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
  25 #include <drm/drm_bridge.h>
  26 #include <drm/drm_device.h>
  27 #include <drm/drm_drv.h>
  28 #include <drm/drm_encoder.h>
  29
  30 #include "drm_crtc_internal.h"
  31
  32 /**
  33  * DOC: overview
  34  *
  35  * Encoders represent the connecting element between the CRTC (as the overall
  36  * pixel pipeline, represented by &struct drm_crtc) and the connectors (as the
  37  * generic sink entity, represented by &struct drm_connector). An encoder takes
  38  * pixel data from a CRTC and converts it to a format suitable for any attached
  39  * connector. Encoders are objects exposed to userspace, originally to allow
  40  * userspace to infer cloning and connector/CRTC restrictions. Unfortunately
  41  * almost all drivers get this wrong, making the uabi pretty much useless. On
  42  * top of that the exposed restrictions are too simple for today's hardware, and
  43  * the recommended way to infer restrictions is by using the
  44  * DRM_MODE_ATOMIC_TEST_ONLY flag for the atomic IOCTL.
  45  *
  46  * Otherwise encoders aren't used in the uapi at all (any modeset request from
  47  * userspace directly connects a connector with a CRTC), drivers are therefore
  48  * free to use them however they wish. Modeset helper libraries make strong use
  49  * of encoders to facilitate code sharing. But for more complex settings it is
  50  * usually better to move shared code into a separate &drm_bridge. Compared to
  51  * encoders, bridges also have the benefit of being purely an internal
  52  * abstraction since they are not exposed to userspace at all.
  53  *
  54  * Encoders are initialized with drm_encoder_init() and cleaned up using
  55  * drm_encoder_cleanup().
  56  */
  57 static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
  58         { DRM_MODE_ENCODER_NONE, "None" },
  59         { DRM_MODE_ENCODER_DAC, "DAC" },
  60         { DRM_MODE_ENCODER_TMDS, "TMDS" },
  61         { DRM_MODE_ENCODER_LVDS, "LVDS" },
  62         { DRM_MODE_ENCODER_TVDAC, "TV" },
  63         { DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
  64         { DRM_MODE_ENCODER_DSI, "DSI" },
  65         { DRM_MODE_ENCODER_DPMST, "DP MST" },
  66         { DRM_MODE_ENCODER_DPI, "DPI" },
  67 };
  68
  69 int drm_encoder_register_all(struct drm_device *dev)
  70 {
  71         struct drm_encoder *encoder;
  72         int ret = 0;
  73
  74         drm_for_each_encoder(encoder, dev) {
  75                 if (encoder->funcs->late_register)
  76                         ret = encoder->funcs->late_register(encoder);
  77                 if (ret)
  78                         return ret;
  79         }
  80
  81         return 0;
  82 }
  83
  84 void drm_encoder_unregister_all(struct drm_device *dev)
  85 {
  86         struct drm_encoder *encoder;
  87
  88         drm_for_each_encoder(encoder, dev) {
  89                 if (encoder->funcs->early_unregister)
  90                         encoder->funcs->early_unregister(encoder);
  91         }
  92 }
  93
  94 /**
  95  * drm_encoder_init - Init a preallocated encoder
  96  * @dev: drm device
  97  * @encoder: the encoder to init
  98  * @funcs: callbacks for this encoder
  99  * @encoder_type: user visible type of the encoder
 100  * @name: printf style format string for the encoder name, or NULL for default name
 101  *
 102  * Initialises a preallocated encoder. Encoder should be subclassed as part of
 103  * driver encoder objects. At driver unload time drm_encoder_cleanup() should be
 104  * called from the driver's &drm_encoder_funcs.destroy hook.
 105  *
 106  * Returns:
 107  * Zero on success, error code on failure.
 108  */
 109 int drm_encoder_init(struct drm_device *dev,
 110                      struct drm_encoder *encoder,
 111                      const struct drm_encoder_funcs *funcs,
 112                      int encoder_type, const char *name, ...)
