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   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/platform_device.h>
  15#include <linux/reset.h>
  16
  17#include <drm/drm_atomic.h>
  18#include <drm/drm_atomic_helper.h>
  19#include <drm/drm_crtc.h>
  20#include <drm/drm_fb_cma_helper.h>
  21#include <drm/drm_fourcc.h>
  22#include <drm/drm_gem_cma_helper.h>
  23#include <drm/drm_plane_helper.h>
  24#include <drm/drm_probe_helper.h>
  25
  26#include "sun4i_backend.h"
  27#include "sun4i_drv.h"
  28#include "sun4i_frontend.h"
  29#include "sun4i_layer.h"
  30#include "sunxi_engine.h"
  31
  32struct sun4i_backend_quirks {
  33	/* backend <-> TCON muxing selection done in backend */
  34	bool needs_output_muxing;
  35
  36	/* alpha at the lowest z position is not always supported */
  37	bool supports_lowest_plane_alpha;
  38};
  39
  40static const u32 sunxi_rgb2yuv_coef[12] = {
  41	0x00000107, 0x00000204, 0x00000064, 0x00000108,
  42	0x00003f69, 0x00003ed6, 0x000001c1, 0x00000808,
  43	0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
  44};
  45
  46static void sun4i_backend_apply_color_correction(struct sunxi_engine *engine)
  47{
  48	int i;
  49
  50	DRM_DEBUG_DRIVER("Applying RGB to YUV color correction\n");
  51
  52	/* Set color correction */
  53	regmap_write(engine->regs, SUN4I_BACKEND_OCCTL_REG,
  54		     SUN4I_BACKEND_OCCTL_ENABLE);
  55
  56	for (i = 0; i < 12; i++)
  57		regmap_write(engine->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
  58			     sunxi_rgb2yuv_coef[i]);
  59}
  60
  61static void sun4i_backend_disable_color_correction(struct sunxi_engine *engine)
  62{
  63	DRM_DEBUG_DRIVER("Disabling color correction\n");
  64
  65	/* Disable color correction */
  66	regmap_update_bits(engine->regs, SUN4I_BACKEND_OCCTL_REG,
  67			   SUN4I_BACKEND_OCCTL_ENABLE, 0);
  68}
  69
  70static void sun4i_backend_commit(struct sunxi_engine *engine)
  71{
  72	DRM_DEBUG_DRIVER("Committing changes\n");
  73
  74	regmap_write(engine->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
  75		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS |
  76		     SUN4I_BACKEND_REGBUFFCTL_LOADCTL);
  77}
  78
  79void sun4i_backend_layer_enable(struct sun4i_backend *backend,
  80				int layer, bool enable)
  81{
  82	u32 val;
  83
  84	DRM_DEBUG_DRIVER("%sabling layer %d\n", enable ? "En" : "Dis",
  85			 layer);
  86
  87	if (enable)
  88		val = SUN4I_BACKEND_MODCTL_LAY_EN(layer);
  89	else
  90		val = 0;
  91
  92	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
  93			   SUN4I_BACKEND_MODCTL_LAY_EN(layer), val);
  94}
  95
  96static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
  97{
  98	switch (format) {
  99	case DRM_FORMAT_ARGB8888:
 100		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB8888;
 101		break;
 102
 103	case DRM_FORMAT_ARGB4444:
 104		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB4444;
 105		break;
 106
 107	case DRM_FORMAT_ARGB1555:
 108		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB1555;
 109		break;
 110
 111	case DRM_FORMAT_RGBA5551:
 112		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA5551;
 113		break;
 114
 115	case DRM_FORMAT_RGBA4444:
 116		*mode = SUN4I_BACKEND_LAY_FBFMT_RGBA4444;
 117		break;
 118
 119	case DRM_FORMAT_XRGB8888:
 120		*mode = SUN4I_BACKEND_LAY_FBFMT_XRGB8888;
 121		break;
 122
 123	case DRM_FORMAT_RGB888:
