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/dma-mapping.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/reset.h>
  17
  18 #include <drm/drm_atomic.h>
  19 #include <drm/drm_atomic_helper.h>
  20 #include <drm/drm_crtc.h>
  21 #include <drm/drm_fb_cma_helper.h>
  22 #include <drm/drm_fourcc.h>
  23 #include <drm/drm_gem_cma_helper.h>
  24 #include <drm/drm_plane_helper.h>
  25 #include <drm/drm_probe_helper.h>
  26
  27 #include "sun4i_backend.h"
  28 #include "sun4i_drv.h"
  29 #include "sun4i_frontend.h"
  30 #include "sun4i_layer.h"
  31 #include "sunxi_engine.h"
  32
  33 struct sun4i_backend_quirks {
  34         /* backend <-> TCON muxing selection done in backend */
  35         bool needs_output_muxing;
  36
  37         /* alpha at the lowest z position is not always supported */
  38         bool supports_lowest_plane_alpha;
  39 };
  40
  41 static const u32 sunxi_rgb2yuv_coef[12] = {
  42         0x00000107, 0x00000204, 0x00000064, 0x00000108,
  43         0x00003f69, 0x00003ed6, 0x000001c1, 0x00000808,
  44         0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
  45 };
  46
  47 static void sun4i_backend_apply_color_correction(struct sunxi_engine *engine)
  48 {
  49         int i;
  50
  51         DRM_DEBUG_DRIVER("Applying RGB to YUV color correction\n");
  52
  53         /* Set color correction */
  54         regmap_write(engine->regs, SUN4I_BACKEND_OCCTL_REG,
  55                      SUN4I_BACKEND_OCCTL_ENABLE);
  56
  57         for (i = 0; i < 12; i++)
  58                 regmap_write(engine->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
  59                              sunxi_rgb2yuv_coef[i]);
  60 }
  61
  62 static void sun4i_backend_disable_color_correction(struct sunxi_engine *engine)
  63 {
  64         DRM_DEBUG_DRIVER("Disabling color correction\n");
  65
  66         /* Disable color correction */
  67         regmap_update_bits(engine->regs, SUN4I_BACKEND_OCCTL_REG,
  68                            SUN4I_BACKEND_OCCTL_ENABLE, 0);
  69 }
  70
  71 static void sun4i_backend_commit(struct sunxi_engine *engine)
  72 {
  73         DRM_DEBUG_DRIVER("Committing changes\n");
  74
  75         regmap_write(engine->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
  76                      SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS |
  77                      SUN4I_BACKEND_REGBUFFCTL_LOADCTL);
  78 }
  79
  80 void sun4i_backend_layer_enable(struct sun4i_backend *backend,
  81                                 int layer, bool enable)
  82 {
  83         u32 val;
  84
  85         DRM_DEBUG_DRIVER("%sabling layer %d\n", enable ? "En" : "Dis",
  86                          layer);
  87
  88         if (enable)
  89                 val = SUN4I_BACKEND_MODCTL_LAY_EN(layer);
  90         else
  91                 val = 0;
  92
  93         regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
  94                            SUN4I_BACKEND_MODCTL_LAY_EN(layer), val);
  95 }
  96
  97 static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
  98 {
  99         switch (format) {
 100         case DRM_FORMAT_ARGB8888:
 101                 *mode = SUN4I_BACKEND_LAY_FBFMT_ARGB8888;
 102                 break;
 103
 104         case DRM_FORMAT_ARGB4444:
 105                 *mode = SUN4I_BACKEND_LAY_FBFMT_ARGB4444;
 106                 break;
 107
 108         case DRM_FORMAT_ARGB1555:
 109                 *mode = SUN4I_BACKEND_LAY_FBFMT_ARGB1555;
 110                 break;
 111
 112         case DRM_FORMAT_RGBA5551:
 113                 *mode = SUN4I_BACKEND_LAY_FBFMT_RGBA5551;
 114                 break;
 115
 116         case DRM_FORMAT_RGBA4444:
 117                 *mode = SUN4I_BACKEND_LAY_FBFMT_RGBA4444;
 118                 break;
 119
 120         case DRM_FORMAT_XRGB8888:
 121                 *mode = SUN4I_BACKEND_LAY_FBFMT_XRGB8888;
 122                 break;
 123
 124         case DRM_FORMAT_RGB888:
 125                 *mode = SUN4I_BACKEND_LAY_FBFMT_RGB888;
 126                 break;
 127
 128         case DRM_FORMAT_RGB565:
 129                 *mode = SUN4I_BACKEND_LAY_FBFMT_RGB565;
 130                 break;
 131
 132         default:
