drivers/gpu/drm/drm_simple_kms_helper.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Noralf Trønnes
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/slab.h>
   8
   9 #include <drm/drm_atomic.h>
  10 #include <drm/drm_atomic_helper.h>
  11 #include <drm/drm_bridge.h>
  12 #include <drm/drm_drv.h>
  13 #include <drm/drm_gem_atomic_helper.h>
  14 #include <drm/drm_managed.h>
  15 #include <drm/drm_plane_helper.h>
  16 #include <drm/drm_probe_helper.h>
  17 #include <drm/drm_simple_kms_helper.h>
  18
  19 /**
  20  * DOC: overview
  21  *
  22  * This helper library provides helpers for drivers for simple display
  23  * hardware.
  24  *
  25  * drm_simple_display_pipe_init() initializes a simple display pipeline
  26  * which has only one full-screen scanout buffer feeding one output. The
  27  * pipeline is represented by &struct drm_simple_display_pipe and binds
  28  * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
  29  * entity. Some flexibility for code reuse is provided through a separately
  30  * allocated &drm_connector object and supporting optional &drm_bridge
  31  * encoder drivers.
  32  *
  33  * Many drivers require only a very simple encoder that fulfills the minimum
  34  * requirements of the display pipeline and does not add additional
  35  * functionality. The function drm_simple_encoder_init() provides an
  36  * implementation of such an encoder.
  37  */
  38
  39 static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
  40         .destroy = drm_encoder_cleanup,
  41 };
  42
  43 /**
  44  * drm_simple_encoder_init - Initialize a preallocated encoder with
  45  *                           basic functionality.
  46  * @dev: drm device
  47  * @encoder: the encoder to initialize
  48  * @encoder_type: user visible type of the encoder
  49  *
  50  * Initialises a preallocated encoder that has no further functionality.
  51  * Settings for possible CRTC and clones are left to their initial values.
  52  * The encoder will be cleaned up automatically as part of the mode-setting
  53  * cleanup.
  54  *
  55  * The caller of drm_simple_encoder_init() is responsible for freeing
  56  * the encoder's memory after the encoder has been cleaned up. At the
  57  * moment this only works reliably if the encoder data structure is
  58  * stored in the device structure. Free the encoder's memory as part of
  59  * the device release function.
  60  *
  61  * Note: consider using drmm_simple_encoder_alloc() instead of
  62  * drm_simple_encoder_init() to let the DRM managed resource infrastructure
  63  * take care of cleanup and deallocation.
  64  *
  65  * Returns:
  66  * Zero on success, error code on failure.
  67  */
  68 int drm_simple_encoder_init(struct drm_device *dev,
  69                             struct drm_encoder *encoder,
  70                             int encoder_type)
  71 {
  72         return drm_encoder_init(dev, encoder,
  73                                 &drm_simple_encoder_funcs_cleanup,
  74                                 encoder_type, NULL);
  75 }
  76 EXPORT_SYMBOL(drm_simple_encoder_init);
  77
  78 void *__drmm_simple_encoder_alloc(struct drm_device *dev, size_t size,
  79                                   size_t offset, int encoder_type)
  80 {
  81         return __drmm_encoder_alloc(dev, size, offset, NULL, encoder_type,
  82                                     NULL);
  83 }
  84 EXPORT_SYMBOL(__drmm_simple_encoder_alloc);
  85
  86 static enum drm_mode_status
  87 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
  88                                const struct drm_display_mode *mode)
  89 {
  90         struct drm_simple_display_pipe *pipe;
  91
  92         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
  93         if (!pipe->funcs || !pipe->funcs->mode_valid)
  94                 /* Anything goes */
  95                 return MODE_OK;
  96
  97         return pipe->funcs->mode_valid(pipe, mode);
  98 }
  99
 100 static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
 101                                      struct drm_atomic_state *state)
 102 {
 103         struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
 104                                                                           crtc);
 105         bool has_primary = crtc_state->plane_mask &
 106                            drm_plane_mask(crtc->primary);
 107
 108         /* We always want to have an active plane with an active CRTC */
 109         if (has_primary != crtc_state->enable)
 110                 return -EINVAL;
 111
 112         return drm_atomic_add_affected_planes(state, crtc);
 113 }
 114
 115 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
 116                                        struct drm_atomic_state *state)
 117 {
 118         struct drm_plane *plane;
 119         struct drm_simple_display_pipe *pipe;
 120
 121         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 122         if (!pipe->funcs || !pipe->funcs->enable)
 123                 return;
 124
 125         plane = &pipe->plane;
 126         pipe->funcs->enable(pipe, crtc->state, plane->state);
 127 }
 128
 129 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
 130                                         struct drm_atomic_state *state)
 131 {
 132         struct drm_simple_display_pipe *pipe;
 133
 134         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 135         if (!pipe->funcs || !pipe->funcs->disable)