 124		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB888;
 125		break;
 126
 127	case DRM_FORMAT_RGB565:
 128		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB565;
 129		break;
 130
 131	default:
 132		return -EINVAL;
 133	}
 134
 135	return 0;
 136}
 137
 138static const uint32_t sun4i_backend_formats[] = {
 139	DRM_FORMAT_ARGB1555,
 140	DRM_FORMAT_ARGB4444,
 141	DRM_FORMAT_ARGB8888,
 142	DRM_FORMAT_RGB565,
 143	DRM_FORMAT_RGB888,
 144	DRM_FORMAT_RGBA4444,
 145	DRM_FORMAT_RGBA5551,
 146	DRM_FORMAT_UYVY,
 147	DRM_FORMAT_VYUY,
 148	DRM_FORMAT_XRGB8888,
 149	DRM_FORMAT_YUYV,
 150	DRM_FORMAT_YVYU,
 151};
 152
 153bool sun4i_backend_format_is_supported(uint32_t fmt, uint64_t modifier)
 154{
 155	unsigned int i;
 156
 157	if (modifier != DRM_FORMAT_MOD_LINEAR)
 158		return false;
 159
 160	for (i = 0; i < ARRAY_SIZE(sun4i_backend_formats); i++)
 161		if (sun4i_backend_formats[i] == fmt)
 162			return true;
 163
 164	return false;
 165}
 166
 167int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
 168				     int layer, struct drm_plane *plane)
 169{
 170	struct drm_plane_state *state = plane->state;
 171
 172	DRM_DEBUG_DRIVER("Updating layer %d\n", layer);
 173
 174	if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
 175		DRM_DEBUG_DRIVER("Primary layer, updating global size W: %u H: %u\n",
 176				 state->crtc_w, state->crtc_h);
 177		regmap_write(backend->engine.regs, SUN4I_BACKEND_DISSIZE_REG,
 178			     SUN4I_BACKEND_DISSIZE(state->crtc_w,
 179						   state->crtc_h));
 180	}
 181
 182	/* Set height and width */
 183	DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
 184			 state->crtc_w, state->crtc_h);
 185	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
 186		     SUN4I_BACKEND_LAYSIZE(state->crtc_w,
 187					   state->crtc_h));
 188
 189	/* Set base coordinates */
 190	DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
 191			 state->crtc_x, state->crtc_y);
 192	regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
 193		     SUN4I_BACKEND_LAYCOOR(state->crtc_x,
 194					   state->crtc_y));
 195
 196	return 0;
 197}
 198
 199static int sun4i_backend_update_yuv_format(struct sun4i_backend *backend,
 200					   int layer, struct drm_plane *plane)
 201{
 202	struct drm_plane_state *state = plane->state;
 203	struct drm_framebuffer *fb = state->fb;
 204	const struct drm_format_info *format = fb->format;
 205	const uint32_t fmt = format->format;
 206	u32 val = SUN4I_BACKEND_IYUVCTL_EN;
 207	int i;
 208
 209	for (i = 0; i < ARRAY_SIZE(sunxi_bt601_yuv2rgb_coef); i++)
 210		regmap_write(backend->engine.regs,
 211			     SUN4I_BACKEND_YGCOEF_REG(i),
 212			     sunxi_bt601_yuv2rgb_coef[i]);
 213
 214	/*
 215	 * We should do that only for a single plane, but the
 216	 * framebuffer's atomic_check has our back on this.
 217	 */
 218	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
 219			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN,
 220			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN);
 221
 222	/* TODO: Add support for the multi-planar YUV formats */
 223	if (drm_format_info_is_yuv_packed(format) &&
 224	    drm_format_info_is_yuv_sampling_422(format))
 225		val |= SUN4I_BACKEND_IYUVCTL_FBFMT_PACKED_YUV422;
 226	else
 227		DRM_DEBUG_DRIVER("Unsupported YUV format (0x%x)\n", fmt);
 228
 229	/*
 230	 * Allwinner seems to list the pixel sequence from right to left, while
 231	 * DRM lists it from left to right.
