xref: /linux/drivers/gpu/drm/sun4i/sun4i_backend.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
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_probe_helper.h>
27 
28 #include "sun4i_backend.h"
29 #include "sun4i_drv.h"
30 #include "sun4i_frontend.h"
31 #include "sun4i_layer.h"
32 #include "sunxi_engine.h"
33 
34 struct sun4i_backend_quirks {
35 	/* backend <-> TCON muxing selection done in backend */
36 	bool needs_output_muxing;
37 
38 	/* alpha at the lowest z position is not always supported */
39 	bool supports_lowest_plane_alpha;
40 };
41 
42 static const u32 sunxi_rgb2yuv_coef[12] = {
43 	0x00000107, 0x00000204, 0x00000064, 0x00000108,
44 	0x00003f69, 0x00003ed6, 0x000001c1, 0x00000808,
45 	0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
46 };
47 
48 static void sun4i_backend_apply_color_correction(struct sunxi_engine *engine)
49 {
50 	int i;
51 
52 	DRM_DEBUG_DRIVER("Applying RGB to YUV color correction\n");
53 
54 	/* Set color correction */
55 	regmap_write(engine->regs, SUN4I_BACKEND_OCCTL_REG,
56 		     SUN4I_BACKEND_OCCTL_ENABLE);
57 
58 	for (i = 0; i < 12; i++)
59 		regmap_write(engine->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
60 			     sunxi_rgb2yuv_coef[i]);
61 }
62 
63 static void sun4i_backend_disable_color_correction(struct sunxi_engine *engine)
64 {
65 	DRM_DEBUG_DRIVER("Disabling color correction\n");
66 
67 	/* Disable color correction */
68 	regmap_update_bits(engine->regs, SUN4I_BACKEND_OCCTL_REG,
69 			   SUN4I_BACKEND_OCCTL_ENABLE, 0);
70 }
71 
72 static void sun4i_backend_commit(struct sunxi_engine *engine,
73 				 struct drm_crtc *crtc,
74 				 struct drm_atomic_state *state)
75 {
76 	DRM_DEBUG_DRIVER("Committing changes\n");
77 
78 	regmap_write(engine->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
79 		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS |
80 		     SUN4I_BACKEND_REGBUFFCTL_LOADCTL);
81 }
82 
83 void sun4i_backend_layer_enable(struct sun4i_backend *backend,
84 				int layer, bool enable)
85 {
86 	u32 val;
87 
88 	DRM_DEBUG_DRIVER("%sabling layer %d\n", enable ? "En" : "Dis",
89 			 layer);
90 
91 	if (enable)
92 		val = SUN4I_BACKEND_MODCTL_LAY_EN(layer);
93 	else
94 		val = 0;
95 
96 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
97 			   SUN4I_BACKEND_MODCTL_LAY_EN(layer), val);
98 }
99 
100 static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
101 {
102 	switch (format) {
103 	case DRM_FORMAT_ARGB8888:
104 		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB8888;
105 		break;
106 
107 	case DRM_FORMAT_ARGB4444:
108 		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB4444;
109 		break;
110 
111 	case DRM_FORMAT_ARGB1555:
112 		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB1555;
113 		break;
114 
115 	case DRM_FORMAT_RGBA5551:
116 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA5551;
117 		break;
118 
119 	case DRM_FORMAT_RGBA4444:
120 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA4444;
121 		break;
122 
123 	case DRM_FORMAT_XRGB8888:
124 		*mode = SUN4I_BACKEND_LAY_FBFMT_XRGB8888;
125 		break;
126 
127 	case DRM_FORMAT_RGB888:
128 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB888;
129 		break;
130 
131 	case DRM_FORMAT_RGB565:
132 		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB565;
133 		break;
134 
135 	default:
136 		return -EINVAL;
137 	}
138 
139 	return 0;
140 }
141 
142 static const uint32_t sun4i_backend_formats[] = {
143 	DRM_FORMAT_ARGB1555,
144 	DRM_FORMAT_ARGB4444,
145 	DRM_FORMAT_ARGB8888,
146 	DRM_FORMAT_RGB565,
147 	DRM_FORMAT_RGB888,
148 	DRM_FORMAT_RGBA4444,
149 	DRM_FORMAT_RGBA5551,
150 	DRM_FORMAT_UYVY,
151 	DRM_FORMAT_VYUY,
152 	DRM_FORMAT_XRGB8888,
153 	DRM_FORMAT_YUYV,
154 	DRM_FORMAT_YVYU,
155 };
156 
157 bool sun4i_backend_format_is_supported(uint32_t fmt, uint64_t modifier)
158 {
159 	unsigned int i;
160 
161 	if (modifier != DRM_FORMAT_MOD_LINEAR)
162 		return false;
163 
164 	for (i = 0; i < ARRAY_SIZE(sun4i_backend_formats); i++)
165 		if (sun4i_backend_formats[i] == fmt)
166 			return true;
167 
168 	return false;
169 }
170 
171 int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
172 				     int layer, struct drm_plane *plane)
173 {
174 	struct drm_plane_state *state = plane->state;
175 
176 	DRM_DEBUG_DRIVER("Updating layer %d\n", layer);
177 
178 	/* Set height and width */
179 	DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
180 			 state->crtc_w, state->crtc_h);