 133                 return -EINVAL;
 134         }
 135
 136         return 0;
 137 }
 138
 139 static const uint32_t sun4i_backend_formats[] = {
 140         DRM_FORMAT_ARGB1555,
 141         DRM_FORMAT_ARGB4444,
 142         DRM_FORMAT_ARGB8888,
 143         DRM_FORMAT_RGB565,
 144         DRM_FORMAT_RGB888,
 145         DRM_FORMAT_RGBA4444,
 146         DRM_FORMAT_RGBA5551,
 147         DRM_FORMAT_UYVY,
 148         DRM_FORMAT_VYUY,
 149         DRM_FORMAT_XRGB8888,
 150         DRM_FORMAT_YUYV,
 151         DRM_FORMAT_YVYU,
 152 };
 153
 154 bool sun4i_backend_format_is_supported(uint32_t fmt, uint64_t modifier)
 155 {
 156         unsigned int i;
 157
 158         if (modifier != DRM_FORMAT_MOD_LINEAR)
 159                 return false;
 160
 161         for (i = 0; i < ARRAY_SIZE(sun4i_backend_formats); i++)
 162                 if (sun4i_backend_formats[i] == fmt)
 163                         return true;
 164
 165         return false;
 166 }
 167
 168 int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
 169                                      int layer, struct drm_plane *plane)
 170 {
 171         struct drm_plane_state *state = plane->state;
 172
 173         DRM_DEBUG_DRIVER("Updating layer %d\n", layer);
 174
 175         if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
 176                 DRM_DEBUG_DRIVER("Primary layer, updating global size W: %u H: %u\n",
 177                                  state->crtc_w, state->crtc_h);
 178                 regmap_write(backend->engine.regs, SUN4I_BACKEND_DISSIZE_REG,
 179                              SUN4I_BACKEND_DISSIZE(state->crtc_w,
 180                                                    state->crtc_h));
 181         }
 182
 183         /* Set height and width */
 184         DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
 185                          state->crtc_w, state->crtc_h);
 186         regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
 187                      SUN4I_BACKEND_LAYSIZE(state->crtc_w,
 188                                            state->crtc_h));
 189
 190         /* Set base coordinates */
 191         DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
 192                          state->crtc_x, state->crtc_y);
 193         regmap_write(backend->engine.regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
 194                      SUN4I_BACKEND_LAYCOOR(state->crtc_x,
 195                                            state->crtc_y));
 196
 197         return 0;
 198 }
 199
 200 static int sun4i_backend_update_yuv_format(struct sun4i_backend *backend,
 201                                            int layer, struct drm_plane *plane)
 202 {
 203         struct drm_plane_state *state = plane->state;
 204         struct drm_framebuffer *fb = state->fb;
 205         const struct drm_format_info *format = fb->format;
 206         const uint32_t fmt = format->format;
 207         u32 val = SUN4I_BACKEND_IYUVCTL_EN;
 208         int i;
 209
 210         for (i = 0; i < ARRAY_SIZE(sunxi_bt601_yuv2rgb_coef); i++)
 211                 regmap_write(backend->engine.regs,
 212                              SUN4I_BACKEND_YGCOEF_REG(i),
 213                              sunxi_bt601_yuv2rgb_coef[i]);
 214
 215         /*
 216          * We should do that only for a single plane, but the
 217          * framebuffer's atomic_check has our back on this.
 218          */
 219         regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
 220                            SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN,
 221                            SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN);
 222
 223         /* TODO: Add support for the multi-planar YUV formats */
 224         if (drm_format_info_is_yuv_packed(format) &&
 225             drm_format_info_is_yuv_sampling_422(format))
 226                 val |= SUN4I_BACKEND_IYUVCTL_FBFMT_PACKED_YUV422;
 227         else
 228                 DRM_DEBUG_DRIVER("Unsupported YUV format (0x%x)\n", fmt);
 229
 230         /*
 231          * Allwinner seems to list the pixel sequence from right to left, while
 232          * DRM lists it from left to right.
