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_atomic_state *state)
  90 {
  91         struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
  92                                                                           crtc);
  93         bool has_primary = crtc_state->plane_mask &
  94                            drm_plane_mask(crtc->primary);
  95
  96         /* We always want to have an active plane with an active CRTC */
  97         if (has_primary != crtc_state->enable)
  98                 return -EINVAL;
  99
 100         return drm_atomic_add_affected_planes(state, crtc);
 101 }
 102
 103 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
 104                                        struct drm_atomic_state *state)
 105 {
 106         struct drm_plane *plane;
 107         struct drm_simple_display_pipe *pipe;
 108
 109         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 110         if (!pipe->funcs || !pipe->funcs->enable)
 111                 return;
 112
 113         plane = &pipe->plane;
 114         pipe->funcs->enable(pipe, crtc->state, plane->state);
 115 }
 116
 117 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
 118                                         struct drm_atomic_state *state)
 119 {
 120         struct drm_simple_display_pipe *pipe;
 121
 122         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 123         if (!pipe->funcs || !pipe->funcs->disable)
 124                 return;
 125
 126         pipe->funcs->disable(pipe);
 127 }
 128
 129 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
 130         .mode_valid = drm_simple_kms_crtc_mode_valid,
 131         .atomic_check = drm_simple_kms_crtc_check,
 132         .atomic_enable = drm_simple_kms_crtc_enable,
 133         .atomic_disable = drm_simple_kms_crtc_disable,
 134 };
 135
 136 static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
 137 {
 138         struct drm_simple_display_pipe *pipe;
 139
 140         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 141         if (!pipe->funcs || !pipe->funcs->enable_vblank)
 142                 return 0;
 143
 144         return pipe->funcs->enable_vblank(pipe);
 145 }
 146
 147 static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
 148 {
 149         struct drm_simple_display_pipe *pipe;
 150
 151         pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
 152         if (!pipe->funcs || !pipe->funcs->disable_vblank)
 153                 return;
 154
 155         pipe->funcs->disable_vblank(pipe);
 156 }
 157
 158 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
 159         .reset = drm_atomic_helper_crtc_reset,
 160         .destroy = drm_crtc_cleanup,
 161         .set_config = drm_atomic_helper_set_config,
 162         .page_flip = drm_atomic_helper_page_flip,
 163         .atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
 164         .atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
 165         .enable_vblank = drm_simple_kms_crtc_enable_vblank,
 166         .disable_vblank = drm_simple_kms_crtc_disable_vblank,
 167 };
 168
 169 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
 170                                         struct drm_plane_state *plane_state)
 171 {
 172         struct drm_simple_display_pipe *pipe;
 173         struct drm_crtc_state *crtc_state;
 174         int ret;
 175
 176         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 177         crtc_state = drm_atomic_get_new_crtc_state(plane_state->state,
 178                                                    &pipe->crtc);
 179
 180         ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
 181                                                   DRM_PLANE_HELPER_NO_SCALING,
 182                                                   DRM_PLANE_HELPER_NO_SCALING,
 183                                                   false, true);
 184         if (ret)
 185                 return ret;
 186
 187         if (!plane_state->visible)
 188                 return 0;
 189
 190         if (!pipe->funcs || !pipe->funcs->check)
 191                 return 0;
 192
 193         return pipe->funcs->check(pipe, plane_state, crtc_state);
 194 }
 195
 196 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
 197                                         struct drm_plane_state *old_pstate)
 198 {
 199         struct drm_simple_display_pipe *pipe;
 200
 201         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 202         if (!pipe->funcs || !pipe->funcs->update)
 203                 return;
 204
 205         pipe->funcs->update(pipe, old_pstate);
 206 }
 207
 208 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
 209                                            struct drm_plane_state *state)
 210 {
 211         struct drm_simple_display_pipe *pipe;
 212
 213         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 214         if (!pipe->funcs || !pipe->funcs->prepare_fb)
 215                 return 0;
 216
 217         return pipe->funcs->prepare_fb(pipe, state);
 218 }
 219
 220 static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
 221                                             struct drm_plane_state *state)
