1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016 Noralf Trønnes
4  */
5 
6 #include <linux/module.h>
7 #include <linux/slab.h>
8 
9 #include <drm/drm_atomic.h>
10 #include <drm/drm_atomic_helper.h>
11 #include <drm/drm_bridge.h>
12 #include <drm/drm_drv.h>
13 #include <drm/drm_gem_atomic_helper.h>
14 #include <drm/drm_managed.h>
15 #include <drm/drm_plane_helper.h>
16 #include <drm/drm_probe_helper.h>
17 #include <drm/drm_simple_kms_helper.h>
18 
19 /**
20  * DOC: overview
21  *
22  * This helper library provides helpers for drivers for simple display
23  * hardware.
24  *
25  * drm_simple_display_pipe_init() initializes a simple display pipeline
26  * which has only one full-screen scanout buffer feeding one output. The
27  * pipeline is represented by &struct drm_simple_display_pipe and binds
28  * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
29  * entity. Some flexibility for code reuse is provided through a separately
30  * allocated &drm_connector object and supporting optional &drm_bridge
31  * encoder drivers.
32  *
33  * Many drivers require only a very simple encoder that fulfills the minimum
34  * requirements of the display pipeline and does not add additional
35  * functionality. The function drm_simple_encoder_init() provides an
36  * implementation of such an encoder.
37  */
38 
39 static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
40 	.destroy = drm_encoder_cleanup,
41 };
42 
43 /**
44  * drm_simple_encoder_init - Initialize a preallocated encoder with
45  *                           basic functionality.
46  * @dev: drm device
47  * @encoder: the encoder to initialize
48  * @encoder_type: user visible type of the encoder
49  *
50  * Initialises a preallocated encoder that has no further functionality.
51  * Settings for possible CRTC and clones are left to their initial values.
52  * The encoder will be cleaned up automatically as part of the mode-setting
53  * cleanup.
54  *
55  * The caller of drm_simple_encoder_init() is responsible for freeing
56  * the encoder's memory after the encoder has been cleaned up. At the
57  * moment this only works reliably if the encoder data structure is
58  * stored in the device structure. Free the encoder's memory as part of
59  * the device release function.
60  *
61  * Note: consider using drmm_simple_encoder_alloc() instead of
62  * drm_simple_encoder_init() to let the DRM managed resource infrastructure
63  * take care of cleanup and deallocation.
64  *
65  * Returns:
66  * Zero on success, error code on failure.
67  */
68 int drm_simple_encoder_init(struct drm_device *dev,
69 			    struct drm_encoder *encoder,
70 			    int encoder_type)
71 {
72 	return drm_encoder_init(dev, encoder,
73 				&drm_simple_encoder_funcs_cleanup,
74 				encoder_type, NULL);
75 }
76 EXPORT_SYMBOL(drm_simple_encoder_init);
77 
78 void *__drmm_simple_encoder_alloc(struct drm_device *dev, size_t size,
79 				  size_t offset, int encoder_type)
80 {
81 	return __drmm_encoder_alloc(dev, size, offset, NULL, encoder_type,
82 				    NULL);
83 }
84 EXPORT_SYMBOL(__drmm_simple_encoder_alloc);
85 
86 static enum drm_mode_status
87 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
88 			       const struct drm_display_mode *mode)
89 {
90 	struct drm_simple_display_pipe *pipe;
91 
92 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
93 	if (!pipe->funcs || !pipe->funcs->mode_valid)
94 		/* Anything goes */
95 		return MODE_OK;
96 
97 	return pipe->funcs->mode_valid(pipe, mode);
98 }
99 
100 static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
101 				     struct drm_atomic_state *state)
102 {
103 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
104 	int ret;
105 
106 	ret = drm_atomic_helper_check_crtc_state(crtc_state, false);
107 	if (ret)
108 		return ret;
109 
110 	return drm_atomic_add_affected_planes(state, crtc);
111 }
112 
113 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
114 				       struct drm_atomic_state *state)
115 {
116 	struct drm_plane *plane;
117 	struct drm_simple_display_pipe *pipe;
118 
119 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
120 	if (!pipe->funcs || !pipe->funcs->enable)
121 		return;
122 
123 	plane = &pipe->plane;
124 	pipe->funcs->enable(pipe, crtc->state, plane->state);
125 }
126 
127 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
128 					struct drm_atomic_state *state)
129 {
130 	struct drm_simple_display_pipe *pipe;
131 
132 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
133 	if (!pipe->funcs || !pipe->funcs->disable)
134 		return;
135 
136 	pipe->funcs->disable(pipe);
137 }
138 
139 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
140 	.mode_valid = drm_simple_kms_crtc_mode_valid,
141 	.atomic_check = drm_simple_kms_crtc_check,
142 	.atomic_enable = drm_simple_kms_crtc_enable,
143 	.atomic_disable = drm_simple_kms_crtc_disable,
