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 <linux/slab.h>
 25
 26#include <drm/drm_flip_work.h>
 27#include <drm/drm_print.h>
 28#include <drm/drm_util.h>
 29
 30/**
 31 * drm_flip_work_allocate_task - allocate a flip-work task
 32 * @data: data associated to the task
 33 * @flags: allocator flags
 34 *
 35 * Allocate a drm_flip_task object and attach private data to it.
 36 */
 37struct drm_flip_task *drm_flip_work_allocate_task(void *data, gfp_t flags)
 38{
 39	struct drm_flip_task *task;
 40
 41	task = kzalloc(sizeof(*task), flags);
 42	if (task)
 43		task->data = data;
 44
 45	return task;
 46}
 47EXPORT_SYMBOL(drm_flip_work_allocate_task);
 48
 49/**
 50 * drm_flip_work_queue_task - queue a specific task
 51 * @work: the flip-work
 52 * @task: the task to handle
 53 *
 54 * Queues task, that will later be run (passed back to drm_flip_func_t
 55 * func) on a work queue after drm_flip_work_commit() is called.
 56 */
 57void drm_flip_work_queue_task(struct drm_flip_work *work,
 58			      struct drm_flip_task *task)
 59{
 60	unsigned long flags;
 61
 62	spin_lock_irqsave(&work->lock, flags);
 63	list_add_tail(&task->node, &work->queued);
 64	spin_unlock_irqrestore(&work->lock, flags);
 65}
 66EXPORT_SYMBOL(drm_flip_work_queue_task);
 67
 68/**
 69 * drm_flip_work_queue - queue work
 70 * @work: the flip-work
 71 * @val: the value to queue
 72 *
 73 * Queues work, that will later be run (passed back to drm_flip_func_t
 74 * func) on a work queue after drm_flip_work_commit() is called.
 75 */
 76void drm_flip_work_queue(struct drm_flip_work *work, void *val)
 77{
 78	struct drm_flip_task *task;
 79
 80	task = drm_flip_work_allocate_task(val,
 81				drm_can_sleep() ? GFP_KERNEL : GFP_ATOMIC);
 82	if (task) {
 83		drm_flip_work_queue_task(work, task);
 84	} else {
 85		DRM_ERROR("%s could not allocate task!\n", work->name);
 86		work->func(work, val);
 87	}
 88}
 89EXPORT_SYMBOL(drm_flip_work_queue);
 90
 91/**
 92 * drm_flip_work_commit - commit queued work
 93 * @work: the flip-work
 94 * @wq: the work-queue to run the queued work on
 95 *
 96 * Trigger work previously queued by drm_flip_work_queue() to run
 97 * on a workqueue.  The typical usage would be to queue work (via
 98 * drm_flip_work_queue()) at any point (from vblank irq and/or
 99 * prior), and then from vblank irq commit the queued work.
100 */
101void drm_flip_work_commit(struct drm_flip_work *work,
102		struct workqueue_struct *wq)
103{
104	unsigned long flags;
105
106	spin_lock_irqsave(&work->lock, flags);
107	list_splice_tail(&work->queued, &work->commited);
108	INIT_LIST_HEAD(&work->queued);
109	spin_unlock_irqrestore(&work->lock, flags);
110	queue_work(wq, &work->worker);
111}
112EXPORT_SYMBOL(drm_flip_work_commit);
113
114static void flip_worker(struct work_struct *w)
115{
116	struct drm_flip_work *work = container_of(w, struct drm_flip_work, worker);
117	struct list_head tasks;
118	unsigned long flags;
119
120	while (1) {
121		struct drm_flip_task *task, *tmp;
122
123		INIT_LIST_HEAD(&tasks);
124		spin_lock_irqsave(&work->lock, flags);
125		list_splice_tail(&work->commited, &tasks);
126		INIT_LIST_HEAD(&work->commited);
127		spin_unlock_irqrestore(&work->lock, flags);
128
129		if (list_empty(&tasks))
130			break;
131
132		list_for_each_entry_safe(task, tmp, &tasks, node) {
133			work->func(work, task->data);
134			kfree(task);
135		}
136	}
137}
138
139/**
140 * drm_flip_work_init - initialize flip-work
141 * @work: the flip-work to initialize
142 * @name: debug name
143 * @func: the callback work function
144 *
145 * Initializes/allocates resources for the flip-work
146 */
147void drm_flip_work_init(struct drm_flip_work *work,
148		const char *name, drm_flip_func_t func)
149{
150	work->name = name;
151	INIT_LIST_HEAD(&work->queued);
152	INIT_LIST_HEAD(&work->commited);
153	spin_lock_init(&work->lock);
154	work->func = func;
155
156	INIT_WORK(&work->worker, flip_worker);
157}
158EXPORT_SYMBOL(drm_flip_work_init);
159
160/**
161 * drm_flip_work_cleanup - cleans up flip-work
162 * @work: the flip-work to cleanup
163 *
164 * Destroy resources allocated for the flip-work
165 */
166void drm_flip_work_cleanup(struct drm_flip_work *work)
167{
168	WARN_ON(!list_empty(&work->queued) || !list_empty(&work->commited));
169}
170EXPORT_SYMBOL(drm_flip_work_cleanup);