 232	 */
 233	switch (fmt) {
 234	case DRM_FORMAT_YUYV:
 235		val |= SUN4I_BACKEND_IYUVCTL_FBPS_VYUY;
 236		break;
 237	case DRM_FORMAT_YVYU:
 238		val |= SUN4I_BACKEND_IYUVCTL_FBPS_UYVY;
 239		break;
 240	case DRM_FORMAT_UYVY:
 241		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YVYU;
 242		break;
 243	case DRM_FORMAT_VYUY:
 244		val |= SUN4I_BACKEND_IYUVCTL_FBPS_YUYV;
 245		break;
 246	default:
 247		DRM_DEBUG_DRIVER("Unsupported YUV pixel sequence (0x%x)\n",
 248				 fmt);
 249	}
 250
 251	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVCTL_REG, val);
 252
 253	return 0;
 254}
 255
 256int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
 257				       int layer, struct drm_plane *plane)
 258{
 259	struct drm_plane_state *state = plane->state;
 260	struct drm_framebuffer *fb = state->fb;
 261	bool interlaced = false;
 262	u32 val;
 263	int ret;
 264
 265	/* Clear the YUV mode */
 266	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
 267			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
 268
 269	if (plane->state->crtc)
 270		interlaced = plane->state->crtc->state->adjusted_mode.flags
 271			& DRM_MODE_FLAG_INTERLACE;
 272
 273	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 274			   SUN4I_BACKEND_MODCTL_ITLMOD_EN,
 275			   interlaced ? SUN4I_BACKEND_MODCTL_ITLMOD_EN : 0);
 276
 277	DRM_DEBUG_DRIVER("Switching display backend interlaced mode %s\n",
 278			 interlaced ? "on" : "off");
 279
 280	val = SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA(state->alpha >> 8);
 281	if (state->alpha != DRM_BLEND_ALPHA_OPAQUE)
 282		val |= SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN;
 283	regmap_update_bits(backend->engine.regs,
 284			   SUN4I_BACKEND_ATTCTL_REG0(layer),
 285			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_MASK |
 286			   SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN,
 287			   val);
 288
 289	if (fb->format->is_yuv)
 290		return sun4i_backend_update_yuv_format(backend, layer, plane);
 291
 292	ret = sun4i_backend_drm_format_to_layer(fb->format->format, &val);
 293	if (ret) {
 294		DRM_DEBUG_DRIVER("Invalid format\n");
 295		return ret;
 296	}
 297
 298	regmap_update_bits(backend->engine.regs,
 299			   SUN4I_BACKEND_ATTCTL_REG1(layer),
 300			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
 301
 302	return 0;
 303}
 304
 305int sun4i_backend_update_layer_frontend(struct sun4i_backend *backend,
 306					int layer, uint32_t fmt)
 307{
 308	u32 val;
 309	int ret;
 310
 311	ret = sun4i_backend_drm_format_to_layer(fmt, &val);
 312	if (ret) {
 313		DRM_DEBUG_DRIVER("Invalid format\n");
 314		return ret;
 315	}
 316
 317	regmap_update_bits(backend->engine.regs,
 318			   SUN4I_BACKEND_ATTCTL_REG0(layer),
 319			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN,
 320			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN);
 321
 322	regmap_update_bits(backend->engine.regs,
 323			   SUN4I_BACKEND_ATTCTL_REG1(layer),
 324			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
 325
 326	return 0;
 327}
 328
 329static int sun4i_backend_update_yuv_buffer(struct sun4i_backend *backend,
 330					   struct drm_framebuffer *fb,
 331					   dma_addr_t paddr)
 332{
 333	/* TODO: Add support for the multi-planar YUV formats */
 334	DRM_DEBUG_DRIVER("Setting packed YUV buffer address to %pad\n", &paddr);
 335	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVADD_REG(0), paddr);
 336
 337	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
 338	regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVLINEWIDTH_REG(0),
 339		     fb->pitches[0] * 8);
 340
 341	return 0;
 342}
 343
 344int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
 345				      int layer, struct drm_plane *plane)
 346{
 347	struct drm_plane_state *state = plane->state;
