drivers/gpu/drm/drm_encoder.c

   1 /*
   2  * Copyright (c) 2016 Intel Corporation
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and its
   5  * documentation for any purpose is hereby granted without fee, provided that
   6  * the above copyright notice appear in all copies and that both that copyright
   7  * notice and this permission notice appear in supporting documentation, and
   8  * that the name of the copyright holders not be used in advertising or
   9  * publicity pertaining to distribution of the software without specific,
  10  * written prior permission.  The copyright holders make no representations
  11  * about the suitability of this software for any purpose.  It is provided "as
  12  * is" without express or implied warranty.
  13  *
  14  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20  * OF THIS SOFTWARE.
  21  */
  22
  23 #include <linux/export.h>
  24 #include <drm/drmP.h>
  25 #include <drm/drm_encoder.h>
  26
  27 #include "drm_crtc_internal.h"
  28
  29 /**
  30  * DOC: overview
  31  *
  32  * Encoders represent the connecting element between the CRTC (as the overall
  33  * pixel pipeline, represented by struct &drm_crtc) and the connectors (as the
  34  * generic sink entity, represented by struct &drm_connector). Encoders are
  35  * objects exposed to userspace, originally to allow userspace to infer cloning
  36  * and connector/CRTC restrictions. Unfortunately almost all drivers get this
  37  * wrong, making the uabi pretty much useless. On top of that the exposed
  38  * restrictions are too simple for todays hardware, and the recommend way to
  39  * infer restrictions is by using the DRM_MODE_ATOMIC_TEST_ONLY flag for the
  40  * atomic IOCTL.
  41  *
  42  * Otherwise encoders aren't used in the uapi at all (any modeset request from
  43  * userspace directly connects a connector with a CRTC), drivers are therefore
  44  * free to use them however they wish. Modeset helper libraries make strong use
  45  * of encoders to facilitate code sharing. But for more complex settings it is
  46  * usually better to move shared code into a separate &drm_bridge. Compared to
  47  * encoders bridges also have the benefit of not being purely an internal
  48  * abstraction since they are not exposed to userspace at all.
  49  *
  50  * Encoders are initialized with drm_encoder_init() and cleaned up using
  51  * drm_encoder_cleanup().
  52  */
  53 static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
  54         { DRM_MODE_ENCODER_NONE, "None" },
  55         { DRM_MODE_ENCODER_DAC, "DAC" },
  56         { DRM_MODE_ENCODER_TMDS, "TMDS" },
  57         { DRM_MODE_ENCODER_LVDS, "LVDS" },
  58         { DRM_MODE_ENCODER_TVDAC, "TV" },
  59         { DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
  60         { DRM_MODE_ENCODER_DSI, "DSI" },
  61         { DRM_MODE_ENCODER_DPMST, "DP MST" },
  62         { DRM_MODE_ENCODER_DPI, "DPI" },
  63 };
  64
  65 int drm_encoder_register_all(struct drm_device *dev)
  66 {
  67         struct drm_encoder *encoder;
  68         int ret = 0;
  69
  70         drm_for_each_encoder(encoder, dev) {
  71                 if (encoder->funcs->late_register)
  72                         ret = encoder->funcs->late_register(encoder);
  73                 if (ret)
  74                         return ret;
  75         }
  76
  77         return 0;
  78 }
  79
  80 void drm_encoder_unregister_all(struct drm_device *dev)
  81 {
  82         struct drm_encoder *encoder;
  83
  84         drm_for_each_encoder(encoder, dev) {
  85                 if (encoder->funcs->early_unregister)
  86                         encoder->funcs->early_unregister(encoder);
  87         }
  88 }
  89
  90 /**
  91  * drm_encoder_init - Init a preallocated encoder
  92  * @dev: drm device
  93  * @encoder: the encoder to init
  94  * @funcs: callbacks for this encoder
  95  * @encoder_type: user visible type of the encoder
  96  * @name: printf style format string for the encoder name, or NULL for default name
  97  *
  98  * Initialises a preallocated encoder. Encoder should be subclassed as part of
  99  * driver encoder objects. At driver unload time drm_encoder_cleanup() should be
 100  * called from the driver's destroy hook in &drm_encoder_funcs.
 101  *
 102  * Returns:
 103  * Zero on success, error code on failure.
