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_plane_helper.h>
13 #include <drm/drm_probe_helper.h>
14 #include <drm/drm_simple_kms_helper.h>
15 
16 /**
17  * DOC: overview
18  *
19  * This helper library provides helpers for drivers for simple display
20  * hardware.
21  *
22  * drm_simple_display_pipe_init() initializes a simple display pipeline
23  * which has only one full-screen scanout buffer feeding one output. The
24  * pipeline is represented by &struct drm_simple_display_pipe and binds
25  * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
26  * entity. Some flexibility for code reuse is provided through a separately
27  * allocated &drm_connector object and supporting optional &drm_bridge
28  * encoder drivers.
29  *
30  * Many drivers require only a very simple encoder that fulfills the minimum
31  * requirements of the display pipeline and does not add additional
32  * functionality. The function drm_simple_encoder_init() provides an
33  * implementation of such an encoder.
34  */
35 
36 static const struct drm_encoder_funcs drm_simple_encoder_funcs_cleanup = {
37 	.destroy = drm_encoder_cleanup,
38 };
39 
40 /**
41  * drm_simple_encoder_init - Initialize a preallocated encoder with
42  *                           basic functionality.
43  * @dev: drm device
44  * @encoder: the encoder to initialize
45  * @encoder_type: user visible type of the encoder
46  *
47  * Initialises a preallocated encoder that has no further functionality.
48  * Settings for possible CRTC and clones are left to their initial values.
49  * The encoder will be cleaned up automatically as part of the mode-setting
50  * cleanup.
51  *
52  * The caller of drm_simple_encoder_init() is responsible for freeing
53  * the encoder's memory after the encoder has been cleaned up. At the
54  * moment this only works reliably if the encoder data structure is
55  * stored in the device structure. Free the encoder's memory as part of
56  * the device release function.
57  *
58  * FIXME: Later improvements to DRM's resource management may allow for
59  *        an automated kfree() of the encoder's memory.
60  *
61  * Returns:
62  * Zero on success, error code on failure.
63  */
64 int drm_simple_encoder_init(struct drm_device *dev,
65 			    struct drm_encoder *encoder,
66 			    int encoder_type)
67 {
68 	return drm_encoder_init(dev, encoder,
69 				&drm_simple_encoder_funcs_cleanup,
70 				encoder_type, NULL);
71 }
72 EXPORT_SYMBOL(drm_simple_encoder_init);
73 
74 static enum drm_mode_status
75 drm_simple_kms_crtc_mode_valid(struct drm_crtc *crtc,
76 			       const struct drm_display_mode *mode)
77 {
78 	struct drm_simple_display_pipe *pipe;
79 
80 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
81 	if (!pipe->funcs || !pipe->funcs->mode_valid)
82 		/* Anything goes */
83 		return MODE_OK;
84 
85 	return pipe->funcs->mode_valid(pipe, mode);
86 }
87 
88 static int drm_simple_kms_crtc_check(struct drm_crtc *crtc,
89 				     struct drm_crtc_state *state)
90 {
91 	bool has_primary = state->plane_mask &
92 			   drm_plane_mask(crtc->primary);
93 
94 	/* We always want to have an active plane with an active CRTC */
95 	if (has_primary != state->enable)
96 		return -EINVAL;
97 
98 	return drm_atomic_add_affected_planes(state->state, crtc);
99 }
100 
101 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc,
102 				       struct drm_crtc_state *old_state)
103 {
104 	struct drm_plane *plane;
105 	struct drm_simple_display_pipe *pipe;
106 
107 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
108 	if (!pipe->funcs || !pipe->funcs->enable)
109 		return;
110 
111 	plane = &pipe->plane;
112 	pipe->funcs->enable(pipe, crtc->state, plane->state);
113 }
114 
115 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc,
116 					struct drm_crtc_state *old_state)
117 {
118 	struct drm_simple_display_pipe *pipe;
119 
120 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
121 	if (!pipe->funcs || !pipe->funcs->disable)
122 		return;
123 
124 	pipe->funcs->disable(pipe);
125 }
126 
127 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
128 	.mode_valid = drm_simple_kms_crtc_mode_valid,
129 	.atomic_check = drm_simple_kms_crtc_check,
130 	.atomic_enable = drm_simple_kms_crtc_enable,
131 	.atomic_disable = drm_simple_kms_crtc_disable,
132 };
133 
134 static int drm_simple_kms_crtc_enable_vblank(struct drm_crtc *crtc)
135 {
136 	struct drm_simple_display_pipe *pipe;
137 
138 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
139 	if (!pipe->funcs || !pipe->funcs->enable_vblank)
140 		return 0;
141 
142 	return pipe->funcs->enable_vblank(pipe);
143 }
144 
145 static void drm_simple_kms_crtc_disable_vblank(struct drm_crtc *crtc)
146 {
147 	struct drm_simple_display_pipe *pipe;
148 
149 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
150 	if (!pipe->funcs || !pipe->funcs->disable_vblank)
151 		return;
152 
153 	pipe->funcs->disable_vblank(pipe);
154 }
155 
156 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
157 	.reset = drm_atomic_helper_crtc_reset,
158 	.destroy = drm_crtc_cleanup,
159 	.set_config = drm_atomic_helper_set_config,
160 	.page_flip = drm_atomic_helper_page_flip,
161 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
162 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
163 	.enable_vblank = drm_simple_kms_crtc_enable_vblank,
164 	.disable_vblank = drm_simple_kms_crtc_disable_vblank,
165 };
166 
167 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
168 					struct drm_plane_state *plane_state)
169 {
170 	struct drm_simple_display_pipe *pipe;