 348	struct drm_framebuffer *fb = state->fb;
 349	u32 lo_paddr, hi_paddr;
 350	dma_addr_t paddr;
 351
 352	/* Set the line width */
 353	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
 354	regmap_write(backend->engine.regs,
 355		     SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
 356		     fb->pitches[0] * 8);
 357
 358	/* Get the start of the displayed memory */
 359	paddr = drm_fb_cma_get_gem_addr(fb, state, 0);
 360	DRM_DEBUG_DRIVER("Setting buffer address to %pad\n", &paddr);
 361
 362	if (fb->format->is_yuv)
 363		return sun4i_backend_update_yuv_buffer(backend, fb, paddr);
 364
 365	/* Write the 32 lower bits of the address (in bits) */
 366	lo_paddr = paddr << 3;
 367	DRM_DEBUG_DRIVER("Setting address lower bits to 0x%x\n", lo_paddr);
 368	regmap_write(backend->engine.regs,
 369		     SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
 370		     lo_paddr);
 371
 372	/* And the upper bits */
 373	hi_paddr = paddr >> 29;
 374	DRM_DEBUG_DRIVER("Setting address high bits to 0x%x\n", hi_paddr);
 375	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
 376			   SUN4I_BACKEND_LAYFB_H4ADD_MSK(layer),
 377			   SUN4I_BACKEND_LAYFB_H4ADD(layer, hi_paddr));
 378
 379	return 0;
 380}
 381
 382int sun4i_backend_update_layer_zpos(struct sun4i_backend *backend, int layer,
 383				    struct drm_plane *plane)
 384{
 385	struct drm_plane_state *state = plane->state;
 386	struct sun4i_layer_state *p_state = state_to_sun4i_layer_state(state);
 387	unsigned int priority = state->normalized_zpos;
 388	unsigned int pipe = p_state->pipe;
 389
 390	DRM_DEBUG_DRIVER("Setting layer %d's priority to %d and pipe %d\n",
 391			 layer, priority, pipe);
 392	regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
 393			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK |
 394			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL_MASK,
 395			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(p_state->pipe) |
 396			   SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL(priority));
 397
 398	return 0;
 399}
 400
 401void sun4i_backend_cleanup_layer(struct sun4i_backend *backend,
 402				 int layer)
 403{
 404	regmap_update_bits(backend->engine.regs,
 405			   SUN4I_BACKEND_ATTCTL_REG0(layer),
 406			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN |
 407			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
 408}
 409
 410static bool sun4i_backend_plane_uses_scaler(struct drm_plane_state *state)
 411{
 412	u16 src_h = state->src_h >> 16;
 413	u16 src_w = state->src_w >> 16;
 414
 415	DRM_DEBUG_DRIVER("Input size %dx%d, output size %dx%d\n",
 416			 src_w, src_h, state->crtc_w, state->crtc_h);
 417
 418	if ((state->crtc_h != src_h) || (state->crtc_w != src_w))
 419		return true;
 420
 421	return false;
 422}
 423
 424static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
 425{
 426	struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
 427	struct sun4i_backend *backend = layer->backend;
 428	uint32_t format = state->fb->format->format;
 429	uint64_t modifier = state->fb->modifier;
 430
 431	if (IS_ERR(backend->frontend))
 432		return false;
 433
 434	if (!sun4i_frontend_format_is_supported(format, modifier))
 435		return false;
 436
 437	if (!sun4i_backend_format_is_supported(format, modifier))
 438		return true;
 439
 440	/*
 441	 * TODO: The backend alone allows 2x and 4x integer scaling, including
 442	 * support for an alpha component (which the frontend doesn't support).
 443	 * Use the backend directly instead of the frontend in this case, with
 444	 * another test to return false.
 445	 */
 446
 447	if (sun4i_backend_plane_uses_scaler(state))
 448		return true;
 449
 450	/*
 451	 * Here the format is supported by both the frontend and the backend
 452	 * and no frontend scaling is required, so use the backend directly.
