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 #include <drm/drmP.h>
28 #include <drm/drm_rect.h>
29 
30 #define SUBPIXEL_MASK 0xffff
31 
32 /*
33  * This is the minimal list of formats that seem to be safe for modeset use
34  * with all current DRM drivers.  Most hardware can actually support more
35  * formats than this and drivers may specify a more accurate list when
36  * creating the primary plane.  However drivers that still call
37  * drm_plane_init() will use this minimal format list as the default.
38  */
39 const static uint32_t safe_modeset_formats[] = {
40        DRM_FORMAT_XRGB8888,
41        DRM_FORMAT_ARGB8888,
42 };
43 
44 /*
45  * Returns the connectors currently associated with a CRTC.  This function
46  * should be called twice:  once with a NULL connector list to retrieve
47  * the list size, and once with the properly allocated list to be filled in.
48  */
49 static int get_connectors_for_crtc(struct drm_crtc *crtc,
50 				   struct drm_connector **connector_list,
51 				   int num_connectors)
52 {
53 	struct drm_device *dev = crtc->dev;
54 	struct drm_connector *connector;
55 	int count = 0;
56 
57 	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
58 		if (connector->encoder && connector->encoder->crtc == crtc) {
59 			if (connector_list != NULL && count < num_connectors)
60 				*(connector_list++) = connector;
61 
62 			count++;
63 		}
64 
65 	return count;
66 }
67 
68 /**
69  * drm_primary_helper_update() - Helper for primary plane update
70  * @plane: plane object to update
71  * @crtc: owning CRTC of owning plane
72  * @fb: framebuffer to flip onto plane
73  * @crtc_x: x offset of primary plane on crtc
74  * @crtc_y: y offset of primary plane on crtc
75  * @crtc_w: width of primary plane rectangle on crtc
76  * @crtc_h: height of primary plane rectangle on crtc
77  * @src_x: x offset of @fb for panning
78  * @src_y: y offset of @fb for panning
79  * @src_w: width of source rectangle in @fb
80  * @src_h: height of source rectangle in @fb
81  *
82  * Provides a default plane update handler for primary planes.  This is handler
83  * is called in response to a userspace SetPlane operation on the plane with a
84  * non-NULL framebuffer.  We call the driver's modeset handler to update the
85  * framebuffer.
86  *
87  * SetPlane() on a primary plane of a disabled CRTC is not supported, and will
88  * return an error.
89  *
90  * Note that we make some assumptions about hardware limitations that may not be
91  * true for all hardware --
92  *   1) Primary plane cannot be repositioned.
93  *   2) Primary plane cannot be scaled.
94  *   3) Primary plane must cover the entire CRTC.
95  *   4) Subpixel positioning is not supported.
96  * Drivers for hardware that don't have these restrictions can provide their
97  * own implementation rather than using this helper.
98  *
99  * RETURNS:
100  * Zero on success, error code on failure
101  */
102 int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
103 			      struct drm_framebuffer *fb,
104 			      int crtc_x, int crtc_y,
105 			      unsigned int crtc_w, unsigned int crtc_h,
106 			      uint32_t src_x, uint32_t src_y,
107 			      uint32_t src_w, uint32_t src_h)
108 {
109 	struct drm_mode_set set = {
110 		.crtc = crtc,
111 		.fb = fb,
112 		.mode = &crtc->mode,
113 		.x = src_x >> 16,
114 		.y = src_y >> 16,
115 	};
116 	struct drm_rect dest = {
117 		.x1 = crtc_x,
118 		.y1 = crtc_y,
119 		.x2 = crtc_x + crtc_w,
120 		.y2 = crtc_y + crtc_h,
121 	};
122 	struct drm_rect clip = {
123 		.x2 = crtc->mode.hdisplay,
124 		.y2 = crtc->mode.vdisplay,
125 	};
126 	struct drm_connector **connector_list;
127 	struct drm_framebuffer *tmpfb;
128 	int num_connectors, ret;
129 
130 	if (!crtc->enabled) {
131 		DRM_DEBUG_KMS("Cannot update primary plane of a disabled CRTC.\n");
132 		return -EINVAL;
133 	}
134 
135 	/* Disallow subpixel positioning */
136 	if ((src_x | src_y | src_w | src_h) & SUBPIXEL_MASK) {
137 		DRM_DEBUG_KMS("Primary plane does not support subpixel positioning\n");
138 		return -EINVAL;
139 	}
140 
141 	/* Primary planes are locked to their owning CRTC */
142 	if (plane->possible_crtcs != drm_crtc_mask(crtc)) {
143 		DRM_DEBUG_KMS("Cannot change primary plane CRTC\n");
144 		return -EINVAL;
145 	}
146 
147 	/* Disallow scaling */
148 	if (crtc_w != src_w || crtc_h != src_h) {
149 		DRM_DEBUG_KMS("Can't scale primary plane\n");
150 		return -EINVAL;
151 	}
152 
153 	/* Make sure primary plane covers entire CRTC */
154 	drm_rect_intersect(&dest, &clip);
155 	if (dest.x1 != 0 || dest.y1 != 0 ||
156 	    dest.x2 != crtc->mode.hdisplay || dest.y2 != crtc->mode.vdisplay) {
157 		DRM_DEBUG_KMS("Primary plane must cover entire CRTC\n");
158 		return -EINVAL;
159 	}
160 
161 	/* Framebuffer must be big enough to cover entire plane */
162 	ret = drm_crtc_check_viewport(crtc, crtc_x, crtc_y, &crtc->mode, fb);
163 	if (ret)
164 		return ret;
165 
166 	/* Find current connectors for CRTC */
167 	num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
168 	BUG_ON(num_connectors == 0);
169 	connector_list = kzalloc(num_connectors * sizeof(*connector_list),
170 				 GFP_KERNEL);
171 	if (!connector_list)
172 		return -ENOMEM;
173 	get_connectors_for_crtc(crtc, connector_list, num_connectors);
174 
175 	set.connectors = connector_list;
176 	set.num_connectors = num_connectors;
177 
178 	/*
179 	 * set_config() adjusts crtc->primary->fb; however the DRM setplane
180 	 * code that called us expects to handle the framebuffer update and
181 	 * reference counting; save and restore the current fb before
182 	 * calling it.