 222 {
 223         struct drm_simple_display_pipe *pipe;
 224
 225         pipe = container_of(plane, struct drm_simple_display_pipe, plane);
 226         if (!pipe->funcs || !pipe->funcs->cleanup_fb)
 227                 return;
 228
 229         pipe->funcs->cleanup_fb(pipe, state);
 230 }
 231
 232 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
 233                                                 uint32_t format,
 234                                                 uint64_t modifier)
 235 {
 236         return modifier == DRM_FORMAT_MOD_LINEAR;
 237 }
 238
 239 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
 240         .prepare_fb = drm_simple_kms_plane_prepare_fb,
 241         .cleanup_fb = drm_simple_kms_plane_cleanup_fb,
 242         .atomic_check = drm_simple_kms_plane_atomic_check,
 243         .atomic_update = drm_simple_kms_plane_atomic_update,
 244 };
 245
 246 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
 247         .update_plane           = drm_atomic_helper_update_plane,
 248         .disable_plane          = drm_atomic_helper_disable_plane,
 249         .destroy                = drm_plane_cleanup,
 250         .reset                  = drm_atomic_helper_plane_reset,
 251         .atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
 252         .atomic_destroy_state   = drm_atomic_helper_plane_destroy_state,
 253         .format_mod_supported   = drm_simple_kms_format_mod_supported,
 254 };
 255
 256 /**
 257  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
 258  * @pipe: simple display pipe object
 259  * @bridge: bridge to attach
 260  *
 261  * Makes it possible to still use the drm_simple_display_pipe helpers when
 262  * a DRM bridge has to be used.
 263  *
 264  * Note that you probably want to initialize the pipe by passing a NULL
 265  * connector to drm_simple_display_pipe_init().
 266  *
 267  * Returns:
 268  * Zero on success, negative error code on failure.
 269  */
 270 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
 271                                           struct drm_bridge *bridge)
 272 {
 273         return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
 274 }
 275 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
 276
 277 /**
 278  * drm_simple_display_pipe_init - Initialize a simple display pipeline
 279  * @dev: DRM device
 280  * @pipe: simple display pipe object to initialize
 281  * @funcs: callbacks for the display pipe (optional)
 282  * @formats: array of supported formats (DRM_FORMAT\_\*)
 283  * @format_count: number of elements in @formats
 284  * @format_modifiers: array of formats modifiers
 285  * @connector: connector to attach and register (optional)
 286  *
 287  * Sets up a display pipeline which consist of a really simple
 288  * plane-crtc-encoder pipe.
 289  *
 290  * If a connector is supplied, the pipe will be coupled with the provided
 291  * connector. You may supply a NULL connector when using drm bridges, that
 292  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
 293  *
 294  * Teardown of a simple display pipe is all handled automatically by the drm
 295  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
 296  * release the memory for the structure themselves.
 297  *
 298  * Returns:
 299  * Zero on success, negative error code on failure.
 300  */
 301 int drm_simple_display_pipe_init(struct drm_device *dev,
 302                         struct drm_simple_display_pipe *pipe,
 303                         const struct drm_simple_display_pipe_funcs *funcs,
 304                         const uint32_t *formats, unsigned int format_count,
 305                         const uint64_t *format_modifiers,
 306                         struct drm_connector *connector)
 307 {
 308         struct drm_encoder *encoder = &pipe->encoder;
 309         struct drm_plane *plane = &pipe->plane;
 310         struct drm_crtc *crtc = &pipe->crtc;
 311         int ret;
 312
 313         pipe->connector = connector;
 314         pipe->funcs = funcs;
 315
 316         drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
 317         ret = drm_universal_plane_init(dev, plane, 0,
 318                                        &drm_simple_kms_plane_funcs,
 319                                        formats, format_count,
 320                                        format_modifiers,
 321                                        DRM_PLANE_TYPE_PRIMARY, NULL);
 322         if (ret)
 323                 return ret;
 324
 325         drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
 326         ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
 327                                         &drm_simple_kms_crtc_funcs, NULL);
 328         if (ret)
 329                 return ret;
 330
 331         encoder->possible_crtcs = drm_crtc_mask(crtc);
 332         ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
 333         if (ret || !connector)
 334                 return ret;
 335
 336         return drm_connector_attach_encoder(connector, encoder);
 337 }
 338 EXPORT_SYMBOL(drm_simple_display_pipe_init);
 339
 340 MODULE_LICENSE("GPL");