 233          */
 234         switch (fmt) {
 235         case DRM_FORMAT_YUYV:
 236                 val |= SUN4I_BACKEND_IYUVCTL_FBPS_VYUY;
 237                 break;
 238         case DRM_FORMAT_YVYU:
 239                 val |= SUN4I_BACKEND_IYUVCTL_FBPS_UYVY;
 240                 break;
 241         case DRM_FORMAT_UYVY:
 242                 val |= SUN4I_BACKEND_IYUVCTL_FBPS_YVYU;
 243                 break;
 244         case DRM_FORMAT_VYUY:
 245                 val |= SUN4I_BACKEND_IYUVCTL_FBPS_YUYV;
 246                 break;
 247         default:
 248                 DRM_DEBUG_DRIVER("Unsupported YUV pixel sequence (0x%x)\n",
 249                                  fmt);
 250         }
 251
 252         regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVCTL_REG, val);
 253
 254         return 0;
 255 }
 256
 257 int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
 258                                        int layer, struct drm_plane *plane)
 259 {
 260         struct drm_plane_state *state = plane->state;
 261         struct drm_framebuffer *fb = state->fb;
 262         bool interlaced = false;
 263         u32 val;
 264         int ret;
 265
 266         /* Clear the YUV mode */
 267         regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
 268                            SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
 269
 270         if (plane->state->crtc)
 271                 interlaced = plane->state->crtc->state->adjusted_mode.flags
 272                         & DRM_MODE_FLAG_INTERLACE;
 273
 274         regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 275                            SUN4I_BACKEND_MODCTL_ITLMOD_EN,
 276                            interlaced ? SUN4I_BACKEND_MODCTL_ITLMOD_EN : 0);
 277
 278         DRM_DEBUG_DRIVER("Switching display backend interlaced mode %s\n",
 279                          interlaced ? "on" : "off");
 280
 281         val = SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA(state->alpha >> 8);
 282         if (state->alpha != DRM_BLEND_ALPHA_OPAQUE)
 283                 val |= SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN;
 284         regmap_update_bits(backend->engine.regs,
 285                            SUN4I_BACKEND_ATTCTL_REG0(layer),
 286                            SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_MASK |
 287                            SUN4I_BACKEND_ATTCTL_REG0_LAY_GLBALPHA_EN,
 288                            val);
 289
 290         if (fb->format->is_yuv)
 291                 return sun4i_backend_update_yuv_format(backend, layer, plane);
 292
 293         ret = sun4i_backend_drm_format_to_layer(fb->format->format, &val);
 294         if (ret) {
 295                 DRM_DEBUG_DRIVER("Invalid format\n");
 296                 return ret;
 297         }
 298
 299         regmap_update_bits(backend->engine.regs,
 300                            SUN4I_BACKEND_ATTCTL_REG1(layer),
 301                            SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
 302
 303         return 0;
 304 }
 305
 306 int sun4i_backend_update_layer_frontend(struct sun4i_backend *backend,
 307                                         int layer, uint32_t fmt)
 308 {
 309         u32 val;
 310         int ret;
 311
 312         ret = sun4i_backend_drm_format_to_layer(fmt, &val);
 313         if (ret) {
 314                 DRM_DEBUG_DRIVER("Invalid format\n");
 315                 return ret;
 316         }
 317
 318         regmap_update_bits(backend->engine.regs,
 319                            SUN4I_BACKEND_ATTCTL_REG0(layer),
 320                            SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN,
 321                            SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN);
 322
 323         regmap_update_bits(backend->engine.regs,
 324                            SUN4I_BACKEND_ATTCTL_REG1(layer),
 325                            SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
 326
 327         return 0;
 328 }
 329
 330 static int sun4i_backend_update_yuv_buffer(struct sun4i_backend *backend,
 331                                            struct drm_framebuffer *fb,
 332                                            dma_addr_t paddr)
 333 {
 334         /* TODO: Add support for the multi-planar YUV formats */
 335         DRM_DEBUG_DRIVER("Setting packed YUV buffer address to %pad\n", &paddr);
 336         regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVADD_REG(0), paddr);
 337
 338         DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
 339         regmap_write(backend->engine.regs, SUN4I_BACKEND_IYUVLINEWIDTH_REG(0),
 340                      fb->pitches[0] * 8);
 341
 342         return 0;
 343 }
 344
 345 int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