183 	 *
184 	 * N.B., we call set_config() directly here rather than using
185 	 * drm_mode_set_config_internal.  We're reprogramming the same
186 	 * connectors that were already in use, so we shouldn't need the extra
187 	 * cross-CRTC fb refcounting to accomodate stealing connectors.
188 	 * drm_mode_setplane() already handles the basic refcounting for the
189 	 * framebuffers involved in this operation.
190 	 */
191 	tmpfb = plane->fb;
192 	ret = crtc->funcs->set_config(&set);
193 	plane->fb = tmpfb;
194 
195 	kfree(connector_list);
196 	return ret;
197 }
198 EXPORT_SYMBOL(drm_primary_helper_update);
199 
200 /**
201  * drm_primary_helper_disable() - Helper for primary plane disable
202  * @plane: plane to disable
203  *
204  * Provides a default plane disable handler for primary planes.  This is handler
205  * is called in response to a userspace SetPlane operation on the plane with a
206  * NULL framebuffer parameter.  It unconditionally fails the disable call with
207  * -EINVAL the only way to disable the primary plane without driver support is
208  * to disable the entier CRTC. Which does not match the plane ->disable hook.
209  *
210  * Note that some hardware may be able to disable the primary plane without
211  * disabling the whole CRTC.  Drivers for such hardware should provide their
212  * own disable handler that disables just the primary plane (and they'll likely
213  * need to provide their own update handler as well to properly re-enable a
214  * disabled primary plane).
215  *
216  * RETURNS:
217  * Unconditionally returns -EINVAL.
218  */
219 int drm_primary_helper_disable(struct drm_plane *plane)
220 {
221 	return -EINVAL;
222 }
223 EXPORT_SYMBOL(drm_primary_helper_disable);
224 
225 /**
226  * drm_primary_helper_destroy() - Helper for primary plane destruction
227  * @plane: plane to destroy
228  *
229  * Provides a default plane destroy handler for primary planes.  This handler
230  * is called during CRTC destruction.  We disable the primary plane, remove
231  * it from the DRM plane list, and deallocate the plane structure.
232  */
233 void drm_primary_helper_destroy(struct drm_plane *plane)
234 {
235 	plane->funcs->disable_plane(plane);
236 	drm_plane_cleanup(plane);
237 	kfree(plane);
238 }
239 EXPORT_SYMBOL(drm_primary_helper_destroy);
240 
241 const struct drm_plane_funcs drm_primary_helper_funcs = {
242 	.update_plane = drm_primary_helper_update,
243 	.disable_plane = drm_primary_helper_disable,
244 	.destroy = drm_primary_helper_destroy,
245 };
246 EXPORT_SYMBOL(drm_primary_helper_funcs);
247 
248 /**
249  * drm_primary_helper_create_plane() - Create a generic primary plane
250  * @dev: drm device
251  * @formats: pixel formats supported, or NULL for a default safe list
252  * @num_formats: size of @formats; ignored if @formats is NULL
253  *
254  * Allocates and initializes a primary plane that can be used with the primary
255  * plane helpers.  Drivers that wish to use driver-specific plane structures or
256  * provide custom handler functions may perform their own allocation and
257  * initialization rather than calling this function.
258  */
259 struct drm_plane *drm_primary_helper_create_plane(struct drm_device *dev,
260 						  const uint32_t *formats,
261 						  int num_formats)
262 {
263 	struct drm_plane *primary;
264 	int ret;
265 
266 	primary = kzalloc(sizeof(*primary), GFP_KERNEL);
267 	if (primary == NULL) {
268 		DRM_DEBUG_KMS("Failed to allocate primary plane\n");
269 		return NULL;
270 	}
271 
272 	if (formats == NULL) {
273 		formats = safe_modeset_formats;
274 		num_formats = ARRAY_SIZE(safe_modeset_formats);
275 	}
276 
277 	/* possible_crtc's will be filled in later by crtc_init */
278 	ret = drm_plane_init(dev, primary, 0, &drm_primary_helper_funcs,
279 			     formats, num_formats,
280 			     DRM_PLANE_TYPE_PRIMARY);
281 	if (ret) {
282 		kfree(primary);
283 		primary = NULL;
284 	}
285 
286 	return primary;
287 }
288 EXPORT_SYMBOL(drm_primary_helper_create_plane);
289 
290 /**
291  * drm_crtc_init - Legacy CRTC initialization function
292  * @dev: DRM device
293  * @crtc: CRTC object to init
294  * @funcs: callbacks for the new CRTC
295  *
296  * Initialize a CRTC object with a default helper-provided primary plane and no
297  * cursor plane.
298  *
299  * Returns:
300  * Zero on success, error code on failure.
301  */
302 int drm_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
303 		  const struct drm_crtc_funcs *funcs)
304 {
305 	struct drm_plane *primary;
306 
307 	primary = drm_primary_helper_create_plane(dev, NULL, 0);
308 	return drm_crtc_init_with_planes(dev, crtc, primary, NULL, funcs);
309 }
310 EXPORT_SYMBOL(drm_crtc_init);
311