net: enetc: implement software lockstep for port MAC registers

Currently the enetc driver duplicates its writes to the PM0 registers
also to PM1, but it doesn't do this consistently - for example we write
to ENETC_PM0_MAXFRM but not to ENETC_PM1_MAXFRM.

Create enetc_port_mac_wr() which writes both the PM0 and PM1 register
with the same value (if frame preemption is supported on this port).
Also create enetc_port_mac_rd() which reads from PM0 - the assumption
being that PM1 contains just the same value.

This will be necessary when we enable the MAC Merge layer properly, and
the pMAC becomes operational.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 16 insertions, 2 deletions

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index 347e698cbedc..159ae740ba3c 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -11,6 +11,20 @@
 #include <net/pkt_sched.h>
 #include <net/tso.h>
 
+u32 enetc_port_mac_rd(struct enetc_si *si, u32 reg)
+{
+	return enetc_port_rd(&si->hw, reg);
+}
+EXPORT_SYMBOL_GPL(enetc_port_mac_rd);
+
+void enetc_port_mac_wr(struct enetc_si *si, u32 reg, u32 val)
+{
+	enetc_port_wr(&si->hw, reg, val);
+	if (si->hw_features & ENETC_SI_F_QBU)
+		enetc_port_wr(&si->hw, reg + ENETC_PMAC_OFFSET, val);
+}
+EXPORT_SYMBOL_GPL(enetc_port_mac_wr);
+
 static int enetc_num_stack_tx_queues(struct enetc_ndev_priv *priv)
 {
 	int num_tx_rings = priv->num_tx_rings;
@@ -243,8 +257,8 @@ static int enetc_map_tx_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb)
 			if (udp)
 				val |= ENETC_PM0_SINGLE_STEP_CH;
 
-			enetc_port_wr(hw, ENETC_PM0_SINGLE_STEP, val);
-			enetc_port_wr(hw, ENETC_PM1_SINGLE_STEP, val);
+			enetc_port_mac_wr(priv->si, ENETC_PM0_SINGLE_STEP,
+					  val);
 		} else if (do_twostep_tstamp) {
 			skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
 			e_flags |= ENETC_TXBD_E_FLAGS_TWO_STEP_PTP;