 346                                       int layer, struct drm_plane *plane)
 347 {
 348         struct drm_plane_state *state = plane->state;
 349         struct drm_framebuffer *fb = state->fb;
 350         u32 lo_paddr, hi_paddr;
 351         dma_addr_t paddr;
 352
 353         /* Set the line width */
 354         DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
 355         regmap_write(backend->engine.regs,
 356                      SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
 357                      fb->pitches[0] * 8);
 358
 359         /* Get the start of the displayed memory */
 360         paddr = drm_fb_cma_get_gem_addr(fb, state, 0);
 361         DRM_DEBUG_DRIVER("Setting buffer address to %pad\n", &paddr);
 362
 363         if (fb->format->is_yuv)
 364                 return sun4i_backend_update_yuv_buffer(backend, fb, paddr);
 365
 366         /* Write the 32 lower bits of the address (in bits) */
 367         lo_paddr = paddr << 3;
 368         DRM_DEBUG_DRIVER("Setting address lower bits to 0x%x\n", lo_paddr);
 369         regmap_write(backend->engine.regs,
 370                      SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
 371                      lo_paddr);
 372
 373         /* And the upper bits */
 374         hi_paddr = paddr >> 29;
 375         DRM_DEBUG_DRIVER("Setting address high bits to 0x%x\n", hi_paddr);
 376         regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
 377                            SUN4I_BACKEND_LAYFB_H4ADD_MSK(layer),
 378                            SUN4I_BACKEND_LAYFB_H4ADD(layer, hi_paddr));
 379
 380         return 0;
 381 }
 382
 383 int sun4i_backend_update_layer_zpos(struct sun4i_backend *backend, int layer,
 384                                     struct drm_plane *plane)
 385 {
 386         struct drm_plane_state *state = plane->state;
 387         struct sun4i_layer_state *p_state = state_to_sun4i_layer_state(state);
 388         unsigned int priority = state->normalized_zpos;
 389         unsigned int pipe = p_state->pipe;
 390
 391         DRM_DEBUG_DRIVER("Setting layer %d's priority to %d and pipe %d\n",
 392                          layer, priority, pipe);
 393         regmap_update_bits(backend->engine.regs, SUN4I_BACKEND_ATTCTL_REG0(layer),
 394                            SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK |
 395                            SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL_MASK,
 396                            SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(p_state->pipe) |
 397                            SUN4I_BACKEND_ATTCTL_REG0_LAY_PRISEL(priority));
 398
 399         return 0;
 400 }
 401
 402 void sun4i_backend_cleanup_layer(struct sun4i_backend *backend,
 403                                  int layer)
 404 {
 405         regmap_update_bits(backend->engine.regs,
 406                            SUN4I_BACKEND_ATTCTL_REG0(layer),
 407                            SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN |
 408                            SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
 409 }
 410
 411 static bool sun4i_backend_plane_uses_scaler(struct drm_plane_state *state)
 412 {
 413         u16 src_h = state->src_h >> 16;
 414         u16 src_w = state->src_w >> 16;
 415
 416         DRM_DEBUG_DRIVER("Input size %dx%d, output size %dx%d\n",
 417                          src_w, src_h, state->crtc_w, state->crtc_h);
 418
 419         if ((state->crtc_h != src_h) || (state->crtc_w != src_w))
 420                 return true;
 421
 422         return false;
 423 }
 424
 425 static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
 426 {
 427         struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
 428         struct sun4i_backend *backend = layer->backend;
 429         uint32_t format = state->fb->format->format;
 430         uint64_t modifier = state->fb->modifier;
 431
 432         if (IS_ERR(backend->frontend))
 433                 return false;
 434
 435         if (!sun4i_frontend_format_is_supported(format, modifier))
 436                 return false;
 437
 438         if (!sun4i_backend_format_is_supported(format, modifier))
 439                 return true;
 440
 441         /*
 442          * TODO: The backend alone allows 2x and 4x integer scaling, including
 443          * support for an alpha component (which the frontend doesn't support).
 444          * Use the backend directly instead of the frontend in this case, with
 445          * another test to return false.
 446          */
 447
 448         if (sun4i_backend_plane_uses_scaler(state))
 449                 return true;
 450
 451         /*
 452          * Here the format is supported by both the frontend and the backend
 453          * and no frontend scaling is required, so use the backend directly.
