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_device.h>
 26#include <drm/drm_drv.h>
 27#include <drm/drm_encoder.h>
 28
 29#include "drm_crtc_internal.h"
 30
 31/**
 32 * DOC: overview
 33 *
 34 * Encoders represent the connecting element between the CRTC (as the overall
 35 * pixel pipeline, represented by &struct drm_crtc) and the connectors (as the
 36 * generic sink entity, represented by &struct drm_connector). An encoder takes
 37 * pixel data from a CRTC and converts it to a format suitable for any attached
 38 * connector. Encoders are objects exposed to userspace, originally to allow
 39 * userspace to infer cloning and connector/CRTC restrictions. Unfortunately
 40 * almost all drivers get this wrong, making the uabi pretty much useless. On
 41 * top of that the exposed restrictions are too simple for today's hardware, and
 42 * the recommended way to infer restrictions is by using the
 43 * DRM_MODE_ATOMIC_TEST_ONLY flag for the atomic IOCTL.
 44 *
 45 * Otherwise encoders aren't used in the uapi at all (any modeset request from
 46 * userspace directly connects a connector with a CRTC), drivers are therefore
 47 * free to use them however they wish. Modeset helper libraries make strong use
 48 * of encoders to facilitate code sharing. But for more complex settings it is
 49 * usually better to move shared code into a separate &drm_bridge. Compared to
 50 * encoders, bridges also have the benefit of being purely an internal
 51 * abstraction since they are not exposed to userspace at all.
 52 *
 53 * Encoders are initialized with drm_encoder_init() and cleaned up using
 54 * drm_encoder_cleanup().
 55 */
 56static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
 57	{ DRM_MODE_ENCODER_NONE, "None" },
 58	{ DRM_MODE_ENCODER_DAC, "DAC" },
 59	{ DRM_MODE_ENCODER_TMDS, "TMDS" },
 60	{ DRM_MODE_ENCODER_LVDS, "LVDS" },
 61	{ DRM_MODE_ENCODER_TVDAC, "TV" },
 62	{ DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
 63	{ DRM_MODE_ENCODER_DSI, "DSI" },
 64	{ DRM_MODE_ENCODER_DPMST, "DP MST" },
 65	{ DRM_MODE_ENCODER_DPI, "DPI" },
 66};
 67
 68int drm_encoder_register_all(struct drm_device *dev)
 69{
 70	struct drm_encoder *encoder;
 71	int ret = 0;
 72
 73	drm_for_each_encoder(encoder, dev) {
 74		if (encoder->funcs->late_register)
 75			ret = encoder->funcs->late_register(encoder);
 76		if (ret)
 77			return ret;
 78	}
 79
 80	return 0;
 81}
 82
 83void drm_encoder_unregister_all(struct drm_device *dev)
 84{
 85	struct drm_encoder *encoder;
 86
 87	drm_for_each_encoder(encoder, dev) {
 88		if (encoder->funcs->early_unregister)
 89			encoder->funcs->early_unregister(encoder);
 90	}
 91}
 92
 93/**
 94 * drm_encoder_init - Init a preallocated encoder
 95 * @dev: drm device
 96 * @encoder: the encoder to init
 97 * @funcs: callbacks for this encoder
 98 * @encoder_type: user visible type of the encoder
 99 * @name: printf style format string for the encoder name, or NULL for default name
100 *
101 * Initialises a preallocated encoder. Encoder should be subclassed as part of
102 * driver encoder objects. At driver unload time drm_encoder_cleanup() should be
103 * called from the driver's &drm_encoder_funcs.destroy hook.
104 *
105 * Returns:
106 * Zero on success, error code on failure.
107 */
108int drm_encoder_init(struct drm_device *dev,
109		     struct drm_encoder *encoder,
110		     const struct drm_encoder_funcs *funcs,
111		     int encoder_type, const char *name, ...)
