DMA segment. More...

#include <dma_types.h>

Collaboration diagram for odp_dma_seg_t:

Data Fields
union {
void * addr
	Segment start address in memory. More...

odp_packet_t packet
	Packet handle. More...

struct {
uint32_t pkt_index
	Packet index. More...

uint32_t pkt_len
	Packet length. More...

}
	Packet index configuration.

};
	Segment start address or packet handle.

uint32_t	len
	Segment length in bytes. More...

uint32_t	offset
	Segment start offset into the packet. More...

struct {
union {
struct {
uint16_t full_lines: 1
	Allow full cache line access. More...

uint16_t cache_stash_l3: 1
	Enable L3 cache stashing. More...

} bit
	Segment hints bit field. More...

uint16_t all_bits
	All bits of the bit field structure. More...

}

struct {
struct {
uint32_t offset
	Byte offset into the segment data to start caching from. More...

uint32_t len
	Length in bytes to cache. More...

} l3
	L3 cache stashing.

} cache_stash
	Cache stashing hints. More...

}	hints
	Segment hints. More...

Detailed Description

DMA segment.

Examples: odp_dma_perf.c, and odp_dmafwd.c.

Definition at line 406 of file api/spec/dma_types.h.

Field Documentation

◆ addr

void* odp_dma_seg_t::addr

Segment start address in memory.

Defines segment start when data format is ODP_DMA_FORMAT_ADDR. Ignored with other data formats.

Examples: odp_dma_perf.c.

Definition at line 414 of file api/spec/dma_types.h.

◆ packet

odp_packet_t odp_dma_seg_t::packet

Packet handle.

Defines the packet when data format is ODP_DMA_FORMAT_PACKET. Ignored with other data formats.

Examples: odp_dma_perf.c, and odp_dmafwd.c.

Definition at line 420 of file api/spec/dma_types.h.

◆ pkt_index

uint32_t odp_dma_seg_t::pkt_index

Packet index.

When odp_dma_transfer_param_t::seg_alloc is used, implementation allocates all required destination packets and this pkt_index field can be used to define which packet of the to-be-allocated array of packets is used as the destination for this particular destination segment descriptor. Same pkt_index can be reused across subsequent segments if application wishes to transfer to different offsets of the same destination packet. This means that if application for example uses packet index 0 in each destination segment descriptor (with different 'offset' values), implementation would allocate only a single packet with data being transferred to different offsets of that single destination packet. pkt_index should appear in ascending order, starting from index 0.

Definition at line 439 of file api/spec/dma_types.h.

◆ pkt_len

uint32_t odp_dma_seg_t::pkt_len

Packet length.

Length of the indexed to-be-allocated packet. In case of pkt_index reuse across segment descriptors, each new pkt_index should have a valid 'pkt_len' field set, other descriptor 'pkt_len' fields are ignored for the same pkt_index. 'pkt_len' of a pkt_index cannot be shorter than the total length of odp_dma_seg_t::len fields of the segment descriptors using this packet index.

Definition at line 450 of file api/spec/dma_types.h.

◆ len

uint32_t odp_dma_seg_t::len

Segment length in bytes.

Length in bytes to cache.

Defines segment length with all data formats. The maximum value is defined by max_seg_len capability. When data format is ODP_DMA_FORMAT_PACKET, the value must not exceed odp_packet_len() - 'offset'.

Depending on the implementation, this might be rounded up to a more suitable boundary.

Examples: odp_dma_perf.c, and odp_dmafwd.c.

Definition at line 460 of file api/spec/dma_types.h.

◆ offset

uint32_t odp_dma_seg_t::offset

Segment start offset into the packet.

Byte offset into the segment data to start caching from.

Defines segment start within the packet data. The offset is calculated from odp_packet_data() position, and the value must not exceed odp_packet_len(). Ignored when data format is other than ODP_DMA_FORMAT_PACKET.

Depending on the implementation, this might be rounded down to a more suitable boundary. In case of ODP_DMA_FORMAT_PACKET, offset is in addition to the packet data starting offset.

Examples: odp_dma_perf.c.

Definition at line 468 of file api/spec/dma_types.h.

◆ full_lines

uint16_t odp_dma_seg_t::full_lines

Allow full cache line access.

When set to 1, data on the same cache line with the destination segment is allowed to be overwritten. This hint is ignored on source segments.

Definition at line 487 of file api/spec/dma_types.h.

◆ cache_stash_l3

uint16_t odp_dma_seg_t::cache_stash_l3

Enable L3 cache stashing.

When set to 1, enables potential cache stashing of destination segment data to L3 according to 'cache_stash'.

Definition at line 494 of file api/spec/dma_types.h.

◆

struct { ... } odp_dma_seg_t::bit

Segment hints bit field.

Initialize all unused bits to zero.

◆ all_bits

uint16_t odp_dma_seg_t::all_bits

All bits of the bit field structure.

This can be used to set/clear all bits, or to perform bitwise operations on those.

Definition at line 502 of file api/spec/dma_types.h.

◆

struct { ... } odp_dma_seg_t::cache_stash

Cache stashing hints.

Applicable only to destination segments. Ignored for source segments. Hints implementation to bring specififed cache lines into cache as part of successful transfer completion.

◆

struct { ... } odp_dma_seg_t::hints

Segment hints.

Depending on the implementation, setting these hints may improve performance.

The documentation for this struct was generated from the following file:

api/spec/dma_types.h

Data Fields