 454          */
 455         return false;
 456 }
 457
 458 static bool sun4i_backend_plane_is_supported(struct drm_plane_state *state,
 459                                              bool *uses_frontend)
 460 {
 461         if (sun4i_backend_plane_uses_frontend(state)) {
 462                 *uses_frontend = true;
 463                 return true;
 464         }
 465
 466         *uses_frontend = false;
 467
 468         /* Scaling is not supported without the frontend. */
 469         if (sun4i_backend_plane_uses_scaler(state))
 470                 return false;
 471
 472         return true;
 473 }
 474
 475 static void sun4i_backend_atomic_begin(struct sunxi_engine *engine,
 476                                        struct drm_crtc_state *old_state)
 477 {
 478         u32 val;
 479
 480         WARN_ON(regmap_read_poll_timeout(engine->regs,
 481                                          SUN4I_BACKEND_REGBUFFCTL_REG,
 482                                          val, !(val & SUN4I_BACKEND_REGBUFFCTL_LOADCTL),
 483                                          100, 50000));
 484 }
 485
 486 static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
 487                                       struct drm_crtc_state *crtc_state)
 488 {
 489         struct drm_plane_state *plane_states[SUN4I_BACKEND_NUM_LAYERS] = { 0 };
 490         struct sun4i_backend *backend = engine_to_sun4i_backend(engine);
 491         struct drm_atomic_state *state = crtc_state->state;
 492         struct drm_device *drm = state->dev;
 493         struct drm_plane *plane;
 494         unsigned int num_planes = 0;
 495         unsigned int num_alpha_planes = 0;
 496         unsigned int num_frontend_planes = 0;
 497         unsigned int num_alpha_planes_max = 1;
 498         unsigned int num_yuv_planes = 0;
 499         unsigned int current_pipe = 0;
 500         unsigned int i;
 501
 502         DRM_DEBUG_DRIVER("Starting checking our planes\n");
 503
 504         if (!crtc_state->planes_changed)
 505                 return 0;
 506
 507         drm_for_each_plane_mask(plane, drm, crtc_state->plane_mask) {
 508                 struct drm_plane_state *plane_state =
 509                         drm_atomic_get_plane_state(state, plane);
 510                 struct sun4i_layer_state *layer_state =
 511                         state_to_sun4i_layer_state(plane_state);
 512                 struct drm_framebuffer *fb = plane_state->fb;
 513                 struct drm_format_name_buf format_name;
 514
 515                 if (!sun4i_backend_plane_is_supported(plane_state,
 516                                                       &layer_state->uses_frontend))
 517                         return -EINVAL;
 518
 519                 if (layer_state->uses_frontend) {
 520                         DRM_DEBUG_DRIVER("Using the frontend for plane %d\n",
 521                                          plane->index);
 522                         num_frontend_planes++;
 523                 } else {
 524                         if (fb->format->is_yuv) {
 525                                 DRM_DEBUG_DRIVER("Plane FB format is YUV\n");
 526                                 num_yuv_planes++;
 527                         }
 528                 }
 529
 530                 DRM_DEBUG_DRIVER("Plane FB format is %s\n",
 531                                  drm_get_format_name(fb->format->format,
 532                                                      &format_name));
 533                 if (fb->format->has_alpha || (plane_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
 534                         num_alpha_planes++;
 535
 536                 DRM_DEBUG_DRIVER("Plane zpos is %d\n",
 537                                  plane_state->normalized_zpos);
 538
 539                 /* Sort our planes by Zpos */
 540                 plane_states[plane_state->normalized_zpos] = plane_state;
 541
 542                 num_planes++;
 543         }
 544
 545         /* All our planes were disabled, bail out */
 546         if (!num_planes)
 547                 return 0;
 548
 549         /*
 550          * The hardware is a bit unusual here.
 551          *
 552          * Even though it supports 4 layers, it does the composition
 553          * in two separate steps.
 554          *
 555          * The first one is assigning a layer to one of its two
 556          * pipes. If more that 1 layer is assigned to the same pipe,
 557          * and if pixels overlaps, the pipe will take the pixel from
 558          * the layer with the highest priority.
 559          *
 560          * The second step is the actual alpha blending, that takes
 561          * the two pipes as input, and uses the potential alpha
 562          * component to do the transparency between the two.
 563          *
 564          * This two-step scenario makes us unable to guarantee a
 565          * robust alpha blending between the 4 layers in all
 566          * situations, since this means that we need to have one layer
 567          * with alpha at the lowest position of our two pipes.
