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 | #include <linux/slab.h> |
16 | |
17 | /** |
18 | * struct dma_fence_chain - fence to represent an node of a fence chain |
19 | * @base: fence base class |
20 | * @prev: previous fence of the chain |
21 | * @prev_seqno: original previous seqno before garbage collection |
22 | * @fence: encapsulated fence |
23 | * @lock: spinlock for fence handling |
24 | */ |
25 | struct dma_fence_chain { |
26 | struct dma_fence base; |
27 | struct dma_fence __rcu *prev; |
28 | u64 prev_seqno; |
29 | struct dma_fence *fence; |
30 | union { |
31 | /** |
32 | * @cb: callback for signaling |
33 | * |
34 | * This is used to add the callback for signaling the |
35 | * complection of the fence chain. Never used at the same time |
36 | * as the irq work. |
37 | */ |
38 | struct dma_fence_cb cb; |
39 | |
40 | /** |
41 | * @work: irq work item for signaling |
42 | * |
43 | * Irq work structure to allow us to add the callback without |
44 | * running into lock inversion. Never used at the same time as |
45 | * the callback. |
46 | */ |
47 | struct irq_work work; |
48 | }; |
49 | spinlock_t lock; |
50 | }; |
51 | |
52 | |
53 | /** |
54 | * to_dma_fence_chain - cast a fence to a dma_fence_chain |
55 | * @fence: fence to cast to a dma_fence_array |
56 | * |
57 | * Returns NULL if the fence is not a dma_fence_chain, |
58 | * or the dma_fence_chain otherwise. |
59 | */ |
60 | static inline struct dma_fence_chain * |
61 | to_dma_fence_chain(struct dma_fence *fence) |
62 | { |
63 | if (!fence || !dma_fence_is_chain(fence)) |
64 | return NULL; |
65 | |
66 | return container_of(fence, struct dma_fence_chain, base); |
67 | } |
68 | |
69 | /** |
70 | * dma_fence_chain_contained - return the contained fence |
71 | * @fence: the fence to test |
72 | * |
73 | * If the fence is a dma_fence_chain the function returns the fence contained |
74 | * inside the chain object, otherwise it returns the fence itself. |
75 | */ |
76 | static inline struct dma_fence * |
77 | dma_fence_chain_contained(struct dma_fence *fence) |
78 | { |
79 | struct dma_fence_chain *chain = to_dma_fence_chain(fence); |
80 | |
81 | return chain ? chain->fence : fence; |
82 | } |
83 | |
84 | /** |
85 | * dma_fence_chain_alloc |
86 | * |
87 | * Returns a new struct dma_fence_chain object or NULL on failure. |
88 | */ |
89 | static inline struct dma_fence_chain *dma_fence_chain_alloc(void) |
90 | { |
91 | return kmalloc(size: sizeof(struct dma_fence_chain), GFP_KERNEL); |
92 | }; |
93 | |
94 | /** |
95 | * dma_fence_chain_free |
96 | * @chain: chain node to free |
97 | * |
98 | * Frees up an allocated but not used struct dma_fence_chain object. This |
99 | * doesn't need an RCU grace period since the fence was never initialized nor |
100 | * published. After dma_fence_chain_init() has been called the fence must be |
101 | * released by calling dma_fence_put(), and not through this function. |
102 | */ |
103 | static inline void dma_fence_chain_free(struct dma_fence_chain *chain) |
104 | { |
105 | kfree(objp: chain); |
106 | }; |
107 | |
108 | /** |
109 | * dma_fence_chain_for_each - iterate over all fences in chain |
110 | * @iter: current fence |
111 | * @head: starting point |
112 | * |
113 | * Iterate over all fences in the chain. We keep a reference to the current |
114 | * fence while inside the loop which must be dropped when breaking out. |
115 | * |
116 | * For a deep dive iterator see dma_fence_unwrap_for_each(). |
117 | */ |
118 | #define dma_fence_chain_for_each(iter, head) \ |
119 | for (iter = dma_fence_get(head); iter; \ |
120 | iter = dma_fence_chain_walk(iter)) |
121 | |
122 | struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence); |
123 | int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno); |
124 | void dma_fence_chain_init(struct dma_fence_chain *chain, |
125 | struct dma_fence *prev, |
126 | struct dma_fence *fence, |
127 | uint64_t seqno); |
128 | |
129 | #endif /* __LINUX_DMA_FENCE_CHAIN_H */ |
130 | |