arm: mvebu: Add CRS328-4C-20S-4S board

MikroTik CRS328-4C-20S-4S board has a switch chip with an integrated
Marvell Prestera 98DX3236 CPU.

This commit includes two board variants, namely the factory
default one and a Bit variant. The Bit board variant has a
bigger Macronix flash.

Add basic U-Boot, UART and SPI flash support.

Signed-off-by: Luka Kovacic <luka.kovacic@sartura.hr>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Cc: Jakov Petrina <jakov.petrina@sartura.hr>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/armada-xp-crs328-4c-20s-4s.dtsi b/arch/arm/dts/armada-xp-crs328-4c-20s-4s.dtsi
new file mode 100644
index 0000000..daff1af
--- /dev/null
+++ b/arch/arm/dts/armada-xp-crs328-4c-20s-4s.dtsi
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Device Tree file for CRS328-4C-20S-4S+ board
+ *
+ * Copyright (C) 2016 Allied Telesis Labs
+ * Copyright (C) 2020 Sartura Ltd.
+ *
+ * Based on armada-xp-db.dts
+ *
+ * Note: this Device Tree assumes that the bootloader has remapped the
+ * internal registers to 0xf1000000 (instead of the default
+ * 0xd0000000). The 0xf1000000 is the default used by the recent,
+ * DT-capable, U-Boot bootloaders provided by Marvell. Some earlier
+ * boards were delivered with an older version of the bootloader that
+ * left internal registers mapped at 0xd0000000. If you are in this
+ * situation, you should either update your bootloader (preferred
+ * solution) or the below Device Tree should be adjusted.
+ */
+
+/dts-v1/;
+#include "armada-xp-98dx3236.dtsi"
+#include "armada-xp-crs328-4c-20s-4s-u-boot.dtsi"
+
+/ {
+	model = "CRS328-4C-20S-4S+";
+	compatible = "marvell,armadaxp-98dx3236", "marvell,armadaxp-mv78260", "marvell,armadaxp", "marvell,armada-370-xp";
+
+	chosen {
+		stdout-path = "serial0:115200n8";
+		bootargs = "console=ttyS0,115200 earlyprintk";
+	};
+
+	aliases {
+		spi0 = &spi0;
+	};
+
+	memory {
+		device_type = "memory";
+		reg = <0 0x00000000 0 0x20000000>; /* 512 MB */
+	};
+};
+
+&L2 {
+	arm,parity-enable;
+	marvell,ecc-enable;
+};
+
+&devbus_bootcs {
+	status = "okay";
+
+	/* Device Bus parameters are required */
+
+	/* Read parameters */
+	devbus,bus-width    = <16>;
+	devbus,turn-off-ps  = <60000>;
+	devbus,badr-skew-ps = <0>;
+	devbus,acc-first-ps = <124000>;
+	devbus,acc-next-ps  = <248000>;
+	devbus,rd-setup-ps  = <0>;
+	devbus,rd-hold-ps   = <0>;
+
+	/* Write parameters */
+	devbus,sync-enable = <0>;
+	devbus,wr-high-ps  = <60000>;
+	devbus,wr-low-ps   = <60000>;
+	devbus,ale-wr-ps   = <60000>;
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&uart1 {
+	status = "okay";
+};
+
+&i2c0 {
+	clock-frequency = <100000>;
+	status = "okay";
+};
+
+&usb0 {
+	status = "okay";
+};
+
+&spi0 {
+	status = "okay";
+
+	spi-flash@0 {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "spi-flash", "jedec,spi-nor";
+		reg = <0>; /* Chip select 0 */
+		spi-max-frequency = <108000000>;
+		m25p,fast-read;
+
+		partition@u-boot {
+			reg = <0x00000000 0x001f0000>;
+			label = "u-boot";
+		};
+		partition@u-boot-env {
+			reg = <0x001f0000 0x00010000>;
+			label = "u-boot-env";
+		};
+		partition@ubi1 {
+			reg = <0x00200000 0x00e00000>;
+			label = "ubi1";
+		};
+	};
+};