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  1/*
  2 * Copyright (C) 2015 Free Electrons
  3 * Copyright (C) 2015 NextThing Co
  4 *
  5 * Maxime Ripard <maxime.ripard@free-electrons.com>
  6 *
  7 * This program is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU General Public License as
  9 * published by the Free Software Foundation; either version 2 of
 10 * the License, or (at your option) any later version.
 11 */
 12
 13#include <drm/drmP.h>
 14#include <drm/drm_atomic.h>
 15#include <drm/drm_atomic_helper.h>
 16#include <drm/drm_crtc.h>
 17#include <drm/drm_crtc_helper.h>
 18#include <drm/drm_fb_cma_helper.h>
 19#include <drm/drm_gem_cma_helper.h>
 20#include <drm/drm_plane_helper.h>
 21
 22#include <linux/component.h>
 23#include <linux/list.h>
 24#include <linux/of_device.h>
 25#include <linux/of_graph.h>
 26#include <linux/reset.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
 39static const u32 sunxi_rgb2yuv_coef[12] = {
 40	0x00000107, 0x00000204, 0x00000064, 0x00000108,
 41	0x00003f69, 0x00003ed6, 0x000001c1, 0x00000808,
 42	0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
 43};
 44
 45/*
 46 * These coefficients are taken from the A33 BSP from Allwinner.
 47 *
 48 * The formula is for each component, each coefficient being multiplied by
 49 * 1024 and each constant being multiplied by 16:
 50 * G = 1.164 * Y - 0.391 * U - 0.813 * V + 135
 51 * R = 1.164 * Y + 1.596 * V - 222
 52 * B = 1.164 * Y + 2.018 * U + 276
 53 *
 54 * This seems to be a conversion from Y[16:235] UV[16:240] to RGB[0:255],
 55 * following the BT601 spec.
 56 */
 57static const u32 sunxi_bt601_yuv2rgb_coef[12] = {
 58	0x000004a7, 0x00001e6f, 0x00001cbf, 0x00000877,
 59	0x000004a7, 0x00000000, 0x00000662, 0x00003211,
 60	0x000004a7, 0x00000812, 0x00000000, 0x00002eb1,
 61};
 62
 63static inline bool sun4i_backend_format_is_planar_yuv(uint32_t format)
 64{
 65	switch (format) {
 66	case DRM_FORMAT_YUV411:
 67	case DRM_FORMAT_YUV422:
 68	case DRM_FORMAT_YUV444:
 69		return true;
 70	default:
 71		return false;
 72	}
 73}
 74
 75static inline bool sun4i_backend_format_is_packed_yuv422(uint32_t format)
 76{
 77	switch (format) {
 78	case DRM_FORMAT_YUYV:
 79	case DRM_FORMAT_YVYU:
 80	case DRM_FORMAT_UYVY:
 81	case DRM_FORMAT_VYUY:
 82		return true;
 83
 84	default:
 85		return false;
 86	}
 87}
 88
 89static inline bool sun4i_backend_format_is_yuv(uint32_t format)
 90{
 91	return sun4i_backend_format_is_planar_yuv(format) ||
 92		sun4i_backend_format_is_packed_yuv422(format);
 93}
 94
 95static void sun4i_backend_apply_color_correction(struct sunxi_engine *engine)
 96{
 97	int i;
 98
 99	DRM_DEBUG_DRIVER("Applying RGB to YUV color correction\n");
100
101	/* Set color correction */
102	regmap_write(engine->regs, SUN4I_BACKEND_OCCTL_REG,
103		     SUN4I_BACKEND_OCCTL_ENABLE);
104
105	for (i = 0; i < 12; i++)
106		regmap_write(engine->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
107			     sunxi_rgb2yuv_coef[i]);
108}
109
110static void sun4i_backend_disable_color_correction(struct sunxi_engine *engine)
111{
112	DRM_DEBUG_DRIVER("Disabling color correction\n");
113
114	/* Disable color correction */
115	regmap_update_bits(engine->regs, SUN4I_BACKEND_OCCTL_REG,
116			   SUN4I_BACKEND_OCCTL_ENABLE, 0);
117}
118
119static void sun4i_backend_commit(struct sunxi_engine *engine)
120{
121	DRM_DEBUG_DRIVER("Committing changes\n");
122
123	regmap_write(engine->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
124		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS |
125		     SUN4I_BACKEND_REGBUFFCTL_LOADCTL);
126}
127
128void sun4i_backend_layer_enable(struct sun4i_backend *backend,
