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_plane_helper.h>
29 #include <drm/drm_rect.h>
30 #include <drm/drm_plane_helper.h>
31 
32 #define SUBPIXEL_MASK 0xffff
33 
34 /*
35  * This is the minimal list of formats that seem to be safe for modeset use
36  * with all current DRM drivers.  Most hardware can actually support more
37  * formats than this and drivers may specify a more accurate list when
38  * creating the primary plane.  However drivers that still call
39  * drm_plane_init() will use this minimal format list as the default.
40  */
41 static const uint32_t safe_modeset_formats[] = {
42 	DRM_FORMAT_XRGB8888,
43 	DRM_FORMAT_ARGB8888,
44 };
45 
46 /*
47  * Returns the connectors currently associated with a CRTC.  This function
48  * should be called twice:  once with a NULL connector list to retrieve
49  * the list size, and once with the properly allocated list to be filled in.
50  */
51 static int get_connectors_for_crtc(struct drm_crtc *crtc,
52 				   struct drm_connector **connector_list,
53 				   int num_connectors)
54 {
55 	struct drm_device *dev = crtc->dev;
56 	struct drm_connector *connector;
57 	int count = 0;
58 
59 	/*
60 	 * Note: Once we change the plane hooks to more fine-grained locking we
61 	 * need to grab the connection_mutex here to be able to make these
62 	 * checks.
63 	 */
64 	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
65 
66 	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
67 		if (connector->encoder && connector->encoder->crtc == crtc) {
68 			if (connector_list != NULL && count < num_connectors)
69 				*(connector_list++) = connector;
70 
71 			count++;
72 		}
73 
74 	return count;
75 }
76 
77 /**
78  * drm_plane_helper_check_update() - Check plane update for validity
79  * @plane: plane object to update
80  * @crtc: owning CRTC of owning plane
81  * @fb: framebuffer to flip onto plane
82  * @src: source coordinates in 16.16 fixed point
83  * @dest: integer destination coordinates
84  * @clip: integer clipping coordinates
85  * @min_scale: minimum @src:@dest scaling factor in 16.16 fixed point
86  * @max_scale: maximum @src:@dest scaling factor in 16.16 fixed point
87  * @can_position: is it legal to position the plane such that it
88  *                doesn't cover the entire crtc?  This will generally
89  *                only be false for primary planes.
90  * @can_update_disabled: can the plane be updated while the crtc
91  *                       is disabled?
92  * @visible: output parameter indicating whether plane is still visible after
93  *           clipping
94  *
95  * Checks that a desired plane update is valid.  Drivers that provide
96  * their own plane handling rather than helper-provided implementations may
97  * still wish to call this function to avoid duplication of error checking
98  * code.
99  *
100  * RETURNS:
101  * Zero if update appears valid, error code on failure
102  */
103 int drm_plane_helper_check_update(struct drm_plane *plane,
104 				    struct drm_crtc *crtc,
105 				    struct drm_framebuffer *fb,
106 				    struct drm_rect *src,
107 				    struct drm_rect *dest,
108 				    const struct drm_rect *clip,
109 				    int min_scale,
110 				    int max_scale,
111 				    bool can_position,
112 				    bool can_update_disabled,
113 				    bool *visible)
114 {
115 	int hscale, vscale;
116 
117 	if (!crtc->enabled && !can_update_disabled) {
118 		DRM_DEBUG_KMS("Cannot update plane of a disabled CRTC.\n");
119 		return -EINVAL;
120 	}
121 
122 	/* Check scaling */
123 	hscale = drm_rect_calc_hscale(src, dest, min_scale, max_scale);
124 	vscale = drm_rect_calc_vscale(src, dest, min_scale, max_scale);
125 	if (hscale < 0 || vscale < 0) {
126 		DRM_DEBUG_KMS("Invalid scaling of plane\n");
127 		return -ERANGE;
128 	}
129 
130 	*visible = drm_rect_clip_scaled(src, dest, clip, hscale, vscale);
131 	if (!*visible)
132 		/*
133 		 * Plane isn't visible; some drivers can handle this
134 		 * so we just return success here.  Drivers that can't
135 		 * (including those that use the primary plane helper's
136 		 * update function) will return an error from their
137 		 * update_plane handler.
