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net: ipa: header pad field only valid for AP->modem endpoint

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Only QMAP endpoints should be configured to find a pad size field
within packet headers.  They are found in the first byte of the QMAP
header (and the hardware fills only the 6 bits in that byte that
constitute the pad_len field).

The RMNet driver assumes the pad_len field is valid for received
packets, so we want to ensure the pad_len field is filled in that
case.  That driver also assumes the length in the QMAP header
includes the pad bytes.

The RMNet driver does *not* pad the packets it sends, so the pad_len
field can be ignored.

Fix ipa_endpoint_init_hdr_ext() so it only marks the pad field
offset valid for QMAP RX endpoints, and in that case indicates
that the length field in the header includes the pad bytes.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alex Elder 2020-06-11 14:48:33 -05:00 committed by David S. Miller
parent 636edeaad5
commit f330fda331
1 changed files with 15 additions and 4 deletions
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19
drivers/net/ipa/ipa_endpoint.c
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@ -467,7 +467,7 @@ static void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint)
header_size += sizeof(struct rmnet_map_ul_csum_header);
val |= u32_encode_bits(header_size, HDR_LEN_FMASK);
/* Define how to fill mux_id in a received QMAP header */
/* Define how to fill fields in a received QMAP header */
if (!endpoint->toward_ipa) {
u32 off; /* Field offset within header */
@ -499,10 +499,21 @@ static void ipa_endpoint_init_hdr_ext(struct ipa_endpoint *endpoint)
u32 val = 0;
val |= HDR_ENDIANNESS_FMASK; /* big endian */
val |= HDR_TOTAL_LEN_OR_PAD_VALID_FMASK;
/* HDR_TOTAL_LEN_OR_PAD is 0 (pad, not total_len) */
/* A QMAP header contains a 6 bit pad field at offset 0. The RMNet
* driver assumes this field is meaningful in packets it receives,
* and assumes the header's payload length includes that padding.
* The RMNet driver does *not* pad packets it sends, however, so
* the pad field (although 0) should be ignored.
*/
if (endpoint->data->qmap && !endpoint->toward_ipa) {
val |= HDR_TOTAL_LEN_OR_PAD_VALID_FMASK;
/* HDR_TOTAL_LEN_OR_PAD is 0 (pad, not total_len) */
val |= HDR_PAYLOAD_LEN_INC_PADDING_FMASK;
/* HDR_TOTAL_LEN_OR_PAD_OFFSET is 0 */
}
/* HDR_PAYLOAD_LEN_INC_PADDING is 0 */
/* HDR_TOTAL_LEN_OR_PAD_OFFSET is 0 */
if (!endpoint->toward_ipa)
val |= u32_encode_bits(pad_align, HDR_PAD_TO_ALIGNMENT_FMASK);