1 /*
2  * Copyright (C) 2016 Noralf Trønnes
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  */
9 
10 #include <drm/drmP.h>
11 #include <drm/drm_atomic.h>
12 #include <drm/drm_atomic_helper.h>
13 #include <drm/drm_crtc_helper.h>
14 #include <drm/drm_plane_helper.h>
15 #include <drm/drm_simple_kms_helper.h>
16 #include <linux/slab.h>
17 
18 /**
19  * DOC: overview
20  *
21  * This helper library provides helpers for drivers for simple display
22  * hardware.
23  *
24  * drm_simple_display_pipe_init() initializes a simple display pipeline
25  * which has only one full-screen scanout buffer feeding one output. The
26  * pipeline is represented by struct &drm_simple_display_pipe and binds
27  * together &drm_plane, &drm_crtc and &drm_encoder structures into one fixed
28  * entity. Some flexibility for code reuse is provided through a separately
29  * allocated &drm_connector object and supporting optional &drm_bridge
30  * encoder drivers.
31  */
32 
33 static const struct drm_encoder_funcs drm_simple_kms_encoder_funcs = {
34 	.destroy = drm_encoder_cleanup,
35 };
36 
37 static void drm_simple_kms_crtc_enable(struct drm_crtc *crtc)
38 {
39 	struct drm_simple_display_pipe *pipe;
40 
41 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
42 	if (!pipe->funcs || !pipe->funcs->enable)
43 		return;
44 
45 	pipe->funcs->enable(pipe, crtc->state);
46 }
47 
48 static void drm_simple_kms_crtc_disable(struct drm_crtc *crtc)
49 {
50 	struct drm_simple_display_pipe *pipe;
51 
52 	pipe = container_of(crtc, struct drm_simple_display_pipe, crtc);
53 	if (!pipe->funcs || !pipe->funcs->disable)
54 		return;
55 
56 	pipe->funcs->disable(pipe);
57 }
58 
59 static const struct drm_crtc_helper_funcs drm_simple_kms_crtc_helper_funcs = {
60 	.disable = drm_simple_kms_crtc_disable,
61 	.enable = drm_simple_kms_crtc_enable,
62 };
63 
64 static const struct drm_crtc_funcs drm_simple_kms_crtc_funcs = {
65 	.reset = drm_atomic_helper_crtc_reset,
66 	.destroy = drm_crtc_cleanup,
67 	.set_config = drm_atomic_helper_set_config,
68 	.page_flip = drm_atomic_helper_page_flip,
69 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
70 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
71 };
72 
73 static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane,
74 					struct drm_plane_state *plane_state)
75 {
76 	struct drm_rect src = {
77 		.x1 = plane_state->src_x,
78 		.y1 = plane_state->src_y,
79 		.x2 = plane_state->src_x + plane_state->src_w,
80 		.y2 = plane_state->src_y + plane_state->src_h,
81 	};
82 	struct drm_rect dest = {
83 		.x1 = plane_state->crtc_x,
84 		.y1 = plane_state->crtc_y,
85 		.x2 = plane_state->crtc_x + plane_state->crtc_w,
86 		.y2 = plane_state->crtc_y + plane_state->crtc_h,
87 	};
88 	struct drm_rect clip = { 0 };
89 	struct drm_simple_display_pipe *pipe;
90 	struct drm_crtc_state *crtc_state;
91 	bool visible;
92 	int ret;
93 
94 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
95 	crtc_state = drm_atomic_get_existing_crtc_state(plane_state->state,
96 							&pipe->crtc);
97 	if (crtc_state->enable != !!plane_state->crtc)
98 		return -EINVAL; /* plane must match crtc enable state */
99 
100 	if (!crtc_state->enable)
101 		return 0; /* nothing to check when disabling or disabled */
102 
103 	clip.x2 = crtc_state->adjusted_mode.hdisplay;
104 	clip.y2 = crtc_state->adjusted_mode.vdisplay;
105 	ret = drm_plane_helper_check_update(plane, &pipe->crtc,
106 					    plane_state->fb,
107 					    &src, &dest, &clip,
108 					    plane_state->rotation,
