drivers/gpu/drm/sun4i/sun4i_backend.c

   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
  32 struct 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
  40 static const u32 sunxi_rgb2yuv_coef[12] = {
  41         0x00000107, 0x00000204, 0x00000064, 0x00000108,
  42         0x00003f69, 0x00003ed6, 0x000001c1, 0x00000808,
  43         0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
  44 };
  45
  46 static 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
  61 static 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
  70 static 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
  79 void 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
  96 static 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
 138 static 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
 153 bool 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
 167 int 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
 199 static 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
 256 int 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
 305 int 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
 329 static 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
 344 int 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
 382 int 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
 401 void 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
 410 static 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
 424 static 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
 457 static 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
 474 static 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
 485 static 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
 629 static 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
 659 static int sun4i_backend_init_sat(struct device *dev) {
 660         struct sun4i_backend *backend = dev_get_drvdata(dev);
 661         int ret;
 662
 663         backend->sat_reset = devm_reset_control_get(dev, "sat");
 664         if (IS_ERR(backend->sat_reset)) {
 665                 dev_err(dev, "Couldn't get the SAT reset line\n");
 666                 return PTR_ERR(backend->sat_reset);
 667         }
 668
 669         ret = reset_control_deassert(backend->sat_reset);
 670         if (ret) {
 671                 dev_err(dev, "Couldn't deassert the SAT reset line\n");
 672                 return ret;
 673         }
 674
 675         backend->sat_clk = devm_clk_get(dev, "sat");
 676         if (IS_ERR(backend->sat_clk)) {
 677                 dev_err(dev, "Couldn't get our SAT clock\n");
 678                 ret = PTR_ERR(backend->sat_clk);
 679                 goto err_assert_reset;
 680         }
 681
 682         ret = clk_prepare_enable(backend->sat_clk);
 683         if (ret) {
 684                 dev_err(dev, "Couldn't enable the SAT clock\n");
 685                 return ret;
 686         }
 687
 688         return 0;
 689
 690 err_assert_reset:
 691         reset_control_assert(backend->sat_reset);
 692         return ret;
 693 }
 694
 695 static int sun4i_backend_free_sat(struct device *dev) {
 696         struct sun4i_backend *backend = dev_get_drvdata(dev);
 697
 698         clk_disable_unprepare(backend->sat_clk);
 699         reset_control_assert(backend->sat_reset);
 700
 701         return 0;
 702 }
 703
 704 /*
 705  * The display backend can take video output from the display frontend, or
 706  * the display enhancement unit on the A80, as input for one it its layers.
 707  * This relationship within the display pipeline is encoded in the device
 708  * tree with of_graph, and we use it here to figure out which backend, if
 709  * there are 2 or more, we are currently probing. The number would be in
 710  * the "reg" property of the upstream output port endpoint.
 711  */
 712 static int sun4i_backend_of_get_id(struct device_node *node)
 713 {
 714         struct device_node *ep, *remote;
 715         struct of_endpoint of_ep;
 716
 717         /* Input port is 0, and we want the first endpoint. */
 718         ep = of_graph_get_endpoint_by_regs(node, 0, -1);
 719         if (!ep)
 720                 return -EINVAL;
 721
 722         remote = of_graph_get_remote_endpoint(ep);
 723         of_node_put(ep);
 724         if (!remote)
 725                 return -EINVAL;
 726
 727         of_graph_parse_endpoint(remote, &of_ep);
 728         of_node_put(remote);
 729         return of_ep.id;
 730 }
 731
 732 /* TODO: This needs to take multiple pipelines into account */
 733 static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv,
 734                                                           struct device_node *node)
 735 {
 736         struct device_node *port, *ep, *remote;
 737         struct sun4i_frontend *frontend;
 738
