xref: /openbmc/linux/drivers/gpu/drm/omapdrm/omap_crtc.c (revision 93707cbabcc8baf2b2b5f4a99c1f08ee83eb7abd)
1 /*
2  * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
3  * Author: Rob Clark <rob@ti.com>
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 as published by
7  * the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program.  If not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #include <drm/drm_atomic.h>
19 #include <drm/drm_atomic_helper.h>
20 #include <drm/drm_crtc.h>
21 #include <drm/drm_crtc_helper.h>
22 #include <drm/drm_mode.h>
23 #include <drm/drm_plane_helper.h>
24 #include <linux/math64.h>
25 
26 #include "omap_drv.h"
27 
28 #define to_omap_crtc_state(x) container_of(x, struct omap_crtc_state, base)
29 
30 struct omap_crtc_state {
31 	/* Must be first. */
32 	struct drm_crtc_state base;
33 	/* Shadow values for legacy userspace support. */
34 	unsigned int rotation;
35 	unsigned int zpos;
36 };
37 
38 #define to_omap_crtc(x) container_of(x, struct omap_crtc, base)
39 
40 struct omap_crtc {
41 	struct drm_crtc base;
42 
43 	const char *name;
44 	enum omap_channel channel;
45 
46 	struct videomode vm;
47 
48 	bool ignore_digit_sync_lost;
49 
50 	bool enabled;
51 	bool pending;
52 	wait_queue_head_t pending_wait;
53 	struct drm_pending_vblank_event *event;
54 };
55 
56 /* -----------------------------------------------------------------------------
57  * Helper Functions
58  */
59 
60 struct videomode *omap_crtc_timings(struct drm_crtc *crtc)
61 {
62 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
63 	return &omap_crtc->vm;
64 }
65 
66 enum omap_channel omap_crtc_channel(struct drm_crtc *crtc)
67 {
68 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
69 	return omap_crtc->channel;
70 }
71 
72 static bool omap_crtc_is_pending(struct drm_crtc *crtc)
73 {
74 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
75 	unsigned long flags;
76 	bool pending;
77 
78 	spin_lock_irqsave(&crtc->dev->event_lock, flags);
79 	pending = omap_crtc->pending;
80 	spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
81 
82 	return pending;
83 }
84 
85 int omap_crtc_wait_pending(struct drm_crtc *crtc)
86 {
87 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
88 
89 	/*
90 	 * Timeout is set to a "sufficiently" high value, which should cover
91 	 * a single frame refresh even on slower displays.
92 	 */
93 	return wait_event_timeout(omap_crtc->pending_wait,
94 				  !omap_crtc_is_pending(crtc),
95 				  msecs_to_jiffies(250));
96 }
97 
98 /* -----------------------------------------------------------------------------
99  * DSS Manager Functions
100  */
101 
102 /*
103  * Manager-ops, callbacks from output when they need to configure
104  * the upstream part of the video pipe.
