Add imx93-var-som support

Add support for the Variscite VAR-SOM-IMX93 evaluation kit. The SoM
consists of an NXP iMX93 dual A55 CPU. The SoM is mounted on a Variscite
Symphony SBC.

Signed-off-by: Mathieu Othacehe <m.othacehe@gmail.com>
diff --git a/board/variscite/common/eth.c b/board/variscite/common/eth.c
new file mode 100644
index 0000000..a794533
--- /dev/null
+++ b/board/variscite/common/eth.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2023 Variscite Ltd.
+ */
+#include <net.h>
+#include <miiphy.h>
+#include <env.h>
+#include "../common/imx9_eeprom.h"
+
+#define CHAR_BIT 8
+
+static u64 mac2int(const u8 hwaddr[])
+{
+	u8 i;
+	u64 ret = 0;
+	const u8 *p = hwaddr;
+
+	for (i = 6; i > 0; i--)
+		ret |= (u64)*p++ << (CHAR_BIT * (i - 1));
+
+	return ret;
+}
+
+static void int2mac(const u64 mac, u8 *hwaddr)
+{
+	u8 i;
+	u8 *p = hwaddr;
+
+	for (i = 6; i > 0; i--)
+		*p++ = mac >> (CHAR_BIT * (i - 1));
+}
+
+int var_setup_mac(struct var_eeprom *eeprom)
+{
+	int ret;
+	unsigned char enetaddr[6];
+	u64 addr;
+	unsigned char enet1addr[6];
+
+	ret = eth_env_get_enetaddr("ethaddr", enetaddr);
+	if (ret)
+		return 0;
+
+	ret = var_eeprom_get_mac(eeprom, enetaddr);
+	if (ret)
+		return ret;
+
+	if (!is_valid_ethaddr(enetaddr))
+		return -EINVAL;
+
+	eth_env_set_enetaddr("ethaddr", enetaddr);
+
+	addr = mac2int(enetaddr);
+	int2mac(addr + 1, enet1addr);
+	eth_env_set_enetaddr("eth1addr", enet1addr);
+
+	return 0;
+}