138 		 */
139 		return 0;
140 
141 	if (!can_position && !drm_rect_equals(dest, clip)) {
142 		DRM_DEBUG_KMS("Plane must cover entire CRTC\n");
143 		return -EINVAL;
144 	}
145 
146 	return 0;
147 }
148 EXPORT_SYMBOL(drm_plane_helper_check_update);
149 
150 /**
151  * drm_primary_helper_update() - Helper for primary plane update
152  * @plane: plane object to update
153  * @crtc: owning CRTC of owning plane
154  * @fb: framebuffer to flip onto plane
155  * @crtc_x: x offset of primary plane on crtc
156  * @crtc_y: y offset of primary plane on crtc
157  * @crtc_w: width of primary plane rectangle on crtc
158  * @crtc_h: height of primary plane rectangle on crtc
159  * @src_x: x offset of @fb for panning
160  * @src_y: y offset of @fb for panning
161  * @src_w: width of source rectangle in @fb
162  * @src_h: height of source rectangle in @fb
163  *
164  * Provides a default plane update handler for primary planes.  This is handler
165  * is called in response to a userspace SetPlane operation on the plane with a
166  * non-NULL framebuffer.  We call the driver's modeset handler to update the
167  * framebuffer.
168  *
169  * SetPlane() on a primary plane of a disabled CRTC is not supported, and will
170  * return an error.
171  *
172  * Note that we make some assumptions about hardware limitations that may not be
173  * true for all hardware --
174  *   1) Primary plane cannot be repositioned.
175  *   2) Primary plane cannot be scaled.
176  *   3) Primary plane must cover the entire CRTC.
177  *   4) Subpixel positioning is not supported.
178  * Drivers for hardware that don't have these restrictions can provide their
179  * own implementation rather than using this helper.
180  *
181  * RETURNS:
182  * Zero on success, error code on failure
183  */
184 int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
185 			      struct drm_framebuffer *fb,
186 			      int crtc_x, int crtc_y,
187 			      unsigned int crtc_w, unsigned int crtc_h,
188 			      uint32_t src_x, uint32_t src_y,
189 			      uint32_t src_w, uint32_t src_h)
190 {
191 	struct drm_mode_set set = {
192 		.crtc = crtc,
193 		.fb = fb,
194 		.mode = &crtc->mode,
195 		.x = src_x >> 16,
196 		.y = src_y >> 16,
197 	};
198 	struct drm_rect src = {
199 		.x1 = src_x,
200 		.y1 = src_y,
201 		.x2 = src_x + src_w,
202 		.y2 = src_y + src_h,
203 	};
204 	struct drm_rect dest = {
205 		.x1 = crtc_x,
206 		.y1 = crtc_y,
207 		.x2 = crtc_x + crtc_w,
208 		.y2 = crtc_y + crtc_h,
209 	};
210 	const struct drm_rect clip = {
211 		.x2 = crtc->mode.hdisplay,
212 		.y2 = crtc->mode.vdisplay,
213 	};
214 	struct drm_connector **connector_list;
215 	int num_connectors, ret;
216 	bool visible;
217 
218 	ret = drm_plane_helper_check_update(plane, crtc, fb,
219 					    &src, &dest, &clip,
220 					    DRM_PLANE_HELPER_NO_SCALING,
221 					    DRM_PLANE_HELPER_NO_SCALING,
222 					    false, false, &visible);
223 	if (ret)
224 		return ret;
225 
226 	if (!visible)
227 		/*
228 		 * Primary plane isn't visible.  Note that unless a driver
229 		 * provides their own disable function, this will just
230 		 * wind up returning -EINVAL to userspace.
231 		 */
232 		return plane->funcs->disable_plane(plane);
233 
234 	/* Find current connectors for CRTC */
235 	num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
236 	BUG_ON(num_connectors == 0);
237 	connector_list = kzalloc(num_connectors * sizeof(*connector_list),
238 				 GFP_KERNEL);
239 	if (!connector_list)
240 		return -ENOMEM;
241 	get_connectors_for_crtc(crtc, connector_list, num_connectors);
242 
243 	set.connectors = connector_list;
244 	set.num_connectors = num_connectors;
245 
246 	/*
247 	 * We call set_config() directly here rather than using
248 	 * drm_mode_set_config_internal.  We're reprogramming the same
249 	 * connectors that were already in use, so we shouldn't need the extra
250 	 * cross-CRTC fb refcounting to accomodate stealing connectors.
251 	 * drm_mode_setplane() already handles the basic refcounting for the
252 	 * framebuffers involved in this operation.
