LXR linux/drivers/dma-buf/dma-fence-array.c

   1/*
   2 * dma-fence-array: aggregate fences to be waited together
   3 *
   4 * Copyright (C) 2016 Collabora Ltd
   5 * Copyright (C) 2016 Advanced Micro Devices, Inc.
   6 * Authors:
   7 *      Gustavo Padovan <gustavo@padovan.org>
   8 *      Christian König <christian.koenig@amd.com>
   9 *
  10 * This program is free software; you can redistribute it and/or modify it
  11 * under the terms of the GNU General Public License version 2 as published by
  12 * the Free Software Foundation.
  13 *
  14 * This program is distributed in the hope that it will be useful, but WITHOUT
  15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  17 * more details.
  18 */
  19
  20#include <linux/export.h>
  21#include <linux/slab.h>
  22#include <linux/dma-fence-array.h>
  23
  24static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
  25{
  26        return "dma_fence_array";
  27}
  28
  29static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
  30{
  31        return "unbound";
  32}
  33
  34static void irq_dma_fence_array_work(struct irq_work *wrk)
  35{
  36        struct dma_fence_array *array = container_of(wrk, typeof(*array), work);
  37
  38        dma_fence_signal(&array->base);
  39        dma_fence_put(&array->base);
  40}
  41
  42static void dma_fence_array_cb_func(struct dma_fence *f,
  43                                    struct dma_fence_cb *cb)
  44{
  45        struct dma_fence_array_cb *array_cb =
  46                container_of(cb, struct dma_fence_array_cb, cb);
  47        struct dma_fence_array *array = array_cb->array;
  48
  49        if (atomic_dec_and_test(&array->num_pending))
  50                irq_work_queue(&array->work);
  51        else
  52                dma_fence_put(&array->base);
  53}
  54
  55static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
  56{
  57        struct dma_fence_array *array = to_dma_fence_array(fence);
  58        struct dma_fence_array_cb *cb = (void *)(&array[1]);
  59        unsigned i;
  60
  61        for (i = 0; i < array->num_fences; ++i) {
  62                cb[i].array = array;
  63                /*
  64                 * As we may report that the fence is signaled before all
  65                 * callbacks are complete, we need to take an additional
  66                 * reference count on the array so that we do not free it too
  67                 * early. The core fence handling will only hold the reference
  68                 * until we signal the array as complete (but that is now
  69                 * insufficient).
  70                 */
  71                dma_fence_get(&array->base);
  72                if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
  73                                           dma_fence_array_cb_func)) {
  74                        dma_fence_put(&array->base);
  75                        if (atomic_dec_and_test(&array->num_pending))
  76                                return false;
  77                }
  78        }
  79
  80        return true;
  81}
  82
  83static bool dma_fence_array_signaled(struct dma_fence *fence)
  84{
  85        struct dma_fence_array *array = to_dma_fence_array(fence);
  86
  87        return atomic_read(&array->num_pending) <= 0;
  88}
  89
  90static void dma_fence_array_release(struct dma_fence *fence)
  91{
  92        struct dma_fence_array *array = to_dma_fence_array(fence);
  93        unsigned i;
  94
  95        for (i = 0; i < array->num_fences; ++i)
  96                dma_fence_put(array->fences[i]);
  97
  98        kfree(array->fences);
  99        dma_fence_free(fence);
 100}
 101
 102const struct dma_fence_ops dma_fence_array_ops = {
 103        .get_driver_name = dma_fence_array_get_driver_name,
 104        .get_timeline_name = dma_fence_array_get_timeline_name,
 105        .enable_signaling = dma_fence_array_enable_signaling,
 106        .signaled = dma_fence_array_signaled,
 107        .wait = dma_fence_default_wait,
 108        .release = dma_fence_array_release,
 109};
 110EXPORT_SYMBOL(dma_fence_array_ops);
 111
 112/**
 113 * dma_fence_array_create - Create a custom fence array
 114 * @num_fences:         [in]    number of fences to add in the array
 115 * @fences:             [in]    array containing the fences
 116 * @context:            [in]    fence context to use
 117 * @seqno:              [in]    sequence number to use
 118 * @signal_on_any:      [in]    signal on any fence in the array
 119 *
 120 * Allocate a dma_fence_array object and initialize the base fence with
 121 * dma_fence_init().
 122 * In case of error it returns NULL.
 123 *
 124 * The caller should allocate the fences array with num_fences size
 125 * and fill it with the fences it wants to add to the object. Ownership of this
 126 * array is taken and dma_fence_put() is used on each fence on release.
 127 *
 128 * If @signal_on_any is true the fence array signals if any fence in the array
 129 * signals, otherwise it signals when all fences in the array signal.
 130 */
 131struct dma_fence_array *dma_fence_array_create(int num_fences,
 132                                               struct dma_fence **fences,
 133                                               u64 context, unsigned seqno,
 134                                               bool signal_on_any)
 135{
 136        struct dma_fence_array *array;
 137        size_t size = sizeof(*array);
 138
 139        /* Allocate the callback structures behind the array. */
 140        size += num_fences * sizeof(struct dma_fence_array_cb);
 141        array = kzalloc(size, GFP_KERNEL);
 142        if (!array)
 143                return NULL;
 144
 145        spin_lock_init(&array->lock);
 146        dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
 147                       context, seqno);
 148        init_irq_work(&array->work, irq_dma_fence_array_work);
 149
 150        array->num_fences = num_fences;
 151        atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
 152        array->fences = fences;
 153
 154        return array;
 155}
 156EXPORT_SYMBOL(dma_fence_array_create);
 157
 158/**
 159 * dma_fence_match_context - Check if all fences are from the given context
 160 * @fence:              [in]    fence or fence array
 161 * @context:            [in]    fence context to check all fences against
 162 *
 163 * Checks the provided fence or, for a fence array, all fences in the array
 164 * against the given context. Returns false if any fence is from a different
 165 * context.
 166 */
 167bool dma_fence_match_context(struct dma_fence *fence, u64 context)
 168{
 169        struct dma_fence_array *array = to_dma_fence_array(fence);
 170        unsigned i;
 171
 172        if (!dma_fence_is_array(fence))
 173                return fence->context == context;
 174
 175        for (i = 0; i < array->num_fences; i++) {
 176                if (array->fences[i]->context != context)
 177                        return false;
 178        }
 179
 180        return true;
 181}
 182EXPORT_SYMBOL(dma_fence_match_context);
 183