openrisc: add support for LiteX

This adds support for a basic LiteX-based SoC with a mor1kx soft CPU.
Signed-off-by: Filip Kokosinski <fkokosinski@antmicro.com>
Signed-off-by: Mateusz Holenko <mholenko@antmicro.com>
[shorne: Merged in soc-cntl patch, removed CROSS_COMPILE, sort MAINT.]
Signed-off-by: Stafford Horne <shorne@gmail.com>

MAINTAINERS

@@ -10177,6 +10177,7 @@ M:	Karol Gugala <kgugala@antmicro.com>
 M:	Mateusz Holenko <mholenko@antmicro.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/*/litex,*.yaml
+F:	arch/openrisc/boot/dts/or1klitex.dts
 F:	drivers/soc/litex/litex_soc_ctrl.c
 F:	drivers/tty/serial/liteuart.c
 F:	include/linux/litex.h

arch/openrisc/boot/dts/or1klitex.dts

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * LiteX-based System on Chip
+ *
+ * Copyright (C) 2019 Antmicro <www.antmicro.com>
+ */
+
+/dts-v1/;
+/ {
+	compatible = "opencores,or1ksim";
+	#address-cells = <1>;
+	#size-cells = <1>;
+	interrupt-parent = <&pic>;
+
+	aliases {
+		serial0 = &serial0;
+	};
+
+	chosen {
+		bootargs = "console=liteuart";
+	};
+
+	memory@0 {
+		device_type = "memory";
+		reg = <0x00000000 0x10000000>;
+	};
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		cpu@0 {
+			compatible = "opencores,or1200-rtlsvn481";
+			reg = <0>;
+			clock-frequency = <100000000>;
+		};
+	};
+
+	pic: pic {
+		compatible = "opencores,or1k-pic";
+		#interrupt-cells = <1>;
+		interrupt-controller;
+	};
+
+	serial0: serial@e0002000 {
+		device_type = "serial";
+		compatible = "litex,liteuart";
+		reg = <0xe0002000 0x100>;
+	};
+
+	soc_ctrl0: soc_controller@e0000000 {
+			compatible = "litex,soc-controller";
+			reg = <0xe0000000 0xc>;
+			status = "okay";
+	};
+};

arch/openrisc/configs/or1klitex_defconfig

+CONFIG_BLK_DEV_INITRD=y
+CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y
+CONFIG_BUG_ON_DATA_CORRUPTION=y
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+CONFIG_EMBEDDED=y
+CONFIG_HZ_100=y
+CONFIG_INITRAMFS_SOURCE="openrisc-rootfs.cpio.gz"
+CONFIG_OF_OVERLAY=y
+CONFIG_OPENRISC_BUILTIN_DTB="or1klitex"
+CONFIG_PANIC_ON_OOPS=y
+CONFIG_PRINTK_TIME=y
+CONFIG_LITEX_SOC_CONTROLLER=y
+CONFIG_SERIAL_LITEUART=y
+CONFIG_SERIAL_LITEUART_CONSOLE=y
+CONFIG_SOFTLOCKUP_DETECTOR=y
+CONFIG_TTY_PRINTK=y