209 	if (helper->funcs->gamma_get == NULL)
210 		return;
211 
212 	r_base = crtc->gamma_store;
213 	g_base = r_base + crtc->gamma_size;
214 	b_base = g_base + crtc->gamma_size;
215 
216 	for (i = 0; i < crtc->gamma_size; i++)
217 		helper->funcs->gamma_get(crtc, &r_base[i], &g_base[i], &b_base[i], i);
218 }
219 
220 static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
221 {
222 	uint16_t *r_base, *g_base, *b_base;
223 
224 	if (crtc->funcs->gamma_set == NULL)
225 		return;
226 
227 	r_base = crtc->gamma_store;
228 	g_base = r_base + crtc->gamma_size;
229 	b_base = g_base + crtc->gamma_size;
230 
231 	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
232 }
233 
234 /**
235  * drm_fb_helper_debug_enter - implementation for ->fb_debug_enter
236  * @info: fbdev registered by the helper
237  */
238 int drm_fb_helper_debug_enter(struct fb_info *info)
239 {
240 	struct drm_fb_helper *helper = info->par;
241 	struct drm_crtc_helper_funcs *funcs;
242 	int i;
243 
244 	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
245 		for (i = 0; i < helper->crtc_count; i++) {
246 			struct drm_mode_set *mode_set =
247 				&helper->crtc_info[i].mode_set;
248 
249 			if (!mode_set->crtc->enabled)
250 				continue;
251 
252 			funcs =	mode_set->crtc->helper_private;
253 			drm_fb_helper_save_lut_atomic(mode_set->crtc, helper);
254 			funcs->mode_set_base_atomic(mode_set->crtc,
255 						    mode_set->fb,
256 						    mode_set->x,
257 						    mode_set->y,
258 						    ENTER_ATOMIC_MODE_SET);
259 		}
260 	}
261 
262 	return 0;
263 }
264 EXPORT_SYMBOL(drm_fb_helper_debug_enter);
265 
266 /* Find the real fb for a given fb helper CRTC */
267 static struct drm_framebuffer *drm_mode_config_fb(struct drm_crtc *crtc)
268 {
269 	struct drm_device *dev = crtc->dev;
270 	struct drm_crtc *c;
271 
272 	list_for_each_entry(c, &dev->mode_config.crtc_list, head) {
273 		if (crtc->base.id == c->base.id)
274 			return c->primary->fb;
275 	}
276 
277 	return NULL;
278 }
279 
280 /**
281  * drm_fb_helper_debug_leave - implementation for ->fb_debug_leave
282  * @info: fbdev registered by the helper
283  */
284 int drm_fb_helper_debug_leave(struct fb_info *info)
285 {
286 	struct drm_fb_helper *helper = info->par;
287 	struct drm_crtc *crtc;
288 	struct drm_crtc_helper_funcs *funcs;
289 	struct drm_framebuffer *fb;
290 	int i;
291 
292 	for (i = 0; i < helper->crtc_count; i++) {
293 		struct drm_mode_set *mode_set = &helper->crtc_info[i].mode_set;
294 		crtc = mode_set->crtc;
295 		funcs = crtc->helper_private;
296 		fb = drm_mode_config_fb(crtc);
297 
298 		if (!crtc->enabled)
299 			continue;
300 
301 		if (!fb) {
302 			DRM_ERROR("no fb to restore??\n");
303 			continue;
304 		}
305 
306 		drm_fb_helper_restore_lut_atomic(mode_set->crtc);
307 		funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
308 					    crtc->y, LEAVE_ATOMIC_MODE_SET);
309 	}
310 
311 	return 0;
312 }
313 EXPORT_SYMBOL(drm_fb_helper_debug_leave);
314 
315 static bool restore_fbdev_mode(struct drm_fb_helper *fb_helper)
316 {
317 	struct drm_device *dev = fb_helper->dev;
318 	struct drm_plane *plane;
319 	bool error = false;
320 	int i;
321 
322 	drm_warn_on_modeset_not_all_locked(dev);
323 
324 	list_for_each_entry(plane, &dev->mode_config.plane_list, head) {
325 		if (plane->type != DRM_PLANE_TYPE_PRIMARY)
326 			drm_plane_force_disable(plane);
327 
328 		if (dev->mode_config.rotation_property) {
329 			drm_mode_plane_set_obj_prop(plane,
330 						    dev->mode_config.rotation_property,
331 						    BIT(DRM_ROTATE_0));
332 		}
333 	}
334 
335 	for (i = 0; i < fb_helper->crtc_count; i++) {
336 		struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
337 		struct drm_crtc *crtc = mode_set->crtc;
338 		int ret;
339 
340 		if (crtc->funcs->cursor_set) {
341 			ret = crtc->funcs->cursor_set(crtc, NULL, 0, 0, 0);
342 			if (ret)
343 				error = true;
344 		}
345 
346 		ret = drm_mode_set_config_internal(mode_set);
347 		if (ret)
348 			error = true;
349 	}
350 	return error;
351 }
352 /**
353  * drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
354  * @fb_helper: fbcon to restore
355  *
356  * This should be called from driver's drm ->lastclose callback
357  * when implementing an fbcon on top of kms using this helper. This ensures that
358  * the user isn't greeted with a black screen when e.g. X dies.
359  *
360  * Use this variant if you need to bypass locking (panic), or already
361  * hold all modeset locks.  Otherwise use drm_fb_helper_restore_fbdev_mode_unlocked()
362  */
363 static bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
364 {
365 	return restore_fbdev_mode(fb_helper);
366 }
367 
368 /**
369  * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
370  * @fb_helper: fbcon to restore
371  *
372  * This should be called from driver's drm ->lastclose callback
373  * when implementing an fbcon on top of kms using this helper. This ensures that
374  * the user isn't greeted with a black screen when e.g. X dies.
375  */
376 bool drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
377 {
378 	struct drm_device *dev = fb_helper->dev;
379 	bool ret;
380 	bool do_delayed = false;
381 
382 	drm_modeset_lock_all(dev);
383 	ret = restore_fbdev_mode(fb_helper);
384 
385 	do_delayed = fb_helper->delayed_hotplug;
386 	if (do_delayed)
387 		fb_helper->delayed_hotplug = false;
388 	drm_modeset_unlock_all(dev);
389 
390 	if (do_delayed)
391 		drm_fb_helper_hotplug_event(fb_helper);
392 	return ret;
393 }
394 EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
395 
396 /*
397  * restore fbcon display for all kms driver's using this helper, used for sysrq
398  * and panic handling.
399  */
400 static bool drm_fb_helper_force_kernel_mode(void)
401 {
402 	bool ret, error = false;
403 	struct drm_fb_helper *helper;
404 
405 	if (list_empty(&kernel_fb_helper_list))
406 		return false;
407 
408 	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
409 		struct drm_device *dev = helper->dev;
410 
411 		if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
412 			continue;
413 
414 		/*
415 		 * NOTE: Use trylock mode to avoid deadlocks and sleeping in
416 		 * panic context.
417 		 */
418 		if (__drm_modeset_lock_all(dev, true) != 0) {
419 			error = true;
420 			continue;
421 		}
422 
423 		ret = drm_fb_helper_restore_fbdev_mode(helper);
424 		if (ret)
425 			error = true;
426 
427 		drm_modeset_unlock_all(dev);
428 	}
429 	return error;
430 }
431 
432 static int drm_fb_helper_panic(struct notifier_block *n, unsigned long ununsed,
433 			void *panic_str)
434 {
435 	/*
436 	 * It's a waste of time and effort to switch back to text console
437 	 * if the kernel should reboot before panic messages can be seen.
