xref: /openbmc/linux/drivers/gpu/drm/sun4i/sun4i_layer.c (revision e983940270f10fe8551baf0098be76ea478294a3)
1 /*
2  * Copyright (C) 2015 Free Electrons
3  * Copyright (C) 2015 NextThing Co
4  *
5  * Maxime Ripard <maxime.ripard@free-electrons.com>
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License as
9  * published by the Free Software Foundation; either version 2 of
10  * the License, or (at your option) any later version.
11  */
12 
13 #include <drm/drm_atomic_helper.h>
14 #include <drm/drm_crtc.h>
15 #include <drm/drm_plane_helper.h>
16 #include <drm/drmP.h>
17 
18 #include "sun4i_backend.h"
19 #include "sun4i_drv.h"
20 #include "sun4i_layer.h"
21 
22 struct sun4i_plane_desc {
23 	       enum drm_plane_type     type;
24 	       u8                      pipe;
25 	       const uint32_t          *formats;
26 	       uint32_t                nformats;
27 };
28 
29 static int sun4i_backend_layer_atomic_check(struct drm_plane *plane,
30 					    struct drm_plane_state *state)
31 {
32 	return 0;
33 }
34 
35 static void sun4i_backend_layer_atomic_disable(struct drm_plane *plane,
36 					       struct drm_plane_state *old_state)
37 {
38 	struct sun4i_layer *layer = plane_to_sun4i_layer(plane);
39 	struct sun4i_drv *drv = layer->drv;
40 	struct sun4i_backend *backend = drv->backend;
41 
42 	sun4i_backend_layer_enable(backend, layer->id, false);
43 }
44 
45 static void sun4i_backend_layer_atomic_update(struct drm_plane *plane,
46 					      struct drm_plane_state *old_state)
47 {
48 	struct sun4i_layer *layer = plane_to_sun4i_layer(plane);
49 	struct sun4i_drv *drv = layer->drv;
50 	struct sun4i_backend *backend = drv->backend;
51 
52 	sun4i_backend_update_layer_coord(backend, layer->id, plane);
53 	sun4i_backend_update_layer_formats(backend, layer->id, plane);
54 	sun4i_backend_update_layer_buffer(backend, layer->id, plane);
55 	sun4i_backend_layer_enable(backend, layer->id, true);
56 }
57 
58 static struct drm_plane_helper_funcs sun4i_backend_layer_helper_funcs = {
59 	.atomic_check	= sun4i_backend_layer_atomic_check,
60 	.atomic_disable	= sun4i_backend_layer_atomic_disable,
61 	.atomic_update	= sun4i_backend_layer_atomic_update,
62 };
63 
64 static const struct drm_plane_funcs sun4i_backend_layer_funcs = {
65 	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
66 	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
67 	.destroy		= drm_plane_cleanup,
68 	.disable_plane		= drm_atomic_helper_disable_plane,
69 	.reset			= drm_atomic_helper_plane_reset,
70 	.update_plane		= drm_atomic_helper_update_plane,
71 };
72 
73 static const uint32_t sun4i_backend_layer_formats_primary[] = {
74 	DRM_FORMAT_ARGB8888,
75 	DRM_FORMAT_RGB888,
76 	DRM_FORMAT_XRGB8888,
77 };
78 
79 static const uint32_t sun4i_backend_layer_formats_overlay[] = {
80 	DRM_FORMAT_ARGB8888,
81 	DRM_FORMAT_RGB888,
82 	DRM_FORMAT_XRGB8888,
83 };
84 
85 static const struct sun4i_plane_desc sun4i_backend_planes[] = {
86 	{
87 		.type = DRM_PLANE_TYPE_PRIMARY,
88 		.pipe = 0,
89 		.formats = sun4i_backend_layer_formats_primary,
90 		.nformats = ARRAY_SIZE(sun4i_backend_layer_formats_primary),