181 	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
182 		     SUN4I_BACKEND_LAYSIZE(state->crtc_w,
183 					   state->crtc_h));
184 
185 	/* Set base coordinates */
186 	DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
187 			 state->crtc_x, state->crtc_y);
188 	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
189 		     SUN4I_BACKEND_LAYCOOR(state->crtc_x,
190 					   state->crtc_y));
191 
192 	return 0;
193 }
194 
195 static int sun4i_backend_update_yuv_format(struct sun4i_backend *backend,
196 					   int layer, struct drm_plane *plane)
197 {
198 	struct drm_plane_state *state = plane->state;
199 	struct drm_framebuffer *fb = state->fb;
200 	const struct drm_format_info *format = fb->format;
201 	const uint32_t fmt = format->format;
202 	u32 val = SUN4I_BACKEND_IYUVCTL_EN;
203 	int i;
204 
205 	for (i = 0; i < ARRAY_SIZE(sunxi_bt601_yuv2rgb_coef); i++)
206 		regmap_write(backend->engine.regs,
207 			     SUN4I_BACKEND_YGCOEF_REG(i),
208 			     sunxi_bt601_yuv2rgb_coef[i]);
209 
210 	/*
211 	 * We should do that only for a single plane, but the
212 	 * framebuffer's atomic_check has our back on this.
213 	 */
214 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
215 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN,
216 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN);
217 
218 	/* TODO: Add support for the multi-planar YUV formats */
219 	if (drm_format_info_is_yuv_packed(format) &&
220 	    drm_format_info_is_yuv_sampling_422(format))
221 		val |= SUN4I_BACKEND_IYUVCTL_FBFMT_PACKED_YUV422;
222 	else
223 		DRM_DEBUG_DRIVER("Unsupported YUV format (0x%x)\n", fmt);
224 
225 	/*
226 	 * Allwinner seems to list the pixel sequence from right to left, while
227 	 * DRM lists it from left to right.
228 	 */
229 	switch (fmt) {
230 	case DRM_FORMAT_YUYV:
231 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_VYUY;
232 		break;
233 	case DRM_FORMAT_YVYU:
234 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_UYVY;
235 		break;
236 	case DRM_FORMAT_UYVY:
237 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YVYU;
238 		break;
239 	case DRM_FORMAT_VYUY:
240 		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YUYV;
241 		break;
242 	default:
243 		DRM_DEBUG_DRIVER("Unsupported YUV pixel sequence (0x%x)\n",
244 				 fmt);
245 	}
246 
247 	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVCTL_REG, val);
248 
249 	return 0;
250 }
251 
252 int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
253 				       int layer, struct drm_plane *plane)
254 {
255 	struct drm_plane_state *state = plane->state;
256 	struct drm_framebuffer *fb = state->fb;
257 	u32 val;
258 	int ret;
259 
260 	/* Clear the YUV mode */
261 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
262 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
263 
264 	val = SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA(state->alpha >> 8);
265 	if (state->alpha != DRM_BLEND_ALPHA_OPAQUE)
266 		val |= SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN;
267 	regmap_update_bits(backend->engine.regs,
268 			   SUN4I_BACKEND_ATTCTL_REG0(layer),
269 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_MASK |
270 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN,
271 			   val);
272 
273 	if (fb->format->is_yuv)
274 		return sun4i_backend_update_yuv_format(backend, layer, plane);
275 
276 	ret = sun4i_backend_drm_format_to_layer(fb->format->format, &val);
277 	if (ret) {
278 		DRM_DEBUG_DRIVER("Invalid format\n");
279 		return ret;
280 	}
281 
282 	regmap_update_bits(backend->engine.regs,
283 			   SUN4I_BACKEND_ATTCTL_REG1(layer),
284 			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
285 
286 	return 0;
287 }
288 
289 int sun4i_backend_update_layer_frontend(struct sun4i_backend *backend,
290 					int layer, uint32_t fmt)
291 {
292 	u32 val;
293 	int ret;
294 
295 	ret = sun4i_backend_drm_format_to_layer(fmt, &val);
296 	if (ret) {
297 		DRM_DEBUG_DRIVER("Invalid format\n");
298 		return ret;
299 	}
300 
301 	regmap_update_bits(backend->engine.regs,
302 			   SUN4I_BACKEND_ATTCTL_REG0(layer),
303 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN,
304 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN);
305 
306 	regmap_update_bits(backend->engine.regs,
307 			   SUN4I_BACKEND_ATTCTL_REG1(layer),
308 			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
309 
310 	return 0;
311 }
312 
313 static int sun4i_backend_update_yuv_buffer(struct sun4i_backend *backend,