144 };
145 
146 static void drm_simple_kms_crtc_reset(struct drm_crtc *crtc)
147 {
148 	struct drm_simple_display_pipe *pipe;
149 
150 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
151 	if (!pipe->funcs || !pipe->funcs->reset_crtc)
152 		return drm_atomic_helper_crtc_reset(crtc);
153 
154 	return pipe->funcs->reset_crtc(pipe);
155 }
156 
157 static struct drm_crtc_state *drm_simple_kms_crtc_duplicate_state(struct drm_crtc *crtc)
158 {
159 	struct drm_simple_display_pipe *pipe;
160 
161 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
162 	if (!pipe->funcs || !pipe->funcs->duplicate_crtc_state)
163 		return drm_atomic_helper_crtc_duplicate_state(crtc);
164 
165 	return pipe->funcs->duplicate_crtc_state(pipe);
166 }
167 
168 static void drm_simple_kms_crtc_destroy_state(struct drm_crtc *crtc, struct drm_crtc_state *state)
169 {
170 	struct drm_simple_display_pipe *pipe;
171 
172 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
173 	if (!pipe->funcs || !pipe->funcs->destroy_crtc_state)
174 		drm_atomic_helper_crtc_destroy_state(crtc, state);
175 	else
176 		pipe->funcs->destroy_crtc_state(pipe, state);
177 }
178 
179 static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
180 {
181 	struct drm_simple_display_pipe *pipe;
182 
183 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
184 	if (!pipe->funcs || !pipe->funcs->enable_vblank)
185 		return 0;
186 
187 	return pipe->funcs->enable_vblank(pipe);
188 }
189 
190 static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
191 {
192 	struct drm_simple_display_pipe *pipe;
193 
194 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
195 	if (!pipe->funcs || !pipe->funcs->disable_vblank)
196 		return;
197 
198 	pipe->funcs->disable_vblank(pipe);
199 }
200 
201 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
202 	.reset = drm_simple_kms_crtc_reset,
203 	.destroy = drm_crtc_cleanup,
204 	.set_config = drm_atomic_helper_set_config,
205 	.page_flip = drm_atomic_helper_page_flip,
206 	.atomic_duplicate_state = drm_simple_kms_crtc_duplicate_state,
207 	.atomic_destroy_state = drm_simple_kms_crtc_destroy_state,
208 	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
209 	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
210 };
211 
212 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
213 					struct drm_atomic_state *state)
214 {
215 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state,
216 									     plane);
217 	struct drm_simple_display_pipe *pipe;
218 	struct drm_crtc_state *crtc_state;
219 	int ret;
220 
221 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
222 	crtc_state = drm_atomic_get_new_crtc_state(state,
223 						   &pipe->crtc);
224 
225 	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
226 						  DRM_PLANE_HELPER_NO_SCALING,
227 						  DRM_PLANE_HELPER_NO_SCALING,
228 						  false, false);
229 	if (ret)
230 		return ret;
231 
232 	if (!plane_state->visible)
233 		return 0;
234 
235 	if (!pipe->funcs || !pipe->funcs->check)
236 		return 0;
237 
238 	return pipe->funcs->check(pipe, plane_state, crtc_state);
239 }
240 
241 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
242 					struct drm_atomic_state *state)
243 {
244 	struct drm_plane_state *old_pstate = drm_atomic_get_old_plane_state(state,
245 									    plane);
246 	struct drm_simple_display_pipe *pipe;
247 
248 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
249 	if (!pipe->funcs || !pipe->funcs->update)
250 		return;
251 
252 	pipe->funcs->update(pipe, old_pstate);
253 }
254 
255 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
256 					   struct drm_plane_state *state)
257 {
258 	struct drm_simple_display_pipe *pipe;
259 
260 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
261 	if (!pipe->funcs || !pipe->funcs->prepare_fb) {
262 		if (WARN_ON_ONCE(!drm_core_check_feature(plane->dev, DRIVER_GEM)))
263 			return 0;
264 
265 		WARN_ON_ONCE(pipe->funcs && pipe->funcs->cleanup_fb);
266 
267 		return drm_gem_simple_display_pipe_prepare_fb(pipe, state);
268 	}
269 
270 	return pipe->funcs->prepare_fb(pipe, state);
271 }
272 
273 static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
274 					    struct drm_plane_state *state)
275 {
276 	struct drm_simple_display_pipe *pipe;
277 
278 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
279 	if (!pipe->funcs || !pipe->funcs->cleanup_fb)
280 		return;
281 
282 	pipe->funcs->cleanup_fb(pipe, state);
283 }
284 
285 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
286 						uint32_t format,
287 						uint64_t modifier)
288 {
289 	return modifier == DRM_FORMAT_MOD_LINEAR;
290 }
291 
292 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
293 	.prepare_fb = drm_simple_kms_plane_prepare_fb,
294 	.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
295 	.atomic_check = drm_simple_kms_plane_atomic_check,