112{
113	int ret;
114
115	/* encoder index is used with 32bit bitmasks */
116	if (WARN_ON(dev->mode_config.num_encoder >= 32))
117		return -EINVAL;
118
119	ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
120	if (ret)
121		return ret;
122
123	encoder->dev = dev;
124	encoder->encoder_type = encoder_type;
125	encoder->funcs = funcs;
126	if (name) {
127		va_list ap;
128
129		va_start(ap, name);
130		encoder->name = kvasprintf(GFP_KERNEL, name, ap);
131		va_end(ap);
132	} else {
133		encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
134					  drm_encoder_enum_list[encoder_type].name,
135					  encoder->base.id);
136	}
137	if (!encoder->name) {
138		ret = -ENOMEM;
139		goto out_put;
140	}
141
142	list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
143	encoder->index = dev->mode_config.num_encoder++;
144
145out_put:
146	if (ret)
147		drm_mode_object_unregister(dev, &encoder->base);
148
149	return ret;
150}
151EXPORT_SYMBOL(drm_encoder_init);
152
153/**
154 * drm_encoder_cleanup - cleans up an initialised encoder
155 * @encoder: encoder to cleanup
156 *
157 * Cleans up the encoder but doesn't free the object.
158 */
159void drm_encoder_cleanup(struct drm_encoder *encoder)
160{
161	struct drm_device *dev = encoder->dev;
162
163	/* Note that the encoder_list is considered to be static; should we
164	 * remove the drm_encoder at runtime we would have to decrement all
165	 * the indices on the drm_encoder after us in the encoder_list.
166	 */
167
168	if (encoder->bridge) {
169		struct drm_bridge *bridge = encoder->bridge;
170		struct drm_bridge *next;
171
172		while (bridge) {
173			next = bridge->next;
174			drm_bridge_detach(bridge);
175			bridge = next;
176		}
177	}
178
179	drm_mode_object_unregister(dev, &encoder->base);
180	kfree(encoder->name);
181	list_del(&encoder->head);
182	dev->mode_config.num_encoder--;
183
184	memset(encoder, 0, sizeof(*encoder));
185}
186EXPORT_SYMBOL(drm_encoder_cleanup);
187
188static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
189{
190	struct drm_connector *connector;
191	struct drm_device *dev = encoder->dev;
192	bool uses_atomic = false;
193	struct drm_connector_list_iter conn_iter;
194
195	/* For atomic drivers only state objects are synchronously updated and
196	 * protected by modeset locks, so check those first. */
197	drm_connector_list_iter_begin(dev, &conn_iter);
198	drm_for_each_connector_iter(connector, &conn_iter) {
199		if (!connector->state)
200			continue;
201
202		uses_atomic = true;
203
204		if (connector->state->best_encoder != encoder)
205			continue;
206
207		drm_connector_list_iter_end(&conn_iter);
208		return connector->state->crtc;
209	}
210	drm_connector_list_iter_end(&conn_iter);
211
212	/* Don't return stale data (e.g. pending async disable). */
213	if (uses_atomic)
214		return NULL;
215
216	return encoder->crtc;
217}
218
219int drm_mode_getencoder(struct drm_device *dev, void *data,
220			struct drm_file *file_priv)
221{
222	struct drm_mode_get_encoder *enc_resp = data;
223	struct drm_encoder *encoder;
224	struct drm_crtc *crtc;
225
226	if (!drm_core_check_feature(dev, DRIVER_MODESET))
227		return -EOPNOTSUPP;
228
229	encoder = drm_encoder_find(dev, file_priv, enc_resp->encoder_id);
230	if (!encoder)
231		return -ENOENT;
232
233	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
234	crtc = drm_encoder_get_crtc(encoder);
235	if (crtc && drm_lease_held(file_priv, crtc->base.id))
236		enc_resp->crtc_id = crtc->base.id;
237	else
238		enc_resp->crtc_id = 0;
239	drm_modeset_unlock(&dev->mode_config.connection_mutex);
240
241	enc_resp->encoder_type = encoder->encoder_type;
242	enc_resp->encoder_id = encoder->base.id;
243	enc_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv,
244							  encoder->possible_crtcs);
245	enc_resp->possible_clones = encoder->possible_clones;
246
247	return 0;
248}