314 					   struct drm_framebuffer *fb,
315 					   dma_addr_t paddr)
316 {
317 	/* TODO: Add support for the multi-planar YUV formats */
318 	DRM_DEBUG_DRIVER("Setting packed YUV buffer address to %pad\n", &paddr);
319 	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVADD_REG(0), paddr);
320 
321 	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
322 	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVLINEWIDTH_REG(0),
323 		     fb->pitches[0] * 8);
324 
325 	return 0;
326 }
327 
328 int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
329 				      int layer, struct drm_plane *plane)
330 {
331 	struct drm_plane_state *state = plane->state;
332 	struct drm_framebuffer *fb = state->fb;
333 	u32 lo_paddr, hi_paddr;
334 	dma_addr_t dma_addr;
335 
336 	/* Set the line width */
337 	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
338 	regmap_write(backend->engine.regs,
339 		     SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
340 		     fb->pitches[0] * 8);
341 
342 	/* Get the start of the displayed memory */
343 	dma_addr = drm_fb_dma_get_gem_addr(fb, state, 0);
344 	DRM_DEBUG_DRIVER("Setting buffer address to %pad\n", &dma_addr);
345 
346 	if (fb->format->is_yuv)
347 		return sun4i_backend_update_yuv_buffer(backend, fb, dma_addr);
348 
349 	/* Write the 32 lower bits of the address (in bits) */
350 	lo_paddr = dma_addr << 3;
351 	DRM_DEBUG_DRIVER("Setting address lower bits to 0x%x\n", lo_paddr);
352 	regmap_write(backend->engine.regs,
353 		     SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
354 		     lo_paddr);
355 
356 	/* And the upper bits */
357 	hi_paddr = dma_addr >> 29;
358 	DRM_DEBUG_DRIVER("Setting address high bits to 0x%x\n", hi_paddr);
359 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
360 			   SUN4I_BACKEND_LAYFB_H4ADD_MSK(layer),
361 			   SUN4I_BACKEND_LAYFB_H4ADD(layer, hi_paddr));
362 
363 	return 0;
364 }
365 
366 int sun4i_backend_update_layer_zpos(struct sun4i_backend *backend, int layer,
367 				    struct drm_plane *plane)
368 {
369 	struct drm_plane_state *state = plane->state;
370 	struct sun4i_layer_state *p_state = state_to_sun4i_layer_state(state);
371 	unsigned int priority = state->normalized_zpos;
372 	unsigned int pipe = p_state->pipe;
373 
374 	DRM_DEBUG_DRIVER("Setting layer %d's priority to %d and pipe %d\n",
375 			 layer, priority, pipe);
376 	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
377 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK |
378 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL_MASK,
379 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(p_state->pipe) |
380 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL(priority));
381 
382 	return 0;
383 }
384 
385 void sun4i_backend_cleanup_layer(struct sun4i_backend *backend,
386 				 int layer)
387 {
388 	regmap_update_bits(backend->engine.regs,
389 			   SUN4I_BACKEND_ATTCTL_REG0(layer),
390 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN |
391 			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
392 }
393 
394 static bool sun4i_backend_plane_uses_scaler(struct drm_plane_state *state)
395 {
396 	u16 src_h = state->src_h >> 16;
397 	u16 src_w = state->src_w >> 16;
398 
399 	DRM_DEBUG_DRIVER("Input size %dx%d, output size %dx%d\n",
400 			 src_w, src_h, state->crtc_w, state->crtc_h);
401 
402 	if ((state->crtc_h != src_h) || (state->crtc_w != src_w))
403 		return true;
404 
405 	return false;
406 }
407 
408 static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
409 {
410 	struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
411 	struct sun4i_backend *backend = layer->backend;
412 	uint32_t format = state->fb->format->format;
413 	uint64_t modifier = state->fb->modifier;
414 
415 	if (IS_ERR(backend->frontend))
416 		return false;
417 
418 	if (!sun4i_frontend_format_is_supported(format, modifier))
419 		return false;
420 
421 	if (!sun4i_backend_format_is_supported(format, modifier))
422 		return true;
423 
424 	/*
425 	 * TODO: The backend alone allows 2x and 4x integer scaling, including
426 	 * support for an alpha component (which the frontend doesn't support).
427 	 * Use the backend directly instead of the frontend in this case, with
428 	 * another test to return false.
429 	 */
430 
431 	if (sun4i_backend_plane_uses_scaler(state))
432 		return true;
433 
434 	/*
435 	 * Here the format is supported by both the frontend and the backend
436 	 * and no frontend scaling is required, so use the backend directly.