129				int layer, bool enable)
130{
131	u32 val;
132
133	DRM_DEBUG_DRIVER("%sabling layer %d\n", enable ? "En" : "Dis",
134			 layer);
135
136	if (enable)
137		val = SUN4I_BACKEND_MODCTL_LAY_EN(layer);
138	else
139		val = 0;
140
141	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
142			   SUN4I_BACKEND_MODCTL_LAY_EN(layer), val);
143}
144
145static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
146{
147	switch (format) {
148	case DRM_FORMAT_ARGB8888:
149		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB8888;
150		break;
151
152	case DRM_FORMAT_ARGB4444:
153		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB4444;
154		break;
155
156	case DRM_FORMAT_ARGB1555:
157		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB1555;
158		break;
159
160	case DRM_FORMAT_RGBA5551:
161		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA5551;
162		break;
163
164	case DRM_FORMAT_RGBA4444:
165		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA4444;
166		break;
167
168	case DRM_FORMAT_XRGB8888:
169		*mode = SUN4I_BACKEND_LAY_FBFMT_XRGB8888;
170		break;
171
172	case DRM_FORMAT_RGB888:
173		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB888;
174		break;
175
176	case DRM_FORMAT_RGB565:
177		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB565;
178		break;
179
180	default:
181		return -EINVAL;
182	}
183
184	return 0;
185}
186
187int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
188				     int layer, struct drm_plane *plane)
189{
190	struct drm_plane_state *state = plane->state;
191
192	DRM_DEBUG_DRIVER("Updating layer %d\n", layer);
193
194	if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
195		DRM_DEBUG_DRIVER("Primary layer, updating global size W: %u H: %u\n",
196				 state->crtc_w, state->crtc_h);
197		regmap_write(backend->engine.regs, SUN4I_BACKEND_DISSIZE_REG,
198			     SUN4I_BACKEND_DISSIZE(state->crtc_w,
199						   state->crtc_h));
200	}
201
202	/* Set height and width */
203	DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
204			 state->crtc_w, state->crtc_h);
205	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
206		     SUN4I_BACKEND_LAYSIZE(state->crtc_w,
207					   state->crtc_h));
208
209	/* Set base coordinates */
210	DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
211			 state->crtc_x, state->crtc_y);
212	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
213		     SUN4I_BACKEND_LAYCOOR(state->crtc_x,
214					   state->crtc_y));
215
216	return 0;
217}
218
219static int sun4i_backend_update_yuv_format(struct sun4i_backend *backend,
220					   int layer, struct drm_plane *plane)
221{
222	struct drm_plane_state *state = plane->state;
223	struct drm_framebuffer *fb = state->fb;
224	uint32_t format = fb->format->format;
225	u32 val = SUN4I_BACKEND_IYUVCTL_EN;
226	int i;
227
228	for (i = 0; i < ARRAY_SIZE(sunxi_bt601_yuv2rgb_coef); i++)
229		regmap_write(backend->engine.regs,
230			     SUN4I_BACKEND_YGCOEF_REG(i),
231			     sunxi_bt601_yuv2rgb_coef[i]);
232
233	/*
234	 * We should do that only for a single plane, but the
235	 * framebuffer's atomic_check has our back on this.
236	 */
237	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
238			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN,
239			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN);
240
241	/* TODO: Add support for the multi-planar YUV formats */
242	if (sun4i_backend_format_is_packed_yuv422(format))
243		val |= SUN4I_BACKEND_IYUVCTL_FBFMT_PACKED_YUV422;
244	else
245		DRM_DEBUG_DRIVER("Unsupported YUV format (0x%x)\n", format);
246
247	/*
248	 * Allwinner seems to list the pixel sequence from right to left, while
249	 * DRM lists it from left to right.