438 	 */
439 	if (panic_timeout < 0)
440 		return 0;
441 
442 	pr_err("panic occurred, switching back to text console\n");
443 	return drm_fb_helper_force_kernel_mode();
444 }
445 
446 static struct notifier_block paniced = {
447 	.notifier_call = drm_fb_helper_panic,
448 };
449 
450 static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
451 {
452 	struct drm_device *dev = fb_helper->dev;
453 	struct drm_crtc *crtc;
454 	int bound = 0, crtcs_bound = 0;
455 
456 	/* Sometimes user space wants everything disabled, so don't steal the
457 	 * display if there's a master. */
458 	if (dev->primary->master)
459 		return false;
460 
461 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
462 		if (crtc->primary->fb)
463 			crtcs_bound++;
464 		if (crtc->primary->fb == fb_helper->fb)
465 			bound++;
466 	}
467 
468 	if (bound < crtcs_bound)
469 		return false;
470 
471 	return true;
472 }
473 
474 #ifdef CONFIG_MAGIC_SYSRQ
475 static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
476 {
477 	bool ret;
478 	ret = drm_fb_helper_force_kernel_mode();
479 	if (ret == true)
480 		DRM_ERROR("Failed to restore crtc configuration\n");
481 }
482 static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);
483 
484 static void drm_fb_helper_sysrq(int dummy1)
485 {
486 	schedule_work(&drm_fb_helper_restore_work);
487 }
488 
489 static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {
490 	.handler = drm_fb_helper_sysrq,
491 	.help_msg = "force-fb(V)",
492 	.action_msg = "Restore framebuffer console",
493 };
494 #else
495 static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };
496 #endif
497 
498 static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
499 {
500 	struct drm_fb_helper *fb_helper = info->par;
501 	struct drm_device *dev = fb_helper->dev;
502 	struct drm_crtc *crtc;
503 	struct drm_connector *connector;
504 	int i, j;
505 
506 	/*
507 	 * fbdev->blank can be called from irq context in case of a panic.
508 	 * Since we already have our own special panic handler which will
509 	 * restore the fbdev console mode completely, just bail out early.
510 	 */
511 	if (oops_in_progress)
512 		return;
513 
514 	/*
515 	 * For each CRTC in this fb, turn the connectors on/off.
516 	 */
517 	drm_modeset_lock_all(dev);
518 	if (!drm_fb_helper_is_bound(fb_helper)) {
519 		drm_modeset_unlock_all(dev);
520 		return;
521 	}
522 
523 	for (i = 0; i < fb_helper->crtc_count; i++) {
524 		crtc = fb_helper->crtc_info[i].mode_set.crtc;
525 
526 		if (!crtc->enabled)
527 			continue;
528 
529 		/* Walk the connectors & encoders on this fb turning them on/off */
530 		for (j = 0; j < fb_helper->connector_count; j++) {
531 			connector = fb_helper->connector_info[j]->connector;
532 			connector->funcs->dpms(connector, dpms_mode);
533 			drm_object_property_set_value(&connector->base,
534 				dev->mode_config.dpms_property, dpms_mode);
535 		}
536 	}
537 	drm_modeset_unlock_all(dev);
538 }
539 
540 /**
541  * drm_fb_helper_blank - implementation for ->fb_blank
542  * @blank: desired blanking state
543  * @info: fbdev registered by the helper
544  */
545 int drm_fb_helper_blank(int blank, struct fb_info *info)
546 {
547 	switch (blank) {
548 	/* Display: On; HSync: On, VSync: On */
549 	case FB_BLANK_UNBLANK:
550 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
551 		break;
552 	/* Display: Off; HSync: On, VSync: On */
553 	case FB_BLANK_NORMAL:
554 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
555 		break;
556 	/* Display: Off; HSync: Off, VSync: On */
557 	case FB_BLANK_HSYNC_SUSPEND:
558 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
559 		break;
560 	/* Display: Off; HSync: On, VSync: Off */
561 	case FB_BLANK_VSYNC_SUSPEND:
562 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
563 		break;
564 	/* Display: Off; HSync: Off, VSync: Off */
565 	case FB_BLANK_POWERDOWN:
566 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
567 		break;
568 	}
569 	return 0;
570 }
571 EXPORT_SYMBOL(drm_fb_helper_blank);
572 
573 static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
574 {
575 	int i;
576 
577 	for (i = 0; i < helper->connector_count; i++)
578 		kfree(helper->connector_info[i]);
579 	kfree(helper->connector_info);
580 	for (i = 0; i < helper->crtc_count; i++) {
581 		kfree(helper->crtc_info[i].mode_set.connectors);
582 		if (helper->crtc_info[i].mode_set.mode)
583 			drm_mode_destroy(helper->dev, helper->crtc_info[i].mode_set.mode);
584 	}
585 	kfree(helper->crtc_info);
586 }
587 
588 /**
589  * drm_fb_helper_prepare - setup a drm_fb_helper structure
590  * @dev: DRM device
591  * @helper: driver-allocated fbdev helper structure to set up
592  * @funcs: pointer to structure of functions associate with this helper
593  *
594  * Sets up the bare minimum to make the framebuffer helper usable. This is
595  * useful to implement race-free initialization of the polling helpers.
596  */
597 void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
598 			   const struct drm_fb_helper_funcs *funcs)
599 {
600 	INIT_LIST_HEAD(&helper->kernel_fb_list);
601 	helper->funcs = funcs;
602 	helper->dev = dev;
603 }
604 EXPORT_SYMBOL(drm_fb_helper_prepare);
605 
606 /**
607  * drm_fb_helper_init - initialize a drm_fb_helper structure
608  * @dev: drm device
609  * @fb_helper: driver-allocated fbdev helper structure to initialize
610  * @crtc_count: maximum number of crtcs to support in this fbdev emulation
611  * @max_conn_count: max connector count
612  *
613  * This allocates the structures for the fbdev helper with the given limits.
614  * Note that this won't yet touch the hardware (through the driver interfaces)
615  * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
616  * to allow driver writes more control over the exact init sequence.
617  *
618  * Drivers must call drm_fb_helper_prepare() before calling this function.
619  *
620  * RETURNS:
621  * Zero if everything went ok, nonzero otherwise.
