1 /* $NetBSD: drm_encoder.c,v 1.2 2021/12/18 23:44:57 riastradh Exp $ */
2
3 /*
4 * Copyright (c) 2016 Intel Corporation
5 *
6 * Permission to use, copy, modify, distribute, and sell this software and its
7 * documentation for any purpose is hereby granted without fee, provided that
8 * the above copyright notice appear in all copies and that both that copyright
9 * notice and this permission notice appear in supporting documentation, and
10 * that the name of the copyright holders not be used in advertising or
11 * publicity pertaining to distribution of the software without specific,
12 * written prior permission. The copyright holders make no representations
13 * about the suitability of this software for any purpose. It is provided "as
14 * is" without express or implied warranty.
15 *
16 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
17 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
18 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
19 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
20 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
21 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
22 * OF THIS SOFTWARE.
23 */
24
25 #include <sys/cdefs.h>
26 __KERNEL_RCSID(0, "$NetBSD: drm_encoder.c,v 1.2 2021/12/18 23:44:57 riastradh Exp $");
27
28 #include <linux/export.h>
29
30 #include <drm/drm_bridge.h>
31 #include <drm/drm_device.h>
32 #include <drm/drm_drv.h>
33 #include <drm/drm_encoder.h>
34
35 #include "drm_crtc_internal.h"
36
37 /**
38 * DOC: overview
39 *
40 * Encoders represent the connecting element between the CRTC (as the overall
41 * pixel pipeline, represented by &struct drm_crtc) and the connectors (as the
42 * generic sink entity, represented by &struct drm_connector). An encoder takes
43 * pixel data from a CRTC and converts it to a format suitable for any attached
44 * connector. Encoders are objects exposed to userspace, originally to allow
45 * userspace to infer cloning and connector/CRTC restrictions. Unfortunately
46 * almost all drivers get this wrong, making the uabi pretty much useless. On
47 * top of that the exposed restrictions are too simple for today's hardware, and
48 * the recommended way to infer restrictions is by using the
49 * DRM_MODE_ATOMIC_TEST_ONLY flag for the atomic IOCTL.
50 *
51 * Otherwise encoders aren't used in the uapi at all (any modeset request from
52 * userspace directly connects a connector with a CRTC), drivers are therefore
53 * free to use them however they wish. Modeset helper libraries make strong use
54 * of encoders to facilitate code sharing. But for more complex settings it is
55 * usually better to move shared code into a separate &drm_bridge. Compared to
56 * encoders, bridges also have the benefit of being purely an internal
57 * abstraction since they are not exposed to userspace at all.
58 *
59 * Encoders are initialized with drm_encoder_init() and cleaned up using
60 * drm_encoder_cleanup().
61 */
62 static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
63 { DRM_MODE_ENCODER_NONE, "None" },
64 { DRM_MODE_ENCODER_DAC, "DAC" },
65 { DRM_MODE_ENCODER_TMDS, "TMDS" },
66 { DRM_MODE_ENCODER_LVDS, "LVDS" },
67 { DRM_MODE_ENCODER_TVDAC, "TV" },
68 { DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
69 { DRM_MODE_ENCODER_DSI, "DSI" },
70 { DRM_MODE_ENCODER_DPMST, "DP MST" },
71 { DRM_MODE_ENCODER_DPI, "DPI" },
72 };
73
drm_encoder_register_all(struct drm_device * dev)74 int drm_encoder_register_all(struct drm_device *dev)
75 {
76 struct drm_encoder *encoder;
77 int ret = 0;
78
79 drm_for_each_encoder(encoder, dev) {
80 if (encoder->funcs->late_register)
81 ret = encoder->funcs->late_register(encoder);
82 if (ret)
83 return ret;
84 }
85
86 return 0;
87 }
88
drm_encoder_unregister_all(struct drm_device * dev)89 void drm_encoder_unregister_all(struct drm_device *dev)
90 {
91 struct drm_encoder *encoder;
92
93 drm_for_each_encoder(encoder, dev) {
94 if (encoder->funcs->early_unregister)
95 encoder->funcs->early_unregister(encoder);
96 }
97 }
98
99 /**
100 * drm_encoder_init - Init a preallocated encoder
101 * @dev: drm device
102 * @encoder: the encoder to init
103 * @funcs: callbacks for this encoder
104 * @encoder_type: user visible type of the encoder
105 * @name: printf style format string for the encoder name, or NULL for default name
106 *
107 * Initialises a preallocated encoder. Encoder should be subclassed as part of
108 * driver encoder objects. At driver unload time drm_encoder_cleanup() should be
109 * called from the driver's &drm_encoder_funcs.destroy hook.
110 *
111 * Returns:
112 * Zero on success, error code on failure.
