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