 113 {
 114         int ret;
 115
 116         /* encoder index is used with 32bit bitmasks */
 117         if (WARN_ON(dev->mode_config.num_encoder >= 32))
 118                 return -EINVAL;
 119
 120         ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
 121         if (ret)
 122                 return ret;
 123
 124         encoder->dev = dev;
 125         encoder->encoder_type = encoder_type;
 126         encoder->funcs = funcs;
 127         if (name) {
 128                 va_list ap;
 129
 130                 va_start(ap, name);
 131                 encoder->name = kvasprintf(GFP_KERNEL, name, ap);
 132                 va_end(ap);
 133         } else {
 134                 encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
 135                                           drm_encoder_enum_list[encoder_type].name,
 136                                           encoder->base.id);
 137         }
 138         if (!encoder->name) {
 139                 ret = -ENOMEM;
 140                 goto out_put;
 141         }
 142
 143         INIT_LIST_HEAD(&encoder->bridge_chain);
 144         list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
 145         encoder->index = dev->mode_config.num_encoder++;
 146
 147 out_put:
 148         if (ret)
 149                 drm_mode_object_unregister(dev, &encoder->base);
 150
 151         return ret;
 152 }
 153 EXPORT_SYMBOL(drm_encoder_init);
 154
 155 /**
 156  * drm_encoder_cleanup - cleans up an initialised encoder
 157  * @encoder: encoder to cleanup
 158  *
 159  * Cleans up the encoder but doesn't free the object.
 160  */
 161 void drm_encoder_cleanup(struct drm_encoder *encoder)
 162 {
 163         struct drm_device *dev = encoder->dev;
 164         struct drm_bridge *bridge, *next;
 165
 166         /* Note that the encoder_list is considered to be static; should we
 167          * remove the drm_encoder at runtime we would have to decrement all
 168          * the indices on the drm_encoder after us in the encoder_list.
 169          */
 170
 171         list_for_each_entry_safe(bridge, next, &encoder->bridge_chain,
 172                                  chain_node)
 173                 drm_bridge_detach(bridge);
 174
 175         drm_mode_object_unregister(dev, &encoder->base);
 176         kfree(encoder->name);
 177         list_del(&encoder->head);
 178         dev->mode_config.num_encoder--;
 179
 180         memset(encoder, 0, sizeof(*encoder));
 181 }
 182 EXPORT_SYMBOL(drm_encoder_cleanup);
 183
 184 static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
 185 {
 186         struct drm_connector *connector;
 187         struct drm_device *dev = encoder->dev;
 188         bool uses_atomic = false;
 189         struct drm_connector_list_iter conn_iter;
 190
 191         /* For atomic drivers only state objects are synchronously updated and
 192          * protected by modeset locks, so check those first. */
 193         drm_connector_list_iter_begin(dev, &conn_iter);
 194         drm_for_each_connector_iter(connector, &conn_iter) {
 195                 if (!connector->state)
 196                         continue;
 197
 198                 uses_atomic = true;
 199
 200                 if (connector->state->best_encoder != encoder)
 201                         continue;
 202
 203                 drm_connector_list_iter_end(&conn_iter);
 204                 return connector->state->crtc;
 205         }
 206         drm_connector_list_iter_end(&conn_iter);
 207
 208         /* Don't return stale data (e.g. pending async disable). */
 209         if (uses_atomic)
 210                 return NULL;
 211
 212         return encoder->crtc;
 213 }
 214
 215 int drm_mode_getencoder(struct drm_device *dev, void *data,
 216                         struct drm_file *file_priv)
 217 {
 218         struct drm_mode_get_encoder *enc_resp = data;
 219         struct drm_encoder *encoder;
 220         struct drm_crtc *crtc;
 221
 222         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 223                 return -EOPNOTSUPP;
 224
 225         encoder = drm_encoder_find(dev, file_priv, enc_resp->encoder_id);
 226         if (!encoder)
 227                 return -ENOENT;
 228
 229         drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 230         crtc = drm_encoder_get_crtc(encoder);
 231         if (crtc && drm_lease_held(file_priv, crtc->base.id))
 232                 enc_resp->crtc_id = crtc->base.id;
 233         else
 234                 enc_resp->crtc_id = 0;
 235         drm_modeset_unlock(&dev->mode_config.connection_mutex);
 236
 237         enc_resp->encoder_type = encoder->encoder_type;
 238         enc_resp->encoder_id = encoder->base.id;
 239         enc_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv,
 240                                                           encoder->possible_crtcs);
 241         enc_resp->possible_clones = encoder->possible_clones;
 242
 243         return 0;
 244 }