xref: /linux/drivers/gpu/drm/sun4i/sun4i_backend.c (revision f6e8dc9edf963dbc99085e54f6ced6da9daa6100)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2015 Free Electrons
4  * Copyright (C) 2015 NextThing Co
5  *
6  * Maxime Ripard <maxime.ripard@free-electrons.com>
7  */
8 
9 #include <linux/component.h>
10 #include <linux/list.h>
11 #include <linux/module.h>
12 #include <linux/of_device.h>
13 #include <linux/of_graph.h>
14 #include <linux/dma-mapping.h>
15 #include <linux/platform_device.h>
16 #include <linux/reset.h>
17 
18 #include <drm/drm_atomic.h>
19 #include <drm/drm_atomic_helper.h>
20 #include <drm/drm_blend.h>
21 #include <drm/drm_crtc.h>
22 #include <drm/drm_fb_dma_helper.h>
23 #include <drm/drm_fourcc.h>
24 #include <drm/drm_framebuffer.h>
25 #include <drm/drm_gem_dma_helper.h>
26 #include <drm/drm_print.h>
27 #include <drm/drm_probe_helper.h>
28 
29 #include "sun4i_backend.h"
30 #include "sun4i_drv.h"
31 #include "sun4i_frontend.h"
32 #include "sun4i_layer.h"
33 #include "sunxi_engine.h"
34 
35 struct sun4i_backend_quirks {
36 	/* backend <-> TCON muxing selection done in backend */
37 	bool needs_output_muxing;
38 
39 	/* alpha at the lowest z position is not always supported */
40 	bool supports_lowest_plane_alpha;
41 };
42 
43 static const u32 sunxi_rgb2yuv_coef[12] = {
44 	0x00000107, 0x00000204, 0x00000064, 0x00000108,
45 	0x00003f69, 0x00003ed6, 0x000001c1, 0x00000808,
46 	0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
47 };
48 
49 static void sun4i_backend_apply_color_correction(struct sunxi_engine *engine)
50 {
51 	int i;
52 
53 	DRM_DEBUG_DRIVER("Applying RGB to YUV color correction\n");
54 
55 	/* Set color correction */
56 	regmap_write(engine->regs, SUN4I_BACKEND_OCCTL_REG,
57 		     SUN4I_BACKEND_OCCTL_ENABLE);
58 
59 	for (i = 0; i < 12; i++)
60 		regmap_write(engine->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
61 			     sunxi_rgb2yuv_coef[i]);
62 }
63 
64 static void sun4i_backend_disable_color_correction(struct sunxi_engine *engine)
65 {
66 	DRM_DEBUG_DRIVER("Disabling color correction\n");
67 
68 	/* Disable color correction */
69 	regmap_update_bits(engine->regs, SUN4I_BACKEND_OCCTL_REG,
70 			   SUN4I_BACKEND_OCCTL_ENABLE, 0);
71 }
72 
73 static void sun4i_backend_commit(struct sunxi_engine *engine,
74 				 struct drm_crtc *crtc,
75 				 struct drm_atomic_state *state)
76 {
77 	DRM_DEBUG_DRIVER("Committing changes\n");
78 
79 	regmap_write(engine->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
80 		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS |
81 		     SUN4I_BACKEND_REGBUFFCTL_LOADCTL);
82 }
83 
84 void sun4i_backend_layer_enable(struct sun4i_backend *backend,
85 				int layer, bool enable)
86 {
87 	u32 val;
88 
89 	DRM_DEBUG_DRIVER("%sabling layer %d\n", enable ? "En" : "Dis",
90 			 layer);
91 
92 	if (enable)
93 		val = SUN4I_BACKEND_MODCTL_LAY_EN(layer);
94 	else
95 		val = 0;
96 
97 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
98 			   SUN4I_BACKEND_MODCTL_LAY_EN(layer), val);
99 }
100 
101 static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
102 {
103 	switch (format) {
104 	case DRM_FORMAT_ARGB8888:
105 		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB8888;
106 		break;
107 
108 	case DRM_FORMAT_ARGB4444:
109 		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB4444;
110 		break;
111 
112 	case DRM_FORMAT_ARGB1555:
113 		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB1555;
114 		break;
115 
116 	case DRM_FORMAT_RGBA5551:
117 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA5551;
118 		break;
119 
120 	case DRM_FORMAT_RGBA4444:
121 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA4444;
122 		break;
123 
124 	case DRM_FORMAT_XRGB8888:
125 		*mode = SUN4I_BACKEND_LAY_FBFMT_XRGB8888;
126 		break;
127 
128 	case DRM_FORMAT_RGB888:
129 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB888;
130 		break;
131 
132 	case DRM_FORMAT_RGB565:
133 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB565;
134 		break;
135 
136 	default:
137 		return -EINVAL;
138 	}
139 
140 	return 0;
141 }
142 
143 static const uint32_t sun4i_backend_formats[] = {
144 	DRM_FORMAT_ARGB1555,
145 	DRM_FORMAT_ARGB4444,
146 	DRM_FORMAT_ARGB8888,
147 	DRM_FORMAT_RGB565,
148 	DRM_FORMAT_RGB888,
149 	DRM_FORMAT_RGBA4444,
150 	DRM_FORMAT_RGBA5551,
151 	DRM_FORMAT_UYVY,
152 	DRM_FORMAT_VYUY,
153 	DRM_FORMAT_XRGB8888,
154 	DRM_FORMAT_YUYV,
155 	DRM_FORMAT_YVYU,
156 };
157 
158 bool sun4i_backend_format_is_supported(uint32_t fmt, uint64_t modifier)
159 {
160 	unsigned int i;
161 
162 	if (modifier != DRM_FORMAT_MOD_LINEAR)
