net: mvpp2: cls: Bypass C2 internals FIFOs at init

The C2 TCAM has internal FIFOs that are only useful for the built-in
self-tests. Disable these FIFOS at init, as recommended in the
functionnal specs.

Suggested-by: Alan Winkowski <walan@marvell.com>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvpp2/mvpp2.h

@@ -148,6 +148,8 @@
 #define MVPP22_CLS_C2_ATTR2			0x1b6c
 #define     MVPP22_CLS_C2_ATTR2_RSS_EN		BIT(30)
 #define MVPP22_CLS_C2_ATTR3			0x1b70
+#define MVPP22_CLS_C2_TCAM_CTRL			0x1b90
+#define     MVPP22_CLS_C2_TCAM_BYPASS_FIFO	BIT(0)
 
 /* Descriptor Manager Top Registers */
 #define MVPP2_RXQ_NUM_REG			0x2040

drivers/net/ethernet/marvell/mvpp2/mvpp2_cls.c

@@ -923,6 +923,12 @@ void mvpp2_cls_init(struct mvpp2 *priv)
 		mvpp2_cls_c2_write(priv, &c2);
 	}
 
+	/* Disable the FIFO stages in C2 engine, which are only used in BIST
+	 * mode
+	 */
+	mvpp2_write(priv, MVPP22_CLS_C2_TCAM_CTRL,
+		    MVPP22_CLS_C2_TCAM_BYPASS_FIFO);
+
 	mvpp2_cls_port_init_flows(priv);
 }