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 "intel_frontbuffer.h"
 67#include "i915_drv.h"
 68
 69void __intel_fb_obj_invalidate(struct drm_i915_gem_object *obj,
 70			       enum fb_op_origin origin,
 71			       unsigned int frontbuffer_bits)
 72{
 73	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
 74
 75	if (origin == ORIGIN_CS) {
 76		spin_lock(&dev_priv->fb_tracking.lock);
 77		dev_priv->fb_tracking.busy_bits |= frontbuffer_bits;
 78		dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
 79		spin_unlock(&dev_priv->fb_tracking.lock);
 80	}
 81
 82	intel_psr_invalidate(dev_priv, frontbuffer_bits);
 83	intel_edp_drrs_invalidate(dev_priv, frontbuffer_bits);
 84	intel_fbc_invalidate(dev_priv, frontbuffer_bits, origin);
 85}
 86
 87/**
 88 * intel_frontbuffer_flush - flush frontbuffer
 89 * @dev_priv: i915 device
 90 * @frontbuffer_bits: frontbuffer plane tracking bits
 91 * @origin: which operation caused the flush
 92 *
 93 * This function gets called every time rendering on the given planes has
 94 * completed and frontbuffer caching can be started again. Flushes will get
 95 * delayed if they're blocked by some outstanding asynchronous rendering.
 96 *
 97 * Can be called without any locks held.
 98 */
 99static void intel_frontbuffer_flush(struct drm_i915_private *dev_priv,
100				    unsigned frontbuffer_bits,
101				    enum fb_op_origin origin)
102{
103	/* Delay flushing when rings are still busy.*/
104	spin_lock(&dev_priv->fb_tracking.lock);
105	frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
106	spin_unlock(&dev_priv->fb_tracking.lock);
107
108	if (!frontbuffer_bits)
109		return;
110
111	intel_edp_drrs_flush(dev_priv, frontbuffer_bits);
112	intel_psr_flush(dev_priv, frontbuffer_bits, origin);
113	intel_fbc_flush(dev_priv, frontbuffer_bits, origin);
114}
115
116void __intel_fb_obj_flush(struct drm_i915_gem_object *obj,
117			  bool retire,
118			  enum fb_op_origin origin,
119			  unsigned int frontbuffer_bits)
120{
121	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
122
123	if (retire) {
124		spin_lock(&dev_priv->fb_tracking.lock);
125		/* Filter out new bits since rendering started. */
126		frontbuffer_bits &= dev_priv->fb_tracking.busy_bits;
127		dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
128		spin_unlock(&dev_priv->fb_tracking.lock);
129	}
130
131	if (frontbuffer_bits)
132		intel_frontbuffer_flush(dev_priv, frontbuffer_bits, origin);
133}
134
135/**
136 * intel_frontbuffer_flip_prepare - prepare asynchronous frontbuffer flip
137 * @dev_priv: i915 device
138 * @frontbuffer_bits: frontbuffer plane tracking bits
139 *
140 * This function gets called after scheduling a flip on @obj. The actual
141 * frontbuffer flushing will be delayed until completion is signalled with
142 * intel_frontbuffer_flip_complete. If an invalidate happens in between this
143 * flush will be cancelled.
144 *
145 * Can be called without any locks held.
146 */
147void intel_frontbuffer_flip_prepare(struct drm_i915_private *dev_priv,
148				    unsigned frontbuffer_bits)
149{
150	spin_lock(&dev_priv->fb_tracking.lock);
151	dev_priv->fb_tracking.flip_bits |= frontbuffer_bits;
152	/* Remove stale busy bits due to the old buffer. */
153	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
154	spin_unlock(&dev_priv->fb_tracking.lock);
155
156	intel_psr_single_frame_update(dev_priv, frontbuffer_bits);
157}
158
159/**
160 * intel_frontbuffer_flip_complete - complete asynchronous frontbuffer flip
161 * @dev_priv: i915 device
162 * @frontbuffer_bits: frontbuffer plane tracking bits
163 *
164 * This function gets called after the flip has been latched and will complete
165 * on the next vblank. It will execute the flush if it hasn't been cancelled yet.
166 *
167 * Can be called without any locks held.
168 */
169void intel_frontbuffer_flip_complete(struct drm_i915_private *dev_priv,
170				     unsigned frontbuffer_bits)
171{
172	spin_lock(&dev_priv->fb_tracking.lock);
173	/* Mask any cancelled flips. */
174	frontbuffer_bits &= dev_priv->fb_tracking.flip_bits;
175	dev_priv->fb_tracking.flip_bits &= ~frontbuffer_bits;
176	spin_unlock(&dev_priv->fb_tracking.lock);
177
178	if (frontbuffer_bits)
179		intel_frontbuffer_flush(dev_priv,
180					frontbuffer_bits, ORIGIN_FLIP);
181}
182
183/**
184 * intel_frontbuffer_flip - synchronous frontbuffer flip
185 * @dev_priv: i915 device
186 * @frontbuffer_bits: frontbuffer plane tracking bits
187 *
188 * This function gets called after scheduling a flip on @obj. This is for
189 * synchronous plane updates which will happen on the next vblank and which will
190 * not get delayed by pending gpu rendering.
191 *
192 * Can be called without any locks held.
193 */
194void intel_frontbuffer_flip(struct drm_i915_private *dev_priv,
195			    unsigned frontbuffer_bits)
196{
197	spin_lock(&dev_priv->fb_tracking.lock);
198	/* Remove stale busy bits due to the old buffer. */
199	dev_priv->fb_tracking.busy_bits &= ~frontbuffer_bits;
200	spin_unlock(&dev_priv->fb_tracking.lock);
201
202	intel_frontbuffer_flush(dev_priv, frontbuffer_bits, ORIGIN_FLIP);
203}