622  */
623 int drm_fb_helper_init(struct drm_device *dev,
624 		       struct drm_fb_helper *fb_helper,
625 		       int crtc_count, int max_conn_count)
626 {
627 	struct drm_crtc *crtc;
628 	int i;
629 
630 	if (!max_conn_count)
631 		return -EINVAL;
632 
633 	fb_helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
634 	if (!fb_helper->crtc_info)
635 		return -ENOMEM;
636 
637 	fb_helper->crtc_count = crtc_count;
638 	fb_helper->connector_info = kcalloc(dev->mode_config.num_connector, sizeof(struct drm_fb_helper_connector *), GFP_KERNEL);
639 	if (!fb_helper->connector_info) {
640 		kfree(fb_helper->crtc_info);
641 		return -ENOMEM;
642 	}
643 	fb_helper->connector_info_alloc_count = dev->mode_config.num_connector;
644 	fb_helper->connector_count = 0;
645 
646 	for (i = 0; i < crtc_count; i++) {
647 		fb_helper->crtc_info[i].mode_set.connectors =
648 			kcalloc(max_conn_count,
649 				sizeof(struct drm_connector *),
650 				GFP_KERNEL);
651 
652 		if (!fb_helper->crtc_info[i].mode_set.connectors)
653 			goto out_free;
654 		fb_helper->crtc_info[i].mode_set.num_connectors = 0;
655 	}
656 
657 	i = 0;
658 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
659 		fb_helper->crtc_info[i].mode_set.crtc = crtc;
660 		i++;
661 	}
662 
663 	return 0;
664 out_free:
665 	drm_fb_helper_crtc_free(fb_helper);
666 	return -ENOMEM;
667 }
668 EXPORT_SYMBOL(drm_fb_helper_init);
669 
670 void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
671 {
672 	if (!list_empty(&fb_helper->kernel_fb_list)) {
673 		list_del(&fb_helper->kernel_fb_list);
674 		if (list_empty(&kernel_fb_helper_list)) {
675 			pr_info("drm: unregistered panic notifier\n");
676 			atomic_notifier_chain_unregister(&panic_notifier_list,
677 							 &paniced);
678 			unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
679 		}
680 	}
681 
682 	drm_fb_helper_crtc_free(fb_helper);
683 
684 }
685 EXPORT_SYMBOL(drm_fb_helper_fini);
686 
687 static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
688 		     u16 blue, u16 regno, struct fb_info *info)
689 {
690 	struct drm_fb_helper *fb_helper = info->par;
691 	struct drm_framebuffer *fb = fb_helper->fb;
692 	int pindex;
693 
694 	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
695 		u32 *palette;
696 		u32 value;
697 		/* place color in psuedopalette */
698 		if (regno > 16)
699 			return -EINVAL;
700 		palette = (u32 *)info->pseudo_palette;
701 		red >>= (16 - info->var.red.length);
702 		green >>= (16 - info->var.green.length);
703 		blue >>= (16 - info->var.blue.length);
704 		value = (red << info->var.red.offset) |
705 			(green << info->var.green.offset) |
706 			(blue << info->var.blue.offset);
707 		if (info->var.transp.length > 0) {
708 			u32 mask = (1 << info->var.transp.length) - 1;
709 			mask <<= info->var.transp.offset;
710 			value |= mask;
711 		}
712 		palette[regno] = value;
713 		return 0;
714 	}
715 
716 	/*
717 	 * The driver really shouldn't advertise pseudo/directcolor
718 	 * visuals if it can't deal with the palette.
719 	 */
720 	if (WARN_ON(!fb_helper->funcs->gamma_set ||
721 		    !fb_helper->funcs->gamma_get))
722 		return -EINVAL;
723 
724 	pindex = regno;
725 
726 	if (fb->bits_per_pixel == 16) {
727 		pindex = regno << 3;
728 
729 		if (fb->depth == 16 && regno > 63)
730 			return -EINVAL;
731 		if (fb->depth == 15 && regno > 31)
732 			return -EINVAL;
733 
734 		if (fb->depth == 16) {
735 			u16 r, g, b;
736 			int i;
737 			if (regno < 32) {
738 				for (i = 0; i < 8; i++)
739 					fb_helper->funcs->gamma_set(crtc, red,
740 						green, blue, pindex + i);
741 			}
742 
743 			fb_helper->funcs->gamma_get(crtc, &r,
744 						    &g, &b,
745 						    pindex >> 1);
746 
747 			for (i = 0; i < 4; i++)
748 				fb_helper->funcs->gamma_set(crtc, r,
749 							    green, b,
750 							    (pindex >> 1) + i);
751 		}
752 	}
753 
754 	if (fb->depth != 16)
755 		fb_helper->funcs->gamma_set(crtc, red, green, blue, pindex);
756 	return 0;
757 }
758 
759 /**
760  * drm_fb_helper_setcmap - implementation for ->fb_setcmap
761  * @cmap: cmap to set
762  * @info: fbdev registered by the helper
763  */
764 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
765 {
766 	struct drm_fb_helper *fb_helper = info->par;
767 	struct drm_device *dev = fb_helper->dev;
768 	struct drm_crtc_helper_funcs *crtc_funcs;
769 	u16 *red, *green, *blue, *transp;
770 	struct drm_crtc *crtc;
771 	int i, j, rc = 0;
772 	int start;
773 
774 	if (__drm_modeset_lock_all(dev, !!oops_in_progress)) {
775 		return -EBUSY;
776 	}
777 	if (!drm_fb_helper_is_bound(fb_helper)) {
778 		drm_modeset_unlock_all(dev);
779 		return -EBUSY;
780 	}
781 
782 	for (i = 0; i < fb_helper->crtc_count; i++) {
783 		crtc = fb_helper->crtc_info[i].mode_set.crtc;
784 		crtc_funcs = crtc->helper_private;
785 
786 		red = cmap->red;
787 		green = cmap->green;
788 		blue = cmap->blue;
789 		transp = cmap->transp;
790 		start = cmap->start;
791 
792 		for (j = 0; j < cmap->len; j++) {
793 			u16 hred, hgreen, hblue, htransp = 0xffff;
794 
795 			hred = *red++;
796 			hgreen = *green++;
797 			hblue = *blue++;
798 
799 			if (transp)
800 				htransp = *transp++;
801 
802 			rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
803 			if (rc)
804 				goto out;
805 		}
806 		if (crtc_funcs->load_lut)
807 			crtc_funcs->load_lut(crtc);
808 	}
809  out:
810 	drm_modeset_unlock_all(dev);
811 	return rc;
812 }
813 EXPORT_SYMBOL(drm_fb_helper_setcmap);
814 
815 /**
816  * drm_fb_helper_check_var - implementation for ->fb_check_var
817  * @var: screeninfo to check
818  * @info: fbdev registered by the helper
819  */
820 int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
821 			    struct fb_info *info)
822 {
823 	struct drm_fb_helper *fb_helper = info->par;
824 	struct drm_framebuffer *fb = fb_helper->fb;
825 	int depth;
826 
827 	if (var->pixclock != 0 || in_dbg_master())
828 		return -EINVAL;
829 
830 	/* Need to resize the fb object !!! */
831 	if (var->bits_per_pixel > fb->bits_per_pixel ||
832 	    var->xres > fb->width || var->yres > fb->height ||
833 	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
834 		DRM_DEBUG("fb userspace requested width/height/bpp is greater than current fb "
835 			  "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
836 			  var->xres, var->yres, var->bits_per_pixel,
837 			  var->xres_virtual, var->yres_virtual,
838 			  fb->width, fb->height, fb->bits_per_pixel);
839 		return -EINVAL;
840 	}
841 
842 	switch (var->bits_per_pixel) {
843 	case 16:
844 		depth = (var->green.length == 6) ? 16 : 15;
845 		break;
846 	case 32:
847 		depth = (var->transp.length > 0) ? 32 : 24;
848 		break;
849 	default:
850 		depth = var->bits_per_pixel;
851 		break;
852 	}
853 
854 	switch (depth) {
855 	case 8:
856 		var->red.offset = 0;
857 		var->green.offset = 0;
858 		var->blue.offset = 0;
859 		var->red.length = 8;
860 		var->green.length = 8;
861 		var->blue.length = 8;
862 		var->transp.length = 0;
863 		var->transp.offset = 0;
864 		break;
865 	case 15:
866 		var->red.offset = 10;
867 		var->green.offset = 5;
868 		var->blue.offset = 0;
869 		var->red.length = 5;
870 		var->green.length = 5;
871 		var->blue.length = 5;
872 		var->transp.length = 1;
873 		var->transp.offset = 15;
874 		break;
875 	case 16:
876 		var->red.offset = 11;
877 		var->green.offset = 5;
878 		var->blue.offset = 0;
879 		var->red.length = 5;
880 		var->green.length = 6;
881 		var->blue.length = 5;
882 		var->transp.length = 0;
883 		var->transp.offset = 0;
884 		break;
885 	case 24:
886 		var->red.offset = 16;
887 		var->green.offset = 8;
888 		var->blue.offset = 0;
889 		var->red.length = 8;
890 		var->green.length = 8;
891 		var->blue.length = 8;
892 		var->transp.length = 0;
893 		var->transp.offset = 0;
894 		break;
895 	case 32:
896 		var->red.offset = 16;
897 		var->green.offset = 8;
898 		var->blue.offset = 0;
899 		var->red.length = 8;
900 		var->green.length = 8;
901 		var->blue.length = 8;
902 		var->transp.length = 8;
903 		var->transp.offset = 24;
904 		break;
905 	default:
906 		return -EINVAL;
907 	}
908 	return 0;
909 }
910 EXPORT_SYMBOL(drm_fb_helper_check_var);
911 
912 /**
913  * drm_fb_helper_set_par - implementation for ->fb_set_par
914  * @info: fbdev registered by the helper
915  *
916  * This will let fbcon do the mode init and is called at initialization time by
917  * the fbdev core when registering the driver, and later on through the hotplug
918  * callback.