250	 */
251	switch (format) {
252	case DRM_FORMAT_YUYV:
253		val |= SUN4I_BACKEND_IYUVCTL_FBPS_VYUY;
254		break;
255	case DRM_FORMAT_YVYU:
256		val |= SUN4I_BACKEND_IYUVCTL_FBPS_UYVY;
257		break;
258	case DRM_FORMAT_UYVY:
259		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YVYU;
260		break;
261	case DRM_FORMAT_VYUY:
262		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YUYV;
263		break;
264	default:
265		DRM_DEBUG_DRIVER("Unsupported YUV pixel sequence (0x%x)\n",
266				 format);
267	}
268
269	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVCTL_REG, val);
270
271	return 0;
272}
273
274int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
275				       int layer, struct drm_plane *plane)
276{
277	struct drm_plane_state *state = plane->state;
278	struct drm_framebuffer *fb = state->fb;
279	bool interlaced = false;
280	u32 val;
281	int ret;
282
283	/* Clear the YUV mode */
284	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
285			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
286
287	if (plane->state->crtc)
288		interlaced = plane->state->crtc->state->adjusted_mode.flags
289			& DRM_MODE_FLAG_INTERLACE;
290
291	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
292			   SUN4I_BACKEND_MODCTL_ITLMOD_EN,
293			   interlaced ? SUN4I_BACKEND_MODCTL_ITLMOD_EN : 0);
294
295	DRM_DEBUG_DRIVER("Switching display backend interlaced mode %s\n",
296			 interlaced ? "on" : "off");
297
298	if (sun4i_backend_format_is_yuv(fb->format->format))
299		return sun4i_backend_update_yuv_format(backend, layer, plane);
300
301	ret = sun4i_backend_drm_format_to_layer(fb->format->format, &val);
302	if (ret) {
303		DRM_DEBUG_DRIVER("Invalid format\n");
304		return ret;
305	}
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
314int sun4i_backend_update_layer_frontend(struct sun4i_backend *backend,
315					int layer, uint32_t fmt)
316{
317	u32 val;
318	int ret;
319
320	ret = sun4i_backend_drm_format_to_layer(fmt, &val);
321	if (ret) {
322		DRM_DEBUG_DRIVER("Invalid format\n");
323		return ret;
324	}
325
326	regmap_update_bits(backend->engine.regs,
327			   SUN4I_BACKEND_ATTCTL_REG0(layer),
328			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN,
329			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN);
330
331	regmap_update_bits(backend->engine.regs,
332			   SUN4I_BACKEND_ATTCTL_REG1(layer),
333			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
334
335	return 0;
336}
337
338static int sun4i_backend_update_yuv_buffer(struct sun4i_backend *backend,
339					   struct drm_framebuffer *fb,
340					   dma_addr_t paddr)
341{
342	/* TODO: Add support for the multi-planar YUV formats */
343	DRM_DEBUG_DRIVER("Setting packed YUV buffer address to %pad\n", &paddr);
344	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVADD_REG(0), paddr);
345
346	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
347	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVLINEWIDTH_REG(0),
348		     fb->pitches[0] * 8);
349
350	return 0;
351}
352
353int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
354				      int layer, struct drm_plane *plane)
355{
356	struct drm_plane_state *state = plane->state;
357	struct drm_framebuffer *fb = state->fb;
358	u32 lo_paddr, hi_paddr;
359	dma_addr_t paddr;
360
361	/* Set the line width */
362	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
363	regmap_write(backend->engine.regs,
364		     SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
365		     fb->pitches[0] * 8);
366
367	/* Get the start of the displayed memory */
368	paddr = drm_fb_cma_get_gem_addr(fb, state, 0);
369	DRM_DEBUG_DRIVER("Setting buffer address to %pad\n", &paddr);
370
371	/*
372	 * backend DMA accesses DRAM directly, bypassing the system
373	 * bus. As such, the address range is different and the buffer
374	 * address needs to be corrected.