113 */
drm_encoder_init(struct drm_device * dev,struct drm_encoder * encoder,const struct drm_encoder_funcs * funcs,int encoder_type,const char * name,...)114 int drm_encoder_init(struct drm_device *dev,
115 struct drm_encoder *encoder,
116 const struct drm_encoder_funcs *funcs,
117 int encoder_type, const char *name, ...)
118 {
119 int ret;
120
121 /* encoder index is used with 32bit bitmasks */
122 if (WARN_ON(dev->mode_config.num_encoder >= 32))
123 return -EINVAL;
124
125 ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
126 if (ret)
127 return ret;
128
129 encoder->dev = dev;
130 encoder->encoder_type = encoder_type;
131 encoder->funcs = funcs;
132 if (name) {
133 va_list ap;
134
135 va_start(ap, name);
136 encoder->name = kvasprintf(GFP_KERNEL, name, ap);
137 va_end(ap);
138 } else {
139 encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
140 drm_encoder_enum_list[encoder_type].name,
141 encoder->base.id);
142 }
143 if (!encoder->name) {
144 ret = -ENOMEM;
145 goto out_put;
146 }
147
148 INIT_LIST_HEAD(&encoder->bridge_chain);
149 list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
150 encoder->index = dev->mode_config.num_encoder++;
151
152 out_put:
153 if (ret)
154 drm_mode_object_unregister(dev, &encoder->base);
155
156 return ret;
157 }
158 EXPORT_SYMBOL(drm_encoder_init);
159
160 /**
161 * drm_encoder_cleanup - cleans up an initialised encoder
162 * @encoder: encoder to cleanup
163 *
164 * Cleans up the encoder but doesn't free the object.
165 */
drm_encoder_cleanup(struct drm_encoder * encoder)166 void drm_encoder_cleanup(struct drm_encoder *encoder)
167 {
168 struct drm_device *dev = encoder->dev;
169 struct drm_bridge *bridge, *next;
170
171 /* Note that the encoder_list is considered to be static; should we
172 * remove the drm_encoder at runtime we would have to decrement all
173 * the indices on the drm_encoder after us in the encoder_list.
174 */
175
176 list_for_each_entry_safe(bridge, next, &encoder->bridge_chain,
177 chain_node)
178 drm_bridge_detach(bridge);
179
180 drm_mode_object_unregister(dev, &encoder->base);
181 kfree(encoder->name);
182 list_del(&encoder->head);
183 dev->mode_config.num_encoder--;
184
185 memset(encoder, 0, sizeof(*encoder));
186 }
187 EXPORT_SYMBOL(drm_encoder_cleanup);
188
drm_encoder_get_crtc(struct drm_encoder * encoder)189 static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
190 {
191 struct drm_connector *connector;
192 struct drm_device *dev = encoder->dev;
193 bool uses_atomic = false;
194 struct drm_connector_list_iter conn_iter;
195
196 /* For atomic drivers only state objects are synchronously updated and
197 * protected by modeset locks, so check those first. */
198 drm_connector_list_iter_begin(dev, &conn_iter);
199 drm_for_each_connector_iter(connector, &conn_iter) {
200 if (!connector->state)
201 continue;
202
203 uses_atomic = true;
204
205 if (connector->state->best_encoder != encoder)
206 continue;
207
208 drm_connector_list_iter_end(&conn_iter);
209 return connector->state->crtc;
210 }
211 drm_connector_list_iter_end(&conn_iter);
212
213 /* Don't return stale data (e.g. pending async disable). */
214 if (uses_atomic)
215 return NULL;
216
217 return encoder->crtc;
218 }
219
drm_mode_getencoder(struct drm_device * dev,void * data,struct drm_file * file_priv)220 int drm_mode_getencoder(struct drm_device *dev, void *data,
221 struct drm_file *file_priv)
222 {
223 struct drm_mode_get_encoder *enc_resp = data;
224 struct drm_encoder *encoder;
225 struct drm_crtc *crtc;
226
227 if (!drm_core_check_feature(dev, DRIVER_MODESET))
228 return -EOPNOTSUPP;
229
230 encoder = drm_encoder_find(dev, file_priv, enc_resp->encoder_id);
231 if (!encoder)
232 return -ENOENT;
233
234 drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
235 crtc = drm_encoder_get_crtc(encoder);
236 if (crtc && drm_lease_held(file_priv, crtc->base.id))
237 enc_resp->crtc_id = crtc->base.id;
238 else
239 enc_resp->crtc_id = 0;
240 drm_modeset_unlock(&dev->mode_config.connection_mutex);
241
242 enc_resp->encoder_type = encoder->encoder_type;
243 enc_resp->encoder_id = encoder->base.id;
244 enc_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv,
245 encoder->possible_crtcs);
246 enc_resp->possible_clones = encoder->possible_clones;
247
248 return 0;
249 }
250