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). An encoder takes
  35  * pixel data from a CRTC and converts it to a format suitable for any attached
  36  * connector. Encoders are objects exposed to userspace, originally to allow
  37  * userspace to infer cloning and connector/CRTC restrictions. Unfortunately
  38  * almost all drivers get this wrong, making the uabi pretty much useless. On
  39  * top of that the exposed restrictions are too simple for today's hardware, and
  40  * the recommended way to infer restrictions is by using the
  41  * DRM_MODE_ATOMIC_TEST_ONLY flag for the atomic IOCTL.
  42  *
  43  * Otherwise encoders aren't used in the uapi at all (any modeset request from
  44  * userspace directly connects a connector with a CRTC), drivers are therefore
  45  * free to use them however they wish. Modeset helper libraries make strong use
  46  * of encoders to facilitate code sharing. But for more complex settings it is
  47  * usually better to move shared code into a separate &drm_bridge. Compared to
  48  * encoders, bridges also have the benefit of being purely an internal
  49  * abstraction since they are not exposed to userspace at all.
  50  *
  51  * Encoders are initialized with drm_encoder_init() and cleaned up using
  52  * drm_encoder_cleanup().
  53  */
  54 static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
  55         { DRM_MODE_ENCODER_NONE, "None" },
  56         { DRM_MODE_ENCODER_DAC, "DAC" },
  57         { DRM_MODE_ENCODER_TMDS, "TMDS" },
  58         { DRM_MODE_ENCODER_LVDS, "LVDS" },
  59         { DRM_MODE_ENCODER_TVDAC, "TV" },
  60         { DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
  61         { DRM_MODE_ENCODER_DSI, "DSI" },
  62         { DRM_MODE_ENCODER_DPMST, "DP MST" },
  63         { DRM_MODE_ENCODER_DPI, "DPI" },
  64 };
  65
  66 int drm_encoder_register_all(struct drm_device *dev)
  67 {
  68         struct drm_encoder *encoder;
  69         int ret = 0;
  70
  71         drm_for_each_encoder(encoder, dev) {
  72                 if (encoder->funcs->late_register)
  73                         ret = encoder->funcs->late_register(encoder);
  74                 if (ret)
  75                         return ret;
  76         }
  77
  78         return 0;
  79 }
  80
  81 void drm_encoder_unregister_all(struct drm_device *dev)
  82 {
  83         struct drm_encoder *encoder;
  84
  85         drm_for_each_encoder(encoder, dev) {
  86                 if (encoder->funcs->early_unregister)
  87                         encoder->funcs->early_unregister(encoder);
  88         }
  89 }
  90
  91 /**
  92  * drm_encoder_init - Init a preallocated encoder
  93  * @dev: drm device
  94  * @encoder: the encoder to init
  95  * @funcs: callbacks for this encoder
  96  * @encoder_type: user visible type of the encoder
  97  * @name: printf style format string for the encoder name, or NULL for default name
  98  *
  99  * Initialises a preallocated encoder. Encoder should be subclassed as part of
 100  * driver encoder objects. At driver unload time drm_encoder_cleanup() should be
 101  * called from the driver's destroy hook in &drm_encoder_funcs.
 102  *
 103  * Returns:
 104  * Zero on success, error code on failure.
 105  */
 106 int drm_encoder_init(struct drm_device *dev,
 107                      struct drm_encoder *encoder,
 108                      const struct drm_encoder_funcs *funcs,
 109                      int encoder_type, const char *name, ...)
 110 {
 111         int ret;
 112
 113         drm_modeset_lock_all(dev);
 114
 115         ret = drm_mode_object_get(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
 116         if (ret)
 117                 goto out_unlock;
 118
 119         encoder->dev = dev;
 120         encoder->encoder_type = encoder_type;
 121         encoder->funcs = funcs;
 122         if (name) {
 123                 va_list ap;
 124
 125                 va_start(ap, name);
 126                 encoder->name = kvasprintf(GFP_KERNEL, name, ap);
 127                 va_end(ap);
 128         } else {
 129                 encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
 130                                           drm_encoder_enum_list[encoder_type].name,
 131                                           encoder->base.id);
 132         }
 133         if (!encoder->name) {
 134                 ret = -ENOMEM;
 135                 goto out_put;
 136         }
 137
 138         list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
 139         encoder->index = dev->mode_config.num_encoder++;
 140
 141 out_put:
 142         if (ret)
 143                 drm_mode_object_unregister(dev, &encoder->base);
 144
 145 out_unlock:
 146         drm_modeset_unlock_all(dev);
 147
 148         return ret;
 149 }
 150 EXPORT_SYMBOL(drm_encoder_init);
 151
 152 /**
 153  * drm_encoder_cleanup - cleans up an initialised encoder
 154  * @encoder: encoder to cleanup
 155  *
 156  * Cleans up the encoder but doesn't free the object.
 157  */
 158 void drm_encoder_cleanup(struct drm_encoder *encoder)
 159 {
 160         struct drm_device *dev = encoder->dev;
 161
 162         /* Note that the encoder_list is considered to be static; should we
 163          * remove the drm_encoder at runtime we would have to decrement all
 164          * the indices on the drm_encoder after us in the encoder_list.
 165          */
 166
 167         drm_modeset_lock_all(dev);
 168         drm_mode_object_unregister(dev, &encoder->base);
 169         kfree(encoder->name);
 170         list_del(&encoder->head);
 171         dev->mode_config.num_encoder--;
 172         drm_modeset_unlock_all(dev);
 173
 174         memset(encoder, 0, sizeof(*encoder));
 175 }
 176 EXPORT_SYMBOL(drm_encoder_cleanup);
 177
 178 static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
 179 {
 180         struct drm_connector *connector;
 181         struct drm_device *dev = encoder->dev;
 182         bool uses_atomic = false;
 183
 184         /* For atomic drivers only state objects are synchronously updated and
 185          * protected by modeset locks, so check those first. */
 186         drm_for_each_connector(connector, dev) {
 187                 if (!connector->state)
 188                         continue;
 189
 190                 uses_atomic = true;
 191
 192                 if (connector->state->best_encoder != encoder)
 193                         continue;
 194
 195                 return connector->state->crtc;
 196         }
 197
 198         /* Don't return stale data (e.g. pending async disable). */
 199         if (uses_atomic)
 200                 return NULL;
 201
 202         return encoder->crtc;
 203 }
 204
 205 int drm_mode_getencoder(struct drm_device *dev, void *data,
 206                         struct drm_file *file_priv)
 207 {
 208         struct drm_mode_get_encoder *enc_resp = data;
 209         struct drm_encoder *encoder;
 210         struct drm_crtc *crtc;
 211
 212         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 213                 return -EINVAL;
 214
 215         encoder = drm_encoder_find(dev, enc_resp->encoder_id);
 216         if (!encoder)
 217                 return -ENOENT;
 218
 219         drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 220         crtc = drm_encoder_get_crtc(encoder);
 221         if (crtc)
 222                 enc_resp->crtc_id = crtc->base.id;
 223         else
 224                 enc_resp->crtc_id = 0;
 225         drm_modeset_unlock(&dev->mode_config.connection_mutex);
 226
 227         enc_resp->encoder_type = encoder->encoder_type;
 228         enc_resp->encoder_id = encoder->base.id;
 229         enc_resp->possible_crtcs = encoder->possible_crtcs;
 230         enc_resp->possible_clones = encoder->possible_clones;
 231
 232         return 0;
 233 }