375	 */
376	paddr -= PHYS_OFFSET;
377
378	if (sun4i_backend_format_is_yuv(fb->format->format))
379		return sun4i_backend_update_yuv_buffer(backend, fb, paddr);
380
381	/* Write the 32 lower bits of the address (in bits) */
382	lo_paddr = paddr << 3;
383	DRM_DEBUG_DRIVER("Setting address lower bits to 0x%x\n", lo_paddr);
384	regmap_write(backend->engine.regs,
385		     SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
386		     lo_paddr);
387
388	/* And the upper bits */
389	hi_paddr = paddr >> 29;
390	DRM_DEBUG_DRIVER("Setting address high bits to 0x%x\n", hi_paddr);
391	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
392			   SUN4I_BACKEND_LAYFB_H4ADD_MSK(layer),
393			   SUN4I_BACKEND_LAYFB_H4ADD(layer, hi_paddr));
394
395	return 0;
396}
397
398int sun4i_backend_update_layer_zpos(struct sun4i_backend *backend, int layer,
399				    struct drm_plane *plane)
400{
401	struct drm_plane_state *state = plane->state;
402	struct sun4i_layer_state *p_state = state_to_sun4i_layer_state(state);
403	unsigned int priority = state->normalized_zpos;
404	unsigned int pipe = p_state->pipe;
405
406	DRM_DEBUG_DRIVER("Setting layer %d's priority to %d and pipe %d\n",
407			 layer, priority, pipe);
408	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
409			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK |
410			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL_MASK,
411			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(p_state->pipe) |
412			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL(priority));
413
414	return 0;
415}
416
417static bool sun4i_backend_plane_uses_scaler(struct drm_plane_state *state)
418{
419	u16 src_h = state->src_h >> 16;
420	u16 src_w = state->src_w >> 16;
421
422	DRM_DEBUG_DRIVER("Input size %dx%d, output size %dx%d\n",
423			 src_w, src_h, state->crtc_w, state->crtc_h);
424
425	if ((state->crtc_h != src_h) || (state->crtc_w != src_w))
426		return true;
427
428	return false;
429}
430
431static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
432{
433	struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
434	struct sun4i_backend *backend = layer->backend;
435
436	if (IS_ERR(backend->frontend))
437		return false;
438
439	return sun4i_backend_plane_uses_scaler(state);
440}
441
442static void sun4i_backend_atomic_begin(struct sunxi_engine *engine,
443				       struct drm_crtc_state *old_state)
444{
445	u32 val;
446
447	WARN_ON(regmap_read_poll_timeout(engine->regs,
448					 SUN4I_BACKEND_REGBUFFCTL_REG,
449					 val, !(val & SUN4I_BACKEND_REGBUFFCTL_LOADCTL),
450					 100, 50000));
451}
452
453static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
454				      struct drm_crtc_state *crtc_state)
455{
456	struct drm_plane_state *plane_states[SUN4I_BACKEND_NUM_LAYERS] = { 0 };
457	struct drm_atomic_state *state = crtc_state->state;
458	struct drm_device *drm = state->dev;
459	struct drm_plane *plane;
460	unsigned int num_planes = 0;
461	unsigned int num_alpha_planes = 0;
462	unsigned int num_frontend_planes = 0;
463	unsigned int num_yuv_planes = 0;
464	unsigned int current_pipe = 0;
465	unsigned int i;
466
467	DRM_DEBUG_DRIVER("Starting checking our planes\n");
468
469	if (!crtc_state->planes_changed)
470		return 0;
471
472	drm_for_each_plane_mask(plane, drm, crtc_state->plane_mask) {
473		struct drm_plane_state *plane_state =
474			drm_atomic_get_plane_state(state, plane);
475		struct sun4i_layer_state *layer_state =
476			state_to_sun4i_layer_state(plane_state);
477		struct drm_framebuffer *fb = plane_state->fb;
478		struct drm_format_name_buf format_name;
479
480		if (sun4i_backend_plane_uses_frontend(plane_state)) {
481			DRM_DEBUG_DRIVER("Using the frontend for plane %d\n",
482					 plane->index);
483
484			layer_state->uses_frontend = true;
485			num_frontend_planes++;
486		} else {
487			layer_state->uses_frontend = false;
488		}
489
490		DRM_DEBUG_DRIVER("Plane FB format is %s\n",
491				 drm_get_format_name(fb->format->format,
492						     &format_name));
493		if (fb->format->has_alpha)
494			num_alpha_planes++;
495
496		if (sun4i_backend_format_is_yuv(fb->format->format)) {
497			DRM_DEBUG_DRIVER("Plane FB format is YUV\n");
498			num_yuv_planes++;
499		}
500
501		DRM_DEBUG_DRIVER("Plane zpos is %d\n",
502				 plane_state->normalized_zpos);
503
504		/* Sort our planes by Zpos */
505		plane_states[plane_state->normalized_zpos] = plane_state;
506
507		num_planes++;
508	}
509
510	/* All our planes were disabled, bail out */
511	if (!num_planes)
512		return 0;
513
514	/*
515	 * The hardware is a bit unusual here.