919  */
920 int drm_fb_helper_set_par(struct fb_info *info)
921 {
922 	struct drm_fb_helper *fb_helper = info->par;
923 	struct fb_var_screeninfo *var = &info->var;
924 
925 	if (var->pixclock != 0) {
926 		DRM_ERROR("PIXEL CLOCK SET\n");
927 		return -EINVAL;
928 	}
929 
930 	drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper);
931 
932 	return 0;
933 }
934 EXPORT_SYMBOL(drm_fb_helper_set_par);
935 
936 /**
937  * drm_fb_helper_pan_display - implementation for ->fb_pan_display
938  * @var: updated screen information
939  * @info: fbdev registered by the helper
940  */
941 int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
942 			      struct fb_info *info)
943 {
944 	struct drm_fb_helper *fb_helper = info->par;
945 	struct drm_device *dev = fb_helper->dev;
946 	struct drm_mode_set *modeset;
947 	int ret = 0;
948 	int i;
949 
950 	if (__drm_modeset_lock_all(dev, !!oops_in_progress)) {
951 		return -EBUSY;
952 	}
953 	if (!drm_fb_helper_is_bound(fb_helper)) {
954 		drm_modeset_unlock_all(dev);
955 		return -EBUSY;
956 	}
957 
958 	for (i = 0; i < fb_helper->crtc_count; i++) {
959 		modeset = &fb_helper->crtc_info[i].mode_set;
960 
961 		modeset->x = var->xoffset;
962 		modeset->y = var->yoffset;
963 
964 		if (modeset->num_connectors) {
965 			ret = drm_mode_set_config_internal(modeset);
966 			if (!ret) {
967 				info->var.xoffset = var->xoffset;
968 				info->var.yoffset = var->yoffset;
969 			}
970 		}
971 	}
972 	drm_modeset_unlock_all(dev);
973 	return ret;
974 }
975 EXPORT_SYMBOL(drm_fb_helper_pan_display);
976 
977 /*
978  * Allocates the backing storage and sets up the fbdev info structure through
979  * the ->fb_probe callback and then registers the fbdev and sets up the panic
980  * notifier.
981  */
982 static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
983 					 int preferred_bpp)
984 {
985 	int ret = 0;
986 	int crtc_count = 0;
987 	int i;
988 	struct fb_info *info;
989 	struct drm_fb_helper_surface_size sizes;
990 	int gamma_size = 0;
991 
992 	memset(&sizes, 0, sizeof(struct drm_fb_helper_surface_size));
993 	sizes.surface_depth = 24;
994 	sizes.surface_bpp = 32;
995 	sizes.fb_width = (unsigned)-1;
996 	sizes.fb_height = (unsigned)-1;
997 
998 	/* if driver picks 8 or 16 by default use that
999 	   for both depth/bpp */
1000 	if (preferred_bpp != sizes.surface_bpp)
1001 		sizes.surface_depth = sizes.surface_bpp = preferred_bpp;
1002 
1003 	/* first up get a count of crtcs now in use and new min/maxes width/heights */
1004 	for (i = 0; i < fb_helper->connector_count; i++) {
1005 		struct drm_fb_helper_connector *fb_helper_conn = fb_helper->connector_info[i];
1006 		struct drm_cmdline_mode *cmdline_mode;
1007 
1008 		cmdline_mode = &fb_helper_conn->connector->cmdline_mode;
1009 
1010 		if (cmdline_mode->bpp_specified) {
1011 			switch (cmdline_mode->bpp) {
1012 			case 8:
1013 				sizes.surface_depth = sizes.surface_bpp = 8;
1014 				break;
1015 			case 15:
1016 				sizes.surface_depth = 15;
1017 				sizes.surface_bpp = 16;
1018 				break;
1019 			case 16:
1020 				sizes.surface_depth = sizes.surface_bpp = 16;
1021 				break;
1022 			case 24:
1023 				sizes.surface_depth = sizes.surface_bpp = 24;
1024 				break;
1025 			case 32:
1026 				sizes.surface_depth = 24;
1027 				sizes.surface_bpp = 32;
1028 				break;
1029 			}
1030 			break;
1031 		}
1032 	}
1033 
1034 	crtc_count = 0;
1035 	for (i = 0; i < fb_helper->crtc_count; i++) {
1036 		struct drm_display_mode *desired_mode;
1037 		int x, y;
1038 		desired_mode = fb_helper->crtc_info[i].desired_mode;
1039 		x = fb_helper->crtc_info[i].x;
1040 		y = fb_helper->crtc_info[i].y;
1041 		if (desired_mode) {
1042 			if (gamma_size == 0)
1043 				gamma_size = fb_helper->crtc_info[i].mode_set.crtc->gamma_size;
1044 			if (desired_mode->hdisplay + x < sizes.fb_width)
1045 				sizes.fb_width = desired_mode->hdisplay + x;
1046 			if (desired_mode->vdisplay + y < sizes.fb_height)
1047 				sizes.fb_height = desired_mode->vdisplay + y;
1048 			if (desired_mode->hdisplay + x > sizes.surface_width)
1049 				sizes.surface_width = desired_mode->hdisplay + x;
1050 			if (desired_mode->vdisplay + y > sizes.surface_height)
1051 				sizes.surface_height = desired_mode->vdisplay + y;
1052 			crtc_count++;
1053 		}
1054 	}
1055 
1056 	if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
1057 		/* hmm everyone went away - assume VGA cable just fell out
1058 		   and will come back later. */
1059 		DRM_INFO("Cannot find any crtc or sizes - going 1024x768\n");
1060 		sizes.fb_width = sizes.surface_width = 1024;
1061 		sizes.fb_height = sizes.surface_height = 768;
1062 	}
1063 
1064 	/* push down into drivers */
1065 	ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
1066 	if (ret < 0)
1067 		return ret;
1068 
1069 	info = fb_helper->fbdev;
1070 
1071 	/*
1072 	 * Set the fb pointer - usually drm_setup_crtcs does this for hotplug
1073 	 * events, but at init time drm_setup_crtcs needs to be called before
1074 	 * the fb is allocated (since we need to figure out the desired size of
1075 	 * the fb before we can allocate it ...). Hence we need to fix things up
1076 	 * here again.
