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 */
 57static 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
 69int 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
 84void 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 */
109int 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
147out_put:
148	if (ret)
149		drm_mode_object_unregister(dev, &encoder->base);
150
151	return ret;
152}
153EXPORT_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 */
161void 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}
182EXPORT_SYMBOL(drm_encoder_cleanup);
183
184static 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
215int 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}