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
  24 static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
  25 {
  26         return "dma_fence_array";
  27 }
  28
  29 static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
  30 {
  31         return "unbound";
  32 }
  33
  34 static 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
  42 static 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
  55 static 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
  83 static 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
  90 static 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
 102 const 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         .release = dma_fence_array_release,
 108 };
 109 EXPORT_SYMBOL(dma_fence_array_ops);
 110
 111 /**
 112  * dma_fence_array_create - Create a custom fence array
 113  * @num_fences:         [in]    number of fences to add in the array
 114  * @fences:             [in]    array containing the fences
 115  * @context:            [in]    fence context to use
 116  * @seqno:              [in]    sequence number to use
 117  * @signal_on_any:      [in]    signal on any fence in the array
 118  *
 119  * Allocate a dma_fence_array object and initialize the base fence with
 120  * dma_fence_init().
 121  * In case of error it returns NULL.
 122  *
 123  * The caller should allocate the fences array with num_fences size
 124  * and fill it with the fences it wants to add to the object. Ownership of this
 125  * array is taken and dma_fence_put() is used on each fence on release.
 126  *
 127  * If @signal_on_any is true the fence array signals if any fence in the array
 128  * signals, otherwise it signals when all fences in the array signal.
 129  */
 130 struct dma_fence_array *dma_fence_array_create(int num_fences,
 131                                                struct dma_fence **fences,
 132                                                u64 context, unsigned seqno,
 133                                                bool signal_on_any)
 134 {
 135         struct dma_fence_array *array;
 136         size_t size = sizeof(*array);
 137
 138         /* Allocate the callback structures behind the array. */
 139         size += num_fences * sizeof(struct dma_fence_array_cb);
 140         array = kzalloc(size, GFP_KERNEL);
 141         if (!array)
 142                 return NULL;
 143
 144         spin_lock_init(&array->lock);
 145         dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
 146                        context, seqno);
 147         init_irq_work(&array->work, irq_dma_fence_array_work);
 148
 149         array->num_fences = num_fences;
 150         atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
 151         array->fences = fences;
 152
 153         return array;
 154 }
 155 EXPORT_SYMBOL(dma_fence_array_create);
 156
 157 /**
 158  * dma_fence_match_context - Check if all fences are from the given context
 159  * @fence:              [in]    fence or fence array
 160  * @context:            [in]    fence context to check all fences against
 161  *
 162  * Checks the provided fence or, for a fence array, all fences in the array
 163  * against the given context. Returns false if any fence is from a different
 164  * context.
 165  */
 166 bool dma_fence_match_context(struct dma_fence *fence, u64 context)
 167 {
 168         struct dma_fence_array *array = to_dma_fence_array(fence);
 169         unsigned i;
 170
 171         if (!dma_fence_is_array(fence))
 172                 return fence->context == context;
 173
 174         for (i = 0; i < array->num_fences; i++) {
 175                 if (array->fences[i]->context != context)
 176                         return false;
 177         }
 178
 179         return true;
 180 }
 181 EXPORT_SYMBOL(dma_fence_match_context);