1077 	 */
1078 	for (i = 0; i < fb_helper->crtc_count; i++)
1079 		if (fb_helper->crtc_info[i].mode_set.num_connectors)
1080 			fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
1081 
1082 
1083 	info->var.pixclock = 0;
1084 	if (register_framebuffer(info) < 0)
1085 		return -EINVAL;
1086 
1087 	dev_info(fb_helper->dev->dev, "fb%d: %s frame buffer device\n",
1088 			info->node, info->fix.id);
1089 
1090 	/* Switch back to kernel console on panic */
1091 	/* multi card linked list maybe */
1092 	if (list_empty(&kernel_fb_helper_list)) {
1093 		dev_info(fb_helper->dev->dev, "registered panic notifier\n");
1094 		atomic_notifier_chain_register(&panic_notifier_list,
1095 					       &paniced);
1096 		register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
1097 	}
1098 
1099 	list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
1100 
1101 	return 0;
1102 }
1103 
1104 /**
1105  * drm_fb_helper_fill_fix - initializes fixed fbdev information
1106  * @info: fbdev registered by the helper
1107  * @pitch: desired pitch
1108  * @depth: desired depth
1109  *
1110  * Helper to fill in the fixed fbdev information useful for a non-accelerated
1111  * fbdev emulations. Drivers which support acceleration methods which impose
1112  * additional constraints need to set up their own limits.
1113  *
1114  * Drivers should call this (or their equivalent setup code) from their
1115  * ->fb_probe callback.
1116  */
1117 void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
1118 			    uint32_t depth)
1119 {
1120 	info->fix.type = FB_TYPE_PACKED_PIXELS;
1121 	info->fix.visual = depth == 8 ? FB_VISUAL_PSEUDOCOLOR :
1122 		FB_VISUAL_TRUECOLOR;
1123 	info->fix.mmio_start = 0;
1124 	info->fix.mmio_len = 0;
1125 	info->fix.type_aux = 0;
1126 	info->fix.xpanstep = 1; /* doing it in hw */
1127 	info->fix.ypanstep = 1; /* doing it in hw */
1128 	info->fix.ywrapstep = 0;
1129 	info->fix.accel = FB_ACCEL_NONE;
1130 
1131 	info->fix.line_length = pitch;
1132 	return;
1133 }
1134 EXPORT_SYMBOL(drm_fb_helper_fill_fix);
1135 
1136 /**
1137  * drm_fb_helper_fill_var - initalizes variable fbdev information
1138  * @info: fbdev instance to set up
1139  * @fb_helper: fb helper instance to use as template
1140  * @fb_width: desired fb width
1141  * @fb_height: desired fb height
1142  *
1143  * Sets up the variable fbdev metainformation from the given fb helper instance
1144  * and the drm framebuffer allocated in fb_helper->fb.
1145  *
1146  * Drivers should call this (or their equivalent setup code) from their
1147  * ->fb_probe callback after having allocated the fbdev backing
1148  * storage framebuffer.
1149  */
1150 void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper,
1151 			    uint32_t fb_width, uint32_t fb_height)
1152 {
1153 	struct drm_framebuffer *fb = fb_helper->fb;
1154 	info->pseudo_palette = fb_helper->pseudo_palette;
1155 	info->var.xres_virtual = fb->width;
1156 	info->var.yres_virtual = fb->height;
1157 	info->var.bits_per_pixel = fb->bits_per_pixel;
1158 	info->var.accel_flags = FB_ACCELF_TEXT;
1159 	info->var.xoffset = 0;
1160 	info->var.yoffset = 0;
1161 	info->var.activate = FB_ACTIVATE_NOW;
1162 	info->var.height = -1;
1163 	info->var.width = -1;
1164 
1165 	switch (fb->depth) {
1166 	case 8:
1167 		info->var.red.offset = 0;
1168 		info->var.green.offset = 0;
1169 		info->var.blue.offset = 0;
1170 		info->var.red.length = 8; /* 8bit DAC */
1171 		info->var.green.length = 8;
1172 		info->var.blue.length = 8;
1173 		info->var.transp.offset = 0;
1174 		info->var.transp.length = 0;
1175 		break;
1176 	case 15:
1177 		info->var.red.offset = 10;
1178 		info->var.green.offset = 5;
1179 		info->var.blue.offset = 0;
1180 		info->var.red.length = 5;
1181 		info->var.green.length = 5;
1182 		info->var.blue.length = 5;
1183 		info->var.transp.offset = 15;
1184 		info->var.transp.length = 1;
1185 		break;
1186 	case 16:
1187 		info->var.red.offset = 11;
1188 		info->var.green.offset = 5;
1189 		info->var.blue.offset = 0;
1190 		info->var.red.length = 5;
1191 		info->var.green.length = 6;
1192 		info->var.blue.length = 5;
1193 		info->var.transp.offset = 0;
1194 		break;
1195 	case 24:
1196 		info->var.red.offset = 16;
1197 		info->var.green.offset = 8;
1198 		info->var.blue.offset = 0;
1199 		info->var.red.length = 8;
1200 		info->var.green.length = 8;
1201 		info->var.blue.length = 8;
1202 		info->var.transp.offset = 0;
1203 		info->var.transp.length = 0;
1204 		break;
1205 	case 32:
1206 		info->var.red.offset = 16;
1207 		info->var.green.offset = 8;
1208 		info->var.blue.offset = 0;
1209 		info->var.red.length = 8;
1210 		info->var.green.length = 8;
1211 		info->var.blue.length = 8;
1212 		info->var.transp.offset = 24;
1213 		info->var.transp.length = 8;
1214 		break;
1215 	default:
1216 		break;
1217 	}
1218 
1219 	info->var.xres = fb_width;
1220 	info->var.yres = fb_height;
1221 }
1222 EXPORT_SYMBOL(drm_fb_helper_fill_var);
1223 
1224 static int drm_fb_helper_probe_connector_modes(struct drm_fb_helper *fb_helper,
1225 					       uint32_t maxX,
1226 					       uint32_t maxY)
1227 {
1228 	struct drm_connector *connector;
1229 	int count = 0;
1230 	int i;
1231 
1232 	for (i = 0; i < fb_helper->connector_count; i++) {
1233 		connector = fb_helper->connector_info[i]->connector;
1234 		count += connector->funcs->fill_modes(connector, maxX, maxY);
1235 	}
1236 
1237 	return count;
1238 }
1239 
1240 struct drm_display_mode *drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector, int width, int height)
1241 {
1242 	struct drm_display_mode *mode;
1243 
1244 	list_for_each_entry(mode, &fb_connector->connector->modes, head) {
1245 		if (mode->hdisplay > width ||
1246 		    mode->vdisplay > height)
1247 			continue;
1248 		if (mode->type & DRM_MODE_TYPE_PREFERRED)
1249 			return mode;
1250 	}
1251 	return NULL;
1252 }
1253 EXPORT_SYMBOL(drm_has_preferred_mode);
1254 
1255 static bool drm_has_cmdline_mode(struct drm_fb_helper_connector *fb_connector)
1256 {
1257 	return fb_connector->connector->cmdline_mode.specified;
1258 }
1259 
1260 struct drm_display_mode *drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
1261 						      int width, int height)
1262 {
1263 	struct drm_cmdline_mode *cmdline_mode;
1264 	struct drm_display_mode *mode = NULL;
1265 	bool prefer_non_interlace;