 739         port = of_graph_get_port_by_id(node, 0);
 740         if (!port)
 741                 return ERR_PTR(-EINVAL);
 742
 743         for_each_available_child_of_node(port, ep) {
 744                 remote = of_graph_get_remote_port_parent(ep);
 745                 if (!remote)
 746                         continue;
 747                 of_node_put(remote);
 748
 749                 /* does this node match any registered engines? */
 750                 list_for_each_entry(frontend, &drv->frontend_list, list) {
 751                         if (remote == frontend->node) {
 752                                 of_node_put(port);
 753                                 of_node_put(ep);
 754                                 return frontend;
 755                         }
 756                 }
 757         }
 758         of_node_put(port);
 759         return ERR_PTR(-EINVAL);
 760 }
 761
 762 static const struct sunxi_engine_ops sun4i_backend_engine_ops = {
 763         .atomic_begin                   = sun4i_backend_atomic_begin,
 764         .atomic_check                   = sun4i_backend_atomic_check,
 765         .commit                         = sun4i_backend_commit,
 766         .layers_init                    = sun4i_layers_init,
 767         .apply_color_correction         = sun4i_backend_apply_color_correction,
 768         .disable_color_correction       = sun4i_backend_disable_color_correction,
 769         .vblank_quirk                   = sun4i_backend_vblank_quirk,
 770 };
 771
 772 static 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
 779 static 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
 860         ret = clk_set_rate_exclusive(backend->mod_clk, 300000000);
 861         if (ret) {
 862                 dev_err(dev, "Couldn't set the module clock frequency\n");
 863                 goto err_disable_bus_clk;
 864         }
 865
 866         clk_prepare_enable(backend->mod_clk);
 867
 868         backend->ram_clk = devm_clk_get(dev, "ram");
 869         if (IS_ERR(backend->ram_clk)) {
 870                 dev_err(dev, "Couldn't get the backend RAM clock\n");
 871                 ret = PTR_ERR(backend->ram_clk);
 872                 goto err_disable_mod_clk;
 873         }
 874         clk_prepare_enable(backend->ram_clk);
 875
 876         if (of_device_is_compatible(dev->of_node,
 877                                     "allwinner,sun8i-a33-display-backend")) {
 878                 ret = sun4i_backend_init_sat(dev);
 879                 if (ret) {
 880                         dev_err(dev, "Couldn't init SAT resources\n");
 881                         goto err_disable_ram_clk;
 882                 }
 883         }
 884
 885         backend->engine.regs = devm_regmap_init_mmio(dev, regs,
 886                                                      &sun4i_backend_regmap_config);
 887         if (IS_ERR(backend->engine.regs)) {
 888                 dev_err(dev, "Couldn't create the backend regmap\n");
 889                 return PTR_ERR(backend->engine.regs);
 890         }
 891
 892         list_add_tail(&backend->engine.list, &drv->engine_list);
 893
 894         /*
 895          * Many of the backend's layer configuration registers have
 896          * undefined default values. This poses a risk as we use
 897          * regmap_update_bits in some places, and don't overwrite
 898          * the whole register.
 899          *
 900          * Clear the registers here to have something predictable.
 901          */
 902         for (i = 0x800; i < 0x1000; i += 4)
 903                 regmap_write(backend->engine.regs, i, 0);
 904
 905         /* Disable registers autoloading */
 906         regmap_write(backend->engine.regs, SUN4I_BACKEND_REGBUFFCTL_REG,
 907                      SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
 908
 909         /* Enable the backend */
 910         regmap_write(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 911                      SUN4I_BACKEND_MODCTL_DEBE_EN |
 912                      SUN4I_BACKEND_MODCTL_START_CTL);
 913
 914         /* Set output selection if needed */
 915         quirks = of_device_get_match_data(dev);
 916         if (quirks->needs_output_muxing) {
 917                 /*
 918                  * We assume there is no dynamic muxing of backends
 919                  * and TCONs, so we select the backend with same ID.
 920                  *
 921                  * While dynamic selection might be interesting, since
 922                  * the CRTC is tied to the TCON, while the layers are
 923                  * tied to the backends, this means, we will need to
 924                  * switch between groups of layers. There might not be
 925                  * a way to represent this constraint in DRM.