105  *
106  * Most of these we can ignore until we add support for command-mode
107  * panels.. for video-mode the crtc-helpers already do an adequate
108  * job of sequencing the setup of the video pipe in the proper order
109  */
110 
111 /* ovl-mgr-id -> crtc */
112 static struct omap_crtc *omap_crtcs[8];
113 static struct omap_dss_device *omap_crtc_output[8];
114 
115 /* we can probably ignore these until we support command-mode panels: */
116 static int omap_crtc_dss_connect(enum omap_channel channel,
117 		struct omap_dss_device *dst)
118 {
119 	const struct dispc_ops *dispc_ops = dispc_get_ops();
120 
121 	if (omap_crtc_output[channel])
122 		return -EINVAL;
123 
124 	if ((dispc_ops->mgr_get_supported_outputs(channel) & dst->id) == 0)
125 		return -EINVAL;
126 
127 	omap_crtc_output[channel] = dst;
128 	dst->dispc_channel_connected = true;
129 
130 	return 0;
131 }
132 
133 static void omap_crtc_dss_disconnect(enum omap_channel channel,
134 		struct omap_dss_device *dst)
135 {
136 	omap_crtc_output[channel] = NULL;
137 	dst->dispc_channel_connected = false;
138 }
139 
140 static void omap_crtc_dss_start_update(enum omap_channel channel)
141 {
142 }
143 
144 /* Called only from the encoder enable/disable and suspend/resume handlers. */
145 static void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
146 {
147 	struct drm_device *dev = crtc->dev;
148 	struct omap_drm_private *priv = dev->dev_private;
149 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
150 	enum omap_channel channel = omap_crtc->channel;
151 	struct omap_irq_wait *wait;
152 	u32 framedone_irq, vsync_irq;
153 	int ret;
154 
155 	if (WARN_ON(omap_crtc->enabled == enable))
156 		return;
157 
158 	if (omap_crtc_output[channel]->output_type == OMAP_DISPLAY_TYPE_HDMI) {
159 		priv->dispc_ops->mgr_enable(channel, enable);
160 		omap_crtc->enabled = enable;
161 		return;
162 	}
163 
164 	if (omap_crtc->channel == OMAP_DSS_CHANNEL_DIGIT) {
165 		/*
166 		 * Digit output produces some sync lost interrupts during the
167 		 * first frame when enabling, so we need to ignore those.
168 		 */
169 		omap_crtc->ignore_digit_sync_lost = true;
170 	}
171 
172 	framedone_irq = priv->dispc_ops->mgr_get_framedone_irq(channel);
173 	vsync_irq = priv->dispc_ops->mgr_get_vsync_irq(channel);
174 
175 	if (enable) {
176 		wait = omap_irq_wait_init(dev, vsync_irq, 1);
177 	} else {
178 		/*
179 		 * When we disable the digit output, we need to wait for
180 		 * FRAMEDONE to know that DISPC has finished with the output.
181 		 *
182 		 * OMAP2/3 does not have FRAMEDONE irq for digit output, and in
183 		 * that case we need to use vsync interrupt, and wait for both
184 		 * even and odd frames.
185 		 */
186 
187 		if (framedone_irq)
188 			wait = omap_irq_wait_init(dev, framedone_irq, 1);
189 		else
190 			wait = omap_irq_wait_init(dev, vsync_irq, 2);
191 	}
192 
193 	priv->dispc_ops->mgr_enable(channel, enable);
194 	omap_crtc->enabled = enable;
195 
196 	ret = omap_irq_wait(dev, wait, msecs_to_jiffies(100));
197 	if (ret) {
198 		dev_err(dev->dev, "%s: timeout waiting for %s\n",
199 				omap_crtc->name, enable ? "enable" : "disable");
200 	}
201 
202 	if (omap_crtc->channel == OMAP_DSS_CHANNEL_DIGIT) {
203 		omap_crtc->ignore_digit_sync_lost = false;
204 		/* make sure the irq handler sees the value above */
205 		mb();
206 	}
207 }
208 
209 
210 static int omap_crtc_dss_enable(enum omap_channel channel)
211 {
212 	struct omap_crtc *omap_crtc = omap_crtcs[channel];
213 	struct omap_drm_private *priv = omap_crtc->base.dev->dev_private;
214 
215 	priv->dispc_ops->mgr_set_timings(omap_crtc->channel, &omap_crtc->vm);
216 	omap_crtc_set_enabled(&omap_crtc->base, true);
217 
