1/*
  2 * Copyright © 2014 Intel Corporation
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the "Software"),
  6 * to deal in the Software without restriction, including without limitation
  7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  8 * and/or sell copies of the Software, and to permit persons to whom the
  9 * Software is furnished to do so, subject to the following conditions:
 10 *
 11 * The above copyright notice and this permission notice (including the next
 12 * paragraph) shall be included in all copies or substantial portions of the
 13 * Software.
 14 *
 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 21 * DEALINGS IN THE SOFTWARE.
 22 *
 23 * Authors:
 24 *	Daniel Vetter <daniel.vetter@ffwll.ch>
 25 */
 26
 27/**
 28 * DOC: frontbuffer tracking
 29 *
 30 * Many features require us to track changes to the currently active
 31 * frontbuffer, especially rendering targeted at the frontbuffer.
 32 *
 33 * To be able to do so GEM tracks frontbuffers using a bitmask for all possible
 34 * frontbuffer slots through i915_gem_track_fb(). The function in this file are
 35 * then called when the contents of the frontbuffer are invalidated, when
 36 * frontbuffer rendering has stopped again to flush out all the changes and when
 37 * the frontbuffer is exchanged with a flip. Subsystems interested in
 38 * frontbuffer changes (e.g. PSR, FBC, DRRS) should directly put their callbacks
 39 * into the relevant places and filter for the frontbuffer slots that they are
 40 * interested int.
 41 *
 42 * On a high level there are two types of powersaving features. The first one
 43 * work like a special cache (FBC and PSR) and are interested when they should
 44 * stop caching and when to restart caching. This is done by placing callbacks
 45 * into the invalidate and the flush functions: At invalidate the caching must
 46 * be stopped and at flush time it can be restarted. And maybe they need to know
 47 * when the frontbuffer changes (e.g. when the hw doesn't initiate an invalidate
 48 * and flush on its own) which can be achieved with placing callbacks into the
 49 * flip functions.
 50 *
 51 * The other type of display power saving feature only cares about busyness
 52 * (e.g. DRRS). In that case all three (invalidate, flush and flip) indicate
 53 * busyness. There is no direct way to detect idleness. Instead an idle timer
 54 * work delayed work should be started from the flush and flip functions and
 55 * cancelled as soon as busyness is detected.
 56 *
 57 * Note that there's also an older frontbuffer activity tracking scheme which
 58 * just tracks general activity. This is done by the various mark_busy and
 59 * mark_idle functions. For display power management features using these
 60 * functions is deprecated and should be avoided.
 61 */
 62
 63#include <drm/drmP.h>
 64
 65#include "intel_drv.h"
 66#include "i915_drv.h"
 67
 68/**
 69 * intel_fb_obj_invalidate - invalidate frontbuffer object
 70 * @obj: GEM object to invalidate
 71 * @origin: which operation caused the invalidation
 72 *
 73 * This function gets called every time rendering on the given object starts and
 74 * frontbuffer caching (fbc, low refresh rate for DRRS, panel self refresh) must
 75 * be invalidated. For ORIGIN_CS any subsequent invalidation will be delayed
 76 * until the rendering completes or a flip on this frontbuffer plane is
 77 * scheduled.
 78 */
 79void intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
 80			     enum fb_op_origin origin)
 81{
 82	struct drm_device *dev = obj->base.dev;
 83	struct drm_i915_private *dev_priv = to_i915(dev);
 84
 85	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 86
 87	if (!obj->frontbuffer_bits)
 88		return;
 89
 90	if (origin == ORIGIN_CS) {
 91		mutex_lock(&dev_priv->fb_tracking.lock);
 92		dev_priv->fb_tracking.busy_bits
 93			|= obj->frontbuffer_bits;
 94		dev_priv->fb_tracking.flip_bits
 95			&= ~obj->frontbuffer_bits;
 96		mutex_unlock(&dev_priv->fb_tracking.lock);
 97	}
 98
 99	intel_psr_invalidate(dev, obj->frontbuffer_bits);
100	intel_edp_drrs_invalidate(dev, obj->frontbuffer_bits);
101	intel_fbc_invalidate(dev_priv, obj->frontbuffer_bits, origin);
102}
103
104/**
105 * intel_frontbuffer_flush - flush frontbuffer
106 * @dev: DRM device
107 * @frontbuffer_bits: frontbuffer plane tracking bits
108 * @origin: which operation caused the flush
109 *
110 * This function gets called every time rendering on the given planes has
111 * completed and frontbuffer caching can be started again. Flushes will get
112 * delayed if they're blocked by some outstanding asynchronous rendering.
