132 lines
3.7 KiB
C
132 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* fence-chain: chain fences together in a timeline
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*
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* Copyright (C) 2018 Advanced Micro Devices, Inc.
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* Authors:
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* Christian König <christian.koenig@amd.com>
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*/
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#ifndef __LINUX_DMA_FENCE_CHAIN_H
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#define __LINUX_DMA_FENCE_CHAIN_H
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#include <linux/dma-fence.h>
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#include <linux/irq_work.h>
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#include <linux/slab.h>
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/**
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* struct dma_fence_chain - fence to represent an node of a fence chain
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* @base: fence base class
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* @prev: previous fence of the chain
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* @prev_seqno: original previous seqno before garbage collection
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* @fence: encapsulated fence
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* @lock: spinlock for fence handling
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*/
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struct dma_fence_chain {
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struct dma_fence base;
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struct dma_fence __rcu *prev;
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u64 prev_seqno;
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struct dma_fence *fence;
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union {
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/**
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* @cb: callback for signaling
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*
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* This is used to add the callback for signaling the
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* complection of the fence chain. Never used at the same time
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* as the irq work.
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*/
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struct dma_fence_cb cb;
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/**
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* @work: irq work item for signaling
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*
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* Irq work structure to allow us to add the callback without
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* running into lock inversion. Never used at the same time as
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* the callback.
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*/
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struct irq_work work;
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};
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spinlock_t lock;
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};
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/**
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* to_dma_fence_chain - cast a fence to a dma_fence_chain
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* @fence: fence to cast to a dma_fence_array
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*
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* Returns NULL if the fence is not a dma_fence_chain,
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* or the dma_fence_chain otherwise.
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*/
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static inline struct dma_fence_chain *
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to_dma_fence_chain(struct dma_fence *fence)
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{
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if (!fence || !dma_fence_is_chain(fence))
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return NULL;
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return container_of(fence, struct dma_fence_chain, base);
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}
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/**
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* dma_fence_chain_contained - return the contained fence
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* @fence: the fence to test
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*
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* If the fence is a dma_fence_chain the function returns the fence contained
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* inside the chain object, otherwise it returns the fence itself.
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*/
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static inline struct dma_fence *
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dma_fence_chain_contained(struct dma_fence *fence)
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{
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struct dma_fence_chain *chain = to_dma_fence_chain(fence);
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return chain ? chain->fence : fence;
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}
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/**
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* dma_fence_chain_alloc
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*
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* Returns a new struct dma_fence_chain object or NULL on failure.
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*
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* This specialized allocator has to be a macro for its allocations to be
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* accounted separately (to have a separate alloc_tag). The typecast is
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* intentional to enforce typesafety.
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*/
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#define dma_fence_chain_alloc() \
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((struct dma_fence_chain *)kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL))
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/**
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* dma_fence_chain_free
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* @chain: chain node to free
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*
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* Frees up an allocated but not used struct dma_fence_chain object. This
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* doesn't need an RCU grace period since the fence was never initialized nor
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* published. After dma_fence_chain_init() has been called the fence must be
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* released by calling dma_fence_put(), and not through this function.
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*/
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static inline void dma_fence_chain_free(struct dma_fence_chain *chain)
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{
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kfree(chain);
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};
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/**
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* dma_fence_chain_for_each - iterate over all fences in chain
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* @iter: current fence
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* @head: starting point
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*
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* Iterate over all fences in the chain. We keep a reference to the current
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* fence while inside the loop which must be dropped when breaking out.
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*
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* For a deep dive iterator see dma_fence_unwrap_for_each().
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*/
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#define dma_fence_chain_for_each(iter, head) \
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for (iter = dma_fence_get(head); iter; \
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iter = dma_fence_chain_walk(iter))
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struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence);
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int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno);
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void dma_fence_chain_init(struct dma_fence_chain *chain,
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struct dma_fence *prev,
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struct dma_fence *fence,
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uint64_t seqno);
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#endif /* __LINUX_DMA_FENCE_CHAIN_H */
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