 453	 */
 454	return false;
 455}
 456
 457static bool sun4i_backend_plane_is_supported(struct drm_plane_state *state,
 458					     bool *uses_frontend)
 459{
 460	if (sun4i_backend_plane_uses_frontend(state)) {
 461		*uses_frontend = true;
 462		return true;
 463	}
 464
 465	*uses_frontend = false;
 466
 467	/* Scaling is not supported without the frontend. */
 468	if (sun4i_backend_plane_uses_scaler(state))
 469		return false;
 470
 471	return true;
 472}
 473
 474static void sun4i_backend_atomic_begin(struct sunxi_engine *engine,
 475				       struct drm_crtc_state *old_state)
 476{
 477	u32 val;
 478
 479	WARN_ON(regmap_read_poll_timeout(engine->regs,
 480					 SUN4I_BACKEND_REGBUFFCTL_REG,
 481					 val, !(val & SUN4I_BACKEND_REGBUFFCTL_LOADCTL),
 482					 100, 50000));
 483}
 484
 485static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
 486				      struct drm_crtc_state *crtc_state)
 487{
 488	struct drm_plane_state *plane_states[SUN4I_BACKEND_NUM_LAYERS] = { 0 };
 489	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
 490	struct drm_atomic_state *state = crtc_state->state;
 491	struct drm_device *drm = state->dev;
 492	struct drm_plane *plane;
 493	unsigned int num_planes = 0;
 494	unsigned int num_alpha_planes = 0;
 495	unsigned int num_frontend_planes = 0;
 496	unsigned int num_alpha_planes_max = 1;
 497	unsigned int num_yuv_planes = 0;
 498	unsigned int current_pipe = 0;
 499	unsigned int i;
 500
 501	DRM_DEBUG_DRIVER("Starting checking our planes\n");
 502
 503	if (!crtc_state->planes_changed)
 504		return 0;
 505
 506	drm_for_each_plane_mask(plane, drm, crtc_state->plane_mask) {
 507		struct drm_plane_state *plane_state =
 508			drm_atomic_get_plane_state(state, plane);
 509		struct sun4i_layer_state *layer_state =
 510			state_to_sun4i_layer_state(plane_state);
 511		struct drm_framebuffer *fb = plane_state->fb;
 512		struct drm_format_name_buf format_name;
 513
 514		if (!sun4i_backend_plane_is_supported(plane_state,
 515						      &layer_state->uses_frontend))
 516			return -EINVAL;
 517
 518		if (layer_state->uses_frontend) {
 519			DRM_DEBUG_DRIVER("Using the frontend for plane %d\n",
 520					 plane->index);
 521			num_frontend_planes++;
 522		} else {
 523			if (fb->format->is_yuv) {
 524				DRM_DEBUG_DRIVER("Plane FB format is YUV\n");
 525				num_yuv_planes++;
 526			}
 527		}
 528
 529		DRM_DEBUG_DRIVER("Plane FB format is %s\n",
 530				 drm_get_format_name(fb->format->format,
 531						     &format_name));
 532		if (fb->format->has_alpha || (plane_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
 533			num_alpha_planes++;
 534
 535		DRM_DEBUG_DRIVER("Plane zpos is %d\n",
 536				 plane_state->normalized_zpos);
 537
 538		/* Sort our planes by Zpos */
 539		plane_states[plane_state->normalized_zpos] = plane_state;
 540
 541		num_planes++;
 542	}
 543
 544	/* All our planes were disabled, bail out */
 545	if (!num_planes)
 546		return 0;
 547
 548	/*
 549	 * The hardware is a bit unusual here.
 550	 *
 551	 * Even though it supports 4 layers, it does the composition
 552	 * in two separate steps.
 553	 *
 554	 * The first one is assigning a layer to one of its two
 555	 * pipes. If more that 1 layer is assigned to the same pipe,
 556	 * and if pixels overlaps, the pipe will take the pixel from
 557	 * the layer with the highest priority.
 558	 *
 559	 * The second step is the actual alpha blending, that takes
 560	 * the two pipes as input, and uses the potential alpha
 561	 * component to do the transparency between the two.
 562	 *
 563	 * This two-step scenario makes us unable to guarantee a
 564	 * robust alpha blending between the 4 layers in all
 565	 * situations, since this means that we need to have one layer
 566	 * with alpha at the lowest position of our two pipes.
 567	 *
 568	 * However, we cannot even do that on every platform, since
 569	 * the hardware has a bug where the lowest plane of the lowest
 570	 * pipe (pipe 0, priority 0), if it has any alpha, will
 571	 * discard the pixel data entirely and just display the pixels
 572	 * in the background color (black by default).
 573	 *
 574	 * This means that on the affected platforms, we effectively
 575	 * have only three valid configurations with alpha, all of
 576	 * them with the alpha being on pipe1 with the lowest
 577	 * position, which can be 1, 2 or 3 depending on the number of
 578	 * planes and their zpos.
