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Commit 2b6fc24b authored by Subash Abhinov Kasiviswanathan's avatar Subash Abhinov Kasiviswanathan
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net: qualcomm: rmnet: Add support for TX checksum offload 



TX checksum offload applies to TCP / UDP packets which are not
fragmented using the MAPv4 checksum trailer. The following needs to be
done to have checksum computed in hardware -

1. Set the checksum start offset and inset offset.
2. Set the csum_enabled bit
3. Compute and set 1's complement of partial checksum field in
   transport header.

CRs-Fixed: 2156182
Change-Id: I49c01f0b3404d7897b3d2ab99f95ec69787e4b08
Signed-off-by: default avatarSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
parent 348d753d

drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c

+8 −0
Original line number Diff line number Diff line
@@ -141,11 +141,19 @@ static int rmnet_map_egress_handler(struct sk_buff *skb, 
	additional_header_len = 0;

	required_headroom = sizeof(struct rmnet_map_header);



	if (port->data_format & RMNET_EGRESS_FORMAT_MAP_CKSUMV4) {

		additional_header_len = sizeof(struct rmnet_map_ul_csum_header);

		required_headroom += additional_header_len;

	}



	if (skb_headroom(skb) < required_headroom) {

		if (pskb_expand_head(skb, required_headroom, 0, GFP_KERNEL))

			goto fail;

	}



	if (port->data_format & RMNET_EGRESS_FORMAT_MAP_CKSUMV4)

		rmnet_map_checksum_uplink_packet(skb, orig_dev);



	map_header = rmnet_map_add_map_header(skb, additional_header_len, 0);

	if (!map_header)

		goto fail;

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

+2 −0
Original line number Diff line number Diff line
@@ -89,5 +89,7 @@ struct rmnet_map_header *rmnet_map_add_map_header(struct sk_buff *skb, 
						  int hdrlen, int pad);

void rmnet_map_command(struct sk_buff *skb, struct rmnet_port *port);

int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len);

void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,

				      struct net_device *orig_dev);



#endif /* _RMNET_MAP_H_ */

drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c

+120 −0
Original line number Diff line number Diff line
@@ -171,6 +171,86 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, 
}

#endif



static void rmnet_map_complement_ipv4_txporthdr_csum_field(void *iphdr)

{

	struct iphdr *ip4h = (struct iphdr *)iphdr;

	void *txphdr;

	u16 *csum;



	txphdr = iphdr + ip4h->ihl * 4;



	if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) {

		csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr);

		*csum = ~(*csum);

	}

}



static void

rmnet_map_ipv4_ul_csum_header(void *iphdr,

			      struct rmnet_map_ul_csum_header *ul_header,

			      struct sk_buff *skb)

{

	struct iphdr *ip4h = (struct iphdr *)iphdr;

	__be16 *hdr = (__be16 *)ul_header, offset;



	offset = htons((__force u16)(skb_transport_header(skb) -

				     (unsigned char *)iphdr));

	ul_header->csum_start_offset = offset;

	ul_header->csum_insert_offset = skb->csum_offset;

	ul_header->csum_enabled = 1;

	if (ip4h->protocol == IPPROTO_UDP)

		ul_header->udp_ip4_ind = 1;

	else

		ul_header->udp_ip4_ind = 0;



	/* Changing remaining fields to network order */

	hdr++;

	*hdr = htons((__force u16)*hdr);



	skb->ip_summed = CHECKSUM_NONE;



	rmnet_map_complement_ipv4_txporthdr_csum_field(iphdr);

}



#if IS_ENABLED(CONFIG_IPV6)

static void rmnet_map_complement_ipv6_txporthdr_csum_field(void *ip6hdr)

{

	struct ipv6hdr *ip6h = (struct ipv6hdr *)ip6hdr;

	void *txphdr;

	u16 *csum;



	txphdr = ip6hdr + sizeof(struct ipv6hdr);



	if (ip6h->nexthdr == IPPROTO_TCP || ip6h->nexthdr == IPPROTO_UDP) {

		csum = (u16 *)rmnet_map_get_csum_field(ip6h->nexthdr, txphdr);

		*csum = ~(*csum);

	}

}



static void

rmnet_map_ipv6_ul_csum_header(void *ip6hdr,

			      struct rmnet_map_ul_csum_header *ul_header,

			      struct sk_buff *skb)

{

	__be16 *hdr = (__be16 *)ul_header, offset;



	offset = htons((__force u16)(skb_transport_header(skb) -

				     (unsigned char *)ip6hdr));

	ul_header->csum_start_offset = offset;

	ul_header->csum_insert_offset = skb->csum_offset;

	ul_header->csum_enabled = 1;

	ul_header->udp_ip4_ind = 0;



	/* Changing remaining fields to network order */

	hdr++;

	*hdr = htons((__force u16)*hdr);



	skb->ip_summed = CHECKSUM_NONE;



	rmnet_map_complement_ipv6_txporthdr_csum_field(ip6hdr);

}

#endif



/* Adds MAP header to front of skb->data

 * Padding is calculated and set appropriately in MAP header. Mux ID is

 * initialized to 0.
@@ -281,3 +361,43 @@ int rmnet_map_checksum_downlink_packet(struct sk_buff *skb, u16 len) 


	return 0;

}



/* Generates UL checksum meta info header for IPv4 and IPv6 over TCP and UDP

 * packets that are supported for UL checksum offload.

 */

void rmnet_map_checksum_uplink_packet(struct sk_buff *skb,

				      struct net_device *orig_dev)

{

	struct rmnet_map_ul_csum_header *ul_header;

	void *iphdr;



	ul_header = (struct rmnet_map_ul_csum_header *)

		    skb_push(skb, sizeof(struct rmnet_map_ul_csum_header));



	if (unlikely(!(orig_dev->features &

		     (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM))))

		goto sw_csum;



	if (skb->ip_summed == CHECKSUM_PARTIAL) {

		iphdr = (char *)ul_header +

			sizeof(struct rmnet_map_ul_csum_header);



		if (skb->protocol == htons(ETH_P_IP)) {

			rmnet_map_ipv4_ul_csum_header(iphdr, ul_header, skb);

			return;

		} else if (skb->protocol == htons(ETH_P_IPV6)) {

#if IS_ENABLED(CONFIG_IPV6)

			rmnet_map_ipv6_ul_csum_header(iphdr, ul_header, skb);

			return;

#else

			goto sw_csum;

#endif

		}

	}



sw_csum:

	ul_header->csum_start_offset = 0;

	ul_header->csum_insert_offset = 0;

	ul_header->csum_enabled = 0;

	ul_header->udp_ip4_ind = 0;

}

drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c

+1 −0
Original line number Diff line number Diff line
@@ -189,6 +189,7 @@ int rmnet_vnd_newlink(u8 id, struct net_device *rmnet_dev, 
		return -EBUSY;



	rmnet_dev->hw_features = NETIF_F_RXCSUM;

	rmnet_dev->hw_features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;



	rc = register_netdevice(rmnet_dev);

	if (!rc) {