163 		return false;
164 
165 	for (i = 0; i < ARRAY_SIZE(sun4i_backend_formats); i++)
166 		if (sun4i_backend_formats[i] == fmt)
167 			return true;
168 
169 	return false;
170 }
171 
172 int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
173 				     int layer, struct drm_plane *plane)
174 {
175 	struct drm_plane_state *state = plane->state;
176 
177 	DRM_DEBUG_DRIVER("Updating layer %d\n", layer);
178 
179 	/* Set height and width */
180 	DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
181 			 state->crtc_w, state->crtc_h);
182 	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
183 		     SUN4I_BACKEND_LAYSIZE(state->crtc_w,
184 					   state->crtc_h));
185 
186 	/* Set base coordinates */
187 	DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
188 			 state->crtc_x, state->crtc_y);
189 	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
190 		     SUN4I_BACKEND_LAYCOOR(state->crtc_x,
191 					   state->crtc_y));
192 
193 	return 0;
194 }
195 
196 static int sun4i_backend_update_yuv_format(struct sun4i_backend *backend,
197 					   int layer, struct drm_plane *plane)
198 {
199 	struct drm_plane_state *state = plane->state;
200 	struct drm_framebuffer *fb = state->fb;
201 	const struct drm_format_info *format = fb->format;
202 	const uint32_t fmt = format->format;
203 	u32 val = SUN4I_BACKEND_IYUVCTL_EN;
204 	int i;
205 
206 	for (i = 0; i < ARRAY_SIZE(sunxi_bt601_yuv2rgb_coef); i++)
207 		regmap_write(backend->engine.regs,
208 			     SUN4I_BACKEND_YGCOEF_REG(i),
209 			     sunxi_bt601_yuv2rgb_coef[i]);
210 
211 	/*
212 	 * We should do that only for a single plane, but the
213 	 * framebuffer's atomic_check has our back on this.
214 	 */
215 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
216 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN,
217 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN);
218 
219 	/* TODO: Add support for the multi-planar YUV formats */
220 	if (drm_format_info_is_yuv_packed(format) &&
221 	    drm_format_info_is_yuv_sampling_422(format))
222 		val |= SUN4I_BACKEND_IYUVCTL_FBFMT_PACKED_YUV422;
223 	else
224 		DRM_DEBUG_DRIVER("Unsupported YUV format (0x%x)\n", fmt);
225 
226 	/*
227 	 * Allwinner seems to list the pixel sequence from right to left, while
228 	 * DRM lists it from left to right.
229 	 */
230 	switch (fmt) {
231 	case DRM_FORMAT_YUYV:
232 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_VYUY;
233 		break;
234 	case DRM_FORMAT_YVYU:
235 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_UYVY;
236 		break;
237 	case DRM_FORMAT_UYVY:
238 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YVYU;
239 		break;
240 	case DRM_FORMAT_VYUY:
241 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YUYV;
242 		break;
243 	default:
244 		DRM_DEBUG_DRIVER("Unsupported YUV pixel sequence (0x%x)\n",
245 				 fmt);
246 	}
247 
248 	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVCTL_REG, val);
249 
250 	return 0;
251 }
252 
253 int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
254 				       int layer, struct drm_plane *plane)
255 {
256 	struct drm_plane_state *state = plane->state;
257 	struct drm_framebuffer *fb = state->fb;
258 	u32 val;
259 	int ret;
260 
261 	/* Clear the YUV mode */
262 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
263 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
264 
265 	val = SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA(state->alpha >> 8);
266 	if (state->alpha != DRM_BLEND_ALPHA_OPAQUE)
267 		val |= SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN;
268 	regmap_update_bits(backend->engine.regs,
269 			   SUN4I_BACKEND_ATTCTL_REG0(layer),
270 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_MASK |
271 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN,
272 			   val);
273 
274 	if (fb->format->is_yuv)
275 		return sun4i_backend_update_yuv_format(backend, layer, plane);
276 
277 	ret = sun4i_backend_drm_format_to_layer(fb->format->format, &val);
278 	if (ret) {
279 		DRM_DEBUG_DRIVER("Invalid format\n");
280 		return ret;
281 	}
282 
283 	regmap_update_bits(backend->engine.regs,
284 			   SUN4I_BACKEND_ATTCTL_REG1(layer),
285 			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
286 
287 	return 0;
288 }
289 
290 int sun4i_backend_update_layer_frontend(struct sun4i_backend *backend,
291 					int layer, uint32_t fmt)
292 {
293 	u32 val;
294 	int ret;
295 
296 	ret = sun4i_backend_drm_format_to_layer(fmt, &val);
297 	if (ret) {
298 		DRM_DEBUG_DRIVER("Invalid format\n");
299 		return ret;
300 	}
301 