 579	 */
 580
 581	/* For platforms that are not affected by the issue described above. */
 582	if (backend->quirks->supports_lowest_plane_alpha)
 583		num_alpha_planes_max++;
 584
 585	if (num_alpha_planes > num_alpha_planes_max) {
 586		DRM_DEBUG_DRIVER("Too many planes with alpha, rejecting...\n");
 587		return -EINVAL;
 588	}
 589
 590	/* We can't have an alpha plane at the lowest position */
 591	if (!backend->quirks->supports_lowest_plane_alpha &&
 592	    (plane_states[0]->fb->format->has_alpha ||
 593	    (plane_states[0]->alpha != DRM_BLEND_ALPHA_OPAQUE)))
 594		return -EINVAL;
 595
 596	for (i = 1; i < num_planes; i++) {
 597		struct drm_plane_state *p_state = plane_states[i];
 598		struct drm_framebuffer *fb = p_state->fb;
 599		struct sun4i_layer_state *s_state = state_to_sun4i_layer_state(p_state);
 600
 601		/*
 602		 * The only alpha position is the lowest plane of the
 603		 * second pipe.
 604		 */
 605		if (fb->format->has_alpha || (p_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
 606			current_pipe++;
 607
 608		s_state->pipe = current_pipe;
 609	}
 610
 611	/* We can only have a single YUV plane at a time */
 612	if (num_yuv_planes > SUN4I_BACKEND_NUM_YUV_PLANES) {
 613		DRM_DEBUG_DRIVER("Too many planes with YUV, rejecting...\n");
 614		return -EINVAL;
 615	}
 616
 617	if (num_frontend_planes > SUN4I_BACKEND_NUM_FRONTEND_LAYERS) {
 618		DRM_DEBUG_DRIVER("Too many planes going through the frontend, rejecting\n");
 619		return -EINVAL;
 620	}
 621
 622	DRM_DEBUG_DRIVER("State valid with %u planes, %u alpha, %u video, %u YUV\n",
 623			 num_planes, num_alpha_planes, num_frontend_planes,
 624			 num_yuv_planes);
 625
 626	return 0;
 627}
 628
 629static void sun4i_backend_vblank_quirk(struct sunxi_engine *engine)
 630{
 631	struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
 632	struct sun4i_frontend *frontend = backend->frontend;
 633
 634	if (!frontend)
 635		return;
 636
 637	/*
 638	 * In a teardown scenario with the frontend involved, we have
 639	 * to keep the frontend enabled until the next vblank, and
 640	 * only then disable it.
 641	 *
 642	 * This is due to the fact that the backend will not take into
 643	 * account the new configuration (with the plane that used to
 644	 * be fed by the frontend now disabled) until we write to the
 645	 * commit bit and the hardware fetches the new configuration
 646	 * during the next vblank.
 647	 *
 648	 * So we keep the frontend around in order to prevent any
 649	 * visual artifacts.
 650	 */
 651	spin_lock(&backend->frontend_lock);
 652	if (backend->frontend_teardown) {
 653		sun4i_frontend_exit(frontend);
 654		backend->frontend_teardown = false;
 655	}
 656	spin_unlock(&backend->frontend_lock);
 657};
 658
 659static 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
 690err_assert_reset:
 691	reset_control_assert(backend->sat_reset);
 692	return ret;
 693}
 694
 695static 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 */
 712static 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 */
 733static 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
 762static 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};
 771
 772static struct regmap_config sun4i_backend_regmap_config = {
 773	.reg_bits	= 32,
 774	.val_bits	= 32,
 775	.reg_stride	= 4,
 776	.max_register	= 0x5800,
 777};
 778
 779static int sun4i_backend_bind(struct device *dev, struct device *master,
 780			      void *data)
 781{
 782	struct platform_device *pdev = to_platform_device(dev);
 783	struct drm_device *drm = data;
 784	struct sun4i_drv *drv = drm->dev_private;
 785	struct sun4i_backend *backend;
 786	const struct sun4i_backend_quirks *quirks;
 787	struct resource *res;
 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_find_property(dev->of_node, "interconnects", NULL)) {
 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	} else {
 809		/*
 810		 * If we don't have the interconnect property, most likely
 811		 * because of an old DT, we need to set the DMA offset by hand
 812		 * on our device since the RAM mapping is at 0 for the DMA bus,
 813		 * unlike the CPU.
