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 <el...@linaro.org>
---
drivers/net/ipa/ipa_endpoint.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index bf3e8ced3ee0..9f50d0d11704 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -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);
--
2.25.1