302 	regmap_update_bits(backend->engine.regs,
303 			   SUN4I_BACKEND_ATTCTL_REG0(layer),
304 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN,
305 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN);
306 
307 	regmap_update_bits(backend->engine.regs,
308 			   SUN4I_BACKEND_ATTCTL_REG1(layer),
309 			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
310 
311 	return 0;
312 }
313 
314 static int sun4i_backend_update_yuv_buffer(struct sun4i_backend *backend,
315 					   struct drm_framebuffer *fb,
316 					   dma_addr_t paddr)
317 {
318 	/* TODO: Add support for the multi-planar YUV formats */
319 	DRM_DEBUG_DRIVER("Setting packed YUV buffer address to %pad\n", &paddr);
320 	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVADD_REG(0), paddr);
321 
322 	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
323 	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVLINEWIDTH_REG(0),
324 		     fb->pitches[0] * 8);
325 
326 	return 0;
327 }
328 
329 int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
330 				      int layer, struct drm_plane *plane)
331 {
332 	struct drm_plane_state *state = plane->state;
333 	struct drm_framebuffer *fb = state->fb;
334 	u32 lo_paddr, hi_paddr;
335 	dma_addr_t dma_addr;
336 
337 	/* Set the line width */
338 	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
339 	regmap_write(backend->engine.regs,
340 		     SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
341 		     fb->pitches[0] * 8);
342 
343 	/* Get the start of the displayed memory */
344 	dma_addr = drm_fb_dma_get_gem_addr(fb, state, 0);
345 	DRM_DEBUG_DRIVER("Setting buffer address to %pad\n", &dma_addr);
346 
347 	if (fb->format->is_yuv)
348 		return sun4i_backend_update_yuv_buffer(backend, fb, dma_addr);
349 
350 	/* Write the 32 lower bits of the address (in bits) */
351 	lo_paddr = dma_addr << 3;
352 	DRM_DEBUG_DRIVER("Setting address lower bits to 0x%x\n", lo_paddr);
353 	regmap_write(backend->engine.regs,
354 		     SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
355 		     lo_paddr);
356 
357 	/* And the upper bits */
358 	hi_paddr = dma_addr >> 29;
359 	DRM_DEBUG_DRIVER("Setting address high bits to 0x%x\n", hi_paddr);
360 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
361 			   SUN4I_BACKEND_LAYFB_H4ADD_MSK(layer),
362 			   SUN4I_BACKEND_LAYFB_H4ADD(layer, hi_paddr));
363 
364 	return 0;
365 }
366 
367 int sun4i_backend_update_layer_zpos(struct sun4i_backend *backend, int layer,
368 				    struct drm_plane *plane)
369 {
370 	struct drm_plane_state *state = plane->state;
371 	struct sun4i_layer_state *p_state = state_to_sun4i_layer_state(state);
372 	unsigned int priority = state->normalized_zpos;
373 	unsigned int pipe = p_state->pipe;
374 
375 	DRM_DEBUG_DRIVER("Setting layer %d's priority to %d and pipe %d\n",
376 			 layer, priority, pipe);
377 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
378 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK |
379 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL_MASK,
380 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(p_state->pipe) |
381 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL(priority));
382 
383 	return 0;
384 }
385 
386 void sun4i_backend_cleanup_layer(struct sun4i_backend *backend,
387 				 int layer)
388 {
389 	regmap_update_bits(backend->engine.regs,
390 			   SUN4I_BACKEND_ATTCTL_REG0(layer),
391 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN |
392 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
393 }
394 
395 static bool sun4i_backend_plane_uses_scaler(struct drm_plane_state *state)
396 {
397 	u16 src_h = state->src_h >> 16;
398 	u16 src_w = state->src_w >> 16;
399 
400 	DRM_DEBUG_DRIVER("Input size %dx%d, output size %dx%d\n",
401 			 src_w, src_h, state->crtc_w, state->crtc_h);
402 
403 	if ((state->crtc_h != src_h) || (state->crtc_w != src_w))
404 		return true;
405 
406 	return false;
407 }
408 
409 static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
410 {
411 	struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
412 	struct sun4i_backend *backend = layer->backend;
413 	uint32_t format = state->fb->format->format;
414 	uint64_t modifier = state->fb->modifier;
415 
416 	if (IS_ERR(backend->frontend))
417 		return false;
418 
419 	if (!sun4i_frontend_format_is_supported(format, modifier))
420 		return false;
421 
422 	if (!sun4i_backend_format_is_supported(format, modifier))
423 		return true;
424 
425 	/*
426 	 * TODO: The backend alone allows 2x and 4x integer scaling, including
427 	 * support for an alpha component (which the frontend doesn't support).
