MSCC: add board support for the Luton based evaluation board

Adding the support for the Luton boards PCB91 which share common code with
the Ocelots boards, including board code, device tree and configuration.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

board/mscc/luton/Kconfig

@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+
+if SOC_LUTON
+
+config SYS_VENDOR
+	default "mscc"
+
+config SYS_BOARD
+	default "luton"
+
+config SYS_CONFIG_NAME
+	default "luton"
+
+endif

board/mscc/luton/Makefile

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+
+obj-$(CONFIG_SOC_LUTON)	:= luton.o

board/mscc/luton/luton.c

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2018 Microsemi Corporation
+ */
+
+#include <common.h>
+#include <asm/io.h>
+
+#define MSCC_GPIO_ALT0		0x88
+#define MSCC_GPIO_ALT1		0x8C
+
+DECLARE_GLOBAL_DATA_PTR;
+
+void board_debug_uart_init(void)
+{
+	/* too early for the pinctrl driver, so configure the UART pins here */
+	setbits_le32(BASE_DEVCPU_GCB + MSCC_GPIO_ALT0, BIT(30) | BIT(31));
+}
+
+int board_early_init_r(void)
+{
+	/* Prepare SPI controller to be used in master mode */
+	writel(0, BASE_CFG + ICPU_SW_MODE);
+
+	/* Address of boot parameters */
+	gd->bd->bi_boot_params = CONFIG_SYS_SDRAM_BASE;
+	return 0;
+}