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