include/linux/dma-fence-chain.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * fence-chain: chain fences together in a timeline
   4  *
   5  * Copyright (C) 2018 Advanced Micro Devices, Inc.
   6  * Authors:
   7  *      Christian König <christian.koenig@amd.com>
   8  */
   9
  10 #ifndef __LINUX_DMA_FENCE_CHAIN_H
  11 #define __LINUX_DMA_FENCE_CHAIN_H
  12
  13 #include <linux/dma-fence.h>
  14 #include <linux/irq_work.h>
  15
  16 /**
  17  * struct dma_fence_chain - fence to represent an node of a fence chain
  18  * @base: fence base class
  19  * @lock: spinlock for fence handling
  20  * @prev: previous fence of the chain
  21  * @prev_seqno: original previous seqno before garbage collection
  22  * @fence: encapsulated fence
  23  * @cb: callback structure for signaling
  24  * @work: irq work item for signaling
  25  */
  26 struct dma_fence_chain {
  27         struct dma_fence base;
  28         spinlock_t lock;
  29         struct dma_fence __rcu *prev;
  30         u64 prev_seqno;
  31         struct dma_fence *fence;
  32         struct dma_fence_cb cb;
  33         struct irq_work work;
  34 };
  35
  36 extern const struct dma_fence_ops dma_fence_chain_ops;
  37
  38 /**
  39  * to_dma_fence_chain - cast a fence to a dma_fence_chain
  40  * @fence: fence to cast to a dma_fence_array
  41  *
  42  * Returns NULL if the fence is not a dma_fence_chain,
  43  * or the dma_fence_chain otherwise.
  44  */
  45 static inline struct dma_fence_chain *
  46 to_dma_fence_chain(struct dma_fence *fence)
  47 {
  48         if (!fence || fence->ops != &dma_fence_chain_ops)
  49                 return NULL;
  50
  51         return container_of(fence, struct dma_fence_chain, base);
  52 }
  53
  54 /**
  55  * dma_fence_chain_for_each - iterate over all fences in chain
  56  * @iter: current fence
  57  * @head: starting point
  58  *
  59  * Iterate over all fences in the chain. We keep a reference to the current
  60  * fence while inside the loop which must be dropped when breaking out.
  61  */
  62 #define dma_fence_chain_for_each(iter, head)    \
  63         for (iter = dma_fence_get(head); iter; \
  64              iter = dma_fence_chain_walk(iter))
  65
  66 struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence);
  67 int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno);
  68 void dma_fence_chain_init(struct dma_fence_chain *chain,
  69                           struct dma_fence *prev,
  70                           struct dma_fence *fence,
  71                           uint64_t seqno);
  72
  73 #endif /* __LINUX_DMA_FENCE_CHAIN_H */