1266 
1267 	cmdline_mode = &fb_helper_conn->connector->cmdline_mode;
1268 	if (cmdline_mode->specified == false)
1269 		return mode;
1270 
1271 	/* attempt to find a matching mode in the list of modes
1272 	 *  we have gotten so far, if not add a CVT mode that conforms
1273 	 */
1274 	if (cmdline_mode->rb || cmdline_mode->margins)
1275 		goto create_mode;
1276 
1277 	prefer_non_interlace = !cmdline_mode->interlace;
1278  again:
1279 	list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
1280 		/* check width/height */
1281 		if (mode->hdisplay != cmdline_mode->xres ||
1282 		    mode->vdisplay != cmdline_mode->yres)
1283 			continue;
1284 
1285 		if (cmdline_mode->refresh_specified) {
1286 			if (mode->vrefresh != cmdline_mode->refresh)
1287 				continue;
1288 		}
1289 
1290 		if (cmdline_mode->interlace) {
1291 			if (!(mode->flags & DRM_MODE_FLAG_INTERLACE))
1292 				continue;
1293 		} else if (prefer_non_interlace) {
1294 			if (mode->flags & DRM_MODE_FLAG_INTERLACE)
1295 				continue;
1296 		}
1297 		return mode;
1298 	}
1299 
1300 	if (prefer_non_interlace) {
1301 		prefer_non_interlace = false;
1302 		goto again;
1303 	}
1304 
1305 create_mode:
1306 	mode = drm_mode_create_from_cmdline_mode(fb_helper_conn->connector->dev,
1307 						 cmdline_mode);
1308 	list_add(&mode->head, &fb_helper_conn->connector->modes);
1309 	return mode;
1310 }
1311 EXPORT_SYMBOL(drm_pick_cmdline_mode);
1312 
1313 static bool drm_connector_enabled(struct drm_connector *connector, bool strict)
1314 {
1315 	bool enable;
1316 
1317 	if (strict)
1318 		enable = connector->status == connector_status_connected;
1319 	else
1320 		enable = connector->status != connector_status_disconnected;
1321 
1322 	return enable;
1323 }
1324 
1325 static void drm_enable_connectors(struct drm_fb_helper *fb_helper,
1326 				  bool *enabled)
1327 {
1328 	bool any_enabled = false;
1329 	struct drm_connector *connector;
1330 	int i = 0;
1331 
1332 	for (i = 0; i < fb_helper->connector_count; i++) {
1333 		connector = fb_helper->connector_info[i]->connector;
1334 		enabled[i] = drm_connector_enabled(connector, true);
1335 		DRM_DEBUG_KMS("connector %d enabled? %s\n", connector->base.id,
1336 			  enabled[i] ? "yes" : "no");
1337 		any_enabled |= enabled[i];
1338 	}
1339 
1340 	if (any_enabled)
1341 		return;
1342 
1343 	for (i = 0; i < fb_helper->connector_count; i++) {
1344 		connector = fb_helper->connector_info[i]->connector;
1345 		enabled[i] = drm_connector_enabled(connector, false);
1346 	}
1347 }
1348 
1349 static bool drm_target_cloned(struct drm_fb_helper *fb_helper,
1350 			      struct drm_display_mode **modes,
1351 			      struct drm_fb_offset *offsets,
1352 			      bool *enabled, int width, int height)
1353 {
1354 	int count, i, j;
1355 	bool can_clone = false;
1356 	struct drm_fb_helper_connector *fb_helper_conn;
1357 	struct drm_display_mode *dmt_mode, *mode;
1358 
1359 	/* only contemplate cloning in the single crtc case */
1360 	if (fb_helper->crtc_count > 1)
1361 		return false;
1362 
1363 	count = 0;
1364 	for (i = 0; i < fb_helper->connector_count; i++) {
1365 		if (enabled[i])
1366 			count++;
1367 	}
1368 
1369 	/* only contemplate cloning if more than one connector is enabled */
1370 	if (count <= 1)
1371 		return false;
1372 
1373 	/* check the command line or if nothing common pick 1024x768 */
1374 	can_clone = true;
1375 	for (i = 0; i < fb_helper->connector_count; i++) {
1376 		if (!enabled[i])
1377 			continue;
1378 		fb_helper_conn = fb_helper->connector_info[i];
1379 		modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
1380 		if (!modes[i]) {
1381 			can_clone = false;
1382 			break;
1383 		}
1384 		for (j = 0; j < i; j++) {
1385 			if (!enabled[j])
1386 				continue;
1387 			if (!drm_mode_equal(modes[j], modes[i]))
1388 				can_clone = false;
1389 		}
1390 	}
1391 
1392 	if (can_clone) {
1393 		DRM_DEBUG_KMS("can clone using command line\n");
1394 		return true;
1395 	}
1396 
1397 	/* try and find a 1024x768 mode on each connector */
1398 	can_clone = true;
1399 	dmt_mode = drm_mode_find_dmt(fb_helper->dev, 1024, 768, 60, false);
1400 
1401 	for (i = 0; i < fb_helper->connector_count; i++) {
1402 
1403 		if (!enabled[i])
1404 			continue;
1405 
1406 		fb_helper_conn = fb_helper->connector_info[i];
1407 		list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
1408 			if (drm_mode_equal(mode, dmt_mode))
1409 				modes[i] = mode;
1410 		}
1411 		if (!modes[i])
1412 			can_clone = false;
1413 	}
1414 
1415 	if (can_clone) {
1416 		DRM_DEBUG_KMS("can clone using 1024x768\n");
1417 		return true;
1418 	}
1419 	DRM_INFO("kms: can't enable cloning when we probably wanted to.\n");
1420 	return false;
1421 }
1422 
1423 static int drm_get_tile_offsets(struct drm_fb_helper *fb_helper,
1424 				struct drm_display_mode **modes,
1425 				struct drm_fb_offset *offsets,
1426 				int idx,
1427 				int h_idx, int v_idx)
1428 {
1429 	struct drm_fb_helper_connector *fb_helper_conn;
1430 	int i;
1431 	int hoffset = 0, voffset = 0;
1432 
1433 	for (i = 0; i < fb_helper->connector_count; i++) {
1434 		fb_helper_conn = fb_helper->connector_info[i];
1435 		if (!fb_helper_conn->connector->has_tile)
1436 			continue;
1437 
1438 		if (!modes[i] && (h_idx || v_idx)) {
1439 			DRM_DEBUG_KMS("no modes for connector tiled %d %d\n", i,
1440 				      fb_helper_conn->connector->base.id);
1441 			continue;
1442 		}
1443 		if (fb_helper_conn->connector->tile_h_loc < h_idx)
1444 			hoffset += modes[i]->hdisplay;
1445 
1446 		if (fb_helper_conn->connector->tile_v_loc < v_idx)
1447 			voffset += modes[i]->vdisplay;
1448 	}
1449 	offsets[idx].x = hoffset;
1450 	offsets[idx].y = voffset;
1451 	DRM_DEBUG_KMS("returned %d %d for %d %d\n", hoffset, voffset, h_idx, v_idx);
1452 	return 0;
1453 }
1454 
1455 static bool drm_target_preferred(struct drm_fb_helper *fb_helper,
1456 				 struct drm_display_mode **modes,
1457 				 struct drm_fb_offset *offsets,
1458 				 bool *enabled, int width, int height)
1459 {
1460 	struct drm_fb_helper_connector *fb_helper_conn;
1461 	int i;
1462 	uint64_t conn_configured = 0, mask;
1463 	int tile_pass = 0;
1464 	mask = (1 << fb_helper->connector_count) - 1;
1465 retry:
1466 	for (i = 0; i < fb_helper->connector_count; i++) {
1467 		fb_helper_conn = fb_helper->connector_info[i];