109 					    DRM_PLANE_HELPER_NO_SCALING,
110 					    DRM_PLANE_HELPER_NO_SCALING,
111 					    false, true, &visible);
112 	if (ret)
113 		return ret;
114 
115 	if (!visible)
116 		return -EINVAL;
117 
118 	if (!pipe->funcs || !pipe->funcs->check)
119 		return 0;
120 
121 	return pipe->funcs->check(pipe, plane_state, crtc_state);
122 }
123 
124 static void drm_simple_kms_plane_atomic_update(struct drm_plane *plane,
125 					struct drm_plane_state *pstate)
126 {
127 	struct drm_simple_display_pipe *pipe;
128 
129 	pipe = container_of(plane, struct drm_simple_display_pipe, plane);
130 	if (!pipe->funcs || !pipe->funcs->update)
131 		return;
132 
133 	pipe->funcs->update(pipe, pstate);
134 }
135 
136 static const struct drm_plane_helper_funcs drm_simple_kms_plane_helper_funcs = {
137 	.atomic_check = drm_simple_kms_plane_atomic_check,
138 	.atomic_update = drm_simple_kms_plane_atomic_update,
139 };
140 
141 static const struct drm_plane_funcs drm_simple_kms_plane_funcs = {
142 	.update_plane		= drm_atomic_helper_update_plane,
143 	.disable_plane		= drm_atomic_helper_disable_plane,
144 	.destroy		= drm_plane_cleanup,
145 	.reset			= drm_atomic_helper_plane_reset,
146 	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
147 	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
148 };
149 
150 /**
151  * drm_simple_display_pipe_init - Initialize a simple display pipeline
152  * @dev: DRM device
153  * @pipe: simple display pipe object to initialize
154  * @funcs: callbacks for the display pipe (optional)
155  * @formats: array of supported formats (%DRM_FORMAT_*)
156  * @format_count: number of elements in @formats
157  * @connector: connector to attach and register
158  *
159  * Sets up a display pipeline which consist of a really simple
160  * plane-crtc-encoder pipe coupled with the provided connector.
161  * Teardown of a simple display pipe is all handled automatically by the drm
162  * core through calling drm_mode_config_cleanup(). Drivers afterwards need to
163  * release the memory for the structure themselves.
164  *
165  * Returns:
166  * Zero on success, negative error code on failure.
167  */
168 int drm_simple_display_pipe_init(struct drm_device *dev,
169 			struct drm_simple_display_pipe *pipe,
170 			const struct drm_simple_display_pipe_funcs *funcs,
171 			const uint32_t *formats, unsigned int format_count,
172 			struct drm_connector *connector)
173 {
174 	struct drm_encoder *encoder = &pipe->encoder;
175 	struct drm_plane *plane = &pipe->plane;
176 	struct drm_crtc *crtc = &pipe->crtc;
177 	int ret;
178 
179 	pipe->connector = connector;
180 	pipe->funcs = funcs;
181 
182 	drm_plane_helper_add(plane, &drm_simple_kms_plane_helper_funcs);
183 	ret = drm_universal_plane_init(dev, plane, 0,
184 				       &drm_simple_kms_plane_funcs,
185 				       formats, format_count,
186 				       DRM_PLANE_TYPE_PRIMARY, NULL);
187 	if (ret)
188 		return ret;
189 
190 	drm_crtc_helper_add(crtc, &drm_simple_kms_crtc_helper_funcs);
191 	ret = drm_crtc_init_with_planes(dev, crtc, plane, NULL,
192 					&drm_simple_kms_crtc_funcs, NULL);
193 	if (ret)
194 		return ret;
195 
196 	encoder->possible_crtcs = 1 << drm_crtc_index(crtc);
197 	ret = drm_encoder_init(dev, encoder, &drm_simple_kms_encoder_funcs,
198 			       DRM_MODE_ENCODER_NONE, NULL);
199 	if (ret)
200 		return ret;
201 
202 	return drm_mode_connector_attach_encoder(connector, encoder);
203 }
204 EXPORT_SYMBOL(drm_simple_display_pipe_init);
205 
206 MODULE_LICENSE("GPL");
207