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_managed.h>
13 #include <drm/drm_plane_helper.h>
14 #include <drm/drm_probe_helper.h>
15 #include <drm/drm_simple_kms_helper.h>
16 
17 /**
18  * DOC: overview
19  *
20  * This helper library provides helpers for drivers for simple display
21  * hardware.
22  *
23  * drm_simple_display_pipe_init() initializes a simple display pipeline
24  * which has only one full-screen scanout buffer feeding one output. The
25  * pipeline is represented by &struct drm_simple_display_pipe and binds
26  * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
27  * entity. Some flexibility for code reuse is provided through a separately
28  * allocated &drm_connector object and supporting optional &drm_bridge
29  * encoder drivers.
30  *
31  * Many drivers require only a very simple encoder that fulfills the minimum
32  * requirements of the display pipeline and does not add additional
33  * functionality. The function drm_simple_encoder_init() provides an
34  * implementation of such an encoder.
35  */
36 
37 static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
38 	.destroy = drm_encoder_cleanup,
39 };
40 
41 /**
42  * drm_simple_encoder_init - Initialize a preallocated encoder with
43  *                           basic functionality.
44  * @dev: drm device
45  * @encoder: the encoder to initialize
46  * @encoder_type: user visible type of the encoder
47  *
48  * Initialises a preallocated encoder that has no further functionality.
49  * Settings for possible CRTC and clones are left to their initial values.
50  * The encoder will be cleaned up automatically as part of the mode-setting
51  * cleanup.
52  *
53  * The caller of drm_simple_encoder_init() is responsible for freeing
54  * the encoder's memory after the encoder has been cleaned up. At the
55  * moment this only works reliably if the encoder data structure is
56  * stored in the device structure. Free the encoder's memory as part of
57  * the device release function.
58  *
59  * Note: consider using drmm_simple_encoder_alloc() instead of
60  * drm_simple_encoder_init() to let the DRM managed resource infrastructure
61  * take care of cleanup and deallocation.
62  *
63  * Returns:
64  * Zero on success, error code on failure.
65  */
66 int drm_simple_encoder_init(struct drm_device *dev,
67 			    struct drm_encoder *encoder,
68 			    int encoder_type)
69 {
70 	return drm_encoder_init(dev, encoder,
71 				&drm_simple_encoder_funcs_cleanup,
72 				encoder_type, NULL);
73 }
74 EXPORT_SYMBOL(drm_simple_encoder_init);
75 
76 void *__drmm_simple_encoder_alloc(struct drm_device *dev, size_t size,
77 				  size_t offset, int encoder_type)
78 {
79 	return __drmm_encoder_alloc(dev, size, offset, NULL, encoder_type,
80 				    NULL);
81 }
82 EXPORT_SYMBOL(__drmm_simple_encoder_alloc);
83 
84 static enum drm_mode_status
85 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
86 			       const struct drm_display_mode *mode)
87 {
88 	struct drm_simple_display_pipe *pipe;
89 
90 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
91 	if (!pipe->funcs || !pipe->funcs->mode_valid)
92 		/* Anything goes */
93 		return MODE_OK;
94 
95 	return pipe->funcs->mode_valid(pipe, mode);
96 }
97 
98 static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
99 				     struct drm_atomic_state *state)
100 {
101 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
102 									  crtc);
103 	bool has_primary = crtc_state->plane_mask &
104 			   drm_plane_mask(crtc->primary);
105 
106 	/* We always want to have an active plane with an active CRTC */
107 	if (has_primary != crtc_state->enable)
108 		return -EINVAL;
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 int drm_simple_kms_crtc_enable_vblank(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->enable_vblank)
152 		return 0;
153 
154 	return pipe->funcs->enable_vblank(pipe);
155 }
156 
157 static void drm_simple_kms_crtc_disable_vblank(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->disable_vblank)
163 		return;
164 
165 	pipe->funcs->disable_vblank(pipe);
166 }
167 
168 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
169 	.reset = drm_atomic_helper_crtc_reset,
170 	.destroy = drm_crtc_cleanup,
171 	.set_config = drm_atomic_helper_set_config,
172 	.page_flip = drm_atomic_helper_page_flip,
173 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
174 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
175 	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
176 	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
177 };
178 
179 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
180 					struct drm_plane_state *plane_state)
181 {
182 	struct drm_simple_display_pipe *pipe;
183 	struct drm_crtc_state *crtc_state;
184 	int ret;
185 
186 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
187 	crtc_state = drm_atomic_get_new_crtc_state(plane_state->state,
188 						   &pipe->crtc);
189 
190 	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
191 						  DRM_PLANE_HELPER_NO_SCALING,
192 						  DRM_PLANE_HELPER_NO_SCALING,
193 						  false, true);
194 	if (ret)
195 		return ret;
196 
197 	if (!plane_state->visible)
198 		return 0;
199 
