1/*
  2 * Copyright (C) 2013 Red Hat
  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 FROM,
 20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 21 * SOFTWARE.
 22 */
 23
 24#include "drmP.h"
 25#include "drm_flip_work.h"
 26
 27/**
 28 * drm_flip_work_queue - queue work
 29 * @work: the flip-work
 30 * @val: the value to queue
 31 *
 32 * Queues work, that will later be run (passed back to drm_flip_func_t
 33 * func) on a work queue after drm_flip_work_commit() is called.
 34 */
 35void drm_flip_work_queue(struct drm_flip_work *work, void *val)
 36{
 37	if (kfifo_put(&work->fifo, val)) {
 38		atomic_inc(&work->pending);
 39	} else {
 40		DRM_ERROR("%s fifo full!\n", work->name);
 41		work->func(work, val);
 42	}
 43}
 44EXPORT_SYMBOL(drm_flip_work_queue);
 45
 46/**
 47 * drm_flip_work_commit - commit queued work
 48 * @work: the flip-work
 49 * @wq: the work-queue to run the queued work on
 50 *
 51 * Trigger work previously queued by drm_flip_work_queue() to run
 52 * on a workqueue.  The typical usage would be to queue work (via
 53 * drm_flip_work_queue()) at any point (from vblank irq and/or
 54 * prior), and then from vblank irq commit the queued work.
 55 */
 56void drm_flip_work_commit(struct drm_flip_work *work,
 57		struct workqueue_struct *wq)
 58{
 59	uint32_t pending = atomic_read(&work->pending);
 60	atomic_add(pending, &work->count);
 61	atomic_sub(pending, &work->pending);
 62	queue_work(wq, &work->worker);
 63}
 64EXPORT_SYMBOL(drm_flip_work_commit);
 65
 66static void flip_worker(struct work_struct *w)
 67{
 68	struct drm_flip_work *work = container_of(w, struct drm_flip_work, worker);
 69	uint32_t count = atomic_read(&work->count);
 70	void *val = NULL;
 71
 72	atomic_sub(count, &work->count);
 73
 74	while(count--)
 75		if (!WARN_ON(!kfifo_get(&work->fifo, &val)))
 76			work->func(work, val);
 77}
 78
 79/**
 80 * drm_flip_work_init - initialize flip-work
 81 * @work: the flip-work to initialize
 82 * @size: the max queue depth
 83 * @name: debug name
 84 * @func: the callback work function
 85 *
 86 * Initializes/allocates resources for the flip-work
 87 *
 88 * RETURNS:
 89 * Zero on success, error code on failure.
 90 */
 91int drm_flip_work_init(struct drm_flip_work *work, int size,
 92		const char *name, drm_flip_func_t func)
 93{
 94	int ret;
 95
 96	work->name = name;
 97	atomic_set(&work->count, 0);
 98	atomic_set(&work->pending, 0);
 99	work->func = func;
100
101	ret = kfifo_alloc(&work->fifo, size, GFP_KERNEL);
102	if (ret) {
103		DRM_ERROR("could not allocate %s fifo\n", name);
104		return ret;
105	}
106
107	INIT_WORK(&work->worker, flip_worker);
108
109	return 0;
110}
111EXPORT_SYMBOL(drm_flip_work_init);
112
113/**
114 * drm_flip_work_cleanup - cleans up flip-work
115 * @work: the flip-work to cleanup
116 *
117 * Destroy resources allocated for the flip-work
118 */
119void drm_flip_work_cleanup(struct drm_flip_work *work)
120{
121	WARN_ON(!kfifo_is_empty(&work->fifo));
122	kfifo_free(&work->fifo);
123}
124EXPORT_SYMBOL(drm_flip_work_cleanup);