f4d949b404
Backport qca8k fixup for mgmt and mdio read/write for kernel 5.15 fixup port dropping and configuration issue. Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> Reviewed-by: Robert Marko <robimarko@gmail.com>
103 lines
3.8 KiB
Diff
103 lines
3.8 KiB
Diff
From 9807ae69746196ee4bbffe7d22d22ab2b61c6ed0 Mon Sep 17 00:00:00 2001
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From: Christian Marangi <ansuelsmth@gmail.com>
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Date: Thu, 29 Dec 2022 17:33:32 +0100
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Subject: [PATCH 1/5] net: dsa: qca8k: fix wrong length value for mgmt eth
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packet
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The assumption that Documentation was right about how this value work was
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wrong. It was discovered that the length value of the mgmt header is in
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step of word size.
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As an example to process 4 byte of data the correct length to set is 2.
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To process 8 byte 4, 12 byte 6, 16 byte 8...
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Odd values will always return the next size on the ack packet.
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(length of 3 (6 byte) will always return 8 bytes of data)
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This means that a value of 15 (0xf) actually means reading/writing 32 bytes
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of data instead of 16 bytes. This behaviour is totally absent and not
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documented in the switch Documentation.
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In fact from Documentation the max value that mgmt eth can process is
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16 byte of data while in reality it can process 32 bytes at once.
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To handle this we always round up the length after deviding it for word
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size. We check if the result is odd and we round another time to align
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to what the switch will provide in the ack packet.
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The workaround for the length limit of 15 is still needed as the length
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reg max value is 0xf(15)
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Reported-by: Ronald Wahl <ronald.wahl@raritan.com>
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Tested-by: Ronald Wahl <ronald.wahl@raritan.com>
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Fixes: 90386223f44e ("net: dsa: qca8k: add support for larger read/write size with mgmt Ethernet")
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Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
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Cc: stable@vger.kernel.org # v5.18+
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Signed-off-by: David S. Miller <davem@davemloft.net>
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---
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drivers/net/dsa/qca/qca8k-8xxx.c | 45 +++++++++++++++++++++++++-------
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1 file changed, 35 insertions(+), 10 deletions(-)
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--- a/drivers/net/dsa/qca/qca8k-8xxx.c
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+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
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@@ -146,7 +146,16 @@ static void qca8k_rw_reg_ack_handler(str
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command = get_unaligned_le32(&mgmt_ethhdr->command);
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cmd = FIELD_GET(QCA_HDR_MGMT_CMD, command);
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+
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len = FIELD_GET(QCA_HDR_MGMT_LENGTH, command);
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+ /* Special case for len of 15 as this is the max value for len and needs to
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+ * be increased before converting it from word to dword.
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+ */
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+ if (len == 15)
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+ len++;
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+
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+ /* We can ignore odd value, we always round up them in the alloc function. */
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+ len *= sizeof(u16);
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/* Make sure the seq match the requested packet */
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if (get_unaligned_le32(&mgmt_ethhdr->seq) == mgmt_eth_data->seq)
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@@ -193,17 +202,33 @@ static struct sk_buff *qca8k_alloc_mdio_
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if (!skb)
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return NULL;
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- /* Max value for len reg is 15 (0xf) but the switch actually return 16 byte
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- * Actually for some reason the steps are:
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- * 0: nothing
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- * 1-4: first 4 byte
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- * 5-6: first 12 byte
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- * 7-15: all 16 byte
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+ /* Hdr mgmt length value is in step of word size.
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+ * As an example to process 4 byte of data the correct length to set is 2.
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+ * To process 8 byte 4, 12 byte 6, 16 byte 8...
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+ *
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+ * Odd values will always return the next size on the ack packet.
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+ * (length of 3 (6 byte) will always return 8 bytes of data)
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+ *
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+ * This means that a value of 15 (0xf) actually means reading/writing 32 bytes
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+ * of data.
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+ *
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+ * To correctly calculate the length we devide the requested len by word and
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+ * round up.
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+ * On the ack function we can skip the odd check as we already handle the
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+ * case here.
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*/
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- if (len == 16)
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- real_len = 15;
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- else
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- real_len = len;
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+ real_len = DIV_ROUND_UP(len, sizeof(u16));
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+
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+ /* We check if the result len is odd and we round up another time to
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+ * the next size. (length of 3 will be increased to 4 as switch will always
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+ * return 8 bytes)
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+ */
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+ if (real_len % sizeof(u16) != 0)
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+ real_len++;
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+
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+ /* Max reg value is 0xf(15) but switch will always return the next size (32 byte) */
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+ if (real_len == 16)
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+ real_len--;
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skb_reset_mac_header(skb);
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skb_set_network_header(skb, skb->len);
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