diff options
Diffstat (limited to 'target/linux/generic/backport-5.15/777-v6.2-01-net-dsa-qca8k-fix-wrong-length-value-for-mgmt-eth-pa.patch')
| -rw-r--r-- | target/linux/generic/backport-5.15/777-v6.2-01-net-dsa-qca8k-fix-wrong-length-value-for-mgmt-eth-pa.patch | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.15/777-v6.2-01-net-dsa-qca8k-fix-wrong-length-value-for-mgmt-eth-pa.patch b/target/linux/generic/backport-5.15/777-v6.2-01-net-dsa-qca8k-fix-wrong-length-value-for-mgmt-eth-pa.patch new file mode 100644 index 0000000000..b61e7ede49 --- /dev/null +++ b/target/linux/generic/backport-5.15/777-v6.2-01-net-dsa-qca8k-fix-wrong-length-value-for-mgmt-eth-pa.patch @@ -0,0 +1,102 @@ +From 9807ae69746196ee4bbffe7d22d22ab2b61c6ed0 Mon Sep 17 00:00:00 2001 +From: Christian Marangi <ansuelsmth@gmail.com> +Date: Thu, 29 Dec 2022 17:33:32 +0100 +Subject: [PATCH 1/5] net: dsa: qca8k: fix wrong length value for mgmt eth + packet + +The assumption that Documentation was right about how this value work was +wrong. It was discovered that the length value of the mgmt header is in +step of word size. + +As an example to process 4 byte of data the correct length to set is 2. +To process 8 byte 4, 12 byte 6, 16 byte 8... + +Odd values will always return the next size on the ack packet. +(length of 3 (6 byte) will always return 8 bytes of data) + +This means that a value of 15 (0xf) actually means reading/writing 32 bytes +of data instead of 16 bytes. This behaviour is totally absent and not +documented in the switch Documentation. + +In fact from Documentation the max value that mgmt eth can process is +16 byte of data while in reality it can process 32 bytes at once. + +To handle this we always round up the length after deviding it for word +size. We check if the result is odd and we round another time to align +to what the switch will provide in the ack packet. +The workaround for the length limit of 15 is still needed as the length +reg max value is 0xf(15) + +Reported-by: Ronald Wahl <ronald.wahl@raritan.com> +Tested-by: Ronald Wahl <ronald.wahl@raritan.com> +Fixes: 90386223f44e ("net: dsa: qca8k: add support for larger read/write size with mgmt Ethernet") +Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> +Cc: stable@vger.kernel.org # v5.18+ +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + drivers/net/dsa/qca/qca8k-8xxx.c | 45 +++++++++++++++++++++++++------- + 1 file changed, 35 insertions(+), 10 deletions(-) + +--- a/drivers/net/dsa/qca/qca8k-8xxx.c ++++ b/drivers/net/dsa/qca/qca8k-8xxx.c +@@ -146,7 +146,16 @@ static void qca8k_rw_reg_ack_handler(str + + command = get_unaligned_le32(&mgmt_ethhdr->command); + cmd = FIELD_GET(QCA_HDR_MGMT_CMD, command); ++ + len = FIELD_GET(QCA_HDR_MGMT_LENGTH, command); ++ /* Special case for len of 15 as this is the max value for len and needs to ++ * be increased before converting it from word to dword. ++ */ ++ if (len == 15) ++ len++; ++ ++ /* We can ignore odd value, we always round up them in the alloc function. */ ++ len *= sizeof(u16); + + /* Make sure the seq match the requested packet */ + if (get_unaligned_le32(&mgmt_ethhdr->seq) == mgmt_eth_data->seq) +@@ -193,17 +202,33 @@ static struct sk_buff *qca8k_alloc_mdio_ + if (!skb) + return NULL; + +- /* Max value for len reg is 15 (0xf) but the switch actually return 16 byte +- * Actually for some reason the steps are: +- * 0: nothing +- * 1-4: first 4 byte +- * 5-6: first 12 byte +- * 7-15: all 16 byte ++ /* Hdr mgmt length value is in step of word size. ++ * As an example to process 4 byte of data the correct length to set is 2. ++ * To process 8 byte 4, 12 byte 6, 16 byte 8... ++ * ++ * Odd values will always return the next size on the ack packet. ++ * (length of 3 (6 byte) will always return 8 bytes of data) ++ * ++ * This means that a value of 15 (0xf) actually means reading/writing 32 bytes ++ * of data. ++ * ++ * To correctly calculate the length we devide the requested len by word and ++ * round up. ++ * On the ack function we can skip the odd check as we already handle the ++ * case here. + */ +- if (len == 16) +- real_len = 15; +- else +- real_len = len; ++ real_len = DIV_ROUND_UP(len, sizeof(u16)); ++ ++ /* We check if the result len is odd and we round up another time to ++ * the next size. (length of 3 will be increased to 4 as switch will always ++ * return 8 bytes) ++ */ ++ if (real_len % sizeof(u16) != 0) ++ real_len++; ++ ++ /* Max reg value is 0xf(15) but switch will always return the next size (32 byte) */ ++ if (real_len == 16) ++ real_len--; + + skb_reset_mac_header(skb); + skb_set_network_header(skb, skb->len); |