437 	 */
438 	return false;
439 }
440 
441 static bool sun4i_backend_plane_is_supported(struct drm_plane_state *state,
442 					     bool *uses_frontend)
443 {
444 	if (sun4i_backend_plane_uses_frontend(state)) {
445 		*uses_frontend = true;
446 		return true;
447 	}
448 
449 	*uses_frontend = false;
450 
451 	/* Scaling is not supported without the frontend. */
452 	if (sun4i_backend_plane_uses_scaler(state))
453 		return false;
454 
455 	return true;
456 }
457 
458 static void sun4i_backend_atomic_begin(struct sunxi_engine *engine,
459 				       struct drm_crtc_state *old_state)
460 {
461 	u32 val;
462 
463 	WARN_ON(regmap_read_poll_timeout(engine->regs,
464 					 SUN4I_BACKEND_REGBUFFCTL_REG,
465 					 val, !(val & SUN4I_BACKEND_REGBUFFCTL_LOADCTL),
466 					 100, 50000));
467 }
468 
469 static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
470 				      struct drm_crtc_state *crtc_state)
471 {
472 	struct drm_plane_state *plane_states[SUN4I_BACKEND_NUM_LAYERS] = { 0 };
473 	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
474 	struct drm_atomic_state *state = crtc_state->state;
475 	struct drm_device *drm = state->dev;
476 	struct drm_plane *plane;
477 	unsigned int num_planes = 0;
478 	unsigned int num_alpha_planes = 0;
479 	unsigned int num_frontend_planes = 0;
480 	unsigned int num_alpha_planes_max = 1;
481 	unsigned int num_yuv_planes = 0;
482 	unsigned int current_pipe = 0;
483 	unsigned int i;
484 
485 	DRM_DEBUG_DRIVER("Starting checking our planes\n");
486 
487 	if (!crtc_state->planes_changed)
488 		return 0;
489 
490 	drm_for_each_plane_mask(plane, drm, crtc_state->plane_mask) {
491 		struct drm_plane_state *plane_state =
492 			drm_atomic_get_plane_state(state, plane);
493 		struct sun4i_layer_state *layer_state =
494 			state_to_sun4i_layer_state(plane_state);
495 		struct drm_framebuffer *fb = plane_state->fb;
496 
497 		if (!sun4i_backend_plane_is_supported(plane_state,
498 						      &layer_state->uses_frontend))
499 			return -EINVAL;
500 
501 		if (layer_state->uses_frontend) {
502 			DRM_DEBUG_DRIVER("Using the frontend for plane %d\n",
503 					 plane->index);
504 			num_frontend_planes++;
505 		} else {
506 			if (fb->format->is_yuv) {
507 				DRM_DEBUG_DRIVER("Plane FB format is YUV\n");
508 				num_yuv_planes++;
509 			}
510 		}
511 
512 		DRM_DEBUG_DRIVER("Plane FB format is %p4cc\n",
513 				 &fb->format->format);
514 		if (fb->format->has_alpha || (plane_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
515 			num_alpha_planes++;
516 
517 		DRM_DEBUG_DRIVER("Plane zpos is %d\n",
518 				 plane_state->normalized_zpos);
519 
520 		/* Sort our planes by Zpos */
521 		plane_states[plane_state->normalized_zpos] = plane_state;
522 
523 		num_planes++;
524 	}
525 
526 	/* All our planes were disabled, bail out */
527 	if (!num_planes)
528 		return 0;
529 
530 	/*
531 	 * The hardware is a bit unusual here.
532 	 *
533 	 * Even though it supports 4 layers, it does the composition
534 	 * in two separate steps.
535 	 *
536 	 * The first one is assigning a layer to one of its two
537 	 * pipes. If more that 1 layer is assigned to the same pipe,
538 	 * and if pixels overlaps, the pipe will take the pixel from
539 	 * the layer with the highest priority.
540 	 *
541 	 * The second step is the actual alpha blending, that takes
542 	 * the two pipes as input, and uses the potential alpha
543 	 * component to do the transparency between the two.
544 	 *
545 	 * This two-step scenario makes us unable to guarantee a
546 	 * robust alpha blending between the 4 layers in all
547 	 * situations, since this means that we need to have one layer
548 	 * with alpha at the lowest position of our two pipes.
549 	 *
550 	 * However, we cannot even do that on every platform, since
551 	 * the hardware has a bug where the lowest plane of the lowest
552 	 * pipe (pipe 0, priority 0), if it has any alpha, will
553 	 * discard the pixel data entirely and just display the pixels
554 	 * in the background color (black by default).
555 	 *
556 	 * This means that on the affected platforms, we effectively
557 	 * have only three valid configurations with alpha, all of
558 	 * them with the alpha being on pipe1 with the lowest
559 	 * position, which can be 1, 2 or 3 depending on the number of
560 	 * planes and their zpos.
