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 * to_dma_fence_chain(struct dma_fence * fence)46to_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 */ 74