171 	struct drm_crtc_state *crtc_state;
172 	int ret;
173 
174 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
175 	crtc_state = drm_atomic_get_new_crtc_state(plane_state->state,
176 						   &pipe->crtc);
177 
178 	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
179 						  DRM_PLANE_HELPER_NO_SCALING,
180 						  DRM_PLANE_HELPER_NO_SCALING,
181 						  false, true);
182 	if (ret)
183 		return ret;
184 
185 	if (!plane_state->visible)
186 		return 0;
187 
188 	if (!pipe->funcs || !pipe->funcs->check)
189 		return 0;
190 
191 	return pipe->funcs->check(pipe, plane_state, crtc_state);
192 }
193 
194 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
195 					struct drm_plane_state *old_pstate)
196 {
197 	struct drm_simple_display_pipe *pipe;
198 
199 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
200 	if (!pipe->funcs || !pipe->funcs->update)
201 		return;
202 
203 	pipe->funcs->update(pipe, old_pstate);
204 }
205 
206 static int drm_simple_kms_plane_prepare_fb(struct drm_plane *plane,
207 					   struct drm_plane_state *state)
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->prepare_fb)
213 		return 0;
214 
215 	return pipe->funcs->prepare_fb(pipe, state);
216 }
217 
218 static void drm_simple_kms_plane_cleanup_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->cleanup_fb)
225 		return;
226 
227 	pipe->funcs->cleanup_fb(pipe, state);
228 }
229 
230 static bool drm_simple_kms_format_mod_supported(struct drm_plane *plane,
231 						uint32_t format,
232 						uint64_t modifier)
233 {
234 	return modifier == DRM_FORMAT_MOD_LINEAR;
235 }
236 
237 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
238 	.prepare_fb = drm_simple_kms_plane_prepare_fb,
239 	.cleanup_fb = drm_simple_kms_plane_cleanup_fb,
240 	.atomic_check = drm_simple_kms_plane_atomic_check,
241 	.atomic_update = drm_simple_kms_plane_atomic_update,
242 };
243 
244 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
245 	.update_plane		= drm_atomic_helper_update_plane,
246 	.disable_plane		= drm_atomic_helper_disable_plane,
247 	.destroy		= drm_plane_cleanup,
248 	.reset			= drm_atomic_helper_plane_reset,
249 	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
250 	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
251 	.format_mod_supported   = drm_simple_kms_format_mod_supported,
252 };
253 
254 /**
255  * drm_simple_display_pipe_attach_bridge - Attach a bridge to the display pipe
256  * @pipe: simple display pipe object
257  * @bridge: bridge to attach
258  *
259  * Makes it possible to still use the drm_simple_display_pipe helpers when
260  * a DRM bridge has to be used.
261  *
262  * Note that you probably want to initialize the pipe by passing a NULL
263  * connector to drm_simple_display_pipe_init().
264  *
265  * Returns:
266  * Zero on success, negative error code on failure.
267  */
268 int drm_simple_display_pipe_attach_bridge(struct drm_simple_display_pipe *pipe,
269 					  struct drm_bridge *bridge)
270 {
271 	return drm_bridge_attach(&pipe->encoder, bridge, NULL, 0);
272 }
273 EXPORT_SYMBOL(drm_simple_display_pipe_attach_bridge);
274 
275 /**
276  * drm_simple_display_pipe_init - Initialize a simple display pipeline
277  * @dev: DRM device
278  * @pipe: simple display pipe object to initialize
279  * @funcs: callbacks for the display pipe (optional)
280  * @formats: array of supported formats (DRM_FORMAT\_\*)
281  * @format_count: number of elements in @formats
282  * @format_modifiers: array of formats modifiers
283  * @connector: connector to attach and register (optional)
284  *
285  * Sets up a display pipeline which consist of a really simple
286  * plane-crtc-encoder pipe.
287  *
288  * If a connector is supplied, the pipe will be coupled with the provided
289  * connector. You may supply a NULL connector when using drm bridges, that
290  * handle connectors themselves (see drm_simple_display_pipe_attach_bridge()).
291  *
292  * Teardown of a simple display pipe is all handled automatically by the drm
293  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
294  * release the memory for the structure themselves.
295  *
296  * Returns:
297  * Zero on success, negative error code on failure.
298  */
299 int drm_simple_display_pipe_init(struct drm_device *dev,
300 			struct drm_simple_display_pipe *pipe,
301 			const struct drm_simple_display_pipe_funcs *funcs,
302 			const uint32_t *formats, unsigned int format_count,
303 			const uint64_t *format_modifiers,
304 			struct drm_connector *connector)
305 {
306 	struct drm_encoder *encoder = &pipe->encoder;
307 	struct drm_plane *plane = &pipe->plane;
308 	struct drm_crtc *crtc = &pipe->crtc;
309 	int ret;
310 
311 	pipe->connector = connector;
312 	pipe->funcs = funcs;
313 
314 	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
315 	ret = drm_universal_plane_init(dev, plane, 0,
316 				       &drm_simple_kms_plane_funcs,
317 				       formats, format_count,
318 				       format_modifiers,
319 				       DRM_PLANE_TYPE_PRIMARY, NULL);
320 	if (ret)
321 		return ret;
322 
323 	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
324 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
325 					&drm_simple_kms_crtc_funcs, NULL);
326 	if (ret)
327 		return ret;
328 
329 	encoder->possible_crtcs = drm_crtc_mask(crtc);
330 	ret = drm_simple_encoder_init(dev, encoder, DRM_MODE_ENCODER_NONE);
331 	if (ret || !connector)
332 		return ret;
333 
334 	return drm_connector_attach_encoder(connector, encoder);
335 }
336 EXPORT_SYMBOL(drm_simple_display_pipe_init);
337 
338 MODULE_LICENSE("GPL");
339