realtek: fix RTL838x receive tag decoding

Commit dc9cc0d3e2a1 ("realtek: add QoS and rate control") replaced a
16 bit reserved field in the RTL83xx packet header with the initial
cpu_tag word, shifting the real cpu_tag fields by one.  Adjusting for
this new shift was partially forgotten in the new RX tag decoders.

This caused the switch to block IGMP, effectively blocking IPv4
multicast.

The bug was partially fixed by commit 9d847244d9fd ("realtek: fix
RTL839X receive tag decoding")

Fix on RTL838x too, including correct NIC_RX_REASON_SPECIAL_TRAP value.

Suggested-by: Jan Hoffmann <jan@3e8.eu>
Fixes: dc9cc0d3e2a1 ("realtek: add QoS and rate control")
Signed-off-by: Bjørn Mork <bjorn@mork.no>

diff --git a/target/linux/realtek/files-5.10/drivers/net/ethernet/rtl838x_eth.c b/target/linux/realtek/files-5.10/drivers/net/ethernet/rtl838x_eth.c
index 0eee06d803ad5d30e76bf0668345d44c7ffca6a2..d9ade6552698a6fd84344abc7fd3aa9b28a84ec9 100644 (file)
--- a/target/linux/realtek/files-5.10/drivers/net/ethernet/rtl838x_eth.c
+++ b/target/linux/realtek/files-5.10/drivers/net/ethernet/rtl838x_eth.c
@@ -58,6 +58,7 @@ struct p_hdr {
        uint16_t        size;           /* buffer size */
        uint16_t        offset;
        uint16_t        len;            /* pkt len */
+       /* cpu_tag[0] is a reserved uint16_t on RTL83xx */
        uint16_t        cpu_tag[10];
 } __packed __aligned(1);
 
@@ -262,13 +263,14 @@ struct dsa_tag {
 
 bool rtl838x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 {
-       t->reason = h->cpu_tag[3] & 0xf;
-       t->queue = (h->cpu_tag[0] & 0xe0) >> 5;
+       /* cpu_tag[0] is reserved. Fields are off-by-one */
+       t->reason = h->cpu_tag[4] & 0xf;
+       t->queue = (h->cpu_tag[1] & 0xe0) >> 5;
        t->port = h->cpu_tag[1] & 0x1f;
        t->crc_error = t->reason == 13;
 
        pr_debug("Reason: %d\n", t->reason);
-       if (t->reason != 4) // NIC_RX_REASON_SPECIAL_TRAP
+       if (t->reason != 6) // NIC_RX_REASON_SPECIAL_TRAP
                t->l2_offloaded = 1;
        else
                t->l2_offloaded = 0;
@@ -278,6 +280,7 @@ bool rtl838x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 
 bool rtl839x_decode_tag(struct p_hdr *h, struct dsa_tag *t)
 {
+       /* cpu_tag[0] is reserved. Fields are off-by-one */
        t->reason = h->cpu_tag[5] & 0x1f;
        t->queue = (h->cpu_tag[3] & 0xe000) >> 13;
        t->port = h->cpu_tag[1] & 0x3f;