561 	 */
562 
563 	/* For platforms that are not affected by the issue described above. */
564 	if (backend->quirks->supports_lowest_plane_alpha)
565 		num_alpha_planes_max++;
566 
567 	if (num_alpha_planes > num_alpha_planes_max) {
568 		DRM_DEBUG_DRIVER("Too many planes with alpha, rejecting...\n");
569 		return -EINVAL;
570 	}
571 
572 	/* We can't have an alpha plane at the lowest position */
573 	if (!backend->quirks->supports_lowest_plane_alpha &&
574 	    (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE))
575 		return -EINVAL;
576 
577 	for (i = 1; i < num_planes; i++) {
578 		struct drm_plane_state *p_state = plane_states[i];
579 		struct drm_framebuffer *fb = p_state->fb;
580 		struct sun4i_layer_state *s_state = state_to_sun4i_layer_state(p_state);
581 
582 		/*
583 		 * The only alpha position is the lowest plane of the
584 		 * second pipe.
585 		 */
586 		if (fb->format->has_alpha || (p_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
587 			current_pipe++;
588 
589 		s_state->pipe = current_pipe;
590 	}
591 
592 	/* We can only have a single YUV plane at a time */
593 	if (num_yuv_planes > SUN4I_BACKEND_NUM_YUV_PLANES) {
594 		DRM_DEBUG_DRIVER("Too many planes with YUV, rejecting...\n");
595 		return -EINVAL;
596 	}
597 
598 	if (num_frontend_planes > SUN4I_BACKEND_NUM_FRONTEND_LAYERS) {
599 		DRM_DEBUG_DRIVER("Too many planes going through the frontend, rejecting\n");
600 		return -EINVAL;
601 	}
602 
603 	DRM_DEBUG_DRIVER("State valid with %u planes, %u alpha, %u video, %u YUV\n",
604 			 num_planes, num_alpha_planes, num_frontend_planes,
605 			 num_yuv_planes);
606 
607 	return 0;
608 }
609 
610 static void sun4i_backend_vblank_quirk(struct sunxi_engine *engine)
611 {
612 	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
613 	struct sun4i_frontend *frontend = backend->frontend;
614 
615 	if (!frontend)
616 		return;
617 
618 	/*
619 	 * In a teardown scenario with the frontend involved, we have
620 	 * to keep the frontend enabled until the next vblank, and
621 	 * only then disable it.
622 	 *
623 	 * This is due to the fact that the backend will not take into
624 	 * account the new configuration (with the plane that used to
625 	 * be fed by the frontend now disabled) until we write to the
626 	 * commit bit and the hardware fetches the new configuration
627 	 * during the next vblank.
628 	 *
629 	 * So we keep the frontend around in order to prevent any
630 	 * visual artifacts.
631 	 */
632 	spin_lock(&backend->frontend_lock);
633 	if (backend->frontend_teardown) {
634 		sun4i_frontend_exit(frontend);
635 		backend->frontend_teardown = false;
636 	}
637 	spin_unlock(&backend->frontend_lock);
638 };
639 
640 static void sun4i_backend_mode_set(struct sunxi_engine *engine,
641 				   const struct drm_display_mode *mode)
642 {
643 	bool interlaced = !!(mode->flags & DRM_MODE_FLAG_INTERLACE);
644 
645 	DRM_DEBUG_DRIVER("Updating global size W: %u H: %u\n",
646 			 mode->hdisplay, mode->vdisplay);
647 
648 	regmap_write(engine->regs, SUN4I_BACKEND_DISSIZE_REG,
649 		     SUN4I_BACKEND_DISSIZE(mode->hdisplay, mode->vdisplay));
650 
651 	regmap_update_bits(engine->regs, SUN4I_BACKEND_MODCTL_REG,
652 			   SUN4I_BACKEND_MODCTL_ITLMOD_EN,
653 			   interlaced ? SUN4I_BACKEND_MODCTL_ITLMOD_EN : 0);
654 
655 	DRM_DEBUG_DRIVER("Switching display backend interlaced mode %s\n",
656 			 interlaced ? "on" : "off");
657 }
658 
659 static int sun4i_backend_init_sat(struct device *dev) {
660 	struct sun4i_backend *backend = dev_get_drvdata(dev);
661 	int ret;
662 
663 	backend->sat_reset = devm_reset_control_get(dev, "sat");
664 	if (IS_ERR(backend->sat_reset)) {
665 		dev_err(dev, "Couldn't get the SAT reset line\n");
666 		return PTR_ERR(backend->sat_reset);
667 	}
668 
669 	ret = reset_control_deassert(backend->sat_reset);
670 	if (ret) {
671 		dev_err(dev, "Couldn't deassert the SAT reset line\n");
672 		return ret;
673 	}
674 
675 	backend->sat_clk = devm_clk_get(dev, "sat");
676 	if (IS_ERR(backend->sat_clk)) {
677 		dev_err(dev, "Couldn't get our SAT clock\n");
678 		ret = PTR_ERR(backend->sat_clk);
679 		goto err_assert_reset;
680 	}
681 
682 	ret = clk_prepare_enable(backend->sat_clk);
683 	if (ret) {
684 		dev_err(dev, "Couldn't enable the SAT clock\n");
685 		return ret;
686 	}
687 
688 	return 0;
689 
690 err_assert_reset:
691 	reset_control_assert(backend->sat_reset);
692 	return ret;
693 }
694 
695 static int sun4i_backend_free_sat(struct device *dev) {
696 	struct sun4i_backend *backend = dev_get_drvdata(dev);
697 
698 	clk_disable_unprepare(backend->sat_clk);
699 	reset_control_assert(backend->sat_reset);
700 
701 	return 0;
702 }
703 
704 /*
705  * The display backend can take video output from the display frontend, or
706  * the display enhancement unit on the A80, as input for one it its layers.
