xref: /linux/drivers/gpu/drm/drm_encoder.c (revision 8e07e0e3964ca4e23ce7b68e2096fe660a888942)
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 #include <drm/drm_managed.h>
30 #include <drm/drm_print.h>
31 
32 #include "drm_crtc_internal.h"
33 
34 /**
35  * DOC: overview
36  *
37  * Encoders represent the connecting element between the CRTC (as the overall
38  * pixel pipeline, represented by &struct drm_crtc) and the connectors (as the
39  * generic sink entity, represented by &struct drm_connector). An encoder takes
40  * pixel data from a CRTC and converts it to a format suitable for any attached
41  * connector. Encoders are objects exposed to userspace, originally to allow
42  * userspace to infer cloning and connector/CRTC restrictions. Unfortunately
43  * almost all drivers get this wrong, making the uabi pretty much useless. On
44  * top of that the exposed restrictions are too simple for today's hardware, and
45  * the recommended way to infer restrictions is by using the
46  * DRM_MODE_ATOMIC_TEST_ONLY flag for the atomic IOCTL.
47  *
48  * Otherwise encoders aren't used in the uapi at all (any modeset request from
49  * userspace directly connects a connector with a CRTC), drivers are therefore
50  * free to use them however they wish. Modeset helper libraries make strong use
51  * of encoders to facilitate code sharing. But for more complex settings it is
52  * usually better to move shared code into a separate &drm_bridge. Compared to
53  * encoders, bridges also have the benefit of being purely an internal
54  * abstraction since they are not exposed to userspace at all.
55  *
56  * Encoders are initialized with drm_encoder_init() and cleaned up using
57  * drm_encoder_cleanup().
58  */
59 static const struct drm_prop_enum_list drm_encoder_enum_list[] = {
60 	{ DRM_MODE_ENCODER_NONE, "None" },
61 	{ DRM_MODE_ENCODER_DAC, "DAC" },
62 	{ DRM_MODE_ENCODER_TMDS, "TMDS" },
63 	{ DRM_MODE_ENCODER_LVDS, "LVDS" },
64 	{ DRM_MODE_ENCODER_TVDAC, "TV" },
65 	{ DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
66 	{ DRM_MODE_ENCODER_DSI, "DSI" },
67 	{ DRM_MODE_ENCODER_DPMST, "DP MST" },
68 	{ DRM_MODE_ENCODER_DPI, "DPI" },
69 };
70 
71 int drm_encoder_register_all(struct drm_device *dev)
72 {
73 	struct drm_encoder *encoder;
74 	int ret = 0;
75 
76 	drm_for_each_encoder(encoder, dev) {
77 		if (encoder->funcs && encoder->funcs->late_register)
78 			ret = encoder->funcs->late_register(encoder);
79 		if (ret)
80 			return ret;
81 	}
82 
83 	return 0;
84 }
85 
86 void drm_encoder_unregister_all(struct drm_device *dev)
87 {
88 	struct drm_encoder *encoder;
89 
90 	drm_for_each_encoder(encoder, dev) {
91 		if (encoder->funcs && encoder->funcs->early_unregister)
92 			encoder->funcs->early_unregister(encoder);
93 	}
94 }
95 
96 __printf(5, 0)
97 static int __drm_encoder_init(struct drm_device *dev,
98 			      struct drm_encoder *encoder,
99 			      const struct drm_encoder_funcs *funcs,
100 			      int encoder_type, const char *name, va_list ap)
101 {
102 	int ret;
103 
104 	/* encoder index is used with 32bit bitmasks */
105 	if (WARN_ON(dev->mode_config.num_encoder >= 32))
106 		return -EINVAL;
107 
108 	ret = drm_mode_object_add(dev, &encoder->base, DRM_MODE_OBJECT_ENCODER);
109 	if (ret)
110 		return ret;
111 
112 	encoder->dev = dev;
113 	encoder->encoder_type = encoder_type;
114 	encoder->funcs = funcs;
115 	if (name) {
116 		encoder->name = kvasprintf(GFP_KERNEL, name, ap);
117 	} else {
118 		encoder->name = kasprintf(GFP_KERNEL, "%s-%d",
119 					  drm_encoder_enum_list[encoder_type].name,
120 					  encoder->base.id);
121 	}
122 	if (!encoder->name) {
123 		ret = -ENOMEM;
124 		goto out_put;
125 	}
126 
127 	INIT_LIST_HEAD(&encoder->bridge_chain);
128 	list_add_tail(&encoder->head, &dev->mode_config.encoder_list);
129 	encoder->index = dev->mode_config.num_encoder++;
130 
131 out_put:
132 	if (ret)
133 		drm_mode_object_unregister(dev, &encoder->base);
134 
135 	return ret;
136 }
137 
138 /**
139  * drm_encoder_init - Init a preallocated encoder
140  * @dev: drm device
141  * @encoder: the encoder to init
142  * @funcs: callbacks for this encoder
143  * @encoder_type: user visible type of the encoder
144  * @name: printf style format string for the encoder name, or NULL for default name
145  *
146  * Initializes a preallocated encoder. Encoder should be subclassed as part of
147  * driver encoder objects. At driver unload time the driver's
148  * &drm_encoder_funcs.destroy hook should call drm_encoder_cleanup() and kfree()
149  * the encoder structure. The encoder structure should not be allocated with
150  * devm_kzalloc().
