net: fec: add set_promisc function

Enabling promiscuous mode is necessary if FEC is the master of a DSA
switch driver where each port has their own MAC address.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
diff --git a/drivers/net/fec_mxc.c b/drivers/net/fec_mxc.c
index 7768049..db2cdaf 100644
--- a/drivers/net/fec_mxc.c
+++ b/drivers/net/fec_mxc.c
@@ -458,6 +458,9 @@
 	else if (fec->xcv_type == RMII)
 		rcntrl |= FEC_RCNTRL_RMII;
 
+	if (fec->promisc)
+		rcntrl |= 0x8;
+
 	writel(rcntrl, &fec->eth->r_cntrl);
 }
 
@@ -1278,6 +1281,15 @@
 	return fec_get_hwaddr(priv->dev_id, pdata->enetaddr);
 }
 
+static int fecmxc_set_promisc(struct udevice *dev, bool enable)
+{
+	struct fec_priv *priv = dev_get_priv(dev);
+
+	priv->promisc = enable;
+
+	return 0;
+}
+
 static int fecmxc_free_pkt(struct udevice *dev, uchar *packet, int length)
 {
 	if (packet)
@@ -1294,6 +1306,7 @@
 	.stop			= fecmxc_halt,
 	.write_hwaddr		= fecmxc_set_hwaddr,
 	.read_rom_hwaddr	= fecmxc_read_rom_hwaddr,
+	.set_promisc		= fecmxc_set_promisc,
 };
 
 static int device_get_phy_addr(struct fec_priv *priv, struct udevice *dev)