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,
104 									  crtc);
105 	bool has_primary = crtc_state->plane_mask &
106 			   drm_plane_mask(crtc->primary);
107 
108 	/* We always want to have an active plane with an active CRTC */
109 	if (has_primary != crtc_state->enable)
110 		return -EINVAL;
111 
112 	return drm_atomic_add_affected_planes(state, crtc);
113 }
114 
115 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
116 				       struct drm_atomic_state *state)
117 {
118 	struct drm_plane *plane;
119 	struct drm_simple_display_pipe *pipe;
120 
121 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
122 	if (!pipe->funcs || !pipe->funcs->enable)
123 		return;
124 
125 	plane = &pipe->plane;
126 	pipe->funcs->enable(pipe, crtc->state, plane->state);
127 }
128 
129 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
130 					struct drm_atomic_state *state)
131 {
132 	struct drm_simple_display_pipe *pipe;
133 
134 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
135 	if (!pipe->funcs || !pipe->funcs->disable)
136 		return;
137 
138 	pipe->funcs->disable(pipe);
139 }
140 
141 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
142 	.mode_valid = drm_simple_kms_crtc_mode_valid,
143 	.atomic_check = drm_simple_kms_crtc_check,
144 	.atomic_enable = drm_simple_kms_crtc_enable,
145 	.atomic_disable = drm_simple_kms_crtc_disable,
146 };
147 
148 static void drm_simple_kms_crtc_reset(struct drm_crtc *crtc)
149 {
150 	struct drm_simple_display_pipe *pipe;
151 
152 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
153 	if (!pipe->funcs || !pipe->funcs->reset_crtc)
154 		return drm_atomic_helper_crtc_reset(crtc);
155 
156 	return pipe->funcs->reset_crtc(pipe);
157 }
158 
159 static struct drm_crtc_state *drm_simple_kms_crtc_duplicate_state(struct drm_crtc *crtc)
160 {
161 	struct drm_simple_display_pipe *pipe;
162 
163 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
164 	if (!pipe->funcs || !pipe->funcs->duplicate_crtc_state)
165 		return drm_atomic_helper_crtc_duplicate_state(crtc);
166 
167 	return pipe->funcs->duplicate_crtc_state(pipe);
168 }
169 
170 static void drm_simple_kms_crtc_destroy_state(struct drm_crtc *crtc, struct drm_crtc_state *state)
171 {
172 	struct drm_simple_display_pipe *pipe;
173 
174 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
175 	if (!pipe->funcs || !pipe->funcs->destroy_crtc_state)
176 		drm_atomic_helper_crtc_destroy_state(crtc, state);
177 	else
178 		pipe->funcs->destroy_crtc_state(pipe, state);
179 }
180 
181 static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
182 {
183 	struct drm_simple_display_pipe *pipe;
184 
185 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
186 	if (!pipe->funcs || !pipe->funcs->enable_vblank)
187 		return 0;
188 
189 	return pipe->funcs->enable_vblank(pipe);
190 }
191 
192 static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
193 {
194 	struct drm_simple_display_pipe *pipe;
195 
196 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
197 	if (!pipe->funcs || !pipe->funcs->disable_vblank)
198 		return;
199 
200 	pipe->funcs->disable_vblank(pipe);
201 }
202 
203 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
204 	.reset = drm_simple_kms_crtc_reset,
205 	.destroy = drm_crtc_cleanup,
206 	.set_config = drm_atomic_helper_set_config,
207 	.page_flip = drm_atomic_helper_page_flip,
208 	.atomic_duplicate_state = drm_simple_kms_crtc_duplicate_state,
209 	.atomic_destroy_state = drm_simple_kms_crtc_destroy_state,
210 	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
211 	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
212 };
213 
214 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
215 					struct drm_atomic_state *state)
216 {
217 	struct drm_plane_state *plane_state = drm_atomic_get_new_plane_state(state,
218 									     plane);
219 	struct drm_simple_display_pipe *pipe;
220 	struct drm_crtc_state *crtc_state;
221 	int ret;
222 
223 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
224 	crtc_state = drm_atomic_get_new_crtc_state(state,
225 						   &pipe->crtc);
226 
227 	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
228 						  DRM_PLANE_HELPER_NO_SCALING,
229 						  DRM_PLANE_HELPER_NO_SCALING,
230 						  false, true);
231 	if (ret)
232 		return ret;
233 
234 	if (!plane_state->visible)
235 		return 0;
236 
237 	if (!pipe->funcs || !pipe->funcs->check)
238 		return 0;
239 
240 	return pipe->funcs->check(pipe, plane_state, crtc_state);
241 }
242 
243 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
244 					struct drm_atomic_state *state)
245 {
246 	struct drm_plane_state *old_pstate = drm_atomic_get_old_plane_state(state,
247 									    plane);
248 	struct drm_simple_display_pipe *pipe;
249 
250 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
251 	if (!pipe->funcs || !pipe->funcs->update)
252 		return;
253 
254 	pipe->funcs->update(pipe, old_pstate);
255 }
256 
257 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
258 					   struct drm_plane_state *state)
259 {
260 	struct drm_simple_display_pipe *pipe;
261 
262 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
263 	if (!pipe->funcs || !pipe->funcs->prepare_fb) {
264 		if (WARN_ON_ONCE(!drm_core_check_feature(plane->dev, DRIVER_GEM)))
265 			return 0;
266 
267 		WARN_ON_ONCE(pipe->funcs && pipe->funcs->cleanup_fb);
268 
269 		return drm_gem_simple_display_pipe_prepare_fb(pipe, state);
270 	}
271 
272 	return pipe->funcs->prepare_fb(pipe, state);
273 }
274 
275 static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