151  *
152  * Note: consider using drmm_encoder_alloc() or drmm_encoder_init()
153  * instead of drm_encoder_init() to let the DRM managed resource
154  * infrastructure take care of cleanup and deallocation.
155  *
156  * Returns:
157  * Zero on success, error code on failure.
158  */
159 int drm_encoder_init(struct drm_device *dev,
160 		     struct drm_encoder *encoder,
161 		     const struct drm_encoder_funcs *funcs,
162 		     int encoder_type, const char *name, ...)
163 {
164 	va_list ap;
165 	int ret;
166 
167 	WARN_ON(!funcs->destroy);
168 
169 	va_start(ap, name);
170 	ret = __drm_encoder_init(dev, encoder, funcs, encoder_type, name, ap);
171 	va_end(ap);
172 
173 	return ret;
174 }
175 EXPORT_SYMBOL(drm_encoder_init);
176 
177 /**
178  * drm_encoder_cleanup - cleans up an initialised encoder
179  * @encoder: encoder to cleanup
180  *
181  * Cleans up the encoder but doesn't free the object.
182  */
183 void drm_encoder_cleanup(struct drm_encoder *encoder)
184 {
185 	struct drm_device *dev = encoder->dev;
186 	struct drm_bridge *bridge, *next;
187 
188 	/* Note that the encoder_list is considered to be static; should we
189 	 * remove the drm_encoder at runtime we would have to decrement all
190 	 * the indices on the drm_encoder after us in the encoder_list.
191 	 */
192 
193 	list_for_each_entry_safe(bridge, next, &encoder->bridge_chain,
194 				 chain_node)
195 		drm_bridge_detach(bridge);
196 
197 	drm_mode_object_unregister(dev, &encoder->base);
198 	kfree(encoder->name);
199 	list_del(&encoder->head);
200 	dev->mode_config.num_encoder--;
201 
202 	memset(encoder, 0, sizeof(*encoder));
203 }
204 EXPORT_SYMBOL(drm_encoder_cleanup);
205 
206 static void drmm_encoder_alloc_release(struct drm_device *dev, void *ptr)
207 {
208 	struct drm_encoder *encoder = ptr;
209 
210 	if (WARN_ON(!encoder->dev))
211 		return;
212 
213 	drm_encoder_cleanup(encoder);
214 }
215 
216 __printf(5, 0)
217 static int __drmm_encoder_init(struct drm_device *dev,
218 			       struct drm_encoder *encoder,
219 			       const struct drm_encoder_funcs *funcs,
220 			       int encoder_type,
221 			       const char *name,
222 			       va_list args)
223 {
224 	int ret;
225 
226 	if (drm_WARN_ON(dev, funcs && funcs->destroy))
227 		return -EINVAL;
228 
229 	ret = __drm_encoder_init(dev, encoder, funcs, encoder_type, name, args);
230 	if (ret)
231 		return ret;
232 
233 	ret = drmm_add_action_or_reset(dev, drmm_encoder_alloc_release, encoder);
234 	if (ret)
235 		return ret;
236 
237 	return 0;
238 }
239 
240 void *__drmm_encoder_alloc(struct drm_device *dev, size_t size, size_t offset,
241 			   const struct drm_encoder_funcs *funcs,
242 			   int encoder_type, const char *name, ...)