218 	return 0;
219 }
220 
221 static void omap_crtc_dss_disable(enum omap_channel channel)
222 {
223 	struct omap_crtc *omap_crtc = omap_crtcs[channel];
224 
225 	omap_crtc_set_enabled(&omap_crtc->base, false);
226 }
227 
228 static void omap_crtc_dss_set_timings(enum omap_channel channel,
229 		const struct videomode *vm)
230 {
231 	struct omap_crtc *omap_crtc = omap_crtcs[channel];
232 	DBG("%s", omap_crtc->name);
233 	omap_crtc->vm = *vm;
234 }
235 
236 static void omap_crtc_dss_set_lcd_config(enum omap_channel channel,
237 		const struct dss_lcd_mgr_config *config)
238 {
239 	struct omap_crtc *omap_crtc = omap_crtcs[channel];
240 	struct omap_drm_private *priv = omap_crtc->base.dev->dev_private;
241 
242 	DBG("%s", omap_crtc->name);
243 	priv->dispc_ops->mgr_set_lcd_config(omap_crtc->channel, config);
244 }
245 
246 static int omap_crtc_dss_register_framedone(
247 		enum omap_channel channel,
248 		void (*handler)(void *), void *data)
249 {
250 	return 0;
251 }
252 
253 static void omap_crtc_dss_unregister_framedone(
254 		enum omap_channel channel,
255 		void (*handler)(void *), void *data)
256 {
257 }
258 
259 static const struct dss_mgr_ops mgr_ops = {
260 	.connect = omap_crtc_dss_connect,
261 	.disconnect = omap_crtc_dss_disconnect,
262 	.start_update = omap_crtc_dss_start_update,
263 	.enable = omap_crtc_dss_enable,
264 	.disable = omap_crtc_dss_disable,
265 	.set_timings = omap_crtc_dss_set_timings,
266 	.set_lcd_config = omap_crtc_dss_set_lcd_config,
267 	.register_framedone_handler = omap_crtc_dss_register_framedone,
268 	.unregister_framedone_handler = omap_crtc_dss_unregister_framedone,
269 };
270 
271 /* -----------------------------------------------------------------------------
272  * Setup, Flush and Page Flip
273  */
274 
275 void omap_crtc_error_irq(struct drm_crtc *crtc, uint32_t irqstatus)
276 {
277 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
278 
279 	if (omap_crtc->ignore_digit_sync_lost) {
280 		irqstatus &= ~DISPC_IRQ_SYNC_LOST_DIGIT;
281 		if (!irqstatus)
282 			return;
283 	}
284 
285 	DRM_ERROR_RATELIMITED("%s: errors: %08x\n", omap_crtc->name, irqstatus);
286 }
287 
288 void omap_crtc_vblank_irq(struct drm_crtc *crtc)
289 {
290 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
291 	struct drm_device *dev = omap_crtc->base.dev;
292 	struct omap_drm_private *priv = dev->dev_private;
293 	bool pending;
294 
295 	spin_lock(&crtc->dev->event_lock);
296 	/*
297 	 * If the dispc is busy we're racing the flush operation. Try again on
298 	 * the next vblank interrupt.
299 	 */
300 	if (priv->dispc_ops->mgr_go_busy(omap_crtc->channel)) {
301 		spin_unlock(&crtc->dev->event_lock);
302 		return;
303 	}
304 
305 	/* Send the vblank event if one has been requested. */
306 	if (omap_crtc->event) {
307 		drm_crtc_send_vblank_event(crtc, omap_crtc->event);
308 		omap_crtc->event = NULL;
309 	}
310 
311 	pending = omap_crtc->pending;
312 	omap_crtc->pending = false;
313 	spin_unlock(&crtc->dev->event_lock);
314 
315 	if (pending)
316 		drm_crtc_vblank_put(crtc);
317 
318 	/* Wake up omap_atomic_complete. */
319 	wake_up(&omap_crtc->pending_wait);
320 
321 	DBG("%s: apply done", omap_crtc->name);
322 }
323 
324 static void omap_crtc_write_crtc_properties(struct drm_crtc *crtc)
325 {
326 	struct omap_drm_private *priv = crtc->dev->dev_private;
327 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
328 	struct omap_overlay_manager_info info;
329 
330 	memset(&info, 0, sizeof(info));
331 
332 	info.default_color = 0x000000;
333 	info.trans_enabled = false;
334 	info.partial_alpha_enabled = false;
335 	info.cpr_enable = false;
336 
337 	priv->dispc_ops->mgr_setup(omap_crtc->channel, &info);
338 }
339 