113 *
114 * Can be called without any locks held.
115 */
116static void intel_frontbuffer_flush(struct drm_device *dev,
117				    unsigned frontbuffer_bits,
118				    enum fb_op_origin origin)
119{
120	struct drm_i915_private *dev_priv = to_i915(dev);
121
122	/* Delay flushing when rings are still busy.*/
123	mutex_lock(&dev_priv->fb_tracking.lock);
124	frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
125	mutex_unlock(&dev_priv->fb_tracking.lock);
126
127	if (!frontbuffer_bits)
128		return;
129
130	intel_edp_drrs_flush(dev, frontbuffer_bits);
131	intel_psr_flush(dev, frontbuffer_bits, origin);
132	intel_fbc_flush(dev_priv, frontbuffer_bits, origin);
133}
134
135/**
136 * intel_fb_obj_flush - flush frontbuffer object
137 * @obj: GEM object to flush
138 * @retire: set when retiring asynchronous rendering
139 * @origin: which operation caused the flush
140 *
141 * This function gets called every time rendering on the given object has
142 * completed and frontbuffer caching can be started again. If @retire is true
143 * then any delayed flushes will be unblocked.
144 */
145void intel_fb_obj_flush(struct drm_i915_gem_object *obj,
146			bool retire, enum fb_op_origin origin)
147{
148	struct drm_device *dev = obj->base.dev;
149	struct drm_i915_private *dev_priv = to_i915(dev);
150	unsigned frontbuffer_bits;
151
152	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
153
154	if (!obj->frontbuffer_bits)
155		return;
156
157	frontbuffer_bits = obj->frontbuffer_bits;
158
159	if (retire) {
160		mutex_lock(&dev_priv->fb_tracking.lock);
161		/* Filter out new bits since rendering started. */
162		frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;
163
164		dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
165		mutex_unlock(&dev_priv->fb_tracking.lock);
166	}
167
168	intel_frontbuffer_flush(dev, frontbuffer_bits, origin);
169}
170
171/**
172 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
173 * @dev: DRM device
174 * @frontbuffer_bits: frontbuffer plane tracking bits
175 *
176 * This function gets called after scheduling a flip on @obj. The actual
177 * frontbuffer flushing will be delayed until completion is signalled with
178 * intel_frontbuffer_flip_complete. If an invalidate happens in between this
179 * flush will be cancelled.
180 *
181 * Can be called without any locks held.
182 */
183void intel_frontbuffer_flip_prepare(struct drm_device *dev,
184				    unsigned frontbuffer_bits)
185{
186	struct drm_i915_private *dev_priv = to_i915(dev);
187
188	mutex_lock(&dev_priv->fb_tracking.lock);
189	dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
190	/* Remove stale busy bits due to the old buffer. */
191	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
192	mutex_unlock(&dev_priv->fb_tracking.lock);
193
194	intel_psr_single_frame_update(dev, frontbuffer_bits);
195}
196
197/**
198 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
199 * @dev: DRM device
200 * @frontbuffer_bits: frontbuffer plane tracking bits
201 *
202 * This function gets called after the flip has been latched and will complete
203 * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
204 *
205 * Can be called without any locks held.
206 */
207void intel_frontbuffer_flip_complete(struct drm_device *dev,
208				     unsigned frontbuffer_bits)
209{
210	struct drm_i915_private *dev_priv = to_i915(dev);
211
212	mutex_lock(&dev_priv->fb_tracking.lock);
213	/* Mask any cancelled flips. */
214	frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;
215	dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
216	mutex_unlock(&dev_priv->fb_tracking.lock);
217
218	intel_frontbuffer_flush(dev, frontbuffer_bits, ORIGIN_FLIP);
219}
220
221/**
222 * intel_frontbuffer_flip - synchronous frontbuffer flip
223 * @dev: DRM device
224 * @frontbuffer_bits: frontbuffer plane tracking bits
225 *
226 * This function gets called after scheduling a flip on @obj. This is for
227 * synchronous plane updates which will happen on the next vblank and which will
228 * not get delayed by pending gpu rendering.
229 *
230 * Can be called without any locks held.
231 */
232void intel_frontbuffer_flip(struct drm_device *dev,
233			    unsigned frontbuffer_bits)
234{
235	struct drm_i915_private *dev_priv = to_i915(dev);
236
237	mutex_lock(&dev_priv->fb_tracking.lock);
238	/* Remove stale busy bits due to the old buffer. */
239	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
240	mutex_unlock(&dev_priv->fb_tracking.lock);
241
242	intel_frontbuffer_flush(dev, frontbuffer_bits, ORIGIN_FLIP);
243}