428 	 * Use the backend directly instead of the frontend in this case, with
429 	 * another test to return false.
430 	 */
431 
432 	if (sun4i_backend_plane_uses_scaler(state))
433 		return true;
434 
435 	/*
436 	 * Here the format is supported by both the frontend and the backend
437 	 * and no frontend scaling is required, so use the backend directly.
438 	 */
439 	return false;
440 }
441 
442 static bool sun4i_backend_plane_is_supported(struct drm_plane_state *state,
443 					     bool *uses_frontend)
444 {
445 	if (sun4i_backend_plane_uses_frontend(state)) {
446 		*uses_frontend = true;
447 		return true;
448 	}
449 
450 	*uses_frontend = false;
451 
452 	/* Scaling is not supported without the frontend. */
453 	if (sun4i_backend_plane_uses_scaler(state))
454 		return false;
455 
456 	return true;
457 }
458 
459 static void sun4i_backend_atomic_begin(struct sunxi_engine *engine,
460 				       struct drm_crtc_state *old_state)
461 {
462 	u32 val;
463 
464 	WARN_ON(regmap_read_poll_timeout(engine->regs,
465 					 SUN4I_BACKEND_REGBUFFCTL_REG,
466 					 val, !(val & SUN4I_BACKEND_REGBUFFCTL_LOADCTL),
467 					 100, 50000));
468 }
469 
470 static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
471 				      struct drm_crtc_state *crtc_state)
472 {
473 	struct drm_plane_state *plane_states[SUN4I_BACKEND_NUM_LAYERS] = { 0 };
474 	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
475 	struct drm_atomic_state *state = crtc_state->state;
476 	struct drm_device *drm = state->dev;
477 	struct drm_plane *plane;
478 	unsigned int num_planes = 0;
479 	unsigned int num_alpha_planes = 0;
480 	unsigned int num_frontend_planes = 0;
481 	unsigned int num_alpha_planes_max = 1;
482 	unsigned int num_yuv_planes = 0;
483 	unsigned int current_pipe = 0;
484 	unsigned int i;
485 
486 	DRM_DEBUG_DRIVER("Starting checking our planes\n");
487 
488 	if (!crtc_state->planes_changed)
489 		return 0;
490 
491 	drm_for_each_plane_mask(plane, drm, crtc_state->plane_mask) {
492 		struct drm_plane_state *plane_state =
493 			drm_atomic_get_plane_state(state, plane);
494 		struct sun4i_layer_state *layer_state =
495 			state_to_sun4i_layer_state(plane_state);
496 		struct drm_framebuffer *fb = plane_state->fb;
497 
498 		if (!sun4i_backend_plane_is_supported(plane_state,
499 						      &layer_state->uses_frontend))
500 			return -EINVAL;
501 
502 		if (layer_state->uses_frontend) {
503 			DRM_DEBUG_DRIVER("Using the frontend for plane %d\n",
504 					 plane->index);
505 			num_frontend_planes++;
506 		} else {
507 			if (fb->format->is_yuv) {
508 				DRM_DEBUG_DRIVER("Plane FB format is YUV\n");
509 				num_yuv_planes++;
510 			}
511 		}
512 
513 		DRM_DEBUG_DRIVER("Plane FB format is %p4cc\n",
514 				 &fb->format->format);
515 		if (fb->format->has_alpha || (plane_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
516 			num_alpha_planes++;
517 
518 		DRM_DEBUG_DRIVER("Plane zpos is %d\n",
519 				 plane_state->normalized_zpos);
520 
521 		/* Sort our planes by Zpos */
522 		plane_states[plane_state->normalized_zpos] = plane_state;
523 
524 		num_planes++;
525 	}
526 
527 	/* All our planes were disabled, bail out */
528 	if (!num_planes)
529 		return 0;
530 
531 	/*
532 	 * The hardware is a bit unusual here.
533 	 *
534 	 * Even though it supports 4 layers, it does the composition
535 	 * in two separate steps.
536 	 *
537 	 * The first one is assigning a layer to one of its two
538 	 * pipes. If more that 1 layer is assigned to the same pipe,
539 	 * and if pixels overlaps, the pipe will take the pixel from
540 	 * the layer with the highest priority.
541 	 *
542 	 * The second step is the actual alpha blending, that takes
543 	 * the two pipes as input, and uses the potential alpha
544 	 * component to do the transparency between the two.
545 	 *
546 	 * This two-step scenario makes us unable to guarantee a
547 	 * robust alpha blending between the 4 layers in all
548 	 * situations, since this means that we need to have one layer
549 	 * with alpha at the lowest position of our two pipes.
