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

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * dma-fence-array: aggregate fences to be waited together
   4 *
   5 * Copyright (C) 2016 Collabora Ltd
   6 * Copyright (C) 2016 Advanced Micro Devices, Inc.
   7 * Authors:
   8 *      Gustavo Padovan <gustavo@padovan.org>
   9 *      Christian König <christian.koenig@amd.com>
  10 */
  11
  12#include <linux/export.h>
  13#include <linux/slab.h>
  14#include <linux/dma-fence-array.h>
  15
  16static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
  17{
  18        return "dma_fence_array";
  19}
  20
  21static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
  22{
  23        return "unbound";
  24}
  25
  26static void irq_dma_fence_array_work(struct irq_work *wrk)
  27{
  28        struct dma_fence_array *array = container_of(wrk, typeof(*array), work);
  29
  30        dma_fence_signal(&array->base);
  31        dma_fence_put(&array->base);
  32}
  33
  34static void dma_fence_array_cb_func(struct dma_fence *f,
  35                                    struct dma_fence_cb *cb)
  36{
  37        struct dma_fence_array_cb *array_cb =
  38                container_of(cb, struct dma_fence_array_cb, cb);
  39        struct dma_fence_array *array = array_cb->array;
  40
  41        if (atomic_dec_and_test(&array->num_pending))
  42                irq_work_queue(&array->work);
  43        else
  44                dma_fence_put(&array->base);
  45}
  46
  47static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
  48{
  49        struct dma_fence_array *array = to_dma_fence_array(fence);
  50        struct dma_fence_array_cb *cb = (void *)(&array[1]);
  51        unsigned i;
  52
  53        for (i = 0; i < array->num_fences; ++i) {
  54                cb[i].array = array;
  55                /*
  56                 * As we may report that the fence is signaled before all
  57                 * callbacks are complete, we need to take an additional
  58                 * reference count on the array so that we do not free it too
  59                 * early. The core fence handling will only hold the reference
  60                 * until we signal the array as complete (but that is now
  61                 * insufficient).
  62                 */
  63                dma_fence_get(&array->base);
  64                if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
  65                                           dma_fence_array_cb_func)) {
  66                        dma_fence_put(&array->base);
  67                        if (atomic_dec_and_test(&array->num_pending))
  68                                return false;
  69                }
  70        }
  71
  72        return true;
  73}
  74
  75static bool dma_fence_array_signaled(struct dma_fence *fence)
  76{
  77        struct dma_fence_array *array = to_dma_fence_array(fence);
  78
  79        return atomic_read(&array->num_pending) <= 0;
  80}
  81
  82static void dma_fence_array_release(struct dma_fence *fence)
  83{
  84        struct dma_fence_array *array = to_dma_fence_array(fence);
  85        unsigned i;
  86
  87        for (i = 0; i < array->num_fences; ++i)
  88                dma_fence_put(array->fences[i]);
  89
  90        kfree(array->fences);
  91        dma_fence_free(fence);
  92}
  93
  94const struct dma_fence_ops dma_fence_array_ops = {
  95        .get_driver_name = dma_fence_array_get_driver_name,
  96        .get_timeline_name = dma_fence_array_get_timeline_name,
  97        .enable_signaling = dma_fence_array_enable_signaling,
  98        .signaled = dma_fence_array_signaled,
  99        .release = dma_fence_array_release,
 100};
 101EXPORT_SYMBOL(dma_fence_array_ops);
 102
 103/**
 104 * dma_fence_array_create - Create a custom fence array
 105 * @num_fences:         [in]    number of fences to add in the array
 106 * @fences:             [in]    array containing the fences
 107 * @context:            [in]    fence context to use
 108 * @seqno:              [in]    sequence number to use
 109 * @signal_on_any:      [in]    signal on any fence in the array
 110 *
 111 * Allocate a dma_fence_array object and initialize the base fence with
 112 * dma_fence_init().
 113 * In case of error it returns NULL.
 114 *
 115 * The caller should allocate the fences array with num_fences size
 116 * and fill it with the fences it wants to add to the object. Ownership of this
 117 * array is taken and dma_fence_put() is used on each fence on release.
 118 *
 119 * If @signal_on_any is true the fence array signals if any fence in the array
 120 * signals, otherwise it signals when all fences in the array signal.
 121 */
 122struct dma_fence_array *dma_fence_array_create(int num_fences,
 123                                               struct dma_fence **fences,
 124                                               u64 context, unsigned seqno,
 125                                               bool signal_on_any)
 126{
 127        struct dma_fence_array *array;
 128        size_t size = sizeof(*array);
 129
 130        /* Allocate the callback structures behind the array. */
 131        size += num_fences * sizeof(struct dma_fence_array_cb);
 132        array = kzalloc(size, GFP_KERNEL);
 133        if (!array)
 134                return NULL;
 135
 136        spin_lock_init(&array->lock);
 137        dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
 138                       context, seqno);
 139        init_irq_work(&array->work, irq_dma_fence_array_work);
 140
 141        array->num_fences = num_fences;
 142        atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
 143        array->fences = fences;
 144
 145        return array;
 146}
 147EXPORT_SYMBOL(dma_fence_array_create);
 148
 149/**
 150 * dma_fence_match_context - Check if all fences are from the given context
 151 * @fence:              [in]    fence or fence array
 152 * @context:            [in]    fence context to check all fences against
 153 *
 154 * Checks the provided fence or, for a fence array, all fences in the array
 155 * against the given context. Returns false if any fence is from a different
 156 * context.
 157 */
 158bool dma_fence_match_context(struct dma_fence *fence, u64 context)
 159{
 160        struct dma_fence_array *array = to_dma_fence_array(fence);
 161        unsigned i;
 162
 163        if (!dma_fence_is_array(fence))
 164                return fence->context == context;
 165
 166        for (i = 0; i < array->num_fences; i++) {
 167                if (array->fences[i]->context != context)
 168                        return false;
 169        }
 170
 171        return true;
 172}
 173EXPORT_SYMBOL(dma_fence_match_context);
 174