xref: /linux/drivers/gpu/drm/drm_plane_helper.c (revision 37744feebc086908fd89760650f458ab19071750)
1 /*
2  * Copyright (C) 2014 Intel Corporation
3  *
4  * DRM universal plane helper functions
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
23  * SOFTWARE.
24  */
25 
26 #include <linux/list.h>
27 
28 #include <drm/drm_atomic.h>
29 #include <drm/drm_atomic_helper.h>
30 #include <drm/drm_atomic_uapi.h>
31 #include <drm/drm_crtc_helper.h>
32 #include <drm/drm_device.h>
33 #include <drm/drm_encoder.h>
34 #include <drm/drm_plane_helper.h>
35 #include <drm/drm_rect.h>
36 
37 #define SUBPIXEL_MASK 0xffff
38 
39 /**
40  * DOC: overview
41  *
42  * This helper library has two parts. The first part has support to implement
43  * primary plane support on top of the normal CRTC configuration interface.
44  * Since the legacy &drm_mode_config_funcs.set_config interface ties the primary
45  * plane together with the CRTC state this does not allow userspace to disable
46  * the primary plane itself. The default primary plane only expose XRBG8888 and
47  * ARGB8888 as valid pixel formats for the attached framebuffer.
48  *
49  * Drivers are highly recommended to implement proper support for primary
50  * planes, and newly merged drivers must not rely upon these transitional
51  * helpers.
52  *
53  * The second part also implements transitional helpers which allow drivers to
54  * gradually switch to the atomic helper infrastructure for plane updates. Once
55  * that switch is complete drivers shouldn't use these any longer, instead using
56  * the proper legacy implementations for update and disable plane hooks provided
57  * by the atomic helpers.
58  *
59  * Again drivers are strongly urged to switch to the new interfaces.
60  *
61  * The plane helpers share the function table structures with other helpers,
62  * specifically also the atomic helpers. See &struct drm_plane_helper_funcs for
63  * the details.
64  */
65 
66 /*
67  * Returns the connectors currently associated with a CRTC.  This function
68  * should be called twice:  once with a NULL connector list to retrieve
69  * the list size, and once with the properly allocated list to be filled in.
70  */
71 static int get_connectors_for_crtc(struct drm_crtc *crtc,
72 				   struct drm_connector **connector_list,
73 				   int num_connectors)
74 {
75 	struct drm_device *dev = crtc->dev;
76 	struct drm_connector *connector;
77 	struct drm_connector_list_iter conn_iter;
78 	int count = 0;
79 
80 	/*
81 	 * Note: Once we change the plane hooks to more fine-grained locking we
82 	 * need to grab the connection_mutex here to be able to make these
83 	 * checks.
84 	 */
85 	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
86 
87 	drm_connector_list_iter_begin(dev, &conn_iter);
88 	drm_for_each_connector_iter(connector, &conn_iter) {
89 		if (connector->encoder && connector->encoder->crtc == crtc) {
90 			if (connector_list != NULL && count < num_connectors)
91 				*(connector_list++) = connector;
92 
93 			count++;
94 		}
95 	}
96 	drm_connector_list_iter_end(&conn_iter);
97 
98 	return count;
99 }
100 
101 static int drm_plane_helper_check_update(struct drm_plane *plane,
102 					 struct drm_crtc *crtc,
103 					 struct drm_framebuffer *fb,
104 					 struct drm_rect *src,
105 					 struct drm_rect *dst,
106 					 unsigned int rotation,
107 					 int min_scale,
108 					 int max_scale,
109 					 bool can_position,
110 					 bool can_update_disabled,
111 					 bool *visible)
112 {
113 	struct drm_plane_state plane_state = {
114 		.plane = plane,
115 		.crtc = crtc,
116 		.fb = fb,
117 		.src_x = src->x1,
118 		.src_y = src->y1,
119 		.src_w = drm_rect_width(src),
120 		.src_h = drm_rect_height(src),
121 		.crtc_x = dst->x1,
122 		.crtc_y = dst->y1,
123 		.crtc_w = drm_rect_width(dst),
124 		.crtc_h = drm_rect_height(dst),