550 	 *
551 	 * However, we cannot even do that on every platform, since
552 	 * the hardware has a bug where the lowest plane of the lowest
553 	 * pipe (pipe 0, priority 0), if it has any alpha, will
554 	 * discard the pixel data entirely and just display the pixels
555 	 * in the background color (black by default).
556 	 *
557 	 * This means that on the affected platforms, we effectively
558 	 * have only three valid configurations with alpha, all of
559 	 * them with the alpha being on pipe1 with the lowest
560 	 * position, which can be 1, 2 or 3 depending on the number of
561 	 * planes and their zpos.
562 	 */
563 
564 	/* For platforms that are not affected by the issue described above. */
565 	if (backend->quirks->supports_lowest_plane_alpha)
566 		num_alpha_planes_max++;
567 
568 	if (num_alpha_planes > num_alpha_planes_max) {
569 		DRM_DEBUG_DRIVER("Too many planes with alpha, rejecting...\n");
570 		return -EINVAL;
571 	}
572 
573 	/* We can't have an alpha plane at the lowest position */
574 	if (!backend->quirks->supports_lowest_plane_alpha &&
575 	    (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE))
576 		return -EINVAL;
577 
578 	for (i = 1; i < num_planes; i++) {
579 		struct drm_plane_state *p_state = plane_states[i];
580 		struct drm_framebuffer *fb = p_state->fb;
581 		struct sun4i_layer_state *s_state = state_to_sun4i_layer_state(p_state);
582 
583 		/*
584 		 * The only alpha position is the lowest plane of the
585 		 * second pipe.
586 		 */
587 		if (fb->format->has_alpha || (p_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
588 			current_pipe++;
589 
590 		s_state->pipe = current_pipe;
591 	}
592 
593 	/* We can only have a single YUV plane at a time */
594 	if (num_yuv_planes > SUN4I_BACKEND_NUM_YUV_PLANES) {
595 		DRM_DEBUG_DRIVER("Too many planes with YUV, rejecting...\n");
596 		return -EINVAL;
597 	}
598 
599 	if (num_frontend_planes > SUN4I_BACKEND_NUM_FRONTEND_LAYERS) {
600 		DRM_DEBUG_DRIVER("Too many planes going through the frontend, rejecting\n");
601 		return -EINVAL;
602 	}
603 
604 	DRM_DEBUG_DRIVER("State valid with %u planes, %u alpha, %u video, %u YUV\n",
605 			 num_planes, num_alpha_planes, num_frontend_planes,
606 			 num_yuv_planes);
607 
608 	return 0;
609 }
610 
611 static void sun4i_backend_vblank_quirk(struct sunxi_engine *engine)
612 {
613 	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
614 	struct sun4i_frontend *frontend = backend->frontend;
615 
616 	if (!frontend)
617 		return;
618 
619 	/*
620 	 * In a teardown scenario with the frontend involved, we have
621 	 * to keep the frontend enabled until the next vblank, and
622 	 * only then disable it.
623 	 *
624 	 * This is due to the fact that the backend will not take into
625 	 * account the new configuration (with the plane that used to
626 	 * be fed by the frontend now disabled) until we write to the
627 	 * commit bit and the hardware fetches the new configuration
628 	 * during the next vblank.
629 	 *
630 	 * So we keep the frontend around in order to prevent any
631 	 * visual artifacts.
632 	 */
633 	spin_lock(&backend->frontend_lock);
634 	if (backend->frontend_teardown) {
635 		sun4i_frontend_exit(frontend);
636 		backend->frontend_teardown = false;
637 	}
638 	spin_unlock(&backend->frontend_lock);
639 };
640 
641 static void sun4i_backend_mode_set(struct sunxi_engine *engine,
642 				   const struct drm_display_mode *mode)
643 {
644 	bool interlaced = !!(mode->flags & DRM_MODE_FLAG_INTERLACE);
645 
646 	DRM_DEBUG_DRIVER("Updating global size W: %u H: %u\n",
647 			 mode->hdisplay, mode->vdisplay);
648 
649 	regmap_write(engine->regs, SUN4I_BACKEND_DISSIZE_REG,
650 		     SUN4I_BACKEND_DISSIZE(mode->hdisplay, mode->vdisplay));
651 
652 	regmap_update_bits(engine->regs, SUN4I_BACKEND_MODCTL_REG,
653 			   SUN4I_BACKEND_MODCTL_ITLMOD_EN,
654 			   interlaced ? SUN4I_BACKEND_MODCTL_ITLMOD_EN : 0);
655 
656 	DRM_DEBUG_DRIVER("Switching display backend interlaced mode %s\n",
657 			 interlaced ? "on" : "off");
658 }
659 
660 static int sun4i_backend_init_sat(struct device *dev) {
661 	struct sun4i_backend *backend = dev_get_drvdata(dev);
662 	int ret;
663 
664 	backend->sat_reset = devm_reset_control_get(dev, "sat");
665 	if (IS_ERR(backend->sat_reset)) {
666 		dev_err(dev, "Couldn't get the SAT reset line\n");
667 		return PTR_ERR(backend->sat_reset);
668 	}
669 
