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Commit 53c59769 authored by Subash Abhinov Kasiviswanathan's avatar Subash Abhinov Kasiviswanathan
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net: qualcomm: rmnet: Define the MAPv4 packet formats 



The MAPv4 packet format adds support for RX / TX checksum offload.
For a bi-directional UDP stream at a rate of 570 / 146 Mbps, roughly
10% CPU cycles are saved.

For receive path, there is a checksum trailer appended to the end of
the MAP packet. The valid field indicates if hardware has computed
the checksum. csum_start_offset indicates the offset from the start
of the IP header from which hardware has computed checksum.
csum_length is the number of bytes over which the checksum was
computed and the resulting value is csum_value.

In the transmit path, a header is appended between the end of the MAP
header and the start of the IP packet. csum_start_offset is the offset
in bytes from which hardware will compute the checksum if the
csum_enabled bit is set. udp_ip4_ind indicates if the checksum
value of 0 is valid or not. csum_insert_offset is the offset from the
csum_start_offset where hardware will insert the computed checksum.

The use of this additional packet format for checksum offload is
explained in subsequent patches.

CRs-Fixed: 2156182
Change-Id: I7041a98fcfa4c8b7268d590affe3319ec2f38ebd
Signed-off-by: default avatarSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
parent 28464ef6

drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h

+16 −0
Original line number Diff line number Diff line
@@ -47,6 +47,22 @@ struct rmnet_map_header { 
	u16 pkt_len;

}  __aligned(1);



struct rmnet_map_dl_csum_trailer {

	u8  reserved1;

	u8  valid:1;

	u8  reserved2:7;

	u16 csum_start_offset;

	u16 csum_length;

	__be16 csum_value;

} __aligned(1);



struct rmnet_map_ul_csum_header {

	__be16 csum_start_offset;

	u16 csum_insert_offset:14;

	u16 udp_ip4_ind:1;

	u16 csum_enabled:1;

} __aligned(1);



#define RMNET_MAP_GET_MUX_ID(Y) (((struct rmnet_map_header *) \

				 (Y)->data)->mux_id)

#define RMNET_MAP_GET_CD_BIT(Y) (((struct rmnet_map_header *) \

drivers/net/ethernet/qualcomm/rmnet/rmnet_private.h

+2 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
/* Constants */

#define RMNET_INGRESS_FORMAT_DEAGGREGATION      BIT(0)

#define RMNET_INGRESS_FORMAT_MAP_COMMANDS       BIT(1)

#define RMNET_INGRESS_FORMAT_MAP_CKSUMV4        BIT(2)

#define RMNET_EGRESS_FORMAT_MAP_CKSUMV4         BIT(3)



/* Replace skb->dev to a virtual rmnet device and pass up the stack */

#define RMNET_EPMODE_VND (1)