707  * This relationship within the display pipeline is encoded in the device
708  * tree with of_graph, and we use it here to figure out which backend, if
709  * there are 2 or more, we are currently probing. The number would be in
710  * the "reg" property of the upstream output port endpoint.
711  */
712 static int sun4i_backend_of_get_id(struct device_node *node)
713 {
714 	struct device_node *ep, *remote;
715 	struct of_endpoint of_ep;
716 
717 	/* Input port is 0, and we want the first endpoint. */
718 	ep = of_graph_get_endpoint_by_regs(node, 0, -1);
719 	if (!ep)
720 		return -EINVAL;
721 
722 	remote = of_graph_get_remote_endpoint(ep);
723 	of_node_put(ep);
724 	if (!remote)
725 		return -EINVAL;
726 
727 	of_graph_parse_endpoint(remote, &of_ep);
728 	of_node_put(remote);
729 	return of_ep.id;
730 }
731 
732 /* TODO: This needs to take multiple pipelines into account */
733 static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv,
734 							  struct device_node *node)
735 {
736 	struct device_node *port, *ep, *remote;
737 	struct sun4i_frontend *frontend;
738 
739 	port = of_graph_get_port_by_id(node, 0);
740 	if (!port)
741 		return ERR_PTR(-EINVAL);
742 
743 	for_each_available_child_of_node(port, ep) {
744 		remote = of_graph_get_remote_port_parent(ep);
745 		if (!remote)
746 			continue;
747 		of_node_put(remote);
748 
749 		/* does this node match any registered engines? */
750 		list_for_each_entry(frontend, &drv->frontend_list, list) {
751 			if (remote == frontend->node) {
752 				of_node_put(port);
753 				of_node_put(ep);
754 				return frontend;
755 			}
756 		}
757 	}
758 	of_node_put(port);
759 	return ERR_PTR(-EINVAL);
760 }
761 
762 static const struct sunxi_engine_ops sun4i_backend_engine_ops = {
763 	.atomic_begin			= sun4i_backend_atomic_begin,
764 	.atomic_check			= sun4i_backend_atomic_check,
765 	.commit				= sun4i_backend_commit,
766 	.layers_init			= sun4i_layers_init,
767 	.apply_color_correction		= sun4i_backend_apply_color_correction,
768 	.disable_color_correction	= sun4i_backend_disable_color_correction,
769 	.vblank_quirk			= sun4i_backend_vblank_quirk,
770 	.mode_set			= sun4i_backend_mode_set,
771 };
772 
773 static const struct regmap_config sun4i_backend_regmap_config = {
774 	.reg_bits	= 32,
775 	.val_bits	= 32,
776 	.reg_stride	= 4,
777 	.max_register	= 0x5800,
778 };
779 
780 static int sun4i_backend_bind(struct device *dev, struct device *master,
781 			      void *data)
782 {
783 	struct platform_device *pdev = to_platform_device(dev);
784 	struct drm_device *drm = data;
785 	struct sun4i_drv *drv = drm->dev_private;
786 	struct sun4i_backend *backend;
787 	const struct sun4i_backend_quirks *quirks;
788 	void __iomem *regs;
789 	int i, ret;
790 
791 	backend = devm_kzalloc(dev, sizeof(*backend), GFP_KERNEL);
792 	if (!backend)
793 		return -ENOMEM;
794 	dev_set_drvdata(dev, backend);
795 	spin_lock_init(&backend->frontend_lock);
796 
797 	if (of_property_present(dev->of_node, "interconnects")) {
798 		/*
799 		 * This assume we have the same DMA constraints for all our the
800 		 * devices in our pipeline (all the backends, but also the
801 		 * frontends). This sounds bad, but it has always been the case
802 		 * for us, and DRM doesn't do per-device allocation either, so
803 		 * we would need to fix DRM first...