670 	ret = reset_control_deassert(backend->sat_reset);
671 	if (ret) {
672 		dev_err(dev, "Couldn't deassert the SAT reset line\n");
673 		return ret;
674 	}
675 
676 	backend->sat_clk = devm_clk_get(dev, "sat");
677 	if (IS_ERR(backend->sat_clk)) {
678 		dev_err(dev, "Couldn't get our SAT clock\n");
679 		ret = PTR_ERR(backend->sat_clk);
680 		goto err_assert_reset;
681 	}
682 
683 	ret = clk_prepare_enable(backend->sat_clk);
684 	if (ret) {
685 		dev_err(dev, "Couldn't enable the SAT clock\n");
686 		return ret;
687 	}
688 
689 	return 0;
690 
691 err_assert_reset:
692 	reset_control_assert(backend->sat_reset);
693 	return ret;
694 }
695 
696 static int sun4i_backend_free_sat(struct device *dev) {
697 	struct sun4i_backend *backend = dev_get_drvdata(dev);
698 
699 	clk_disable_unprepare(backend->sat_clk);
700 	reset_control_assert(backend->sat_reset);
701 
702 	return 0;
703 }
704 
705 /*
706  * The display backend can take video output from the display frontend, or
707  * the display enhancement unit on the A80, as input for one it its layers.
708  * This relationship within the display pipeline is encoded in the device
709  * tree with of_graph, and we use it here to figure out which backend, if
710  * there are 2 or more, we are currently probing. The number would be in
711  * the "reg" property of the upstream output port endpoint.
712  */
713 static int sun4i_backend_of_get_id(struct device_node *node)
714 {
715 	struct device_node *ep, *remote;
716 	struct of_endpoint of_ep;
717 
718 	/* Input port is 0, and we want the first endpoint. */
719 	ep = of_graph_get_endpoint_by_regs(node, 0, -1);
720 	if (!ep)
721 		return -EINVAL;
722 
723 	remote = of_graph_get_remote_endpoint(ep);
724 	of_node_put(ep);
725 	if (!remote)
726 		return -EINVAL;
727 
728 	of_graph_parse_endpoint(remote, &of_ep);
729 	of_node_put(remote);
730 	return of_ep.id;
731 }
732 
733 /* TODO: This needs to take multiple pipelines into account */
734 static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv,
735 							  struct device_node *node)
736 {
737 	struct device_node *port, *ep, *remote;
738 	struct sun4i_frontend *frontend;
739 
740 	port = of_graph_get_port_by_id(node, 0);
741 	if (!port)
742 		return ERR_PTR(-EINVAL);
743 
744 	for_each_available_child_of_node(port, ep) {
745 		remote = of_graph_get_remote_port_parent(ep);
746 		if (!remote)
747 			continue;
748 		of_node_put(remote);
749 
750 		/* does this node match any registered engines? */
751 		list_for_each_entry(frontend, &drv->frontend_list, list) {
752 			if (remote == frontend->node) {
753 				of_node_put(port);
754 				of_node_put(ep);
755 				return frontend;
756 			}
757 		}
758 	}
759 	of_node_put(port);
760 	return ERR_PTR(-EINVAL);
761 }
762 
763 static const struct sunxi_engine_ops sun4i_backend_engine_ops = {
764 	.atomic_begin			= sun4i_backend_atomic_begin,
765 	.atomic_check			= sun4i_backend_atomic_check,
766 	.commit				= sun4i_backend_commit,
767 	.layers_init			= sun4i_layers_init,
768 	.apply_color_correction		= sun4i_backend_apply_color_correction,
769 	.disable_color_correction	= sun4i_backend_disable_color_correction,
770 	.vblank_quirk			= sun4i_backend_vblank_quirk,
771 	.mode_set			= sun4i_backend_mode_set,
772 };
773 
774 static const struct regmap_config sun4i_backend_regmap_config = {
775 	.reg_bits	= 32,
776 	.val_bits	= 32,
777 	.reg_stride	= 4,
778 	.max_register	= 0x5800,
779 };
780 
781 static int sun4i_backend_bind(struct device *dev, struct device *master,
782 			      void *data)
783 {
784 	struct platform_device *pdev = to_platform_device(dev);
785 	struct drm_device *drm = data;
786 	struct sun4i_drv *drv = drm->dev_private;
787 	struct sun4i_backend *backend;
788 	const struct sun4i_backend_quirks *quirks;
789 	void __iomem *regs;
790 	int i, ret;
791 
792 	backend = devm_kzalloc(dev, sizeof(*backend), GFP_KERNEL);
793 	if (!backend)
794 		return -ENOMEM;
795 	dev_set_drvdata(dev, backend);
796 	spin_lock_init(&backend->frontend_lock);
797 
798 	if (of_property_present(dev->of_node, "interconnects")) {
799 		/*
800 		 * This assume we have the same DMA constraints for all our the
801 		 * devices in our pipeline (all the backends, but also the
802 		 * frontends). This sounds bad, but it has always been the case
803 		 * for us, and DRM doesn't do per-device allocation either, so
804 		 * we would need to fix DRM first...
