drivers/gpu/drm/drm_flip_work.c

   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  */
  35 void drm_flip_work_queue(struct drm_flip_work *work, void *val)
  36 {
  37         if (kfifo_put(&work->fifo, (const void **)&val)) {
  38                 atomic_inc(&work->pending);
  39         } else {
  40                 DRM_ERROR("%s fifo full!\n", work->name);
  41                 work->func(work, val);
  42         }
  43 }
  44 EXPORT_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  */
  56 void 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 }
  64 EXPORT_SYMBOL(drm_flip_work_commit);
  65
  66 static 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  */
  91 int 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 }
 111 EXPORT_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  */
 119 void drm_flip_work_cleanup(struct drm_flip_work *work)
 120 {
 121         WARN_ON(!kfifo_is_empty(&work->fifo));
 122         kfifo_free(&work->fifo);
 123 }
 124 EXPORT_SYMBOL(drm_flip_work_cleanup);