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
  16 static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
  17 {
  18         return "dma_fence_array";
  19 }
  20
  21 static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
  22 {
  23         return "unbound";
  24 }
  25
  26 static 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
  34 static 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
  47 static 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
  75 static 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
  82 static 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
  94 const 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 };
 101 EXPORT_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  */
 122 struct 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 }
 147 EXPORT_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  */
 158 bool 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 }
 173 EXPORT_SYMBOL(dma_fence_match_context);