340 /* -----------------------------------------------------------------------------
341  * CRTC Functions
342  */
343 
344 static void omap_crtc_destroy(struct drm_crtc *crtc)
345 {
346 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
347 
348 	DBG("%s", omap_crtc->name);
349 
350 	drm_crtc_cleanup(crtc);
351 
352 	kfree(omap_crtc);
353 }
354 
355 static void omap_crtc_arm_event(struct drm_crtc *crtc)
356 {
357 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
358 
359 	WARN_ON(omap_crtc->pending);
360 	omap_crtc->pending = true;
361 
362 	if (crtc->state->event) {
363 		omap_crtc->event = crtc->state->event;
364 		crtc->state->event = NULL;
365 	}
366 }
367 
368 static void omap_crtc_atomic_enable(struct drm_crtc *crtc,
369 				    struct drm_crtc_state *old_state)
370 {
371 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
372 	int ret;
373 
374 	DBG("%s", omap_crtc->name);
375 
376 	spin_lock_irq(&crtc->dev->event_lock);
377 	drm_crtc_vblank_on(crtc);
378 	ret = drm_crtc_vblank_get(crtc);
379 	WARN_ON(ret != 0);
380 
381 	omap_crtc_arm_event(crtc);
382 	spin_unlock_irq(&crtc->dev->event_lock);
383 }
384 
385 static void omap_crtc_atomic_disable(struct drm_crtc *crtc,
386 				     struct drm_crtc_state *old_state)
387 {
388 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
389 
390 	DBG("%s", omap_crtc->name);
391 
392 	spin_lock_irq(&crtc->dev->event_lock);
393 	if (crtc->state->event) {
394 		drm_crtc_send_vblank_event(crtc, crtc->state->event);
395 		crtc->state->event = NULL;
396 	}
397 	spin_unlock_irq(&crtc->dev->event_lock);
398 
399 	drm_crtc_vblank_off(crtc);
400 }
401 
402 static enum drm_mode_status omap_crtc_mode_valid(struct drm_crtc *crtc,
403 					const struct drm_display_mode *mode)
404 {
405 	struct omap_drm_private *priv = crtc->dev->dev_private;
406 
407 	/* Check for bandwidth limit */
408 	if (priv->max_bandwidth) {
409 		/*
410 		 * Estimation for the bandwidth need of a given mode with one
411 		 * full screen plane:
412 		 * bandwidth = resolution * 32bpp * (pclk / (vtotal * htotal))
413 		 *					^^ Refresh rate ^^
414 		 *
415 		 * The interlaced mode is taken into account by using the
416 		 * pixelclock in the calculation.
417 		 *
418 		 * The equation is rearranged for 64bit arithmetic.
419 		 */
420 		uint64_t bandwidth = mode->clock * 1000;
421 		unsigned int bpp = 4;
422 
423 		bandwidth = bandwidth * mode->hdisplay * mode->vdisplay * bpp;
424 		bandwidth = div_u64(bandwidth, mode->htotal * mode->vtotal);
425 
426 		/*
427 		 * Reject modes which would need more bandwidth if used with one
428 		 * full resolution plane (most common use case).
429 		 */
430 		if (priv->max_bandwidth < bandwidth)
431 			return MODE_BAD;
432 	}
433 
434 	return MODE_OK;
435 }
436 
437 static void omap_crtc_mode_set_nofb(struct drm_crtc *crtc)
438 {
439 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
440 	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
441 	struct omap_drm_private *priv = crtc->dev->dev_private;
442 	const u32 flags_mask = DISPLAY_FLAGS_DE_HIGH | DISPLAY_FLAGS_DE_LOW |
443 		DISPLAY_FLAGS_PIXDATA_POSEDGE | DISPLAY_FLAGS_PIXDATA_NEGEDGE |
444 		DISPLAY_FLAGS_SYNC_POSEDGE | DISPLAY_FLAGS_SYNC_NEGEDGE;
445 	unsigned int i;
446 
447 	DBG("%s: set mode: %d:\"%s\" %d %d %d %d %d %d %d %d %d %d 0x%x 0x%x",
448 	    omap_crtc->name, mode->base.id, mode->name,
449 	    mode->vrefresh, mode->clock,
450 	    mode->hdisplay, mode->hsync_start, mode->hsync_end, mode->htotal,
451 	    mode->vdisplay, mode->vsync_start, mode->vsync_end, mode->vtotal,
452 	    mode->type, mode->flags);
453 
454 	drm_display_mode_to_videomode(mode, &omap_crtc->vm);
455 
456 	/*
457 	 * HACK: This fixes the vm flags.