 568          *
 569          * However, we cannot even do that on every platform, since
 570          * the hardware has a bug where the lowest plane of the lowest
 571          * pipe (pipe 0, priority 0), if it has any alpha, will
 572          * discard the pixel data entirely and just display the pixels
 573          * in the background color (black by default).
 574          *
 575          * This means that on the affected platforms, we effectively
 576          * have only three valid configurations with alpha, all of
 577          * them with the alpha being on pipe1 with the lowest
 578          * position, which can be 1, 2 or 3 depending on the number of
 579          * planes and their zpos.
 580          */
 581
 582         /* For platforms that are not affected by the issue described above. */
 583         if (backend->quirks->supports_lowest_plane_alpha)
 584                 num_alpha_planes_max++;
 585
 586         if (num_alpha_planes > num_alpha_planes_max) {
 587                 DRM_DEBUG_DRIVER("Too many planes with alpha, rejecting...\n");
 588                 return -EINVAL;
 589         }
 590
 591         /* We can't have an alpha plane at the lowest position */
 592         if (!backend->quirks->supports_lowest_plane_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 const 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         }
 809
 810         backend->engine.node = dev->of_node;
 811         backend->engine.ops = &sun4i_backend_engine_ops;
 812         backend->engine.id = sun4i_backend_of_get_id(dev->of_node);
 813         if (backend->engine.id < 0)
 814                 return backend->engine.id;
 815
 816         backend->frontend = sun4i_backend_find_frontend(drv, dev->of_node);
 817         if (IS_ERR(backend->frontend))
 818                 dev_warn(dev, "Couldn't find matching frontend, frontend features disabled\n");
 819
 820         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 821         regs = devm_ioremap_resource(dev, res);
 822         if (IS_ERR(regs))
 823                 return PTR_ERR(regs);
 824
 825         backend->reset = devm_reset_control_get(dev, NULL);
 826         if (IS_ERR(backend->reset)) {
 827                 dev_err(dev, "Couldn't get our reset line\n");
 828                 return PTR_ERR(backend->reset);
 829         }
 830
 831         ret = reset_control_deassert(backend->reset);
 832         if (ret) {
 833                 dev_err(dev, "Couldn't deassert our reset line\n");
 834                 return ret;
 835         }
 836
 837         backend->bus_clk = devm_clk_get(dev, "ahb");
 838         if (IS_ERR(backend->bus_clk)) {
 839                 dev_err(dev, "Couldn't get the backend bus clock\n");
 840                 ret = PTR_ERR(backend->bus_clk);
 841                 goto err_assert_reset;
 842         }
 843         clk_prepare_enable(backend->bus_clk);
 844
 845         backend->mod_clk = devm_clk_get(dev, "mod");
 846         if (IS_ERR(backend->mod_clk)) {
 847                 dev_err(dev, "Couldn't get the backend module clock\n");
 848                 ret = PTR_ERR(backend->mod_clk);
 849                 goto err_disable_bus_clk;
 850         }
 851
 852         ret = clk_set_rate_exclusive(backend->mod_clk, 300000000);
 853         if (ret) {
 854                 dev_err(dev, "Couldn't set the module clock frequency\n");
 855                 goto err_disable_bus_clk;
 856         }
 857
 858         clk_prepare_enable(backend->mod_clk);
 859
 860         backend->ram_clk = devm_clk_get(dev, "ram");
 861         if (IS_ERR(backend->ram_clk)) {
 862                 dev_err(dev, "Couldn't get the backend RAM clock\n");
 863                 ret = PTR_ERR(backend->ram_clk);
 864                 goto err_disable_mod_clk;
 865         }
 866         clk_prepare_enable(backend->ram_clk);
 867
 868         if (of_device_is_compatible(dev->of_node,
 869                                     "allwinner,sun8i-a33-display-backend")) {
 870                 ret = sun4i_backend_init_sat(dev);
 871                 if (ret) {
 872                         dev_err(dev, "Couldn't init SAT resources\n");
 873                         goto err_disable_ram_clk;
 874                 }
 875         }
 876
 877         backend->engine.regs = devm_regmap_init_mmio(dev, regs,
 878                                                      &sun4i_backend_regmap_config);
 879         if (IS_ERR(backend->engine.regs)) {
 880                 dev_err(dev, "Couldn't create the backend regmap\n");
 881                 return PTR_ERR(backend->engine.regs);
 882         }
 883
 884         list_add_tail(&backend->engine.list, &drv->engine_list);
 885
 886         /*
 887          * Many of the backend's layer configuration registers have
 888          * undefined default values. This poses a risk as we use
 889          * regmap_update_bits in some places, and don't overwrite
 890          * the whole register.