1468 
1469 		if (conn_configured & (1 << i))
1470 			continue;
1471 
1472 		if (enabled[i] == false) {
1473 			conn_configured |= (1 << i);
1474 			continue;
1475 		}
1476 
1477 		/* first pass over all the untiled connectors */
1478 		if (tile_pass == 0 && fb_helper_conn->connector->has_tile)
1479 			continue;
1480 
1481 		if (tile_pass == 1) {
1482 			if (fb_helper_conn->connector->tile_h_loc != 0 ||
1483 			    fb_helper_conn->connector->tile_v_loc != 0)
1484 				continue;
1485 
1486 		} else {
1487 			if (fb_helper_conn->connector->tile_h_loc != tile_pass -1 &&
1488 			    fb_helper_conn->connector->tile_v_loc != tile_pass - 1)
1489 			/* if this tile_pass doesn't cover any of the tiles - keep going */
1490 				continue;
1491 
1492 			/* find the tile offsets for this pass - need
1493 			   to find all tiles left and above */
1494 			drm_get_tile_offsets(fb_helper, modes, offsets,
1495 					     i, fb_helper_conn->connector->tile_h_loc, fb_helper_conn->connector->tile_v_loc);
1496 		}
1497 		DRM_DEBUG_KMS("looking for cmdline mode on connector %d\n",
1498 			      fb_helper_conn->connector->base.id);
1499 
1500 		/* got for command line mode first */
1501 		modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
1502 		if (!modes[i]) {
1503 			DRM_DEBUG_KMS("looking for preferred mode on connector %d %d\n",
1504 				      fb_helper_conn->connector->base.id, fb_helper_conn->connector->tile_group ? fb_helper_conn->connector->tile_group->id : 0);
1505 			modes[i] = drm_has_preferred_mode(fb_helper_conn, width, height);
1506 		}
1507 		/* No preferred modes, pick one off the list */
1508 		if (!modes[i] && !list_empty(&fb_helper_conn->connector->modes)) {
1509 			list_for_each_entry(modes[i], &fb_helper_conn->connector->modes, head)
1510 				break;
1511 		}
1512 		DRM_DEBUG_KMS("found mode %s\n", modes[i] ? modes[i]->name :
1513 			  "none");
1514 		conn_configured |= (1 << i);
1515 	}
1516 
1517 	if ((conn_configured & mask) != mask) {
1518 		tile_pass++;
1519 		goto retry;
1520 	}
1521 	return true;
1522 }
1523 
1524 static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
1525 			  struct drm_fb_helper_crtc **best_crtcs,
1526 			  struct drm_display_mode **modes,
1527 			  int n, int width, int height)
1528 {
1529 	int c, o;
1530 	struct drm_device *dev = fb_helper->dev;
1531 	struct drm_connector *connector;
1532 	struct drm_connector_helper_funcs *connector_funcs;
1533 	struct drm_encoder *encoder;
1534 	int my_score, best_score, score;
1535 	struct drm_fb_helper_crtc **crtcs, *crtc;
1536 	struct drm_fb_helper_connector *fb_helper_conn;
1537 
1538 	if (n == fb_helper->connector_count)
1539 		return 0;
1540 
1541 	fb_helper_conn = fb_helper->connector_info[n];
1542 	connector = fb_helper_conn->connector;
1543 
1544 	best_crtcs[n] = NULL;
1545 	best_score = drm_pick_crtcs(fb_helper, best_crtcs, modes, n+1, width, height);
1546 	if (modes[n] == NULL)
1547 		return best_score;
1548 
1549 	crtcs = kzalloc(dev->mode_config.num_connector *
1550 			sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
1551 	if (!crtcs)
1552 		return best_score;
1553 
1554 	my_score = 1;
1555 	if (connector->status == connector_status_connected)
1556 		my_score++;
1557 	if (drm_has_cmdline_mode(fb_helper_conn))
1558 		my_score++;
1559 	if (drm_has_preferred_mode(fb_helper_conn, width, height))
1560 		my_score++;
1561 
1562 	connector_funcs = connector->helper_private;
1563 	encoder = connector_funcs->best_encoder(connector);
1564 	if (!encoder)
1565 		goto out;
1566 
1567 	/* select a crtc for this connector and then attempt to configure
1568 	   remaining connectors */
1569 	for (c = 0; c < fb_helper->crtc_count; c++) {
1570 		crtc = &fb_helper->crtc_info[c];
1571 
1572 		if ((encoder->possible_crtcs & (1 << c)) == 0)
1573 			continue;
1574 
1575 		for (o = 0; o < n; o++)
1576 			if (best_crtcs[o] == crtc)
1577 				break;
1578 
1579 		if (o < n) {
1580 			/* ignore cloning unless only a single crtc */
1581 			if (fb_helper->crtc_count > 1)
1582 				continue;
1583 
1584 			if (!drm_mode_equal(modes[o], modes[n]))
1585 				continue;
1586 		}
1587 
1588 		crtcs[n] = crtc;
1589 		memcpy(crtcs, best_crtcs, n * sizeof(struct drm_fb_helper_crtc *));
1590 		score = my_score + drm_pick_crtcs(fb_helper, crtcs, modes, n + 1,
1591 						  width, height);
1592 		if (score > best_score) {
1593 			best_score = score;
1594 			memcpy(best_crtcs, crtcs,
1595 			       dev->mode_config.num_connector *
1596 			       sizeof(struct drm_fb_helper_crtc *));
1597 		}
1598 	}
1599 out:
1600 	kfree(crtcs);
1601 	return best_score;
1602 }
1603 
1604 static void drm_setup_crtcs(struct drm_fb_helper *fb_helper)
1605 {
1606 	struct drm_device *dev = fb_helper->dev;
1607 	struct drm_fb_helper_crtc **crtcs;
1608 	struct drm_display_mode **modes;
1609 	struct drm_fb_offset *offsets;
1610 	struct drm_mode_set *modeset;
1611 	bool *enabled;
1612 	int width, height;
1613 	int i;
1614 
1615 	DRM_DEBUG_KMS("\n");
1616 
1617 	width = dev->mode_config.max_width;
1618 	height = dev->mode_config.max_height;
1619 
1620 	crtcs = kcalloc(dev->mode_config.num_connector,
1621 			sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
1622 	modes = kcalloc(dev->mode_config.num_connector,
1623 			sizeof(struct drm_display_mode *), GFP_KERNEL);
1624 	offsets = kcalloc(dev->mode_config.num_connector,
1625 			  sizeof(struct drm_fb_offset), GFP_KERNEL);
1626 	enabled = kcalloc(dev->mode_config.num_connector,
1627 			  sizeof(bool), GFP_KERNEL);
1628 	if (!crtcs || !modes || !enabled || !offsets) {
1629 		DRM_ERROR("Memory allocation failed\n");
1630 		goto out;
1631 	}
1632 
1633 
1634 	drm_enable_connectors(fb_helper, enabled);
1635 
1636 	if (!(fb_helper->funcs->initial_config &&
1637 	      fb_helper->funcs->initial_config(fb_helper, crtcs, modes,
1638 					       offsets,
1639 					       enabled, width, height))) {
1640 		memset(modes, 0, dev->mode_config.num_connector*sizeof(modes[0]));
1641 		memset(crtcs, 0, dev->mode_config.num_connector*sizeof(crtcs[0]));
1642 		memset(offsets, 0, dev->mode_config.num_connector*sizeof(offsets[0]));
1643 
1644 		if (!drm_target_cloned(fb_helper, modes, offsets,
1645 				       enabled, width, height) &&
1646 		    !drm_target_preferred(fb_helper, modes, offsets,
1647 					  enabled, width, height))