804 		 */
805 		ret = of_dma_configure(drm->dev, dev->of_node, true);
806 		if (ret)
807 			return ret;
808 	}
809 
810 	backend->engine.node = dev->of_node;
811 	backend->engine.ops = &sun4i_backend_engine_ops;
812 	backend->engine.id = sun4i_backend_of_get_id(dev->of_node);
813 	if (backend->engine.id < 0)
814 		return backend->engine.id;
815 
816 	backend->frontend = sun4i_backend_find_frontend(drv, dev->of_node);
817 	if (IS_ERR(backend->frontend))
818 		dev_warn(dev, "Couldn't find matching frontend, frontend features disabled\n");
819 
820 	regs = devm_platform_ioremap_resource(pdev, 0);
821 	if (IS_ERR(regs))
822 		return PTR_ERR(regs);
823 
824 	backend->reset = devm_reset_control_get(dev, NULL);
825 	if (IS_ERR(backend->reset)) {
826 		dev_err(dev, "Couldn't get our reset line\n");
827 		return PTR_ERR(backend->reset);
828 	}
829 
830 	ret = reset_control_deassert(backend->reset);
831 	if (ret) {
832 		dev_err(dev, "Couldn't deassert our reset line\n");
833 		return ret;
834 	}
835 
836 	backend->bus_clk = devm_clk_get(dev, "ahb");
837 	if (IS_ERR(backend->bus_clk)) {
838 		dev_err(dev, "Couldn't get the backend bus clock\n");
839 		ret = PTR_ERR(backend->bus_clk);
840 		goto err_assert_reset;
841 	}
842 	clk_prepare_enable(backend->bus_clk);
843 
844 	backend->mod_clk = devm_clk_get(dev, "mod");
845 	if (IS_ERR(backend->mod_clk)) {
846 		dev_err(dev, "Couldn't get the backend module clock\n");
847 		ret = PTR_ERR(backend->mod_clk);
848 		goto err_disable_bus_clk;
849 	}
850 
851 	ret = clk_set_rate_exclusive(backend->mod_clk, 300000000);
852 	if (ret) {
853 		dev_err(dev, "Couldn't set the module clock frequency\n");
854 		goto err_disable_bus_clk;
855 	}
856 
857 	clk_prepare_enable(backend->mod_clk);
858 
859 	backend->ram_clk = devm_clk_get(dev, "ram");
860 	if (IS_ERR(backend->ram_clk)) {
861 		dev_err(dev, "Couldn't get the backend RAM clock\n");
862 		ret = PTR_ERR(backend->ram_clk);
863 		goto err_disable_mod_clk;
864 	}
865 	clk_prepare_enable(backend->ram_clk);
866 
867 	if (of_device_is_compatible(dev->of_node,
868 				    "allwinner,sun8i-a33-display-backend")) {
869 		ret = sun4i_backend_init_sat(dev);
870 		if (ret) {
871 			dev_err(dev, "Couldn't init SAT resources\n");
872 			goto err_disable_ram_clk;
873 		}
874 	}
875 
876 	backend->engine.regs = devm_regmap_init_mmio(dev, regs,
877 						     &sun4i_backend_regmap_config);
878 	if (IS_ERR(backend->engine.regs)) {
879 		dev_err(dev, "Couldn't create the backend regmap\n");
880 		return PTR_ERR(backend->engine.regs);
881 	}
882 
883 	list_add_tail(&backend->engine.list, &drv->engine_list);
884 
885 	/*
886 	 * Many of the backend's layer configuration registers have
887 	 * undefined default values. This poses a risk as we use
888 	 * regmap_update_bits in some places, and don't overwrite
889 	 * the whole register.
890 	 *
891 	 * Clear the registers here to have something predictable.
892 	 */
893 	for (i = 0x800; i < 0x1000; i += 4)
894 		regmap_write(backend->engine.regs, i, 0);
895 
896 	/* Disable registers autoloading */
897 	regmap_write(backend->engine.regs, SUN4I_BACKEND_REGBUFFCTL_REG,
898 		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
899 
900 	/* Enable the backend */
901 	regmap_write(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
902 		     SUN4I_BACKEND_MODCTL_DEBE_EN |
903 		     SUN4I_BACKEND_MODCTL_START_CTL);
904 
905 	/* Set output selection if needed */
906 	quirks = of_device_get_match_data(dev);
907 	if (quirks->needs_output_muxing) {
908 		/*
909 		 * We assume there is no dynamic muxing of backends
910 		 * and TCONs, so we select the backend with same ID.
911 		 *
912 		 * While dynamic selection might be interesting, since
913 		 * the CRTC is tied to the TCON, while the layers are
914 		 * tied to the backends, this means, we will need to
915 		 * switch between groups of layers. There might not be
916 		 * a way to represent this constraint in DRM.