 814		 */
 815		drm->dev->dma_pfn_offset = PHYS_PFN_OFFSET;
 816	}
 817
 818	backend->engine.node = dev->of_node;
 819	backend->engine.ops = &sun4i_backend_engine_ops;
 820	backend->engine.id = sun4i_backend_of_get_id(dev->of_node);
 821	if (backend->engine.id < 0)
 822		return backend->engine.id;
 823
 824	backend->frontend = sun4i_backend_find_frontend(drv, dev->of_node);
 825	if (IS_ERR(backend->frontend))
 826		dev_warn(dev, "Couldn't find matching frontend, frontend features disabled\n");
 827
 828	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 829	regs = devm_ioremap_resource(dev, res);
 830	if (IS_ERR(regs))
 831		return PTR_ERR(regs);
 832
 833	backend->reset = devm_reset_control_get(dev, NULL);
 834	if (IS_ERR(backend->reset)) {
 835		dev_err(dev, "Couldn't get our reset line\n");
 836		return PTR_ERR(backend->reset);
 837	}
 838
 839	ret = reset_control_deassert(backend->reset);
 840	if (ret) {
 841		dev_err(dev, "Couldn't deassert our reset line\n");
 842		return ret;
 843	}
 844
 845	backend->bus_clk = devm_clk_get(dev, "ahb");
 846	if (IS_ERR(backend->bus_clk)) {
 847		dev_err(dev, "Couldn't get the backend bus clock\n");
 848		ret = PTR_ERR(backend->bus_clk);
 849		goto err_assert_reset;
 850	}
 851	clk_prepare_enable(backend->bus_clk);
 852
 853	backend->mod_clk = devm_clk_get(dev, "mod");
 854	if (IS_ERR(backend->mod_clk)) {
 855		dev_err(dev, "Couldn't get the backend module clock\n");
 856		ret = PTR_ERR(backend->mod_clk);
 857		goto err_disable_bus_clk;
 858	}
 859	clk_prepare_enable(backend->mod_clk);
 860
 861	backend->ram_clk = devm_clk_get(dev, "ram");
 862	if (IS_ERR(backend->ram_clk)) {
 863		dev_err(dev, "Couldn't get the backend RAM clock\n");
 864		ret = PTR_ERR(backend->ram_clk);
 865		goto err_disable_mod_clk;
 866	}
 867	clk_prepare_enable(backend->ram_clk);
 868
 869	if (of_device_is_compatible(dev->of_node,
 870				    "allwinner,sun8i-a33-display-backend")) {
 871		ret = sun4i_backend_init_sat(dev);
 872		if (ret) {
 873			dev_err(dev, "Couldn't init SAT resources\n");
 874			goto err_disable_ram_clk;
 875		}
 876	}
 877
 878	backend->engine.regs = devm_regmap_init_mmio(dev, regs,
 879						     &sun4i_backend_regmap_config);
 880	if (IS_ERR(backend->engine.regs)) {
 881		dev_err(dev, "Couldn't create the backend regmap\n");
 882		return PTR_ERR(backend->engine.regs);
 883	}
 884
 885	list_add_tail(&backend->engine.list, &drv->engine_list);
 886
 887	/*
 888	 * Many of the backend's layer configuration registers have
 889	 * undefined default values. This poses a risk as we use
 890	 * regmap_update_bits in some places, and don't overwrite
 891	 * the whole register.
 892	 *
 893	 * Clear the registers here to have something predictable.
 894	 */
 895	for (i = 0x800; i < 0x1000; i += 4)
 896		regmap_write(backend->engine.regs, i, 0);
 897
 898	/* Disable registers autoloading */
 899	regmap_write(backend->engine.regs, SUN4I_BACKEND_REGBUFFCTL_REG,
 900		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
 901
 902	/* Enable the backend */
 903	regmap_write(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 904		     SUN4I_BACKEND_MODCTL_DEBE_EN |
 905		     SUN4I_BACKEND_MODCTL_START_CTL);
 906
 907	/* Set output selection if needed */
 908	quirks = of_device_get_match_data(dev);
 909	if (quirks->needs_output_muxing) {
 910		/*
 911		 * We assume there is no dynamic muxing of backends
 912		 * and TCONs, so we select the backend with same ID.
 913		 *
 914		 * While dynamic selection might be interesting, since
 915		 * the CRTC is tied to the TCON, while the layers are
 916		 * tied to the backends, this means, we will need to
 917		 * switch between groups of layers. There might not be
 918		 * a way to represent this constraint in DRM.
