linux/drivers/dma-buf/dma-fence-chain.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * fence-chain: chain fences together in a timeline
 *
 * Copyright (C) 2018 Advanced Micro Devices, Inc.
 * Authors:
 *	Christian König <[email protected]>
 */

#include <linux/dma-fence-chain.h>

static bool dma_fence_chain_enable_signaling(struct dma_fence *fence);

/**
 * dma_fence_chain_get_prev - use RCU to get a reference to the previous fence
 * @chain: chain node to get the previous node from
 *
 * Use dma_fence_get_rcu_safe to get a reference to the previous fence of the
 * chain node.
 */
static struct dma_fence *dma_fence_chain_get_prev(struct dma_fence_chain *chain)
{ … }

/**
 * dma_fence_chain_walk - chain walking function
 * @fence: current chain node
 *
 * Walk the chain to the next node. Returns the next fence or NULL if we are at
 * the end of the chain. Garbage collects chain nodes which are already
 * signaled.
 */
struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence)
{ … }
EXPORT_SYMBOL(…);

/**
 * dma_fence_chain_find_seqno - find fence chain node by seqno
 * @pfence: pointer to the chain node where to start
 * @seqno: the sequence number to search for
 *
 * Advance the fence pointer to the chain node which will signal this sequence
 * number. If no sequence number is provided then this is a no-op.
 *
 * Returns EINVAL if the fence is not a chain node or the sequence number has
 * not yet advanced far enough.
 */
int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t seqno)
{ … }
EXPORT_SYMBOL(…);

static const char *dma_fence_chain_get_driver_name(struct dma_fence *fence)
{ … }

static const char *dma_fence_chain_get_timeline_name(struct dma_fence *fence)
{ … }

static void dma_fence_chain_irq_work(struct irq_work *work)
{ … }

static void dma_fence_chain_cb(struct dma_fence *f, struct dma_fence_cb *cb)
{ … }

static bool dma_fence_chain_enable_signaling(struct dma_fence *fence)
{ … }

static bool dma_fence_chain_signaled(struct dma_fence *fence)
{ … }

static void dma_fence_chain_release(struct dma_fence *fence)
{ … }


static void dma_fence_chain_set_deadline(struct dma_fence *fence,
					 ktime_t deadline)
{ … }

const struct dma_fence_ops dma_fence_chain_ops = …;
EXPORT_SYMBOL(…);

/**
 * dma_fence_chain_init - initialize a fence chain
 * @chain: the chain node to initialize
 * @prev: the previous fence
 * @fence: the current fence
 * @seqno: the sequence number to use for the fence chain
 *
 * Initialize a new chain node and either start a new chain or add the node to
 * the existing chain of the previous fence.
 */
void dma_fence_chain_init(struct dma_fence_chain *chain,
			  struct dma_fence *prev,
			  struct dma_fence *fence,
			  uint64_t seqno)
{ … }
EXPORT_SYMBOL(…);