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