516	 *
517	 * Even though it supports 4 layers, it does the composition
518	 * in two separate steps.
519	 *
520	 * The first one is assigning a layer to one of its two
521	 * pipes. If more that 1 layer is assigned to the same pipe,
522	 * and if pixels overlaps, the pipe will take the pixel from
523	 * the layer with the highest priority.
524	 *
525	 * The second step is the actual alpha blending, that takes
526	 * the two pipes as input, and uses the eventual alpha
527	 * component to do the transparency between the two.
528	 *
529	 * This two steps scenario makes us unable to guarantee a
530	 * robust alpha blending between the 4 layers in all
531	 * situations, since this means that we need to have one layer
532	 * with alpha at the lowest position of our two pipes.
533	 *
534	 * However, we cannot even do that, since the hardware has a
535	 * bug where the lowest plane of the lowest pipe (pipe 0,
536	 * priority 0), if it has any alpha, will discard the pixel
537	 * entirely and just display the pixels in the background
538	 * color (black by default).
539	 *
540	 * This means that we effectively have only three valid
541	 * configurations with alpha, all of them with the alpha being
542	 * on pipe1 with the lowest position, which can be 1, 2 or 3
543	 * depending on the number of planes and their zpos.
544	 */
545	if (num_alpha_planes > SUN4I_BACKEND_NUM_ALPHA_LAYERS) {
546		DRM_DEBUG_DRIVER("Too many planes with alpha, rejecting...\n");
547		return -EINVAL;
548	}
549
550	/* We can't have an alpha plane at the lowest position */
551	if (plane_states[0]->fb->format->has_alpha)
552		return -EINVAL;
553
554	for (i = 1; i < num_planes; i++) {
555		struct drm_plane_state *p_state = plane_states[i];
556		struct drm_framebuffer *fb = p_state->fb;
557		struct sun4i_layer_state *s_state = state_to_sun4i_layer_state(p_state);
558
559		/*
560		 * The only alpha position is the lowest plane of the
561		 * second pipe.
562		 */
563		if (fb->format->has_alpha)
564			current_pipe++;
565
566		s_state->pipe = current_pipe;
567	}
568
569	/* We can only have a single YUV plane at a time */
570	if (num_yuv_planes > SUN4I_BACKEND_NUM_YUV_PLANES) {
571		DRM_DEBUG_DRIVER("Too many planes with YUV, rejecting...\n");
572		return -EINVAL;
573	}
574
575	if (num_frontend_planes > SUN4I_BACKEND_NUM_FRONTEND_LAYERS) {
576		DRM_DEBUG_DRIVER("Too many planes going through the frontend, rejecting\n");
577		return -EINVAL;
578	}
579
580	DRM_DEBUG_DRIVER("State valid with %u planes, %u alpha, %u video, %u YUV\n",
581			 num_planes, num_alpha_planes, num_frontend_planes,
582			 num_yuv_planes);
583
584	return 0;
585}
586
587static void sun4i_backend_vblank_quirk(struct sunxi_engine *engine)
588{
589	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
590	struct sun4i_frontend *frontend = backend->frontend;
591
592	if (!frontend)
593		return;
594
595	/*
596	 * In a teardown scenario with the frontend involved, we have
597	 * to keep the frontend enabled until the next vblank, and
598	 * only then disable it.
599	 *
600	 * This is due to the fact that the backend will not take into
601	 * account the new configuration (with the plane that used to
602	 * be fed by the frontend now disabled) until we write to the
603	 * commit bit and the hardware fetches the new configuration
604	 * during the next vblank.
605	 *
606	 * So we keep the frontend around in order to prevent any
607	 * visual artifacts.