296 	.atomic_update = drm_simple_kms_plane_atomic_update,
297 };
298 
299 static void drm_simple_kms_plane_reset(struct drm_plane *plane)
300 {
301 	struct drm_simple_display_pipe *pipe;
302 
303 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
304 	if (!pipe->funcs || !pipe->funcs->reset_plane)
305 		return drm_atomic_helper_plane_reset(plane);
306 
307 	return pipe->funcs->reset_plane(pipe);
308 }
309 
310 static struct drm_plane_state *drm_simple_kms_plane_duplicate_state(struct drm_plane *plane)
311 {
312 	struct drm_simple_display_pipe *pipe;
313 
314 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
315 	if (!pipe->funcs || !pipe->funcs->duplicate_plane_state)
316 		return drm_atomic_helper_plane_duplicate_state(plane);
317 
318 	return pipe->funcs->duplicate_plane_state(pipe);
319 }
320 
321 static void drm_simple_kms_plane_destroy_state(struct drm_plane *plane,
322 					       struct drm_plane_state *state)
323 {
324 	struct drm_simple_display_pipe *pipe;
325 
326 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
327 	if (!pipe->funcs || !pipe->funcs->destroy_plane_state)
328 		drm_atomic_helper_plane_destroy_state(plane, state);
329 	else
330 		pipe->funcs->destroy_plane_state(pipe, state);
331 }
332 
333 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
334 	.update_plane		= drm_atomic_helper_update_plane,
335 	.disable_plane		= drm_atomic_helper_disable_plane,
336 	.destroy		= drm_plane_cleanup,
337 	.reset			= drm_simple_kms_plane_reset,
338 	.atomic_duplicate_state	= drm_simple_kms_plane_duplicate_state,
339 	.atomic_destroy_state	= drm_simple_kms_plane_destroy_state,
340 	.format_mod_supported   = drm_simple_kms_format_mod_supported,
341 };
342 
343 /**
344  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
345  * @pipe: simple display pipe object
346  * @bridge: bridge to attach
347  *
348  * Makes it possible to still use the drm_simple_display_pipe helpers when
349  * a DRM bridge has to be used.
350  *
351  * Note that you probably want to initialize the pipe by passing a NULL
352  * connector to drm_simple_display_pipe_init().
353  *
354  * Returns:
355  * Zero on success, negative error code on failure.
356  */
357 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
358 					  struct drm_bridge *bridge)
359 {
360 	return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
361 }
362 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
363 
364 /**
365  * drm_simple_display_pipe_init - Initialize a simple display pipeline
366  * @dev: DRM device
367  * @pipe: simple display pipe object to initialize
368  * @funcs: callbacks for the display pipe (optional)
369  * @formats: array of supported formats (DRM_FORMAT\_\*)
370  * @format_count: number of elements in @formats
371  * @format_modifiers: array of formats modifiers
372  * @connector: connector to attach and register (optional)
373  *
374  * Sets up a display pipeline which consist of a really simple
375  * plane-crtc-encoder pipe.
376  *
377  * If a connector is supplied, the pipe will be coupled with the provided
378  * connector. You may supply a NULL connector when using drm bridges, that
379  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
380  *
381  * Teardown of a simple display pipe is all handled automatically by the drm
382  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
383  * release the memory for the structure themselves.
384  *
385  * Returns:
386  * Zero on success, negative error code on failure.
387  */
388 int drm_simple_display_pipe_init(struct drm_device *dev,
389 			struct drm_simple_display_pipe *pipe,
390 			const struct drm_simple_display_pipe_funcs *funcs,
391 			const uint32_t *formats, unsigned int format_count,
392 			const uint64_t *format_modifiers,
393 			struct drm_connector *connector)
394 {
395 	struct drm_encoder *encoder = &pipe->encoder;
396 	struct drm_plane *plane = &pipe->plane;
397 	struct drm_crtc *crtc = &pipe->crtc;
398 	int ret;
399 
400 	pipe->connector = connector;
401 	pipe->funcs = funcs;
402 
403 	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
404 	ret = drm_universal_plane_init(dev, plane, 0,
405 				       &drm_simple_kms_plane_funcs,
406 				       formats, format_count,
407 				       format_modifiers,
408 				       DRM_PLANE_TYPE_PRIMARY, NULL);
409 	if (ret)
410 		return ret;
411 
412 	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
413 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
414 					&drm_simple_kms_crtc_funcs, NULL);
415 	if (ret)
416 		return ret;
417 
418 	encoder->possible_crtcs = drm_crtc_mask(crtc);
419 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
420 	if (ret || !connector)
421 		return ret;
422 
423 	return drm_connector_attach_encoder(connector, encoder);
424 }
425 EXPORT_SYMBOL(drm_simple_display_pipe_init);
426 
427 MODULE_LICENSE("GPL");
428