Line data    Source code

       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             : #define PENDING_ERROR 1
      17             : 
      18           0 : static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
      19             : {
      20           0 :         return "dma_fence_array";
      21             : }
      22             : 
      23           0 : static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
      24             : {
      25           0 :         return "unbound";
      26             : }
      27             : 
      28             : static void dma_fence_array_set_pending_error(struct dma_fence_array *array,
      29             :                                               int error)
      30             : {
      31             :         /*
      32             :          * Propagate the first error reported by any of our fences, but only
      33             :          * before we ourselves are signaled.
      34             :          */
      35           0 :         if (error)
      36           0 :                 cmpxchg(&array->base.error, PENDING_ERROR, error);
      37             : }
      38             : 
      39             : static void dma_fence_array_clear_pending_error(struct dma_fence_array *array)
      40             : {
      41             :         /* Clear the error flag if not actually set. */
      42           0 :         cmpxchg(&array->base.error, PENDING_ERROR, 0);
      43             : }
      44             : 
      45           0 : static void irq_dma_fence_array_work(struct irq_work *wrk)
      46             : {
      47           0 :         struct dma_fence_array *array = container_of(wrk, typeof(*array), work);
      48             : 
      49           0 :         dma_fence_array_clear_pending_error(array);
      50             : 
      51           0 :         dma_fence_signal(&array->base);
      52           0 :         dma_fence_put(&array->base);
      53           0 : }
      54             : 
      55           0 : static void dma_fence_array_cb_func(struct dma_fence *f,
      56             :                                     struct dma_fence_cb *cb)
      57             : {
      58           0 :         struct dma_fence_array_cb *array_cb =
      59           0 :                 container_of(cb, struct dma_fence_array_cb, cb);
      60           0 :         struct dma_fence_array *array = array_cb->array;
      61             : 
      62           0 :         dma_fence_array_set_pending_error(array, f->error);
      63             : 
      64           0 :         if (atomic_dec_and_test(&array->num_pending))
      65           0 :                 irq_work_queue(&array->work);
      66             :         else
      67           0 :                 dma_fence_put(&array->base);
      68           0 : }
      69             : 
      70           0 : static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
      71             : {
      72           0 :         struct dma_fence_array *array = to_dma_fence_array(fence);
      73           0 :         struct dma_fence_array_cb *cb = (void *)(&array[1]);
      74             :         unsigned i;
      75             : 
      76           0 :         for (i = 0; i < array->num_fences; ++i) {
      77           0 :                 cb[i].array = array;
      78             :                 /*
      79             :                  * As we may report that the fence is signaled before all
      80             :                  * callbacks are complete, we need to take an additional
      81             :                  * reference count on the array so that we do not free it too
      82             :                  * early. The core fence handling will only hold the reference
      83             :                  * until we signal the array as complete (but that is now
      84             :                  * insufficient).
      85             :                  */
      86           0 :                 dma_fence_get(&array->base);
      87           0 :                 if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
      88             :                                            dma_fence_array_cb_func)) {
      89           0 :                         int error = array->fences[i]->error;
      90             : 
      91           0 :                         dma_fence_array_set_pending_error(array, error);
      92           0 :                         dma_fence_put(&array->base);
      93           0 :                         if (atomic_dec_and_test(&array->num_pending)) {
      94           0 :                                 dma_fence_array_clear_pending_error(array);
      95           0 :                                 return false;
      96             :                         }
      97             :                 }
      98             :         }
      99             : 
     100             :         return true;
     101             : }
     102             : 
     103           0 : static bool dma_fence_array_signaled(struct dma_fence *fence)
     104             : {
     105           0 :         struct dma_fence_array *array = to_dma_fence_array(fence);
     106             : 
     107           0 :         if (atomic_read(&array->num_pending) > 0)
     108             :                 return false;
     109             : 
     110           0 :         dma_fence_array_clear_pending_error(array);
     111           0 :         return true;
     112             : }
     113             : 
     114           0 : static void dma_fence_array_release(struct dma_fence *fence)
     115             : {
     116           0 :         struct dma_fence_array *array = to_dma_fence_array(fence);
     117             :         unsigned i;
     118             : 
     119           0 :         for (i = 0; i < array->num_fences; ++i)
     120           0 :                 dma_fence_put(array->fences[i]);
     121             : 
     122           0 :         kfree(array->fences);
     123           0 :         dma_fence_free(fence);
     124           0 : }
     125             : 
     126             : const struct dma_fence_ops dma_fence_array_ops = {
     127             :         .get_driver_name = dma_fence_array_get_driver_name,
     128             :         .get_timeline_name = dma_fence_array_get_timeline_name,
     129             :         .enable_signaling = dma_fence_array_enable_signaling,
     130             :         .signaled = dma_fence_array_signaled,
     131             :         .release = dma_fence_array_release,
     132             : };
     133             : EXPORT_SYMBOL(dma_fence_array_ops);
     134             : 
     135             : /**
     136             :  * dma_fence_array_create - Create a custom fence array
     137             :  * @num_fences:         [in]    number of fences to add in the array
     138             :  * @fences:             [in]    array containing the fences
     139             :  * @context:            [in]    fence context to use
     140             :  * @seqno:              [in]    sequence number to use
     141             :  * @signal_on_any:      [in]    signal on any fence in the array
     142             :  *
     143             :  * Allocate a dma_fence_array object and initialize the base fence with
     144             :  * dma_fence_init().