91 	},
92 	{
93 		.type = DRM_PLANE_TYPE_OVERLAY,
94 		.pipe = 1,
95 		.formats = sun4i_backend_layer_formats_overlay,
96 		.nformats = ARRAY_SIZE(sun4i_backend_layer_formats_overlay),
97 	},
98 };
99 
100 static struct sun4i_layer *sun4i_layer_init_one(struct drm_device *drm,
101 						const struct sun4i_plane_desc *plane)
102 {
103 	struct sun4i_drv *drv = drm->dev_private;
104 	struct sun4i_layer *layer;
105 	int ret;
106 
107 	layer = devm_kzalloc(drm->dev, sizeof(*layer), GFP_KERNEL);
108 	if (!layer)
109 		return ERR_PTR(-ENOMEM);
110 
111 	ret = drm_universal_plane_init(drm, &layer->plane, BIT(0),
112 				       &sun4i_backend_layer_funcs,
113 				       plane->formats, plane->nformats,
114 				       plane->type, NULL);
115 	if (ret) {
116 		dev_err(drm->dev, "Couldn't initialize layer\n");
117 		return ERR_PTR(ret);
118 	}
119 
120 	drm_plane_helper_add(&layer->plane,
121 			     &sun4i_backend_layer_helper_funcs);
122 	layer->drv = drv;
123 
124 	if (plane->type == DRM_PLANE_TYPE_PRIMARY)
125 		drv->primary = &layer->plane;
126 
127 	return layer;
128 }
129 
130 struct sun4i_layer **sun4i_layers_init(struct drm_device *drm)
131 {
132 	struct sun4i_drv *drv = drm->dev_private;
133 	struct sun4i_layer **layers;
134 	int i;
135 
136 	layers = devm_kcalloc(drm->dev, ARRAY_SIZE(sun4i_backend_planes),
137 			      sizeof(**layers), GFP_KERNEL);
138 	if (!layers)
139 		return ERR_PTR(-ENOMEM);
140 
141 	/*
142 	 * The hardware is a bit unusual here.
143 	 *
144 	 * Even though it supports 4 layers, it does the composition
145 	 * in two separate steps.
146 	 *
147 	 * The first one is assigning a layer to one of its two
148 	 * pipes. If more that 1 layer is assigned to the same pipe,
149 	 * and if pixels overlaps, the pipe will take the pixel from
150 	 * the layer with the highest priority.
151 	 *
152 	 * The second step is the actual alpha blending, that takes
153 	 * the two pipes as input, and uses the eventual alpha
154 	 * component to do the transparency between the two.
155 	 *
156 	 * This two steps scenario makes us unable to guarantee a
157 	 * robust alpha blending between the 4 layers in all
158 	 * situations. So we just expose two layers, one per pipe. On
159 	 * SoCs that support it, sprites could fill the need for more
160 	 * layers.
161 	 */
162 	for (i = 0; i < ARRAY_SIZE(sun4i_backend_planes); i++) {
163 		const struct sun4i_plane_desc *plane = &sun4i_backend_planes[i];
164 		struct sun4i_layer *layer = layers[i];
165 
166 		layer = sun4i_layer_init_one(drm, plane);
167 		if (IS_ERR(layer)) {
168 			dev_err(drm->dev, "Couldn't initialize %s plane\n",
169 				i ? "overlay" : "primary");
170 			return ERR_CAST(layer);
171 		};
172 
173 		DRM_DEBUG_DRIVER("Assigning %s plane to pipe %d\n",
174 				 i ? "overlay" : "primary", plane->pipe);
175 		regmap_update_bits(drv->backend->regs, SUN4I_BACKEND_ATTCTL_REG0(i),
176 				   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL_MASK,
177 				   SUN4I_BACKEND_ATTCTL_REG0_LAY_PIPESEL(plane->pipe));
178 
179 		layer->id = i;
180 	};
181 
182 	return layers;
183 }
184