805 		 */
806 		ret = of_dma_configure(drm->dev, dev->of_node, true);
807 		if (ret)
808 			return ret;
809 	}
810 
811 	backend->engine.node = dev->of_node;
812 	backend->engine.ops = &sun4i_backend_engine_ops;
813 	backend->engine.id = sun4i_backend_of_get_id(dev->of_node);
814 	if (backend->engine.id < 0)
815 		return backend->engine.id;
816 
817 	backend->frontend = sun4i_backend_find_frontend(drv, dev->of_node);
818 	if (IS_ERR(backend->frontend))
819 		dev_warn(dev, "Couldn't find matching frontend, frontend features disabled\n");
820 
821 	regs = devm_platform_ioremap_resource(pdev, 0);
822 	if (IS_ERR(regs))
823 		return PTR_ERR(regs);
824 
825 	backend->reset = devm_reset_control_get(dev, NULL);
826 	if (IS_ERR(backend->reset)) {
827 		dev_err(dev, "Couldn't get our reset line\n");
828 		return PTR_ERR(backend->reset);
829 	}
830 
831 	ret = reset_control_deassert(backend->reset);
832 	if (ret) {
833 		dev_err(dev, "Couldn't deassert our reset line\n");
834 		return ret;
835 	}
836 
837 	backend->bus_clk = devm_clk_get(dev, "ahb");
838 	if (IS_ERR(backend->bus_clk)) {
839 		dev_err(dev, "Couldn't get the backend bus clock\n");
840 		ret = PTR_ERR(backend->bus_clk);
841 		goto err_assert_reset;
842 	}
843 	clk_prepare_enable(backend->bus_clk);
844 
845 	backend->mod_clk = devm_clk_get(dev, "mod");
846 	if (IS_ERR(backend->mod_clk)) {
847 		dev_err(dev, "Couldn't get the backend module clock\n");
848 		ret = PTR_ERR(backend->mod_clk);
849 		goto err_disable_bus_clk;
850 	}
851 
852 	ret = clk_set_rate_exclusive(backend->mod_clk, 300000000);
853 	if (ret) {
854 		dev_err(dev, "Couldn't set the module clock frequency\n");
855 		goto err_disable_bus_clk;
856 	}
857 
858 	clk_prepare_enable(backend->mod_clk);
859 
860 	backend->ram_clk = devm_clk_get(dev, "ram");
861 	if (IS_ERR(backend->ram_clk)) {
862 		dev_err(dev, "Couldn't get the backend RAM clock\n");
863 		ret = PTR_ERR(backend->ram_clk);
864 		goto err_disable_mod_clk;
865 	}
866 	clk_prepare_enable(backend->ram_clk);
867 
868 	if (of_device_is_compatible(dev->of_node,
869 				    "allwinner,sun8i-a33-display-backend")) {
870 		ret = sun4i_backend_init_sat(dev);
871 		if (ret) {
872 			dev_err(dev, "Couldn't init SAT resources\n");
873 			goto err_disable_ram_clk;
874 		}
875 	}
876 
877 	backend->engine.regs = devm_regmap_init_mmio(dev, regs,
878 						     &sun4i_backend_regmap_config);
879 	if (IS_ERR(backend->engine.regs)) {
880 		dev_err(dev, "Couldn't create the backend regmap\n");
881 		return PTR_ERR(backend->engine.regs);
882 	}
883 
884 	list_add_tail(&backend->engine.list, &drv->engine_list);
885 
886 	/*
887 	 * Many of the backend's layer configuration registers have
888 	 * undefined default values. This poses a risk as we use
889 	 * regmap_update_bits in some places, and don't overwrite
890 	 * the whole register.
891 	 *
892 	 * Clear the registers here to have something predictable.
893 	 */
894 	for (i = 0x800; i < 0x1000; i += 4)
895 		regmap_write(backend->engine.regs, i, 0);
896 
897 	/* Disable registers autoloading */
898 	regmap_write(backend->engine.regs, SUN4I_BACKEND_REGBUFFCTL_REG,
899 		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
900 
901 	/* Enable the backend */
902 	regmap_write(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
903 		     SUN4I_BACKEND_MODCTL_DEBE_EN |
904 		     SUN4I_BACKEND_MODCTL_START_CTL);
905 
906 	/* Set output selection if needed */
907 	quirks = of_device_get_match_data(dev);
908 	if (quirks->needs_output_muxing) {
909 		/*
910 		 * We assume there is no dynamic muxing of backends
911 		 * and TCONs, so we select the backend with same ID.