200 	if (!pipe->funcs || !pipe->funcs->check)
201 		return 0;
202 
203 	return pipe->funcs->check(pipe, plane_state, crtc_state);
204 }
205 
206 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
207 					struct drm_plane_state *old_pstate)
208 {
209 	struct drm_simple_display_pipe *pipe;
210 
211 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
212 	if (!pipe->funcs || !pipe->funcs->update)
213 		return;
214 
215 	pipe->funcs->update(pipe, old_pstate);
216 }
217 
218 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
219 					   struct drm_plane_state *state)
220 {
221 	struct drm_simple_display_pipe *pipe;
222 
223 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
224 	if (!pipe->funcs || !pipe->funcs->prepare_fb)
225 		return 0;
226 
227 	return pipe->funcs->prepare_fb(pipe, state);
228 }
229 
230 static void drm_simple_kms_plane_cleanup_fb(struct drm_plane *plane,
231 					    struct drm_plane_state *state)
232 {
233 	struct drm_simple_display_pipe *pipe;
234 
235 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
236 	if (!pipe->funcs || !pipe->funcs->cleanup_fb)
237 		return;
238 
239 	pipe->funcs->cleanup_fb(pipe, state);
240 }
241 
242 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
243 						uint32_t format,
244 						uint64_t modifier)
245 {
246 	return modifier == DRM_FORMAT_MOD_LINEAR;
247 }
248 
249 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
250 	.prepare_fb = drm_simple_kms_plane_prepare_fb,
251 	.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
252 	.atomic_check = drm_simple_kms_plane_atomic_check,
253 	.atomic_update = drm_simple_kms_plane_atomic_update,
254 };
255 
256 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
257 	.update_plane		= drm_atomic_helper_update_plane,
258 	.disable_plane		= drm_atomic_helper_disable_plane,
259 	.destroy		= drm_plane_cleanup,
260 	.reset			= drm_atomic_helper_plane_reset,
261 	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
262 	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
263 	.format_mod_supported   = drm_simple_kms_format_mod_supported,
264 };
265 
266 /**
267  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
268  * @pipe: simple display pipe object
269  * @bridge: bridge to attach
270  *
271  * Makes it possible to still use the drm_simple_display_pipe helpers when
272  * a DRM bridge has to be used.
273  *
274  * Note that you probably want to initialize the pipe by passing a NULL
275  * connector to drm_simple_display_pipe_init().
276  *
277  * Returns:
278  * Zero on success, negative error code on failure.
279  */
280 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
281 					  struct drm_bridge *bridge)
282 {
283 	return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
284 }
285 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
286 
287 /**
288  * drm_simple_display_pipe_init - Initialize a simple display pipeline
289  * @dev: DRM device
290  * @pipe: simple display pipe object to initialize
291  * @funcs: callbacks for the display pipe (optional)
292  * @formats: array of supported formats (DRM_FORMAT\_\*)
293  * @format_count: number of elements in @formats
294  * @format_modifiers: array of formats modifiers
295  * @connector: connector to attach and register (optional)
296  *
297  * Sets up a display pipeline which consist of a really simple
298  * plane-crtc-encoder pipe.
299  *
300  * If a connector is supplied, the pipe will be coupled with the provided
301  * connector. You may supply a NULL connector when using drm bridges, that
302  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
303  *
304  * Teardown of a simple display pipe is all handled automatically by the drm
305  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
306  * release the memory for the structure themselves.
307  *
308  * Returns:
309  * Zero on success, negative error code on failure.
310  */
311 int drm_simple_display_pipe_init(struct drm_device *dev,
312 			struct drm_simple_display_pipe *pipe,
313 			const struct drm_simple_display_pipe_funcs *funcs,
314 			const uint32_t *formats, unsigned int format_count,
315 			const uint64_t *format_modifiers,
316 			struct drm_connector *connector)
317 {
318 	struct drm_encoder *encoder = &pipe->encoder;
319 	struct drm_plane *plane = &pipe->plane;
320 	struct drm_crtc *crtc = &pipe->crtc;
321 	int ret;
322 
323 	pipe->connector = connector;
324 	pipe->funcs = funcs;
325 
326 	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
327 	ret = drm_universal_plane_init(dev, plane, 0,
328 				       &drm_simple_kms_plane_funcs,
329 				       formats, format_count,
330 				       format_modifiers,
331 				       DRM_PLANE_TYPE_PRIMARY, NULL);
332 	if (ret)
333 		return ret;
334 
335 	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
336 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
337 					&drm_simple_kms_crtc_funcs, NULL);
338 	if (ret)
339 		return ret;
340 
341 	encoder->possible_crtcs = drm_crtc_mask(crtc);
342 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
343 	if (ret || !connector)
344 		return ret;
345 
346 	return drm_connector_attach_encoder(connector, encoder);
347 }
348 EXPORT_SYMBOL(drm_simple_display_pipe_init);
349 
350 MODULE_LICENSE("GPL");
351