 926                  */
 927                 regmap_update_bits(backend->engine.regs,
 928                                    SUN4I_BACKEND_MODCTL_REG,
 929                                    SUN4I_BACKEND_MODCTL_OUT_SEL,
 930                                    (backend->engine.id
 931                                     ? SUN4I_BACKEND_MODCTL_OUT_LCD1
 932                                     : SUN4I_BACKEND_MODCTL_OUT_LCD0));
 933         }
 934
 935         backend->quirks = quirks;
 936
 937         return 0;
 938
 939 err_disable_ram_clk:
 940         clk_disable_unprepare(backend->ram_clk);
 941 err_disable_mod_clk:
 942         clk_rate_exclusive_put(backend->mod_clk);
 943         clk_disable_unprepare(backend->mod_clk);
 944 err_disable_bus_clk:
 945         clk_disable_unprepare(backend->bus_clk);
 946 err_assert_reset:
 947         reset_control_assert(backend->reset);
 948         return ret;
 949 }
 950
 951 static void sun4i_backend_unbind(struct device *dev, struct device *master,
 952                                  void *data)
 953 {
 954         struct sun4i_backend *backend = dev_get_drvdata(dev);
 955
 956         list_del(&backend->engine.list);
 957
 958         if (of_device_is_compatible(dev->of_node,
 959                                     "allwinner,sun8i-a33-display-backend"))
 960                 sun4i_backend_free_sat(dev);
 961
 962         clk_disable_unprepare(backend->ram_clk);
 963         clk_rate_exclusive_put(backend->mod_clk);
 964         clk_disable_unprepare(backend->mod_clk);
 965         clk_disable_unprepare(backend->bus_clk);
 966         reset_control_assert(backend->reset);
 967 }
 968
 969 static const struct component_ops sun4i_backend_ops = {
 970         .bind   = sun4i_backend_bind,
 971         .unbind = sun4i_backend_unbind,
 972 };
 973
 974 static int sun4i_backend_probe(struct platform_device *pdev)
 975 {
 976         return component_add(&pdev->dev, &sun4i_backend_ops);
 977 }
 978
 979 static int sun4i_backend_remove(struct platform_device *pdev)
 980 {
 981         component_del(&pdev->dev, &sun4i_backend_ops);
 982
 983         return 0;
 984 }
 985
 986 static const struct sun4i_backend_quirks sun4i_backend_quirks = {
 987         .needs_output_muxing = true,
 988 };
 989
 990 static const struct sun4i_backend_quirks sun5i_backend_quirks = {
 991 };
 992
 993 static const struct sun4i_backend_quirks sun6i_backend_quirks = {
 994 };
 995
 996 static const struct sun4i_backend_quirks sun7i_backend_quirks = {
 997         .needs_output_muxing = true,
 998         .supports_lowest_plane_alpha = true,
 999 };
1000
1001 static const struct sun4i_backend_quirks sun8i_a33_backend_quirks = {
1002         .supports_lowest_plane_alpha = true,
1003 };
1004
1005 static const struct sun4i_backend_quirks sun9i_backend_quirks = {
1006 };
1007
1008 static const struct of_device_id sun4i_backend_of_table[] = {
1009         {
1010                 .compatible = "allwinner,sun4i-a10-display-backend",
1011                 .data = &sun4i_backend_quirks,
1012         },
1013         {
1014                 .compatible = "allwinner,sun5i-a13-display-backend",
1015                 .data = &sun5i_backend_quirks,
1016         },
1017         {
1018                 .compatible = "allwinner,sun6i-a31-display-backend",
1019                 .data = &sun6i_backend_quirks,
1020         },
1021         {
1022                 .compatible = "allwinner,sun7i-a20-display-backend",
1023                 .data = &sun7i_backend_quirks,
1024         },
1025         {
1026                 .compatible = "allwinner,sun8i-a23-display-backend",
1027                 .data = &sun8i_a33_backend_quirks,
1028         },
1029         {
1030                 .compatible = "allwinner,sun8i-a33-display-backend",
1031                 .data = &sun8i_a33_backend_quirks,
1032         },
1033         {
1034                 .compatible = "allwinner,sun9i-a80-display-backend",
1035                 .data = &sun9i_backend_quirks,
1036         },
1037         { }
1038 };
1039 MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);
1040
1041 static struct platform_driver sun4i_backend_platform_driver = {
1042         .probe          = sun4i_backend_probe,
1043         .remove         = sun4i_backend_remove,
1044         .driver         = {
1045                 .name           = "sun4i-backend",
1046                 .of_match_table = sun4i_backend_of_table,
1047         },
1048 };
1049 module_platform_driver(sun4i_backend_platform_driver);
1050
1051 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1052 MODULE_DESCRIPTION("Allwinner A10 Display Backend Driver");
1053 MODULE_LICENSE("GPL");