From 8730f45d1ca5ff60033f5ba022f32e5379d7bb89 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Thu, 11 Jun 2020 14:48:30 -0500 Subject: [PATCH] net: ipa: program metadata mask differently The way the mask value is programmed for QMAP RX endpoints was based on some wrong assumptions about the way metadata containing the QMAP mux_id value is formatted. The metadata value supplied by the modem is *not* in QMAP format, and in fact contains the mux_id we want in its (big endian) low-order byte. That byte must be written by the IPA into offset 1 of the QMAP header it inserts before the received packet. QMAP TX endpoints *do* use a QMAP header as the metadata sent with each packet. The modem assumes this, and based on that assumes the mux_id is in the second byte. To match those assumptions we must program the modem TX (QMAP) endpoint HDR register to indicate the metadata will be found at offset 0 in the message header. The previous configuration managed to work, but it was not working correctly. This patch fixes a bug whose symptom was receipt of messages containing the wrong QMAP mux_id. In fixing this, get rid of ipa_rmnet_mux_id_metadata_mask(), which was more or less defined so there was a separate place to explain what was happening as we generated the mask value. Instead, put a longer description of how this works above ipa_endpoint_init_hdr(), and define the metadata mask to use as a simple constant. Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- drivers/net/ipa/ipa_endpoint.c | 72 ++++++++++++++++++---------------- 1 file changed, 39 insertions(+), 33 deletions(-) diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c index 66649a806dd1..2825dca23ec4 100644 --- a/drivers/net/ipa/ipa_endpoint.c +++ b/drivers/net/ipa/ipa_endpoint.c @@ -32,6 +32,9 @@ /* The amount of RX buffer space consumed by standard skb overhead */ #define IPA_RX_BUFFER_OVERHEAD (PAGE_SIZE - SKB_MAX_ORDER(NET_SKB_PAD, 0)) +/* Where to find the QMAP mux_id for a packet within modem-supplied metadata */ +#define IPA_ENDPOINT_QMAP_METADATA_MASK 0x000000ff /* host byte order */ + #define IPA_ENDPOINT_RESET_AGGR_RETRY_MAX 3 #define IPA_AGGR_TIME_LIMIT_DEFAULT 1000 /* microseconds */ @@ -433,6 +436,24 @@ static void ipa_endpoint_init_cfg(struct ipa_endpoint *endpoint) iowrite32(val, endpoint->ipa->reg_virt + offset); } +/** + * We program QMAP endpoints so each packet received is preceded by a QMAP + * header structure. The QMAP header contains a 1-byte mux_id and 2-byte + * packet size field, and we have the IPA hardware populate both for each + * received packet. The header is configured (in the HDR_EXT register) + * to use big endian format. + * + * The packet size is written into the QMAP header's pkt_len field. That + * location is defined here using the HDR_OFST_PKT_SIZE field. + * + * The mux_id comes from a 4-byte metadata value supplied with each packet + * by the modem. It is *not* a QMAP header, but it does contain the mux_id + * value that we want, in its low-order byte. A bitmask defined in the + * endpoint's METADATA_MASK register defines which byte within the modem + * metadata contains the mux_id. And the OFST_METADATA field programmed + * here indicates where the extracted byte should be placed within the QMAP + * header. + */ static void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint) { u32 offset = IPA_REG_ENDP_INIT_HDR_N_OFFSET(endpoint->endpoint_id); @@ -441,25 +462,31 @@ static void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint) if (endpoint->data->qmap) { size_t header_size = sizeof(struct rmnet_map_header); + /* 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 |= u32_encode_bits(header_size, HDR_LEN_FMASK); - /* metadata is the 4 byte rmnet_map header itself */ - val |= HDR_OFST_METADATA_VALID_FMASK; - val |= u32_encode_bits(0, HDR_OFST_METADATA_FMASK); - /* HDR_ADDITIONAL_CONST_LEN is 0; (IPA->AP only) */ + + /* Define how to fill mux_id in a received QMAP header */ if (!endpoint->toward_ipa) { - u32 size_offset = offsetof(struct rmnet_map_header, - pkt_len); + u32 off; /* Field offset within header */ + + /* Where IPA will write the metadata value */ + off = offsetof(struct rmnet_map_header, mux_id); + val |= u32_encode_bits(off, HDR_OFST_METADATA_FMASK); + /* Where IPA will write the length */ + off = offsetof(struct rmnet_map_header, pkt_len); val |= HDR_OFST_PKT_SIZE_VALID_FMASK; - val |= u32_encode_bits(size_offset, - HDR_OFST_PKT_SIZE_FMASK); + val |= u32_encode_bits(off, HDR_OFST_PKT_SIZE_FMASK); } + /* For QMAP TX, metadata offset is 0 (modem assumes this) */ + val |= HDR_OFST_METADATA_VALID_FMASK; + + /* HDR_ADDITIONAL_CONST_LEN is 0; (RX only) */ /* HDR_A5_MUX is 0 */ /* HDR_LEN_INC_DEAGG_HDR is 0 */ - /* HDR_METADATA_REG_VALID is 0; (AP->IPA only) */ + /* HDR_METADATA_REG_VALID is 0 (TX only) */ } iowrite32(val, endpoint->ipa->reg_virt + offset); @@ -482,28 +509,6 @@ static void ipa_endpoint_init_hdr_ext(struct ipa_endpoint *endpoint) iowrite32(val, endpoint->ipa->reg_virt + offset); } -/** - * Generate a metadata mask value that will select only the mux_id - * field in an rmnet_map header structure. The mux_id is at offset - * 1 byte from the beginning of the structure, but the metadata - * value is treated as a 4-byte unit. So this mask must be computed - * with endianness in mind. Note that ipa_endpoint_init_hdr_metadata_mask() - * will convert this value to the proper byte order. - * - * Marked __always_inline because this is really computing a - * constant value. - */ -static __always_inline __be32 ipa_rmnet_mux_id_metadata_mask(void) -{ - size_t mux_id_offset = offsetof(struct rmnet_map_header, mux_id); - u32 mux_id_mask = 0; - u8 *bytes; - - bytes = (u8 *)&mux_id_mask; - bytes[mux_id_offset] = 0xff; /* mux_id is 1 byte */ - - return cpu_to_be32(mux_id_mask); -} static void ipa_endpoint_init_hdr_metadata_mask(struct ipa_endpoint *endpoint) { @@ -513,8 +518,9 @@ static void ipa_endpoint_init_hdr_metadata_mask(struct ipa_endpoint *endpoint) offset = IPA_REG_ENDP_INIT_HDR_METADATA_MASK_N_OFFSET(endpoint_id); + /* Note that HDR_ENDIANNESS indicates big endian header fields */ if (!endpoint->toward_ipa && endpoint->data->qmap) - val = ipa_rmnet_mux_id_metadata_mask(); + val = cpu_to_be32(IPA_ENDPOINT_QMAP_METADATA_MASK); iowrite32(val, endpoint->ipa->reg_virt + offset); } -- 2.20.1