 136                 return;
 137
 138         pipe->funcs->disable(pipe);
 139 }
 140
 141 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
 142         .mode_valid = drm_simple_kms_crtc_mode_valid,
 143         .atomic_check = drm_simple_kms_crtc_check,
 144         .atomic_enable = drm_simple_kms_crtc_enable,
 145         .atomic_disable = drm_simple_kms_crtc_disable,
 146 };
 147
 148 static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
 149 {
 150         struct drm_simple_display_pipe *pipe;
 151
 152         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 153         if (!pipe->funcs || !pipe->funcs->enable_vblank)
 154                 return 0;
 155
 156         return pipe->funcs->enable_vblank(pipe);
 157 }
 158
 159 static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
 160 {
 161         struct drm_simple_display_pipe *pipe;
 162
 163         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 164         if (!pipe->funcs || !pipe->funcs->disable_vblank)
 165                 return;
 166
 167         pipe->funcs->disable_vblank(pipe);
 168 }
 169
 170 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
 171         .reset = drm_atomic_helper_crtc_reset,
 172         .destroy = drm_crtc_cleanup,
 173         .set_config = drm_atomic_helper_set_config,
 174         .page_flip = drm_atomic_helper_page_flip,
 175         .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 176         .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
 177         .enable_vblank = drm_simple_kms_crtc_enable_vblank,
 178         .disable_vblank = drm_simple_kms_crtc_disable_vblank,
 179 };
 180
 181 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
 182                                         struct drm_atomic_state *state)
 183 {
 184         struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state,
 185                                                                              plane);
 186         struct drm_simple_display_pipe *pipe;
 187         struct drm_crtc_state *crtc_state;
 188         int ret;
 189
 190         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 191         crtc_state = drm_atomic_get_new_crtc_state(state,
 192                                                    &pipe->crtc);
 193
 194         ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
 195                                                   DRM_PLANE_HELPER_NO_SCALING,
 196                                                   DRM_PLANE_HELPER_NO_SCALING,
 197                                                   false, true);
 198         if (ret)
 199                 return ret;
 200
 201         if (!plane_state->visible)
 202                 return 0;
 203
 204         if (!pipe->funcs || !pipe->funcs->check)
 205                 return 0;
 206
 207         return pipe->funcs->check(pipe, plane_state, crtc_state);
 208 }
 209
 210 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
 211                                         struct drm_atomic_state *state)
 212 {
 213         struct drm_plane_state *old_pstate = drm_atomic_get_old_plane_state(state,
 214                                                                             plane);
 215         struct drm_simple_display_pipe *pipe;
 216
 217         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 218         if (!pipe->funcs || !pipe->funcs->update)
 219                 return;
 220
 221         pipe->funcs->update(pipe, old_pstate);
 222 }
 223
 224 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
 225                                            struct drm_plane_state *state)
 226 {
 227         struct drm_simple_display_pipe *pipe;
 228
 229         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 230         if (!pipe->funcs || !pipe->funcs->prepare_fb) {
 231                 if (WARN_ON_ONCE(!drm_core_check_feature(plane->dev, DRIVER_GEM)))
 232                         return 0;
 233
 234                 WARN_ON_ONCE(pipe->funcs && pipe->funcs->cleanup_fb);
 235
 236                 return drm_gem_simple_display_pipe_prepare_fb(pipe, state);
 237         }
 238
 239         return pipe->funcs->prepare_fb(pipe, state);
 240 }
 241
 242 static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
 243                                             struct drm_plane_state *state)
 244 {
 245         struct drm_simple_display_pipe *pipe;
 246
 247         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 248         if (!pipe->funcs || !pipe->funcs->cleanup_fb)
 249                 return;
 250
 251         pipe->funcs->cleanup_fb(pipe, state);
 252 }
 253
 254 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
 255                                                 uint32_t format,
 256                                                 uint64_t modifier)
 257 {
 258         return modifier == DRM_FORMAT_MOD_LINEAR;
 259 }
 260
 261 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
 262         .prepare_fb = drm_simple_kms_plane_prepare_fb,
 263         .cleanup_fb = drm_simple_kms_plane_cleanup_fb,
 264         .atomic_check = drm_simple_kms_plane_atomic_check,
 265         .atomic_update = drm_simple_kms_plane_atomic_update,
 266 };
 267
 268 static void drm_simple_kms_plane_reset(struct drm_plane *plane)
 269 {
 270         struct drm_simple_display_pipe *pipe;
 271