458 	 * struct drm_display_mode does not contain the VSYNC/HSYNC/DE flags
459 	 * and they get lost when converting back and forth between
460 	 * struct drm_display_mode and struct videomode. The hack below
461 	 * goes and fetches the missing flags from the panel drivers.
462 	 *
463 	 * Correct solution would be to use DRM's bus-flags, but that's not
464 	 * easily possible before the omapdrm's panel/encoder driver model
465 	 * has been changed to the DRM model.
466 	 */
467 
468 	for (i = 0; i < priv->num_encoders; ++i) {
469 		struct drm_encoder *encoder = priv->encoders[i];
470 
471 		if (encoder->crtc == crtc) {
472 			struct omap_dss_device *dssdev;
473 
474 			dssdev = omap_encoder_get_dssdev(encoder);
475 
476 			if (dssdev) {
477 				struct videomode vm = {0};
478 
479 				dssdev->driver->get_timings(dssdev, &vm);
480 
481 				omap_crtc->vm.flags |= vm.flags & flags_mask;
482 			}
483 
484 			break;
485 		}
486 	}
487 }
488 
489 static int omap_crtc_atomic_check(struct drm_crtc *crtc,
490 				struct drm_crtc_state *state)
491 {
492 	struct drm_plane_state *pri_state;
493 
494 	if (state->color_mgmt_changed && state->gamma_lut) {
495 		uint length = state->gamma_lut->length /
496 			sizeof(struct drm_color_lut);
497 
498 		if (length < 2)
499 			return -EINVAL;
500 	}
501 
502 	pri_state = drm_atomic_get_new_plane_state(state->state, crtc->primary);
503 	if (pri_state) {
504 		struct omap_crtc_state *omap_crtc_state =
505 			to_omap_crtc_state(state);
506 
507 		/* Mirror new values for zpos and rotation in omap_crtc_state */
508 		omap_crtc_state->zpos = pri_state->zpos;
509 		omap_crtc_state->rotation = pri_state->rotation;
510 	}
511 
512 	return 0;
513 }
514 
515 static void omap_crtc_atomic_begin(struct drm_crtc *crtc,
516 				   struct drm_crtc_state *old_crtc_state)
517 {
518 }
519 
520 static void omap_crtc_atomic_flush(struct drm_crtc *crtc,
521 				   struct drm_crtc_state *old_crtc_state)
522 {
523 	struct omap_drm_private *priv = crtc->dev->dev_private;
524 	struct omap_crtc *omap_crtc = to_omap_crtc(crtc);
525 	int ret;
526 
527 	if (crtc->state->color_mgmt_changed) {
528 		struct drm_color_lut *lut = NULL;
529 		uint length = 0;
530 
531 		if (crtc->state->gamma_lut) {
532 			lut = (struct drm_color_lut *)
533 				crtc->state->gamma_lut->data;
534 			length = crtc->state->gamma_lut->length /
535 				sizeof(*lut);
536 		}
537 		priv->dispc_ops->mgr_set_gamma(omap_crtc->channel, lut, length);
538 	}
539 
540 	omap_crtc_write_crtc_properties(crtc);
541 
542 	/* Only flush the CRTC if it is currently enabled. */
543 	if (!omap_crtc->enabled)
544 		return;
545 
546 	DBG("%s: GO", omap_crtc->name);
547 
548 	ret = drm_crtc_vblank_get(crtc);
549 	WARN_ON(ret != 0);
550 
551 	spin_lock_irq(&crtc->dev->event_lock);
552 	priv->dispc_ops->mgr_go(omap_crtc->channel);
553 	omap_crtc_arm_event(crtc);
554 	spin_unlock_irq(&crtc->dev->event_lock);
555 }
556 
557 static int omap_crtc_atomic_set_property(struct drm_crtc *crtc,
558 					 struct drm_crtc_state *state,
559 					 struct drm_property *property,
560 					 uint64_t val)
561 {
562 	struct omap_drm_private *priv = crtc->dev->dev_private;
563 	struct drm_plane_state *plane_state;
564 
565 	/*
566 	 * Delegate property set to the primary plane. Get the plane state and
567 	 * set the property directly, the shadow copy will be assigned in the
568 	 * omap_crtc_atomic_check callback. This way updates to plane state will
569 	 * always be mirrored in the crtc state correctly.