     145             :  * In case of error it returns NULL.
     146             :  *
     147             :  * The caller should allocate the fences array with num_fences size
     148             :  * and fill it with the fences it wants to add to the object. Ownership of this
     149             :  * array is taken and dma_fence_put() is used on each fence on release.
     150             :  *
     151             :  * If @signal_on_any is true the fence array signals if any fence in the array
     152             :  * signals, otherwise it signals when all fences in the array signal.
     153             :  */
     154           0 : struct dma_fence_array *dma_fence_array_create(int num_fences,
     155             :                                                struct dma_fence **fences,
     156             :                                                u64 context, unsigned seqno,
     157             :                                                bool signal_on_any)
     158             : {
     159             :         struct dma_fence_array *array;
     160           0 :         size_t size = sizeof(*array);
     161             : 
     162           0 :         WARN_ON(!num_fences || !fences);
     163             : 
     164             :         /* Allocate the callback structures behind the array. */
     165           0 :         size += num_fences * sizeof(struct dma_fence_array_cb);
     166           0 :         array = kzalloc(size, GFP_KERNEL);
     167           0 :         if (!array)
     168             :                 return NULL;
     169             : 
     170           0 :         spin_lock_init(&array->lock);
     171           0 :         dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
     172             :                        context, seqno);
     173           0 :         init_irq_work(&array->work, irq_dma_fence_array_work);
     174             : 
     175           0 :         array->num_fences = num_fences;
     176           0 :         atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
     177           0 :         array->fences = fences;
     178             : 
     179           0 :         array->base.error = PENDING_ERROR;
     180             : 
     181             :         /*
     182             :          * dma_fence_array objects should never contain any other fence
     183             :          * containers or otherwise we run into recursion and potential kernel
     184             :          * stack overflow on operations on the dma_fence_array.
     185             :          *
     186             :          * The correct way of handling this is to flatten out the array by the
     187             :          * caller instead.
     188             :          *
     189             :          * Enforce this here by checking that we don't create a dma_fence_array
     190             :          * with any container inside.
     191             :          */
     192           0 :         while (num_fences--)
     193           0 :                 WARN_ON(dma_fence_is_container(fences[num_fences]));
     194             : 
     195             :         return array;
     196             : }
     197             : EXPORT_SYMBOL(dma_fence_array_create);
     198             : 
     199             : /**
     200             :  * dma_fence_match_context - Check if all fences are from the given context
     201             :  * @fence:              [in]    fence or fence array
     202             :  * @context:            [in]    fence context to check all fences against
     203             :  *
     204             :  * Checks the provided fence or, for a fence array, all fences in the array
     205             :  * against the given context. Returns false if any fence is from a different
     206             :  * context.
     207             :  */
     208           0 : bool dma_fence_match_context(struct dma_fence *fence, u64 context)
     209             : {
     210           0 :         struct dma_fence_array *array = to_dma_fence_array(fence);
     211             :         unsigned i;
     212             : 
     213           0 :         if (!dma_fence_is_array(fence))
     214           0 :                 return fence->context == context;
     215             : 
     216           0 :         for (i = 0; i < array->num_fences; i++) {
     217           0 :                 if (array->fences[i]->context != context)
     218             :                         return false;
     219             :         }
     220             : 
     221             :         return true;
     222             : }
     223             : EXPORT_SYMBOL(dma_fence_match_context);
     224             : 
     225           0 : struct dma_fence *dma_fence_array_first(struct dma_fence *head)
     226             : {
     227             :         struct dma_fence_array *array;
     228             : 
     229           0 :         if (!head)
     230             :                 return NULL;
     231             : 
     232           0 :         array = to_dma_fence_array(head);
     233           0 :         if (!array)
     234             :                 return head;
     235             : 
     236           0 :         if (!array->num_fences)
     237             :                 return NULL;
     238             : 
     239           0 :         return array->fences[0];
     240             : }
     241             : EXPORT_SYMBOL(dma_fence_array_first);
     242             : 
     243           0 : struct dma_fence *dma_fence_array_next(struct dma_fence *head,
     244             :                                        unsigned int index)
     245             : {
     246           0 :         struct dma_fence_array *array = to_dma_fence_array(head);
     247             : 
     248           0 :         if (!array || index >= array->num_fences)
     249             :                 return NULL;
     250             : 
     251           0 :         return array->fences[index];
     252             : }
     253             : EXPORT_SYMBOL(dma_fence_array_next);