912 		 *
913 		 * While dynamic selection might be interesting, since
914 		 * the CRTC is tied to the TCON, while the layers are
915 		 * tied to the backends, this means, we will need to
916 		 * switch between groups of layers. There might not be
917 		 * a way to represent this constraint in DRM.
918 		 */
919 		regmap_update_bits(backend->engine.regs,
920 				   SUN4I_BACKEND_MODCTL_REG,
921 				   SUN4I_BACKEND_MODCTL_OUT_SEL,
922 				   (backend->engine.id
923 				    ? SUN4I_BACKEND_MODCTL_OUT_LCD1
924 				    : SUN4I_BACKEND_MODCTL_OUT_LCD0));
925 	}
926 
927 	backend->quirks = quirks;
928 
929 	return 0;
930 
931 err_disable_ram_clk:
932 	clk_disable_unprepare(backend->ram_clk);
933 err_disable_mod_clk:
934 	clk_rate_exclusive_put(backend->mod_clk);
935 	clk_disable_unprepare(backend->mod_clk);
936 err_disable_bus_clk:
937 	clk_disable_unprepare(backend->bus_clk);
938 err_assert_reset:
939 	reset_control_assert(backend->reset);
940 	return ret;
941 }
942 
943 static void sun4i_backend_unbind(struct device *dev, struct device *master,
944 				 void *data)
945 {
946 	struct sun4i_backend *backend = dev_get_drvdata(dev);
947 
948 	list_del(&backend->engine.list);
949 
950 	if (of_device_is_compatible(dev->of_node,
951 				    "allwinner,sun8i-a33-display-backend"))
952 		sun4i_backend_free_sat(dev);
953 
954 	clk_disable_unprepare(backend->ram_clk);
955 	clk_rate_exclusive_put(backend->mod_clk);
956 	clk_disable_unprepare(backend->mod_clk);
957 	clk_disable_unprepare(backend->bus_clk);
958 	reset_control_assert(backend->reset);
959 }
960 
961 static const struct component_ops sun4i_backend_ops = {
962 	.bind	= sun4i_backend_bind,
963 	.unbind	= sun4i_backend_unbind,
964 };
965 
966 static int sun4i_backend_probe(struct platform_device *pdev)
967 {
968 	return component_add(&pdev->dev, &sun4i_backend_ops);
969 }
970 
971 static void sun4i_backend_remove(struct platform_device *pdev)
972 {
973 	component_del(&pdev->dev, &sun4i_backend_ops);
974 }
975 
976 static const struct sun4i_backend_quirks sun4i_backend_quirks = {
977 	.needs_output_muxing = true,
978 };
979 
980 static const struct sun4i_backend_quirks sun5i_backend_quirks = {
981 };
982 
983 static const struct sun4i_backend_quirks sun6i_backend_quirks = {
984 };
985 
986 static const struct sun4i_backend_quirks sun7i_backend_quirks = {
987 	.needs_output_muxing = true,
988 };
989 
990 static const struct sun4i_backend_quirks sun8i_a33_backend_quirks = {
991 	.supports_lowest_plane_alpha = true,
992 };
993 
994 static const struct sun4i_backend_quirks sun9i_backend_quirks = {
995 };
996 
997 static const struct of_device_id sun4i_backend_of_table[] = {
998 	{
999 		.compatible = "allwinner,sun4i-a10-display-backend",
1000 		.data = &sun4i_backend_quirks,
1001 	},
1002 	{
1003 		.compatible = "allwinner,sun5i-a13-display-backend",
1004 		.data = &sun5i_backend_quirks,
1005 	},
1006 	{
1007 		.compatible = "allwinner,sun6i-a31-display-backend",
1008 		.data = &sun6i_backend_quirks,
1009 	},
1010 	{
1011 		.compatible = "allwinner,sun7i-a20-display-backend",
1012 		.data = &sun7i_backend_quirks,
1013 	},
1014 	{
1015 		.compatible = "allwinner,sun8i-a23-display-backend",
1016 		.data = &sun8i_a33_backend_quirks,
1017 	},
1018 	{
1019 		.compatible = "allwinner,sun8i-a33-display-backend",
1020 		.data = &sun8i_a33_backend_quirks,
1021 	},
1022 	{
1023 		.compatible = "allwinner,sun9i-a80-display-backend",
1024 		.data = &sun9i_backend_quirks,
1025 	},
1026 	{ }
1027 };
1028 MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);
1029 
1030 static struct platform_driver sun4i_backend_platform_driver = {
1031 	.probe		= sun4i_backend_probe,
1032 	.remove		= sun4i_backend_remove,
1033 	.driver		= {
1034 		.name		= "sun4i-backend",
1035 		.of_match_table	= sun4i_backend_of_table,
1036 	},
1037 };
1038 module_platform_driver(sun4i_backend_platform_driver);
1039 
1040 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1041 MODULE_DESCRIPTION("Allwinner A10 Display Backend Driver");
1042 MODULE_LICENSE("GPL");
1043