[RFC net-next v2 05/14] net: stmmac: dwxgmac2: Add MAC loopback support

[Jose Abreu]

In preparation for the addition of stmmac selftests we implement the MAC
loopback callback in dwxgmac2 core.

Signed-off-by: Jose Abreu <joabreu@xxxxxxxxxxxx>
Cc: Joao Pinto <jpinto@xxxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Giuseppe Cavallaro <peppe.cavallaro@xxxxxx>
Cc: Alexandre Torgue <alexandre.torgue@xxxxxx>
Cc: Corentin Labbe <clabbe.montjoie@xxxxxxxxx>
---
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h      |  1 +
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
index 085b700a4994..f629ccc8932a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
@@ -29,6 +29,7 @@
 #define XGMAC_CONFIG_GPSL		GENMASK(29, 16)
 #define XGMAC_CONFIG_GPSL_SHIFT		16
 #define XGMAC_CONFIG_S2KP		BIT(11)
+#define XGMAC_CONFIG_LM			BIT(10)
 #define XGMAC_CONFIG_IPC		BIT(9)
 #define XGMAC_CONFIG_JE			BIT(8)
 #define XGMAC_CONFIG_WD			BIT(7)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
index 64b8cb88ea45..c27b3ca052ea 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_core.c
@@ -321,6 +321,18 @@ static void dwxgmac2_set_filter(struct mac_device_info *hw,
 	writel(value, ioaddr + XGMAC_PACKET_FILTER);
 }
 
+static void dwxgmac2_set_mac_loopback(void __iomem *ioaddr, bool enable)
+{
+	u32 value = readl(ioaddr + XGMAC_RX_CONFIG);
+
+	if (enable)
+		value |= XGMAC_CONFIG_LM;
+	else
+		value &= ~XGMAC_CONFIG_LM;
+
+	writel(value, ioaddr + XGMAC_RX_CONFIG);
+}
+
 const struct stmmac_ops dwxgmac210_ops = {
 	.core_init = dwxgmac2_core_init,
 	.set_mac = dwxgmac2_set_mac,
@@ -350,6 +362,7 @@ const struct stmmac_ops dwxgmac210_ops = {
 	.pcs_get_adv_lp = NULL,
 	.debug = NULL,
 	.set_filter = dwxgmac2_set_filter,
+	.set_mac_loopback = dwxgmac2_set_mac_loopback,
 };
 
 int dwxgmac2_setup(struct stmmac_priv *priv)
-- 
2.7.4