drm: add flip-work helper

A small helper to queue up work to do, from workqueue context, after a
flip.  Typically useful to defer unreffing buffers that may be read by
the display controller until vblank.

v1: original
v2: wire up docbook + couple docbook fixes

Signed-off-by: Rob Clark <robdclark@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Rob Clark 2013-08-07 14:41:54 -04:00 committed by Dave Airlie
parent b17df86ece
commit cabaafc789
4 changed files with 207 additions and 1 deletions

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@ -2211,6 +2211,12 @@ void intel_crt_init(struct drm_device *dev)
!Pinclude/drm/drm_rect.h rect utils
!Iinclude/drm/drm_rect.h
!Edrivers/gpu/drm/drm_rect.c
</sect2>
<sect2>
<title>Flip-work Helper Reference</title>
!Pinclude/drm/drm_flip_work.h flip utils
!Iinclude/drm/drm_flip_work.h
!Edrivers/gpu/drm/drm_flip_work.c
</sect2>
<sect2>
<title>VMA Offset Manager</title>

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@ -13,7 +13,7 @@ drm-y := drm_auth.o drm_buffer.o drm_bufs.o drm_cache.o \
drm_crtc.o drm_modes.o drm_edid.o \
drm_info.o drm_debugfs.o drm_encoder_slave.o \
drm_trace_points.o drm_global.o drm_prime.o \
drm_rect.o drm_vma_manager.o
drm_rect.o drm_vma_manager.o drm_flip_work.o
drm-$(CONFIG_COMPAT) += drm_ioc32.o
drm-$(CONFIG_DRM_GEM_CMA_HELPER) += drm_gem_cma_helper.o

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@ -0,0 +1,124 @@
/*
* Copyright (C) 2013 Red Hat
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "drmP.h"
#include "drm_flip_work.h"
/**
* drm_flip_work_queue - queue work
* @work: the flip-work
* @val: the value to queue
*
* Queues work, that will later be run (passed back to drm_flip_func_t
* func) on a work queue after drm_flip_work_commit() is called.
*/
void drm_flip_work_queue(struct drm_flip_work *work, void *val)
{
if (kfifo_put(&work->fifo, (const void **)&val)) {
atomic_inc(&work->pending);
} else {
DRM_ERROR("%s fifo full!\n", work->name);
work->func(work, val);
}
}
EXPORT_SYMBOL(drm_flip_work_queue);
/**
* drm_flip_work_commit - commit queued work
* @work: the flip-work
* @wq: the work-queue to run the queued work on
*
* Trigger work previously queued by drm_flip_work_queue() to run
* on a workqueue. The typical usage would be to queue work (via
* drm_flip_work_queue()) at any point (from vblank irq and/or
* prior), and then from vblank irq commit the queued work.
*/
void drm_flip_work_commit(struct drm_flip_work *work,
struct workqueue_struct *wq)
{
uint32_t pending = atomic_read(&work->pending);
atomic_add(pending, &work->count);
atomic_sub(pending, &work->pending);
queue_work(wq, &work->worker);
}
EXPORT_SYMBOL(drm_flip_work_commit);
static void flip_worker(struct work_struct *w)
{
struct drm_flip_work *work = container_of(w, struct drm_flip_work, worker);
uint32_t count = atomic_read(&work->count);
void *val = NULL;
atomic_sub(count, &work->count);
while(count--)
if (!WARN_ON(!kfifo_get(&work->fifo, &val)))
work->func(work, val);
}
/**
* drm_flip_work_init - initialize flip-work
* @work: the flip-work to initialize
* @size: the max queue depth
* @name: debug name
* @func: the callback work function
*
* Initializes/allocates resources for the flip-work
*
* RETURNS:
* Zero on success, error code on failure.
*/
int drm_flip_work_init(struct drm_flip_work *work, int size,
const char *name, drm_flip_func_t func)
{
int ret;
work->name = name;
atomic_set(&work->count, 0);
atomic_set(&work->pending, 0);
work->func = func;
ret = kfifo_alloc(&work->fifo, size, GFP_KERNEL);
if (ret) {
DRM_ERROR("could not allocate %s fifo\n", name);
return ret;
}
INIT_WORK(&work->worker, flip_worker);
return 0;
}
EXPORT_SYMBOL(drm_flip_work_init);
/**
* drm_flip_work_cleanup - cleans up flip-work
* @work: the flip-work to cleanup
*
* Destroy resources allocated for the flip-work
*/
void drm_flip_work_cleanup(struct drm_flip_work *work)
{
WARN_ON(!kfifo_is_empty(&work->fifo));
kfifo_free(&work->fifo);
}
EXPORT_SYMBOL(drm_flip_work_cleanup);

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@ -0,0 +1,76 @@
/*
* Copyright (C) 2013 Red Hat
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef DRM_FLIP_WORK_H
#define DRM_FLIP_WORK_H
#include <linux/kfifo.h>
#include <linux/workqueue.h>
/**
* DOC: flip utils
*
* Util to queue up work to run from work-queue context after flip/vblank.
* Typically this can be used to defer unref of framebuffer's, cursor
* bo's, etc until after vblank. The APIs are all safe (and lockless)
* for up to one producer and once consumer at a time. The single-consumer
* aspect is ensured by committing the queued work to a single work-queue.
*/
struct drm_flip_work;
/*
* drm_flip_func_t - callback function
*
* @work: the flip work
* @val: value queued via drm_flip_work_queue()
*
* Callback function to be called for each of the queue'd work items after
* drm_flip_work_commit() is called.
*/
typedef void (*drm_flip_func_t)(struct drm_flip_work *work, void *val);
/**
* struct drm_flip_work - flip work queue
* @name: debug name
* @pending: number of queued but not committed items
* @count: number of committed items
* @func: callback fxn called for each committed item
* @worker: worker which calls @func
*/
struct drm_flip_work {
const char *name;
atomic_t pending, count;
drm_flip_func_t func;
struct work_struct worker;
DECLARE_KFIFO_PTR(fifo, void *);
};
void drm_flip_work_queue(struct drm_flip_work *work, void *val);
void drm_flip_work_commit(struct drm_flip_work *work,
struct workqueue_struct *wq);
int drm_flip_work_init(struct drm_flip_work *work, int size,
const char *name, drm_flip_func_t func);
void drm_flip_work_cleanup(struct drm_flip_work *work);
#endif /* DRM_FLIP_WORK_H */