608	 */
609	spin_lock(&backend->frontend_lock);
610	if (backend->frontend_teardown) {
611		sun4i_frontend_exit(frontend);
612		backend->frontend_teardown = false;
613	}
614	spin_unlock(&backend->frontend_lock);
615};
616
617static int sun4i_backend_init_sat(struct device *dev) {
618	struct sun4i_backend *backend = dev_get_drvdata(dev);
619	int ret;
620
621	backend->sat_reset = devm_reset_control_get(dev, "sat");
622	if (IS_ERR(backend->sat_reset)) {
623		dev_err(dev, "Couldn't get the SAT reset line\n");
624		return PTR_ERR(backend->sat_reset);
625	}
626
627	ret = reset_control_deassert(backend->sat_reset);
628	if (ret) {
629		dev_err(dev, "Couldn't deassert the SAT reset line\n");
630		return ret;
631	}
632
633	backend->sat_clk = devm_clk_get(dev, "sat");
634	if (IS_ERR(backend->sat_clk)) {
635		dev_err(dev, "Couldn't get our SAT clock\n");
636		ret = PTR_ERR(backend->sat_clk);
637		goto err_assert_reset;
638	}
639
640	ret = clk_prepare_enable(backend->sat_clk);
641	if (ret) {
642		dev_err(dev, "Couldn't enable the SAT clock\n");
643		return ret;
644	}
645
646	return 0;
647
648err_assert_reset:
649	reset_control_assert(backend->sat_reset);
650	return ret;
651}
652
653static int sun4i_backend_free_sat(struct device *dev) {
654	struct sun4i_backend *backend = dev_get_drvdata(dev);
655
656	clk_disable_unprepare(backend->sat_clk);
657	reset_control_assert(backend->sat_reset);
658
659	return 0;
660}
661
662/*
663 * The display backend can take video output from the display frontend, or
664 * the display enhancement unit on the A80, as input for one it its layers.
665 * This relationship within the display pipeline is encoded in the device
666 * tree with of_graph, and we use it here to figure out which backend, if
667 * there are 2 or more, we are currently probing. The number would be in
668 * the "reg" property of the upstream output port endpoint.
669 */
670static int sun4i_backend_of_get_id(struct device_node *node)
671{
672	struct device_node *port, *ep;
673	int ret = -EINVAL;
674
675	/* input is port 0 */
676	port = of_graph_get_port_by_id(node, 0);
677	if (!port)
678		return -EINVAL;
679
680	/* try finding an upstream endpoint */
681	for_each_available_child_of_node(port, ep) {
682		struct device_node *remote;
683		u32 reg;
684
685		remote = of_graph_get_remote_endpoint(ep);
686		if (!remote)
687			continue;
688
689		ret = of_property_read_u32(remote, "reg", &reg);
690		if (ret)
691			continue;
692
693		ret = reg;
694	}
695
696	of_node_put(port);
697
698	return ret;
699}
700
701/* TODO: This needs to take multiple pipelines into account */
702static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv,
703							  struct device_node *node)
704{
705	struct device_node *port, *ep, *remote;
706	struct sun4i_frontend *frontend;
707
708	port = of_graph_get_port_by_id(node, 0);
709	if (!port)
710		return ERR_PTR(-EINVAL);
711
712	for_each_available_child_of_node(port, ep) {
713		remote = of_graph_get_remote_port_parent(ep);
714		if (!remote)
715			continue;
716
717		/* does this node match any registered engines? */
718		list_for_each_entry(frontend, &drv->frontend_list, list) {
719			if (remote == frontend->node) {
720				of_node_put(remote);
721				of_node_put(port);
722				return frontend;
723			}
724		}
725	}
726
727	return ERR_PTR(-EINVAL);
728}
729
730static const struct sunxi_engine_ops sun4i_backend_engine_ops = {
731	.atomic_begin			= sun4i_backend_atomic_begin,
732	.atomic_check			= sun4i_backend_atomic_check,
733	.commit				= sun4i_backend_commit,
734	.layers_init			= sun4i_layers_init,
735	.apply_color_correction		= sun4i_backend_apply_color_correction,
736	.disable_color_correction	= sun4i_backend_disable_color_correction,
737	.vblank_quirk			= sun4i_backend_vblank_quirk,
738};
739
740static struct regmap_config sun4i_backend_regmap_config = {
741	.reg_bits	= 32,
742	.val_bits	= 32,
743	.reg_stride	= 4,