570 	 */
571 	plane_state = drm_atomic_get_plane_state(state->state, crtc->primary);
572 	if (IS_ERR(plane_state))
573 		return PTR_ERR(plane_state);
574 
575 	if (property == crtc->primary->rotation_property)
576 		plane_state->rotation = val;
577 	else if (property == priv->zorder_prop)
578 		plane_state->zpos = val;
579 	else
580 		return -EINVAL;
581 
582 	return 0;
583 }
584 
585 static int omap_crtc_atomic_get_property(struct drm_crtc *crtc,
586 					 const struct drm_crtc_state *state,
587 					 struct drm_property *property,
588 					 uint64_t *val)
589 {
590 	struct omap_drm_private *priv = crtc->dev->dev_private;
591 	struct omap_crtc_state *omap_state = to_omap_crtc_state(state);
592 
593 	if (property == crtc->primary->rotation_property)
594 		*val = omap_state->rotation;
595 	else if (property == priv->zorder_prop)
596 		*val = omap_state->zpos;
597 	else
598 		return -EINVAL;
599 
600 	return 0;
601 }
602 
603 static void omap_crtc_reset(struct drm_crtc *crtc)
604 {
605 	if (crtc->state)
606 		__drm_atomic_helper_crtc_destroy_state(crtc->state);
607 
608 	kfree(crtc->state);
609 	crtc->state = kzalloc(sizeof(struct omap_crtc_state), GFP_KERNEL);
610 
611 	if (crtc->state)
612 		crtc->state->crtc = crtc;
613 }
614 
615 static struct drm_crtc_state *
616 omap_crtc_duplicate_state(struct drm_crtc *crtc)
617 {
618 	struct omap_crtc_state *state, *current_state;
619 
620 	if (WARN_ON(!crtc->state))
621 		return NULL;
622 
623 	current_state = to_omap_crtc_state(crtc->state);
624 
625 	state = kmalloc(sizeof(*state), GFP_KERNEL);
626 	if (!state)
627 		return NULL;
628 
629 	__drm_atomic_helper_crtc_duplicate_state(crtc, &state->base);
630 
631 	state->zpos = current_state->zpos;
632 	state->rotation = current_state->rotation;
633 
634 	return &state->base;
635 }
636 
637 static const struct drm_crtc_funcs omap_crtc_funcs = {
638 	.reset = omap_crtc_reset,
639 	.set_config = drm_atomic_helper_set_config,
640 	.destroy = omap_crtc_destroy,
641 	.page_flip = drm_atomic_helper_page_flip,
642 	.gamma_set = drm_atomic_helper_legacy_gamma_set,
643 	.atomic_duplicate_state = omap_crtc_duplicate_state,
644 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
645 	.atomic_set_property = omap_crtc_atomic_set_property,
646 	.atomic_get_property = omap_crtc_atomic_get_property,
647 	.enable_vblank = omap_irq_enable_vblank,
648 	.disable_vblank = omap_irq_disable_vblank,
649 };
650 
651 static const struct drm_crtc_helper_funcs omap_crtc_helper_funcs = {
652 	.mode_set_nofb = omap_crtc_mode_set_nofb,
653 	.atomic_check = omap_crtc_atomic_check,
654 	.atomic_begin = omap_crtc_atomic_begin,
655 	.atomic_flush = omap_crtc_atomic_flush,
656 	.atomic_enable = omap_crtc_atomic_enable,
