net: dsa: rzn1-a5psw: enable management frames for CPU port

Currently, management frame were discarded before reaching the CPU port due
to a misconfiguration of the MGMT_CONFIG register. Enable them by setting
the correct value in this register in order to correctly receive management
frame and handle STP.

Fixes: 888cdb89 ("net: dsa: rzn1-a5psw: add Renesas RZ/N1 advanced 5 port switch driver")
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Reviewed-by: Piotr Raczynski <piotr.raczynski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/rzn1_a5psw.c

@@ -673,7 +673,7 @@ static int a5psw_setup(struct dsa_switch *ds)
 	}
 
 	/* Configure management port */
-	reg = A5PSW_CPU_PORT | A5PSW_MGMT_CFG_DISCARD;
+	reg = A5PSW_CPU_PORT | A5PSW_MGMT_CFG_ENABLE;
 	a5psw_reg_writel(a5psw, A5PSW_MGMT_CFG, reg);
 
 	/* Set pattern 0 to forward all frame to mgmt port */

drivers/net/dsa/rzn1_a5psw.h

@@ -36,7 +36,7 @@
 #define A5PSW_INPUT_LEARN_BLOCK(p)	BIT(p)
 
 #define A5PSW_MGMT_CFG			0x20
-#define A5PSW_MGMT_CFG_DISCARD		BIT(7)
+#define A5PSW_MGMT_CFG_ENABLE		BIT(6)
 
 #define A5PSW_MODE_CFG			0x24
 #define A5PSW_MODE_STATS_RESET		BIT(31)