243 {
244 	void *container;
245 	struct drm_encoder *encoder;
246 	va_list ap;
247 	int ret;
248 
249 	container = drmm_kzalloc(dev, size, GFP_KERNEL);
250 	if (!container)
251 		return ERR_PTR(-ENOMEM);
252 
253 	encoder = container + offset;
254 
255 	va_start(ap, name);
256 	ret = __drmm_encoder_init(dev, encoder, funcs, encoder_type, name, ap);
257 	va_end(ap);
258 	if (ret)
259 		return ERR_PTR(ret);
260 
261 	return container;
262 }
263 EXPORT_SYMBOL(__drmm_encoder_alloc);
264 
265 /**
266  * drmm_encoder_init - Initialize a preallocated encoder
267  * @dev: drm device
268  * @encoder: the encoder to init
269  * @funcs: callbacks for this encoder (optional)
270  * @encoder_type: user visible type of the encoder
271  * @name: printf style format string for the encoder name, or NULL for default name
272  *
273  * Initializes a preallocated encoder. Encoder should be subclassed as
274  * part of driver encoder objects. Cleanup is automatically handled
275  * through registering drm_encoder_cleanup() with drmm_add_action(). The
276  * encoder structure should be allocated with drmm_kzalloc().
277  *
278  * The @drm_encoder_funcs.destroy hook must be NULL.
279  *
280  * Returns:
281  * Zero on success, error code on failure.
282  */
283 int drmm_encoder_init(struct drm_device *dev, struct drm_encoder *encoder,
284 		      const struct drm_encoder_funcs *funcs,
285 		      int encoder_type, const char *name, ...)
286 {
287 	va_list ap;
288 	int ret;
289 
290 	va_start(ap, name);
291 	ret = __drmm_encoder_init(dev, encoder, funcs, encoder_type, name, ap);
292 	va_end(ap);
293 	if (ret)
294 		return ret;
295 
296 	return 0;
297 }
298 EXPORT_SYMBOL(drmm_encoder_init);
299 
300 static struct drm_crtc *drm_encoder_get_crtc(struct drm_encoder *encoder)
301 {
302 	struct drm_connector *connector;
303 	struct drm_device *dev = encoder->dev;
304 	bool uses_atomic = false;
305 	struct drm_connector_list_iter conn_iter;
306 
307 	/* For atomic drivers only state objects are synchronously updated and
308 	 * protected by modeset locks, so check those first. */
309 	drm_connector_list_iter_begin(dev, &conn_iter);
310 	drm_for_each_connector_iter(connector, &conn_iter) {
311 		if (!connector->state)
312 			continue;
313 
314 		uses_atomic = true;
315 
316 		if (connector->state->best_encoder != encoder)
317 			continue;
318 
319 		drm_connector_list_iter_end(&conn_iter);
320 		return connector->state->crtc;
321 	}
322 	drm_connector_list_iter_end(&conn_iter);
323 
324 	/* Don't return stale data (e.g. pending async disable). */
325 	if (uses_atomic)
326 		return NULL;
327 
328 	return encoder->crtc;
329 }
330 
331 int drm_mode_getencoder(struct drm_device *dev, void *data,
332 			struct drm_file *file_priv)
333 {
334 	struct drm_mode_get_encoder *enc_resp = data;
335 	struct drm_encoder *encoder;
336 	struct drm_crtc *crtc;
337 
338 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
339 		return -EOPNOTSUPP;
340 
341 	encoder = drm_encoder_find(dev, file_priv, enc_resp->encoder_id);
342 	if (!encoder)
343 		return -ENOENT;
344 
345 	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
346 	crtc = drm_encoder_get_crtc(encoder);
347 	if (crtc && drm_lease_held(file_priv, crtc->base.id))
348 		enc_resp->crtc_id = crtc->base.id;
349 	else
350 		enc_resp->crtc_id = 0;
351 	drm_modeset_unlock(&dev->mode_config.connection_mutex);
352 
353 	enc_resp->encoder_type = encoder->encoder_type;
354 	enc_resp->encoder_id = encoder->base.id;
355 	enc_resp->possible_crtcs = drm_lease_filter_crtcs(file_priv,
356 							  encoder->possible_crtcs);
357 	enc_resp->possible_clones = encoder->possible_clones;
358 
359 	return 0;
360 }
361