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