657 	.atomic_disable = omap_crtc_atomic_disable,
658 	.mode_valid = omap_crtc_mode_valid,
659 };
660 
661 /* -----------------------------------------------------------------------------
662  * Init and Cleanup
663  */
664 
665 static const char *channel_names[] = {
666 	[OMAP_DSS_CHANNEL_LCD] = "lcd",
667 	[OMAP_DSS_CHANNEL_DIGIT] = "tv",
668 	[OMAP_DSS_CHANNEL_LCD2] = "lcd2",
669 	[OMAP_DSS_CHANNEL_LCD3] = "lcd3",
670 };
671 
672 void omap_crtc_pre_init(void)
673 {
674 	memset(omap_crtcs, 0, sizeof(omap_crtcs));
675 
676 	dss_install_mgr_ops(&mgr_ops);
677 }
678 
679 void omap_crtc_pre_uninit(void)
680 {
681 	dss_uninstall_mgr_ops();
682 }
683 
684 /* initialize crtc */
685 struct drm_crtc *omap_crtc_init(struct drm_device *dev,
686 		struct drm_plane *plane, struct omap_dss_device *dssdev)
687 {
688 	struct omap_drm_private *priv = dev->dev_private;
689 	struct drm_crtc *crtc = NULL;
690 	struct omap_crtc *omap_crtc;
691 	enum omap_channel channel;
692 	struct omap_dss_device *out;
693 	int ret;
694 
695 	out = omapdss_find_output_from_display(dssdev);
696 	channel = out->dispc_channel;
697 	omap_dss_put_device(out);
698 
699 	DBG("%s", channel_names[channel]);
700 
701 	/* Multiple displays on same channel is not allowed */
702 	if (WARN_ON(omap_crtcs[channel] != NULL))
703 		return ERR_PTR(-EINVAL);
704 
705 	omap_crtc = kzalloc(sizeof(*omap_crtc), GFP_KERNEL);
706 	if (!omap_crtc)
707 		return ERR_PTR(-ENOMEM);
708 
709 	crtc = &omap_crtc->base;
710 
711 	init_waitqueue_head(&omap_crtc->pending_wait);
712 
713 	omap_crtc->channel = channel;
714 	omap_crtc->name = channel_names[channel];
715 
716 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
717 					&omap_crtc_funcs, NULL);
718 	if (ret < 0) {
719 		dev_err(dev->dev, "%s(): could not init crtc for: %s\n",
720 			__func__, dssdev->name);
721 		kfree(omap_crtc);
722 		return ERR_PTR(ret);
723 	}
724 
725 	drm_crtc_helper_add(crtc, &omap_crtc_helper_funcs);
726 
727 	/* The dispc API adapts to what ever size, but the HW supports
728 	 * 256 element gamma table for LCDs and 1024 element table for
729 	 * OMAP_DSS_CHANNEL_DIGIT. X server assumes 256 element gamma
730 	 * tables so lets use that. Size of HW gamma table can be
731 	 * extracted with dispc_mgr_gamma_size(). If it returns 0
732 	 * gamma table is not supprted.
733 	 */
734 	if (priv->dispc_ops->mgr_gamma_size(channel)) {
735 		uint gamma_lut_size = 256;
736 
737 		drm_crtc_enable_color_mgmt(crtc, 0, false, gamma_lut_size);
738 		drm_mode_crtc_set_gamma_size(crtc, gamma_lut_size);
739 	}
740 
741 	omap_plane_install_properties(crtc->primary, &crtc->base);
742 
743 	omap_crtcs[channel] = omap_crtc;
744 
745 	return crtc;
746 }
747