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