 104  */
 105 int drm_encoder_init(struct drm_device *dev,
 106                      struct drm_encoder *encoder,
 107                      const struct drm_encoder_funcs *funcs,
 108                      int encoder_type, const char *name, ...)
 109 {
 110         int ret;
 111
 112         drm_modeset_lock_all(dev);
 113
 114         ret = drm_mode_object_get(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
 115         if (ret)
 116                 goto out_unlock;
 117
 118         encoder->dev = dev;
 119         encoder->encoder_type = encoder_type;
 120         encoder->funcs = funcs;
 121         if (name) {
 122                 va_list ap;
 123
 124                 va_start(ap, name);
 125                 encoder->name = kvasprintf(GFP_KERNEL, name, ap);
 126                 va_end(ap);
 127         } else {
 128                 encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
 129                                           drm_encoder_enum_list[encoder_type].name,
 130                                           encoder->base.id);
 131         }
 132         if (!encoder->name) {
 133                 ret = -ENOMEM;
 134                 goto out_put;
 135         }
 136
 137         list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
 138         encoder->index = dev->mode_config.num_encoder++;
 139
 140 out_put:
 141         if (ret)
 142                 drm_mode_object_unregister(dev, &encoder->base);
 143
 144 out_unlock:
 145         drm_modeset_unlock_all(dev);
 146
 147         return ret;
 148 }
 149 EXPORT_SYMBOL(drm_encoder_init);
 150
 151 /**
 152  * drm_encoder_cleanup - cleans up an initialised encoder
 153  * @encoder: encoder to cleanup
 154  *
 155  * Cleans up the encoder but doesn't free the object.
 156  */
 157 void drm_encoder_cleanup(struct drm_encoder *encoder)
 158 {
 159         struct drm_device *dev = encoder->dev;
 160
 161         /* Note that the encoder_list is considered to be static; should we
 162          * remove the drm_encoder at runtime we would have to decrement all
 163          * the indices on the drm_encoder after us in the encoder_list.
 164          */
 165
 166         drm_modeset_lock_all(dev);
 167         drm_mode_object_unregister(dev, &encoder->base);
 168         kfree(encoder->name);
 169         list_del(&encoder->head);
 170         dev->mode_config.num_encoder--;
 171         drm_modeset_unlock_all(dev);
 172
 173         memset(encoder, 0, sizeof(*encoder));
 174 }
 175 EXPORT_SYMBOL(drm_encoder_cleanup);
 176
 177 static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
 178 {
 179         struct drm_connector *connector;
 180         struct drm_device *dev = encoder->dev;
 181         bool uses_atomic = false;
 182
 183         /* For atomic drivers only state objects are synchronously updated and
 184          * protected by modeset locks, so check those first. */
 185         drm_for_each_connector(connector, dev) {
 186                 if (!connector->state)
 187                         continue;
 188
 189                 uses_atomic = true;
 190
 191                 if (connector->state->best_encoder != encoder)
 192                         continue;
 193
 194                 return connector->state->crtc;
 195         }
 196
 197         /* Don't return stale data (e.g. pending async disable). */
 198         if (uses_atomic)
 199                 return NULL;
 200
 201         return encoder->crtc;
 202 }
 203
 204 int drm_mode_getencoder(struct drm_device *dev, void *data,
 205                         struct drm_file *file_priv)
 206 {
 207         struct drm_mode_get_encoder *enc_resp = data;
 208         struct drm_encoder *encoder;
 209         struct drm_crtc *crtc;
 210
 211         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 212                 return -EINVAL;
 213
 214         encoder = drm_encoder_find(dev, enc_resp->encoder_id);
 215         if (!encoder)
 216                 return -ENOENT;
 217
 218         drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 219         crtc = drm_encoder_get_crtc(encoder);
 220         if (crtc)
 221                 enc_resp->crtc_id = crtc->base.id;
 222         else
 223                 enc_resp->crtc_id = 0;
 224         drm_modeset_unlock(&dev->mode_config.connection_mutex);
 225
 226         enc_resp->encoder_type = encoder->encoder_type;
 227         enc_resp->encoder_id = encoder->base.id;
 228         enc_resp->possible_crtcs = encoder->possible_crtcs;
 229         enc_resp->possible_clones = encoder->possible_clones;
 230
 231         return 0;
 232 }