125 		.rotation = rotation,
126 		.visible = *visible,
127 	};
128 	struct drm_crtc_state crtc_state = {
129 		.crtc = crtc,
130 		.enable = crtc->enabled,
131 		.mode = crtc->mode,
132 	};
133 	int ret;
134 
135 	ret = drm_atomic_helper_check_plane_state(&plane_state, &crtc_state,
136 						  min_scale, max_scale,
137 						  can_position,
138 						  can_update_disabled);
139 	if (ret)
140 		return ret;
141 
142 	*src = plane_state.src;
143 	*dst = plane_state.dst;
144 	*visible = plane_state.visible;
145 
146 	return 0;
147 }
148 
149 static int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
150 				     struct drm_framebuffer *fb,
151 				     int crtc_x, int crtc_y,
152 				     unsigned int crtc_w, unsigned int crtc_h,
153 				     uint32_t src_x, uint32_t src_y,
154 				     uint32_t src_w, uint32_t src_h,
155 				     struct drm_modeset_acquire_ctx *ctx)
156 {
157 	struct drm_mode_set set = {
158 		.crtc = crtc,
159 		.fb = fb,
160 		.mode = &crtc->mode,
161 		.x = src_x >> 16,
162 		.y = src_y >> 16,
163 	};
164 	struct drm_rect src = {
165 		.x1 = src_x,
166 		.y1 = src_y,
167 		.x2 = src_x + src_w,
168 		.y2 = src_y + src_h,
169 	};
170 	struct drm_rect dest = {
171 		.x1 = crtc_x,
172 		.y1 = crtc_y,
173 		.x2 = crtc_x + crtc_w,
174 		.y2 = crtc_y + crtc_h,
175 	};
176 	struct drm_connector **connector_list;
177 	int num_connectors, ret;
178 	bool visible;
179 
180 	ret = drm_plane_helper_check_update(plane, crtc, fb,
181 					    &src, &dest,
182 					    DRM_MODE_ROTATE_0,
183 					    DRM_PLANE_HELPER_NO_SCALING,
184 					    DRM_PLANE_HELPER_NO_SCALING,
185 					    false, false, &visible);
186 	if (ret)
187 		return ret;
188 
189 	if (!visible)
190 		/*
191 		 * Primary plane isn't visible.  Note that unless a driver
192 		 * provides their own disable function, this will just
193 		 * wind up returning -EINVAL to userspace.
194 		 */
195 		return plane->funcs->disable_plane(plane, ctx);
196 
197 	/* Find current connectors for CRTC */
198 	num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
199 	BUG_ON(num_connectors == 0);
200 	connector_list = kcalloc(num_connectors, sizeof(*connector_list),
201 				 GFP_KERNEL);
202 	if (!connector_list)
203 		return -ENOMEM;
204 	get_connectors_for_crtc(crtc, connector_list, num_connectors);
205 
206 	set.connectors = connector_list;
207 	set.num_connectors = num_connectors;
208 
209 	/*
210 	 * We call set_config() directly here rather than using
211 	 * drm_mode_set_config_internal.  We're reprogramming the same
212 	 * connectors that were already in use, so we shouldn't need the extra
213 	 * cross-CRTC fb refcounting to accomodate stealing connectors.
214 	 * drm_mode_setplane() already handles the basic refcounting for the
215 	 * framebuffers involved in this operation.
216 	 */
217 	ret = crtc->funcs->set_config(&set, ctx);
218 
219 	kfree(connector_list);
220 	return ret;
221 }
222 
223 static int drm_primary_helper_disable(struct drm_plane *plane,
224 				      struct drm_modeset_acquire_ctx *ctx)
225 {
226 	return -EINVAL;
227 }
228 
229 /**
230  * drm_primary_helper_destroy() - Helper for primary plane destruction
231  * @plane: plane to destroy
232  *
233  * Provides a default plane destroy handler for primary planes.  This handler
234  * is called during CRTC destruction.  We disable the primary plane, remove
235  * it from the DRM plane list, and deallocate the plane structure.
236  */
237 void drm_primary_helper_destroy(struct drm_plane *plane)
238 {
239 	drm_plane_cleanup(plane);
240 	kfree(plane);
241 }
242 EXPORT_SYMBOL(drm_primary_helper_destroy);
243 
244 const struct drm_plane_funcs drm_primary_helper_funcs = {
245 	.update_plane = drm_primary_helper_update,
246 	.disable_plane = drm_primary_helper_disable,
247 	.destroy = drm_primary_helper_destroy,
248 };
249 EXPORT_SYMBOL(drm_primary_helper_funcs);
250