 919		 */
 920		regmap_update_bits(backend->engine.regs,
 921				   SUN4I_BACKEND_MODCTL_REG,
 922				   SUN4I_BACKEND_MODCTL_OUT_SEL,
 923				   (backend->engine.id
 924				    ? SUN4I_BACKEND_MODCTL_OUT_LCD1
 925				    : SUN4I_BACKEND_MODCTL_OUT_LCD0));
 926	}
 927
 928	backend->quirks = quirks;
 929
 930	return 0;
 931
 932err_disable_ram_clk:
 933	clk_disable_unprepare(backend->ram_clk);
 934err_disable_mod_clk:
 935	clk_disable_unprepare(backend->mod_clk);
 936err_disable_bus_clk:
 937	clk_disable_unprepare(backend->bus_clk);
 938err_assert_reset:
 939	reset_control_assert(backend->reset);
 940	return ret;
 941}
 942
 943static void sun4i_backend_unbind(struct device *dev, struct device *master,
 944				 void *data)
 945{
 946	struct sun4i_backend *backend = dev_get_drvdata(dev);
 947
 948	list_del(&backend->engine.list);
 949
 950	if (of_device_is_compatible(dev->of_node,
 951				    "allwinner,sun8i-a33-display-backend"))
 952		sun4i_backend_free_sat(dev);
 953
 954	clk_disable_unprepare(backend->ram_clk);
 955	clk_disable_unprepare(backend->mod_clk);
 956	clk_disable_unprepare(backend->bus_clk);
 957	reset_control_assert(backend->reset);
 958}
 959
 960static const struct component_ops sun4i_backend_ops = {
 961	.bind	= sun4i_backend_bind,
 962	.unbind	= sun4i_backend_unbind,
 963};
 964
 965static int sun4i_backend_probe(struct platform_device *pdev)
 966{
 967	return component_add(&pdev->dev, &sun4i_backend_ops);
 968}
 969
 970static int sun4i_backend_remove(struct platform_device *pdev)
 971{
 972	component_del(&pdev->dev, &sun4i_backend_ops);
 973
 974	return 0;
 975}
 976
 977static const struct sun4i_backend_quirks sun4i_backend_quirks = {
 978	.needs_output_muxing = true,
 979};
 980
 981static const struct sun4i_backend_quirks sun5i_backend_quirks = {
 982};
 983
 984static const struct sun4i_backend_quirks sun6i_backend_quirks = {
 985};
 986
 987static const struct sun4i_backend_quirks sun7i_backend_quirks = {
 988	.needs_output_muxing = true,
 989	.supports_lowest_plane_alpha = true,
 990};
 991
 992static const struct sun4i_backend_quirks sun8i_a33_backend_quirks = {
 993	.supports_lowest_plane_alpha = true,
 994};
 995
 996static const struct sun4i_backend_quirks sun9i_backend_quirks = {
 997};
 998
 999static const struct of_device_id sun4i_backend_of_table[] = {
1000	{
1001		.compatible = "allwinner,sun4i-a10-display-backend",
1002		.data = &sun4i_backend_quirks,
1003	},
1004	{
1005		.compatible = "allwinner,sun5i-a13-display-backend",
1006		.data = &sun5i_backend_quirks,
1007	},
1008	{
1009		.compatible = "allwinner,sun6i-a31-display-backend",
1010		.data = &sun6i_backend_quirks,
1011	},
1012	{
1013		.compatible = "allwinner,sun7i-a20-display-backend",
1014		.data = &sun7i_backend_quirks,
1015	},
1016	{
1017		.compatible = "allwinner,sun8i-a23-display-backend",
1018		.data = &sun8i_a33_backend_quirks,
1019	},
1020	{
1021		.compatible = "allwinner,sun8i-a33-display-backend",
1022		.data = &sun8i_a33_backend_quirks,
1023	},
1024	{
1025		.compatible = "allwinner,sun9i-a80-display-backend",
1026		.data = &sun9i_backend_quirks,
1027	},
1028	{ }
1029};
1030MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);
1031
1032static struct platform_driver sun4i_backend_platform_driver = {
1033	.probe		= sun4i_backend_probe,
1034	.remove		= sun4i_backend_remove,
1035	.driver		= {
1036		.name		= "sun4i-backend",
1037		.of_match_table	= sun4i_backend_of_table,
1038	},
1039};
1040module_platform_driver(sun4i_backend_platform_driver);
1041
1042MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1043MODULE_DESCRIPTION("Allwinner A10 Display Backend Driver");
1044MODULE_LICENSE("GPL");