253 	 */
254 	ret = crtc->funcs->set_config(&set);
255 
256 	kfree(connector_list);
257 	return ret;
258 }
259 EXPORT_SYMBOL(drm_primary_helper_update);
260 
261 /**
262  * drm_primary_helper_disable() - Helper for primary plane disable
263  * @plane: plane to disable
264  *
265  * Provides a default plane disable handler for primary planes.  This is handler
266  * is called in response to a userspace SetPlane operation on the plane with a
267  * NULL framebuffer parameter.  It unconditionally fails the disable call with
268  * -EINVAL the only way to disable the primary plane without driver support is
269  * to disable the entier CRTC. Which does not match the plane ->disable hook.
270  *
271  * Note that some hardware may be able to disable the primary plane without
272  * disabling the whole CRTC.  Drivers for such hardware should provide their
273  * own disable handler that disables just the primary plane (and they'll likely
274  * need to provide their own update handler as well to properly re-enable a
275  * disabled primary plane).
276  *
277  * RETURNS:
278  * Unconditionally returns -EINVAL.
279  */
280 int drm_primary_helper_disable(struct drm_plane *plane)
281 {
282 	return -EINVAL;
283 }
284 EXPORT_SYMBOL(drm_primary_helper_disable);
285 
286 /**
287  * drm_primary_helper_destroy() - Helper for primary plane destruction
288  * @plane: plane to destroy
289  *
290  * Provides a default plane destroy handler for primary planes.  This handler
291  * is called during CRTC destruction.  We disable the primary plane, remove
292  * it from the DRM plane list, and deallocate the plane structure.
293  */
294 void drm_primary_helper_destroy(struct drm_plane *plane)
295 {
296 	drm_plane_cleanup(plane);
297 	kfree(plane);
298 }
299 EXPORT_SYMBOL(drm_primary_helper_destroy);
300 
301 const struct drm_plane_funcs drm_primary_helper_funcs = {
302 	.update_plane = drm_primary_helper_update,
303 	.disable_plane = drm_primary_helper_disable,
304 	.destroy = drm_primary_helper_destroy,
305 };
306 EXPORT_SYMBOL(drm_primary_helper_funcs);
307 
308 /**
309  * drm_primary_helper_create_plane() - Create a generic primary plane
310  * @dev: drm device
311  * @formats: pixel formats supported, or NULL for a default safe list
312  * @num_formats: size of @formats; ignored if @formats is NULL
313  *
314  * Allocates and initializes a primary plane that can be used with the primary
315  * plane helpers.  Drivers that wish to use driver-specific plane structures or
316  * provide custom handler functions may perform their own allocation and
317  * initialization rather than calling this function.
318  */
319 struct drm_plane *drm_primary_helper_create_plane(struct drm_device *dev,
320 						  const uint32_t *formats,
321 						  int num_formats)
322 {
323 	struct drm_plane *primary;
324 	int ret;
325 
326 	primary = kzalloc(sizeof(*primary), GFP_KERNEL);
327 	if (primary == NULL) {
328 		DRM_DEBUG_KMS("Failed to allocate primary plane\n");
329 		return NULL;
330 	}
331 
332 	if (formats == NULL) {
333 		formats = safe_modeset_formats;
334 		num_formats = ARRAY_SIZE(safe_modeset_formats);
335 	}
336 
337 	/* possible_crtc's will be filled in later by crtc_init */
338 	ret = drm_universal_plane_init(dev, primary, 0,
339 				       &drm_primary_helper_funcs,
340 				       formats, num_formats,
341 				       DRM_PLANE_TYPE_PRIMARY);
342 	if (ret) {
343 		kfree(primary);
344 		primary = NULL;
345 	}
346 
347 	return primary;
348 }
349 EXPORT_SYMBOL(drm_primary_helper_create_plane);
350 
351 /**
352  * drm_crtc_init - Legacy CRTC initialization function
353  * @dev: DRM device
354  * @crtc: CRTC object to init
355  * @funcs: callbacks for the new CRTC
356  *
357  * Initialize a CRTC object with a default helper-provided primary plane and no
358  * cursor plane.
359  *
360  * Returns:
361  * Zero on success, error code on failure.
362  */
363 int drm_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
364 		  const struct drm_crtc_funcs *funcs)
365 {
366 	struct drm_plane *primary;
367 
368 	primary = drm_primary_helper_create_plane(dev, NULL, 0);
369 	return drm_crtc_init_with_planes(dev, crtc, primary, NULL, funcs);
370 }
371 EXPORT_SYMBOL(drm_crtc_init);
372