 891          *
 892          * Clear the registers here to have something predictable.
 893          */
 894         for (i = 0x800; i < 0x1000; i += 4)
 895                 regmap_write(backend->engine.regs, i, 0);
 896
 897         /* Disable registers autoloading */
 898         regmap_write(backend->engine.regs, SUN4I_BACKEND_REGBUFFCTL_REG,
 899                      SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
 900
 901         /* Enable the backend */
 902         regmap_write(backend->engine.regs, SUN4I_BACKEND_MODCTL_REG,
 903                      SUN4I_BACKEND_MODCTL_DEBE_EN |
 904                      SUN4I_BACKEND_MODCTL_START_CTL);
 905
 906         /* Set output selection if needed */
 907         quirks = of_device_get_match_data(dev);
 908         if (quirks->needs_output_muxing) {
 909                 /*
 910                  * We assume there is no dynamic muxing of backends
 911                  * and TCONs, so we select the backend with same ID.
 912                  *
 913                  * While dynamic selection might be interesting, since
 914                  * the CRTC is tied to the TCON, while the layers are
 915                  * tied to the backends, this means, we will need to
 916                  * switch between groups of layers. There might not be
 917                  * a way to represent this constraint in DRM.
 918                  */
 919                 regmap_update_bits(backend->engine.regs,
 920                                    SUN4I_BACKEND_MODCTL_REG,
 921                                    SUN4I_BACKEND_MODCTL_OUT_SEL,
 922                                    (backend->engine.id
 923                                     ? SUN4I_BACKEND_MODCTL_OUT_LCD1
 924                                     : SUN4I_BACKEND_MODCTL_OUT_LCD0));
 925         }
 926
 927         backend->quirks = quirks;
 928
 929         return 0;
 930
 931 err_disable_ram_clk:
 932         clk_disable_unprepare(backend->ram_clk);
 933 err_disable_mod_clk:
 934         clk_rate_exclusive_put(backend->mod_clk);
 935         clk_disable_unprepare(backend->mod_clk);
 936 err_disable_bus_clk:
 937         clk_disable_unprepare(backend->bus_clk);
 938 err_assert_reset:
 939         reset_control_assert(backend->reset);
 940         return ret;
 941 }
 942
 943 static 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_rate_exclusive_put(backend->mod_clk);
 956         clk_disable_unprepare(backend->mod_clk);
 957         clk_disable_unprepare(backend->bus_clk);
 958         reset_control_assert(backend->reset);
 959 }
 960
 961 static const struct component_ops sun4i_backend_ops = {
 962         .bind   = sun4i_backend_bind,
 963         .unbind = sun4i_backend_unbind,
 964 };
 965
 966 static int sun4i_backend_probe(struct platform_device *pdev)
 967 {
 968         return component_add(&pdev->dev, &sun4i_backend_ops);
 969 }
 970
 971 static int sun4i_backend_remove(struct platform_device *pdev)
 972 {
 973         component_del(&pdev->dev, &sun4i_backend_ops);
 974
 975         return 0;
 976 }
 977
 978 static const struct sun4i_backend_quirks sun4i_backend_quirks = {
 979         .needs_output_muxing = true,
 980 };
 981
 982 static const struct sun4i_backend_quirks sun5i_backend_quirks = {
 983 };
 984
 985 static const struct sun4i_backend_quirks sun6i_backend_quirks = {
 986 };
 987
 988 static const struct sun4i_backend_quirks sun7i_backend_quirks = {
 989         .needs_output_muxing = true,
 990 };
 991
 992 static const struct sun4i_backend_quirks sun8i_a33_backend_quirks = {
 993         .supports_lowest_plane_alpha = true,
 994 };
 995
 996 static const struct sun4i_backend_quirks sun9i_backend_quirks = {
 997 };
 998
 999 static 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 };
1030 MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);
1031
1032 static 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 };
1040 module_platform_driver(sun4i_backend_platform_driver);
1041
1042 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1043 MODULE_DESCRIPTION("Allwinner A10 Display Backend Driver");
1044 MODULE_LICENSE("GPL");