Commit 5567d4d9 authored by Alex Elder's avatar Alex Elder Committed by David S. Miller
Browse files

net: ipa: add support for inline checksum offload 



Starting with IPA v4.5, IP payload checksum offload is implemented
differently.

Prior to v4.5, the IPA hardware appends an rmnet_map_dl_csum_trailer
structure to each packet if checksum offload is enabled in the
download direction (modem->AP).  In the upload direction (AP->modem)
a rmnet_map_ul_csum_header structure is prepended before each sent
packet.

Starting with IPA v4.5, checksum offload is implemented using a
single new rmnet_map_v5_csum_header structure which sits between
the QMAP header and the packet data.  The same header structure
is used in both directions.

The new header contains a header type (CSUM_OFFLOAD); a checksum
flag; and a flag indicating whether any other headers follow this
one.  The checksum flag indicates whether the hardware should
compute (and insert) the checksum on a sent packet.  On a received
packet the checksum flag indicates whether the hardware confirms the
checksum value in the payload is correct.

Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fcd1a530

drivers/net/ipa/ipa_endpoint.c

+36 −11
Original line number Diff line number Diff line
@@ -457,28 +457,34 @@ int ipa_endpoint_modem_exception_reset_all(struct ipa *ipa) 
static void ipa_endpoint_init_cfg(struct ipa_endpoint *endpoint)

{

	u32 offset = IPA_REG_ENDP_INIT_CFG_N_OFFSET(endpoint->endpoint_id);

	enum ipa_cs_offload_en enabled;

	u32 val = 0;



	/* FRAG_OFFLOAD_EN is 0 */

	if (endpoint->data->checksum) {

		enum ipa_version version = endpoint->ipa->version;



		if (endpoint->toward_ipa) {

			u32 checksum_offset;



			val |= u32_encode_bits(IPA_CS_OFFLOAD_UL,

					       CS_OFFLOAD_EN_FMASK);

			/* Checksum header offset is in 4-byte units */

			checksum_offset = sizeof(struct rmnet_map_header);

			checksum_offset /= sizeof(u32);

			val |= u32_encode_bits(checksum_offset,

					       CS_METADATA_HDR_OFFSET_FMASK);



			enabled = version < IPA_VERSION_4_5

					? IPA_CS_OFFLOAD_UL

					: IPA_CS_OFFLOAD_INLINE;

		} else {

			val |= u32_encode_bits(IPA_CS_OFFLOAD_DL,

					       CS_OFFLOAD_EN_FMASK);

			enabled = version < IPA_VERSION_4_5

					? IPA_CS_OFFLOAD_DL

					: IPA_CS_OFFLOAD_INLINE;

		}

	} else {

		val |= u32_encode_bits(IPA_CS_OFFLOAD_NONE,

				       CS_OFFLOAD_EN_FMASK);

		enabled = IPA_CS_OFFLOAD_NONE;

	}

	val |= u32_encode_bits(enabled, CS_OFFLOAD_EN_FMASK);

	/* CS_GEN_QMB_MASTER_SEL is 0 */



	iowrite32(val, endpoint->ipa->reg_virt + offset);
@@ -498,6 +504,27 @@ static void ipa_endpoint_init_nat(struct ipa_endpoint *endpoint) 
	iowrite32(val, endpoint->ipa->reg_virt + offset);

}



static u32

ipa_qmap_header_size(enum ipa_version version, struct ipa_endpoint *endpoint)

{

	u32 header_size = sizeof(struct rmnet_map_header);



	/* Without checksum offload, we just have the MAP header */

	if (!endpoint->data->checksum)

		return header_size;



	if (version < IPA_VERSION_4_5) {

		/* Checksum header inserted for AP TX endpoints only */

		if (endpoint->toward_ipa)

			header_size += sizeof(struct rmnet_map_ul_csum_header);

	} else {

		/* Checksum header is used in both directions */

		header_size += sizeof(struct rmnet_map_v5_csum_header);

	}



	return header_size;

}



/**

 * ipa_endpoint_init_hdr() - Initialize HDR endpoint configuration register

 * @endpoint:	Endpoint pointer
@@ -526,13 +553,11 @@ static void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint) 
	u32 val = 0;



	if (endpoint->data->qmap) {

		size_t header_size = sizeof(struct rmnet_map_header);

		enum ipa_version version = ipa->version;

		size_t header_size;



		/* We might supply a checksum header after the QMAP header */

		if (endpoint->toward_ipa && endpoint->data->checksum)

			header_size += sizeof(struct rmnet_map_ul_csum_header);

		val |= ipa_header_size_encoded(version, header_size);

		header_size = ipa_qmap_header_size(version, endpoint);

		val = ipa_header_size_encoded(version, header_size);



		/* Define how to fill fields in a received QMAP header */

		if (!endpoint->toward_ipa) {

drivers/net/ipa/ipa_reg.h

+1 −0
Original line number Diff line number Diff line
@@ -368,6 +368,7 @@ enum ipa_cs_offload_en { 
	IPA_CS_OFFLOAD_NONE		= 0x0,

	IPA_CS_OFFLOAD_UL		= 0x1,	/* Before IPA v4.5 (TX) */

	IPA_CS_OFFLOAD_DL		= 0x2,	/* Before IPA v4.5 (RX) */

	IPA_CS_OFFLOAD_INLINE		= 0x1,	/* IPA v4.5 (TX and RX) */

};



/* Valid only for TX (IPA consumer) endpoints */