276 					    struct drm_plane_state *state)
277 {
278 	struct drm_simple_display_pipe *pipe;
279 
280 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
281 	if (!pipe->funcs || !pipe->funcs->cleanup_fb)
282 		return;
283 
284 	pipe->funcs->cleanup_fb(pipe, state);
285 }
286 
287 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
288 						uint32_t format,
289 						uint64_t modifier)
290 {
291 	return modifier == DRM_FORMAT_MOD_LINEAR;
292 }
293 
294 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
295 	.prepare_fb = drm_simple_kms_plane_prepare_fb,
296 	.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
297 	.atomic_check = drm_simple_kms_plane_atomic_check,
298 	.atomic_update = drm_simple_kms_plane_atomic_update,
299 };
300 
301 static void drm_simple_kms_plane_reset(struct drm_plane *plane)
302 {
303 	struct drm_simple_display_pipe *pipe;
304 
305 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
306 	if (!pipe->funcs || !pipe->funcs->reset_plane)
307 		return drm_atomic_helper_plane_reset(plane);
308 
309 	return pipe->funcs->reset_plane(pipe);
310 }
311 
312 static struct drm_plane_state *drm_simple_kms_plane_duplicate_state(struct drm_plane *plane)
313 {
314 	struct drm_simple_display_pipe *pipe;
315 
316 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
317 	if (!pipe->funcs || !pipe->funcs->duplicate_plane_state)
318 		return drm_atomic_helper_plane_duplicate_state(plane);
319 
320 	return pipe->funcs->duplicate_plane_state(pipe);
321 }
322 
323 static void drm_simple_kms_plane_destroy_state(struct drm_plane *plane,
324 					       struct drm_plane_state *state)
325 {
326 	struct drm_simple_display_pipe *pipe;
327 
328 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
329 	if (!pipe->funcs || !pipe->funcs->destroy_plane_state)
330 		drm_atomic_helper_plane_destroy_state(plane, state);
331 	else
332 		pipe->funcs->destroy_plane_state(pipe, state);
333 }
334 
335 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
336 	.update_plane		= drm_atomic_helper_update_plane,
337 	.disable_plane		= drm_atomic_helper_disable_plane,
338 	.destroy		= drm_plane_cleanup,
339 	.reset			= drm_simple_kms_plane_reset,
340 	.atomic_duplicate_state	= drm_simple_kms_plane_duplicate_state,
341 	.atomic_destroy_state	= drm_simple_kms_plane_destroy_state,
342 	.format_mod_supported   = drm_simple_kms_format_mod_supported,
343 };
344 
345 /**
346  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
347  * @pipe: simple display pipe object
348  * @bridge: bridge to attach
349  *
350  * Makes it possible to still use the drm_simple_display_pipe helpers when
351  * a DRM bridge has to be used.
352  *
353  * Note that you probably want to initialize the pipe by passing a NULL
354  * connector to drm_simple_display_pipe_init().
355  *
356  * Returns:
357  * Zero on success, negative error code on failure.
358  */
359 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
360 					  struct drm_bridge *bridge)
361 {
362 	return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
363 }
364 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
365 
366 /**
367  * drm_simple_display_pipe_init - Initialize a simple display pipeline
368  * @dev: DRM device
369  * @pipe: simple display pipe object to initialize
370  * @funcs: callbacks for the display pipe (optional)
371  * @formats: array of supported formats (DRM_FORMAT\_\*)
372  * @format_count: number of elements in @formats
373  * @format_modifiers: array of formats modifiers
374  * @connector: connector to attach and register (optional)
375  *
376  * Sets up a display pipeline which consist of a really simple
377  * plane-crtc-encoder pipe.
378  *
379  * If a connector is supplied, the pipe will be coupled with the provided
380  * connector. You may supply a NULL connector when using drm bridges, that
381  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
382  *
383  * Teardown of a simple display pipe is all handled automatically by the drm
384  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
385  * release the memory for the structure themselves.
386  *
387  * Returns:
388  * Zero on success, negative error code on failure.
389  */
390 int drm_simple_display_pipe_init(struct drm_device *dev,
391 			struct drm_simple_display_pipe *pipe,
392 			const struct drm_simple_display_pipe_funcs *funcs,
393 			const uint32_t *formats, unsigned int format_count,
394 			const uint64_t *format_modifiers,
395 			struct drm_connector *connector)
396 {
397 	struct drm_encoder *encoder = &pipe->encoder;
398 	struct drm_plane *plane = &pipe->plane;
399 	struct drm_crtc *crtc = &pipe->crtc;
400 	int ret;
401 
402 	pipe->connector = connector;
403 	pipe->funcs = funcs;
404 
405 	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
406 	ret = drm_universal_plane_init(dev, plane, 0,
407 				       &drm_simple_kms_plane_funcs,
408 				       formats, format_count,
409 				       format_modifiers,
410 				       DRM_PLANE_TYPE_PRIMARY, NULL);
411 	if (ret)
412 		return ret;
413 
414 	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
415 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
416 					&drm_simple_kms_crtc_funcs, NULL);
417 	if (ret)
418 		return ret;
419 
420 	encoder->possible_crtcs = drm_crtc_mask(crtc);
421 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
422 	if (ret || !connector)
423 		return ret;
424 
425 	return drm_connector_attach_encoder(connector, encoder);
426 }
427 EXPORT_SYMBOL(drm_simple_display_pipe_init);
428 
429 MODULE_LICENSE("GPL");
430