realtek: rtl93xx: Ignore STP for per port TX

If transmissions are done outside of the DSA switch (directly from the CPU
port), the STP state must not block the transmission. Otherwise, STP frames
are not correctly submitted and the STP frames cannot correctly detect
loops before switching a port in the forwarding state.

The same applies for the LLDP frames. These must be submitted independent
of the STP state to identify neighbors or configure POE limits.

It is not necessary to filter specific destination mac addresses because
the transmission was done outside the bridge/switch in the first place. The
transmission is therefore forced.

Signed-off-by: Issam Hamdi <[email protected]>
Co-developed-by: Sven Eckelmann <[email protected]>
Signed-off-by: Sven Eckelmann <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20184
Signed-off-by: Robert Marko <[email protected]>

target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c

@@ -131,7 +131,10 @@ static void rtl839x_create_tx_header(struct p_hdr *h, unsigned int dest_port, in
 static void rtl930x_create_tx_header(struct p_hdr *h, unsigned int dest_port, int prio)
 {
 	h->cpu_tag[0] = 0x8000;  /* CPU tag marker */
-	h->cpu_tag[1] = 0x0200; /* Set FWD_TYPE to LOGICAL (2) */
+
+	h->cpu_tag[1] = FIELD_PREP(RTL93XX_CPU_TAG1_FWD_MASK,
+				   RTL93XX_CPU_TAG1_FWD_LOGICAL);
+	h->cpu_tag[1] |= FIELD_PREP(RTL93XX_CPU_TAG1_IGNORE_STP_MASK, 1);
 	h->cpu_tag[2] = 0;
 	h->cpu_tag[3] = 0;
 	h->cpu_tag[4] = 0;
@@ -147,7 +150,10 @@ static void rtl930x_create_tx_header(struct p_hdr *h, unsigned int dest_port, in
 static void rtl931x_create_tx_header(struct p_hdr *h, unsigned int dest_port, int prio)
 {
 	h->cpu_tag[0] = 0x8000;  /* CPU tag marker */
-	h->cpu_tag[1] = 0x0200; /* Set FWD_TYPE to LOGICAL (2) */
+
+	h->cpu_tag[1] = FIELD_PREP(RTL93XX_CPU_TAG1_FWD_MASK,
+				   RTL93XX_CPU_TAG1_FWD_LOGICAL);
+	h->cpu_tag[1] |= FIELD_PREP(RTL93XX_CPU_TAG1_IGNORE_STP_MASK, 1);
 	h->cpu_tag[2] = 0;
 	h->cpu_tag[3] = 0;
 	h->cpu_tag[4] = h->cpu_tag[5] = h->cpu_tag[6] = h->cpu_tag[7] = 0;

target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.h

@@ -222,6 +222,21 @@
 /* Registers of the internal Serdes of the 8380 */
 #define RTL838X_SDS4_FIB_REG0			(0xF800)
 
+/* shared CPU tag definitions for RTL930X/RTL931X */
+#define RTL93XX_CPU_TAG1_FWD_MASK		GENMASK(11, 8)
+
+#define RTL93XX_CPU_TAG1_FWD_ALE		0
+#define RTL93XX_CPU_TAG1_FWD_PHYSICAL		1
+#define RTL93XX_CPU_TAG1_FWD_LOGICAL		2
+#define RTL93XX_CPU_TAG1_FWD_TRUNK		3
+#define RTL93XX_CPU_TAG1_FWD_ONE_HOP		4
+#define RTL93XX_CPU_TAG1_FWD_LOGICAL_ONE_HOP	5
+#define RTL93XX_CPU_TAG1_FWD_UCST_CPU_MIN_PORT	6
+#define RTL93XX_CPU_TAG1_FWD_UCST_CPU		7
+#define RTL93XX_CPU_TAG1_FWD_BCST_CPU		8
+
+#define RTL93XX_CPU_TAG1_IGNORE_STP_MASK	GENMASK(2, 2)
+
 /* Default MTU with jumbo frames support */
 #define DEFAULT_MTU 9000