744	.max_register	= 0x5800,
745};
746
747static int sun4i_backend_bind(struct device *dev, struct device *master,
748			      void *data)
749{
750	struct platform_device *pdev = to_platform_device(dev);
751	struct drm_device *drm = data;
752	struct sun4i_drv *drv = drm->dev_private;
753	struct sun4i_backend *backend;
754	const struct sun4i_backend_quirks *quirks;
755	struct resource *res;
756	void __iomem *regs;
757	int i, ret;
758
759	backend = devm_kzalloc(dev, sizeof(*backend), GFP_KERNEL);
760	if (!backend)
761		return -ENOMEM;
762	dev_set_drvdata(dev, backend);
763	spin_lock_init(&backend->frontend_lock);
764
765	backend->engine.node = dev->of_node;
766	backend->engine.ops = &sun4i_backend_engine_ops;
767	backend->engine.id = sun4i_backend_of_get_id(dev->of_node);
768	if (backend->engine.id < 0)
769		return backend->engine.id;
770
771	backend->frontend = sun4i_backend_find_frontend(drv, dev->of_node);
772	if (IS_ERR(backend->frontend))
773		dev_warn(dev, "Couldn't find matching frontend, frontend features disabled\n");
774
775	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
776	regs = devm_ioremap_resource(dev, res);
777	if (IS_ERR(regs))
778		return PTR_ERR(regs);
779
780	backend->reset = devm_reset_control_get(dev, NULL);
781	if (IS_ERR(backend->reset)) {
782		dev_err(dev, "Couldn't get our reset line\n");
783		return PTR_ERR(backend->reset);
784	}
785
786	ret = reset_control_deassert(backend->reset);
787	if (ret) {
788		dev_err(dev, "Couldn't deassert our reset line\n");
789		return ret;
790	}
791
792	backend->bus_clk = devm_clk_get(dev, "ahb");
793	if (IS_ERR(backend->bus_clk)) {
794		dev_err(dev, "Couldn't get the backend bus clock\n");
795		ret = PTR_ERR(backend->bus_clk);
796		goto err_assert_reset;
797	}
798	clk_prepare_enable(backend->bus_clk);
799
800	backend->mod_clk = devm_clk_get(dev, "mod");
801	if (IS_ERR(backend->mod_clk)) {
802		dev_err(dev, "Couldn't get the backend module clock\n");
803		ret = PTR_ERR(backend->mod_clk);
804		goto err_disable_bus_clk;
805	}
806	clk_prepare_enable(backend->mod_clk);
807
808	backend->ram_clk = devm_clk_get(dev, "ram");
809	if (IS_ERR(backend->ram_clk)) {
810		dev_err(dev, "Couldn't get the backend RAM clock\n");
811		ret = PTR_ERR(backend->ram_clk);
812		goto err_disable_mod_clk;
813	}
814	clk_prepare_enable(backend->ram_clk);
815
816	if (of_device_is_compatible(dev->of_node,
817				    "allwinner,sun8i-a33-display-backend")) {
818		ret = sun4i_backend_init_sat(dev);
819		if (ret) {
820			dev_err(dev, "Couldn't init SAT resources\n");
821			goto err_disable_ram_clk;
822		}
823	}
824
825	backend->engine.regs = devm_regmap_init_mmio(dev, regs,
826						     &sun4i_backend_regmap_config);
827	if (IS_ERR(backend->engine.regs)) {
828		dev_err(dev, "Couldn't create the backend regmap\n");
829		return PTR_ERR(backend->engine.regs);
830	}
831
832	list_add_tail(&backend->engine.list, &drv->engine_list);
833
834	/*
835	 * Many of the backend's layer configuration registers have
836	 * undefined default values. This poses a risk as we use
837	 * regmap_update_bits in some places, and don't overwrite
838	 * the whole register.
839	 *
840	 * Clear the registers here to have something predictable.
841	 */
842	for (i = 0x800; i < 0x1000; i += 4)
843		regmap_write(backend->engine.regs, i, 0);
844
845	/* Disable registers autoloading */
846	regmap_write(backend->engine.regs, SUN4I_BACKEND_REGBUFFCTL_REG,
847		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
848
849	/* Enable the backend */
850	regmap_write(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
851		     SUN4I_BACKEND_MODCTL_DEBE_EN |
852		     SUN4I_BACKEND_MODCTL_START_CTL);
853
854	/* Set output selection if needed */
855	quirks = of_device_get_match_data(dev);
856	if (quirks->needs_output_muxing) {
857		/*
858		 * We assume there is no dynamic muxing of backends
859		 * and TCONs, so we select the backend with same ID.