1648 			DRM_ERROR("Unable to find initial modes\n");
1649 
1650 		DRM_DEBUG_KMS("picking CRTCs for %dx%d config\n",
1651 			      width, height);
1652 
1653 		drm_pick_crtcs(fb_helper, crtcs, modes, 0, width, height);
1654 	}
1655 
1656 	/* need to set the modesets up here for use later */
1657 	/* fill out the connector<->crtc mappings into the modesets */
1658 	for (i = 0; i < fb_helper->crtc_count; i++) {
1659 		modeset = &fb_helper->crtc_info[i].mode_set;
1660 		modeset->num_connectors = 0;
1661 		modeset->fb = NULL;
1662 	}
1663 
1664 	for (i = 0; i < fb_helper->connector_count; i++) {
1665 		struct drm_display_mode *mode = modes[i];
1666 		struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
1667 		struct drm_fb_offset *offset = &offsets[i];
1668 		modeset = &fb_crtc->mode_set;
1669 
1670 		if (mode && fb_crtc) {
1671 			DRM_DEBUG_KMS("desired mode %s set on crtc %d (%d,%d)\n",
1672 				      mode->name, fb_crtc->mode_set.crtc->base.id, offset->x, offset->y);
1673 			fb_crtc->desired_mode = mode;
1674 			fb_crtc->x = offset->x;
1675 			fb_crtc->y = offset->y;
1676 			if (modeset->mode)
1677 				drm_mode_destroy(dev, modeset->mode);
1678 			modeset->mode = drm_mode_duplicate(dev,
1679 							   fb_crtc->desired_mode);
1680 			modeset->connectors[modeset->num_connectors++] = fb_helper->connector_info[i]->connector;
1681 			modeset->fb = fb_helper->fb;
1682 			modeset->x = offset->x;
1683 			modeset->y = offset->y;
1684 		}
1685 	}
1686 
1687 	/* Clear out any old modes if there are no more connected outputs. */
1688 	for (i = 0; i < fb_helper->crtc_count; i++) {
1689 		modeset = &fb_helper->crtc_info[i].mode_set;
1690 		if (modeset->num_connectors == 0) {
1691 			BUG_ON(modeset->fb);
1692 			if (modeset->mode)
1693 				drm_mode_destroy(dev, modeset->mode);
1694 			modeset->mode = NULL;
1695 		}
1696 	}
1697 out:
1698 	kfree(crtcs);
1699 	kfree(modes);
1700 	kfree(offsets);
1701 	kfree(enabled);
1702 }
1703 
1704 /**
1705  * drm_fb_helper_initial_config - setup a sane initial connector configuration
1706  * @fb_helper: fb_helper device struct
1707  * @bpp_sel: bpp value to use for the framebuffer configuration
1708  *
1709  * Scans the CRTCs and connectors and tries to put together an initial setup.
1710  * At the moment, this is a cloned configuration across all heads with
1711  * a new framebuffer object as the backing store.
1712  *
1713  * Note that this also registers the fbdev and so allows userspace to call into
1714  * the driver through the fbdev interfaces.
1715  *
1716  * This function will call down into the ->fb_probe callback to let
1717  * the driver allocate and initialize the fbdev info structure and the drm
1718  * framebuffer used to back the fbdev. drm_fb_helper_fill_var() and
1719  * drm_fb_helper_fill_fix() are provided as helpers to setup simple default
1720  * values for the fbdev info structure.
1721  *
1722  * RETURNS:
1723  * Zero if everything went ok, nonzero otherwise.
1724  */
1725 int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
1726 {
1727 	struct drm_device *dev = fb_helper->dev;
1728 	int count = 0;
1729 
1730 	mutex_lock(&dev->mode_config.mutex);
1731 	count = drm_fb_helper_probe_connector_modes(fb_helper,
1732 						    dev->mode_config.max_width,
1733 						    dev->mode_config.max_height);
1734 	mutex_unlock(&dev->mode_config.mutex);
1735 	/*
1736 	 * we shouldn't end up with no modes here.
1737 	 */
1738 	if (count == 0)
1739 		dev_info(fb_helper->dev->dev, "No connectors reported connected with modes\n");
1740 
1741 	drm_setup_crtcs(fb_helper);
1742 
1743 	return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
1744 }
1745 EXPORT_SYMBOL(drm_fb_helper_initial_config);
1746 
1747 /**
1748  * drm_fb_helper_hotplug_event - respond to a hotplug notification by
1749  *                               probing all the outputs attached to the fb
1750  * @fb_helper: the drm_fb_helper
1751  *
1752  * Scan the connectors attached to the fb_helper and try to put together a
1753  * setup after *notification of a change in output configuration.
1754  *
1755  * Called at runtime, takes the mode config locks to be able to check/change the
1756  * modeset configuration. Must be run from process context (which usually means
1757  * either the output polling work or a work item launched from the driver's
1758  * hotplug interrupt).
1759  *
1760  * Note that drivers may call this even before calling
1761  * drm_fb_helper_initial_config but only aftert drm_fb_helper_init. This allows
1762  * for a race-free fbcon setup and will make sure that the fbdev emulation will
1763  * not miss any hotplug events.
1764  *
1765  * RETURNS:
1766  * 0 on success and a non-zero error code otherwise.
1767  */
1768 int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
1769 {
1770 	struct drm_device *dev = fb_helper->dev;
1771 	u32 max_width, max_height;
1772 
1773 	mutex_lock(&fb_helper->dev->mode_config.mutex);
1774 	if (!fb_helper->fb || !drm_fb_helper_is_bound(fb_helper)) {
1775 		fb_helper->delayed_hotplug = true;
1776 		mutex_unlock(&fb_helper->dev->mode_config.mutex);
1777 		return 0;
1778 	}
1779 	DRM_DEBUG_KMS("\n");
1780 
1781 	max_width = fb_helper->fb->width;
1782 	max_height = fb_helper->fb->height;
1783 
1784 	drm_fb_helper_probe_connector_modes(fb_helper, max_width, max_height);
1785 	mutex_unlock(&fb_helper->dev->mode_config.mutex);
1786 
1787 	drm_modeset_lock_all(dev);
1788 	drm_setup_crtcs(fb_helper);
1789 	drm_modeset_unlock_all(dev);
1790 	drm_fb_helper_set_par(fb_helper->fbdev);
1791 
1792 	return 0;
1793 }
1794 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
1795 
1796 /* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
1797  * but the module doesn't depend on any fb console symbols.  At least
1798  * attempt to load fbcon to avoid leaving the system without a usable console.
1799  */
1800 #if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
1801 static int __init drm_fb_helper_modinit(void)
1802 {
1803 	const char *name = "fbcon";
1804 	struct module *fbcon;
1805 
1806 	mutex_lock(&module_mutex);
1807 	fbcon = find_module(name);
1808 	mutex_unlock(&module_mutex);
1809 
1810 	if (!fbcon)
1811 		request_module_nowait(name);
1812 	return 0;
1813 }
1814 
1815 module_init(drm_fb_helper_modinit);
1816 #endif
1817