P4080 PCIe Adapter SDK User Guide Production Release

Freescale Semiconductor
* a software descriptor at the head of the DMA chain, updates the
* fields of that descriptor. Removes EOLN flag on previous link
* descriptor and triggers DMA channel start or continue
*
* @dring – Pointer to the DMA ring of type “struct dma_ring”
* @src_addr – Physical address of the source memory location.
* @dst_addr – Physical address of the destination memory location
* @len – Size of DMA transfer
* @op – Operation to be executed at the end of this DMA transfer
* @p4080_fd – Reference to the FD that triggered this DMA transfer
* @ring_ptr – Pointer to Host or P4080 FD ring
* @pi – Ring index on the FD ring
* @hw_fn_id – Hardware Function identifier
*
* @return – 0 on DMA enqueue success, -1 when DMA ring FULL
*/
The prototype of this API is as follows.
int dma_ring_enq(struct dma_ring *dring, u64 src_addr, u64 dst_addr, int len, int op, void
*p4080_fd, void *ring_ptr, u64 pi, int hw_fn_id);
/**
* API: dma_ring_used_desc – Computes number of DMA descriptors used
* for DMA operation
*
* dring – Pointer to the DMA ring context
*
* @return – Number of used DMA descriptors
*/
The prototype of this API is as follows.
inline int dma_ring_used_desc(struct dma_ring *dring);
/**
* API: dma_ring_free_desc – Computes number of DMA descriptors available
* for DMA operation
*
* dring – Pointer to the DMA ring context
*
* @return – Number of free DMA descriptors
*/
The prototype of this API is as follows.
inline int dma_ring_free_desc(struct dma_ring *dring);
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