860		 *
861		 * While dynamic selection might be interesting, since
862		 * the CRTC is tied to the TCON, while the layers are
863		 * tied to the backends, this means, we will need to
864		 * switch between groups of layers. There might not be
865		 * a way to represent this constraint in DRM.
866		 */
867		regmap_update_bits(backend->engine.regs,
868				   SUN4I_BACKEND_MODCTL_REG,
869				   SUN4I_BACKEND_MODCTL_OUT_SEL,
870				   (backend->engine.id
871				    ? SUN4I_BACKEND_MODCTL_OUT_LCD1
872				    : SUN4I_BACKEND_MODCTL_OUT_LCD0));
873	}
874
875	return 0;
876
877err_disable_ram_clk:
878	clk_disable_unprepare(backend->ram_clk);
879err_disable_mod_clk:
880	clk_disable_unprepare(backend->mod_clk);
881err_disable_bus_clk:
882	clk_disable_unprepare(backend->bus_clk);
883err_assert_reset:
884	reset_control_assert(backend->reset);
885	return ret;
886}
887
888static void sun4i_backend_unbind(struct device *dev, struct device *master,
889				 void *data)
890{
891	struct sun4i_backend *backend = dev_get_drvdata(dev);
892
893	list_del(&backend->engine.list);
894
895	if (of_device_is_compatible(dev->of_node,
896				    "allwinner,sun8i-a33-display-backend"))
897		sun4i_backend_free_sat(dev);
898
899	clk_disable_unprepare(backend->ram_clk);
900	clk_disable_unprepare(backend->mod_clk);
901	clk_disable_unprepare(backend->bus_clk);
902	reset_control_assert(backend->reset);
903}
904
905static const struct component_ops sun4i_backend_ops = {
906	.bind	= sun4i_backend_bind,
907	.unbind	= sun4i_backend_unbind,
908};
909
910static int sun4i_backend_probe(struct platform_device *pdev)
911{
912	return component_add(&pdev->dev, &sun4i_backend_ops);
913}
914
915static int sun4i_backend_remove(struct platform_device *pdev)
916{
917	component_del(&pdev->dev, &sun4i_backend_ops);
918
919	return 0;
920}
921
922static const struct sun4i_backend_quirks sun4i_backend_quirks = {
923	.needs_output_muxing = true,
924};
925
926static const struct sun4i_backend_quirks sun5i_backend_quirks = {
927};
928
929static const struct sun4i_backend_quirks sun6i_backend_quirks = {
930};
931
932static const struct sun4i_backend_quirks sun7i_backend_quirks = {
933	.needs_output_muxing = true,
934};
935
936static const struct sun4i_backend_quirks sun8i_a33_backend_quirks = {
937};
938
939static const struct sun4i_backend_quirks sun9i_backend_quirks = {
940};
941
942static const struct of_device_id sun4i_backend_of_table[] = {
943	{
944		.compatible = "allwinner,sun4i-a10-display-backend",
945		.data = &sun4i_backend_quirks,
946	},
947	{
948		.compatible = "allwinner,sun5i-a13-display-backend",
949		.data = &sun5i_backend_quirks,
950	},
951	{
952		.compatible = "allwinner,sun6i-a31-display-backend",
953		.data = &sun6i_backend_quirks,
954	},
955	{
956		.compatible = "allwinner,sun7i-a20-display-backend",
957		.data = &sun7i_backend_quirks,
958	},
959	{
960		.compatible = "allwinner,sun8i-a33-display-backend",
961		.data = &sun8i_a33_backend_quirks,
962	},
963	{
964		.compatible = "allwinner,sun9i-a80-display-backend",
965		.data = &sun9i_backend_quirks,
966	},
967	{ }
968};
969MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);
970
971static struct platform_driver sun4i_backend_platform_driver = {
972	.probe		= sun4i_backend_probe,
973	.remove		= sun4i_backend_remove,
974	.driver		= {
975		.name		= "sun4i-backend",
976		.of_match_table	= sun4i_backend_of_table,
977	},
978};
979module_platform_driver(sun4i_backend_platform_driver);
980
981MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
982MODULE_DESCRIPTION("Allwinner A10 Display Backend Driver");
983MODULE_LICENSE("GPL");