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 */
 54static 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
 66int 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
 81void 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 */
106int 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	ret = drm_mode_object_get(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
114	if (ret)
115		return ret;
116
117	encoder->dev = dev;
118	encoder->encoder_type = encoder_type;
119	encoder->funcs = funcs;
120	if (name) {
121		va_list ap;
122
123		va_start(ap, name);
124		encoder->name = kvasprintf(GFP_KERNEL, name, ap);
125		va_end(ap);
126	} else {
127		encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
128					  drm_encoder_enum_list[encoder_type].name,
129					  encoder->base.id);
130	}
131	if (!encoder->name) {
132		ret = -ENOMEM;
133		goto out_put;
134	}
135
136	list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
137	encoder->index = dev->mode_config.num_encoder++;
138
139out_put:
140	if (ret)
141		drm_mode_object_unregister(dev, &encoder->base);
142
143	return ret;
144}
145EXPORT_SYMBOL(drm_encoder_init);
146
147/**
148 * drm_encoder_cleanup - cleans up an initialised encoder
149 * @encoder: encoder to cleanup
150 *
151 * Cleans up the encoder but doesn't free the object.
152 */
153void drm_encoder_cleanup(struct drm_encoder *encoder)
154{
155	struct drm_device *dev = encoder->dev;
156
157	/* Note that the encoder_list is considered to be static; should we
158	 * remove the drm_encoder at runtime we would have to decrement all
159	 * the indices on the drm_encoder after us in the encoder_list.
160	 */
161
162	drm_mode_object_unregister(dev, &encoder->base);
163	kfree(encoder->name);
164	list_del(&encoder->head);
165	dev->mode_config.num_encoder--;
166
167	memset(encoder, 0, sizeof(*encoder));
168}
169EXPORT_SYMBOL(drm_encoder_cleanup);
170
171static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
172{
173	struct drm_connector *connector;
174	struct drm_device *dev = encoder->dev;
175	bool uses_atomic = false;
176
177	/* For atomic drivers only state objects are synchronously updated and
178	 * protected by modeset locks, so check those first. */
179	drm_for_each_connector(connector, dev) {
180		if (!connector->state)
181			continue;
182
183		uses_atomic = true;
184
185		if (connector->state->best_encoder != encoder)
186			continue;
187
188		return connector->state->crtc;
189	}
190
191	/* Don't return stale data (e.g. pending async disable). */
192	if (uses_atomic)
193		return NULL;
194
195	return encoder->crtc;
196}
197
198int drm_mode_getencoder(struct drm_device *dev, void *data,
199			struct drm_file *file_priv)
200{
201	struct drm_mode_get_encoder *enc_resp = data;
202	struct drm_encoder *encoder;
203	struct drm_crtc *crtc;
204
205	if (!drm_core_check_feature(dev, DRIVER_MODESET))
206		return -EINVAL;
207
208	encoder = drm_encoder_find(dev, enc_resp->encoder_id);
209	if (!encoder)
210		return -ENOENT;
211
212	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
213	crtc = drm_encoder_get_crtc(encoder);
214	if (crtc)
215		enc_resp->crtc_id = crtc->base.id;
216	else
217		enc_resp->crtc_id = 0;
218	drm_modeset_unlock(&dev->mode_config.connection_mutex);
219
220	enc_resp->encoder_type = encoder->encoder_type;
221	enc_resp->encoder_id = encoder->base.id;
222	enc_resp->possible_crtcs = encoder->possible_crtcs;
223	enc_resp->possible_clones = encoder->possible_clones;
224
225	return 0;
226}