 272         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 273         if (!pipe->funcs || !pipe->funcs->reset_plane)
 274                 return drm_atomic_helper_plane_reset(plane);
 275
 276         return pipe->funcs->reset_plane(pipe);
 277 }
 278
 279 static struct drm_plane_state *drm_simple_kms_plane_duplicate_state(struct drm_plane *plane)
 280 {
 281         struct drm_simple_display_pipe *pipe;
 282
 283         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 284         if (!pipe->funcs || !pipe->funcs->duplicate_plane_state)
 285                 return drm_atomic_helper_plane_duplicate_state(plane);
 286
 287         return pipe->funcs->duplicate_plane_state(pipe);
 288 }
 289
 290 static void drm_simple_kms_plane_destroy_state(struct drm_plane *plane,
 291                                                struct drm_plane_state *state)
 292 {
 293         struct drm_simple_display_pipe *pipe;
 294
 295         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 296         if (!pipe->funcs || !pipe->funcs->destroy_plane_state)
 297                 drm_atomic_helper_plane_destroy_state(plane, state);
 298         else
 299                 pipe->funcs->destroy_plane_state(pipe, state);
 300 }
 301
 302 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
 303         .update_plane           = drm_atomic_helper_update_plane,
 304         .disable_plane          = drm_atomic_helper_disable_plane,
 305         .destroy                = drm_plane_cleanup,
 306         .reset                  = drm_simple_kms_plane_reset,
 307         .atomic_duplicate_state = drm_simple_kms_plane_duplicate_state,
 308         .atomic_destroy_state   = drm_simple_kms_plane_destroy_state,
 309         .format_mod_supported   = drm_simple_kms_format_mod_supported,
 310 };
 311
 312 /**
 313  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
 314  * @pipe: simple display pipe object
 315  * @bridge: bridge to attach
 316  *
 317  * Makes it possible to still use the drm_simple_display_pipe helpers when
 318  * a DRM bridge has to be used.
 319  *
 320  * Note that you probably want to initialize the pipe by passing a NULL
 321  * connector to drm_simple_display_pipe_init().
 322  *
 323  * Returns:
 324  * Zero on success, negative error code on failure.
 325  */
 326 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
 327                                           struct drm_bridge *bridge)
 328 {
 329         return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
 330 }
 331 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
 332
 333 /**
 334  * drm_simple_display_pipe_init - Initialize a simple display pipeline
 335  * @dev: DRM device
 336  * @pipe: simple display pipe object to initialize
 337  * @funcs: callbacks for the display pipe (optional)
 338  * @formats: array of supported formats (DRM_FORMAT\_\*)
 339  * @format_count: number of elements in @formats
 340  * @format_modifiers: array of formats modifiers
 341  * @connector: connector to attach and register (optional)
 342  *
 343  * Sets up a display pipeline which consist of a really simple
 344  * plane-crtc-encoder pipe.
 345  *
 346  * If a connector is supplied, the pipe will be coupled with the provided
 347  * connector. You may supply a NULL connector when using drm bridges, that
 348  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
 349  *
 350  * Teardown of a simple display pipe is all handled automatically by the drm
 351  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
 352  * release the memory for the structure themselves.
 353  *
 354  * Returns:
 355  * Zero on success, negative error code on failure.
 356  */
 357 int drm_simple_display_pipe_init(struct drm_device *dev,
 358                         struct drm_simple_display_pipe *pipe,
 359                         const struct drm_simple_display_pipe_funcs *funcs,
 360                         const uint32_t *formats, unsigned int format_count,
 361                         const uint64_t *format_modifiers,
 362                         struct drm_connector *connector)
 363 {
 364         struct drm_encoder *encoder = &pipe->encoder;
 365         struct drm_plane *plane = &pipe->plane;
 366         struct drm_crtc *crtc = &pipe->crtc;
 367         int ret;
 368
 369         pipe->connector = connector;
 370         pipe->funcs = funcs;
 371
 372         drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
 373         ret = drm_universal_plane_init(dev, plane, 0,
 374                                        &drm_simple_kms_plane_funcs,
 375                                        formats, format_count,
 376                                        format_modifiers,
 377                                        DRM_PLANE_TYPE_PRIMARY, NULL);
 378         if (ret)
 379                 return ret;
 380
 381         drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
 382         ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
 383                                         &drm_simple_kms_crtc_funcs, NULL);
 384         if (ret)
 385                 return ret;
 386
 387         encoder->possible_crtcs = drm_crtc_mask(crtc);
 388         ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
 389         if (ret || !connector)
 390                 return ret;
 391
 392         return drm_connector_attach_encoder(connector, encoder);
 393 }
 394 EXPORT_SYMBOL(drm_simple_display_pipe_init);
 395
 396 MODULE_LICENSE("GPL");