917 		 */
918 		regmap_update_bits(backend->engine.regs,
919 				   SUN4I_BACKEND_MODCTL_REG,
920 				   SUN4I_BACKEND_MODCTL_OUT_SEL,
921 				   (backend->engine.id
922 				    ? SUN4I_BACKEND_MODCTL_OUT_LCD1
923 				    : SUN4I_BACKEND_MODCTL_OUT_LCD0));
924 	}
925 
926 	backend->quirks = quirks;
927 
928 	return 0;
929 
930 err_disable_ram_clk:
931 	clk_disable_unprepare(backend->ram_clk);
932 err_disable_mod_clk:
933 	clk_rate_exclusive_put(backend->mod_clk);
934 	clk_disable_unprepare(backend->mod_clk);
935 err_disable_bus_clk:
936 	clk_disable_unprepare(backend->bus_clk);
937 err_assert_reset:
938 	reset_control_assert(backend->reset);
939 	return ret;
940 }
941 
942 static void sun4i_backend_unbind(struct device *dev, struct device *master,
943 				 void *data)
944 {
945 	struct sun4i_backend *backend = dev_get_drvdata(dev);
946 
947 	list_del(&backend->engine.list);
948 
949 	if (of_device_is_compatible(dev->of_node,
950 				    "allwinner,sun8i-a33-display-backend"))
951 		sun4i_backend_free_sat(dev);
952 
953 	clk_disable_unprepare(backend->ram_clk);
954 	clk_rate_exclusive_put(backend->mod_clk);
955 	clk_disable_unprepare(backend->mod_clk);
956 	clk_disable_unprepare(backend->bus_clk);
957 	reset_control_assert(backend->reset);
958 }
959 
960 static const struct component_ops sun4i_backend_ops = {
961 	.bind	= sun4i_backend_bind,
962 	.unbind	= sun4i_backend_unbind,
963 };
964 
965 static int sun4i_backend_probe(struct platform_device *pdev)
966 {
967 	return component_add(&pdev->dev, &sun4i_backend_ops);
968 }
969 
970 static void sun4i_backend_remove(struct platform_device *pdev)
971 {
972 	component_del(&pdev->dev, &sun4i_backend_ops);
973 }
974 
975 static const struct sun4i_backend_quirks sun4i_backend_quirks = {
976 	.needs_output_muxing = true,
977 };
978 
979 static const struct sun4i_backend_quirks sun5i_backend_quirks = {
980 };
981 
982 static const struct sun4i_backend_quirks sun6i_backend_quirks = {
983 };
984 
985 static const struct sun4i_backend_quirks sun7i_backend_quirks = {
986 	.needs_output_muxing = true,
987 };
988 
989 static const struct sun4i_backend_quirks sun8i_a33_backend_quirks = {
990 	.supports_lowest_plane_alpha = true,
991 };
992 
993 static const struct sun4i_backend_quirks sun9i_backend_quirks = {
994 };
995 
996 static const struct of_device_id sun4i_backend_of_table[] = {
997 	{
998 		.compatible = "allwinner,sun4i-a10-display-backend",
999 		.data = &sun4i_backend_quirks,
1000 	},
1001 	{
1002 		.compatible = "allwinner,sun5i-a13-display-backend",
1003 		.data = &sun5i_backend_quirks,
1004 	},
1005 	{
1006 		.compatible = "allwinner,sun6i-a31-display-backend",
1007 		.data = &sun6i_backend_quirks,
1008 	},
1009 	{
1010 		.compatible = "allwinner,sun7i-a20-display-backend",
1011 		.data = &sun7i_backend_quirks,
1012 	},
1013 	{
1014 		.compatible = "allwinner,sun8i-a23-display-backend",
1015 		.data = &sun8i_a33_backend_quirks,
1016 	},
1017 	{
1018 		.compatible = "allwinner,sun8i-a33-display-backend",
1019 		.data = &sun8i_a33_backend_quirks,
1020 	},
1021 	{
1022 		.compatible = "allwinner,sun9i-a80-display-backend",
1023 		.data = &sun9i_backend_quirks,
1024 	},
1025 	{ }
1026 };
1027 MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);
1028 
1029 static struct platform_driver sun4i_backend_platform_driver = {
1030 	.probe		= sun4i_backend_probe,
1031 	.remove_new	= sun4i_backend_remove,
1032 	.driver		= {
1033 		.name		= "sun4i-backend",
1034 		.of_match_table	= sun4i_backend_of_table,
1035 	},
1036 };
1037 module_platform_driver(sun4i_backend_platform_driver);
1038 
1039 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1040 MODULE_DESCRIPTION("Allwinner A10 Display Backend Driver");
1041 MODULE_LICENSE("GPL");
1042