platform: Add Nuclei UX600 platform

* Nuclei UX600 is a 64-bit RISC-V core developed
  by Nuclei System Technology, see https://nucleisys.com/product.php

* The ISA is configurable in hardware on your demand

Signed-off-by: Huaqi Fang <578567190@qq.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

docs/platform/nuclei_ux600.md

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+
+Nuclei UX600 Platform
+=====================
+
+The **Nuclei UX600** is a 64-bit RISC-V Core which is capable of running Linux.
+
+> Nuclei UX600: single core, pipeline as single-issue and 6~9 variable stages, in-order dispatch and out-of-order write-back, running up to >1.2GHz
+
+To build the platform-specific library and firmware images, provide the
+*PLATFORM=nuclei/ux600* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *Nuclei UX600* platform does not have any platform-specific options.
+
+Building Nuclei UX600 Platform
+------------------------------
+
+```
+make PLATFORM=nuclei/ux600 clean all
+```

platform/nuclei/ux600/config.mk

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+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2020 Nuclei Corporation or its affiliates.
+#
+# Authors:
+#   lujun <lujun@nucleisys.com>
+#   hqfang <578567190@qq.com>
+#
+
+# Compiler flags
+platform-cppflags-y =
+platform-cflags-y =
+platform-asflags-y =
+platform-ldflags-y =
+
+# Command for platform specific "make run"
+platform-runcmd = xl_spike \
+  $(build_dir)/platform/nuclei/ux600/firmware/fw_payload.elf
+
+# Blobs to build
+FW_TEXT_START=0x80000000
+FW_DYNAMIC=y
+FW_JUMP=y
+
+FW_JUMP_ADDR=0x80200000
+FW_JUMP_FDT_ADDR=0x88000000
+FW_PAYLOAD=y
+FW_PAYLOAD_OFFSET=0x200000
+FW_PAYLOAD_FDT_ADDR=0x88000000

platform/nuclei/ux600/objects.mk

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+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2020 Nuclei Corporation or its affiliates.
+#
+# Authors:
+#   lujun <lujun@nuclesys.com>
+#   hqfang <578567190@qq.com>
+#
+
+platform-objs-y += platform.o

platform/nuclei/ux600/platform.c

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+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) Nuclei Corporation or its affiliates.
+ *
+ * Authors:
+ *   lujun <lujun@nucleisys.com>
+ *   hqfang <578567190@qq.com>
+ */
+
+#include <libfdt.h>
+#include <sbi/riscv_asm.h>
+#include <sbi/riscv_io.h>
+#include <sbi/riscv_encoding.h>
+#include <sbi/sbi_console.h>
+#include <sbi/sbi_const.h>
+#include <sbi/sbi_platform.h>
+#include <sbi_utils/fdt/fdt_fixup.h>
+#include <sbi_utils/irqchip/plic.h>
+#include <sbi_utils/serial/sifive-uart.h>
+#include <sbi_utils/sys/clint.h>
+
+/* clang-format off */
+
+#define UX600_HART_COUNT		1
+
+#define UX600_SYS_CLK			1000000000
+
+/* Nuclei timer base address */
+#define UX600_NUCLEI_TIMER_ADDR		0x2000000
+/* The clint compatiable timer offset is 0x1000 against nuclei timer */
+#define UX600_CLINT_TIMER_ADDR		(UX600_NUCLEI_TIMER_ADDR + 0x1000)
+
+#define UX600_PLIC_ADDR			0x8000000
+#define UX600_PLIC_NUM_SOURCES		0x35
+#define UX600_PLIC_NUM_PRIORITIES	7
+
+#define UX600_UART0_ADDR		0x10013000
+#define UX600_UART1_ADDR		0x10023000
+
+#define UX600_DEBUG_UART		UX600_UART0_ADDR
+#define UX600_UART_BAUDRATE		115200
+
+/* clang-format on */
+
+static void ux600_modify_dt(void *fdt)
+{
+	fdt_fixups(fdt);
+}
+
+static int ux600_final_init(bool cold_boot)
+{
+	void *fdt;
+
+	if (!cold_boot)
+		return 0;
+
+	fdt = sbi_scratch_thishart_arg1_ptr();
+	ux600_modify_dt(fdt);
+
+	return 0;
+}
+
+static int ux600_console_init(void)
+{
+	return sifive_uart_init(UX600_DEBUG_UART, UX600_SYS_CLK,
+				UX600_UART_BAUDRATE);
+}
+
+static int ux600_irqchip_init(bool cold_boot)
+{
+	int rc;
+	u32 hartid = current_hartid();
+
+	if (cold_boot) {
+		rc = plic_cold_irqchip_init(UX600_PLIC_ADDR,
+					    UX600_PLIC_NUM_SOURCES,
+					    UX600_HART_COUNT);
+		if (rc)
+			return rc;
+	}
+
+	return plic_warm_irqchip_init(hartid, (hartid) ? (2 * hartid - 1) : 0,
+				      (hartid) ? (2 * hartid) : -1);
+}
+
+static int ux600_ipi_init(bool cold_boot)
+{
+	int rc;
+
+	if (cold_boot) {
+		rc = clint_cold_ipi_init(UX600_CLINT_TIMER_ADDR, UX600_HART_COUNT);
+		if (rc)
+			return rc;
+	}
+
+	return clint_warm_ipi_init();
+}
+
+static int ux600_timer_init(bool cold_boot)
+{
+	int rc;
+
+	if (cold_boot) {
+		rc = clint_cold_timer_init(UX600_CLINT_TIMER_ADDR,
+					   UX600_HART_COUNT, TRUE);
+		if (rc)
+			return rc;
+	}
+
+	return clint_warm_timer_init();
+}
+
+static int ux600_system_reset(u32 type)
+{
+	/* For now nothing to do. */
+	return 0;
+}
+
+const struct sbi_platform_operations platform_ops = {
+	.final_init		= ux600_final_init,
+	.console_putc		= sifive_uart_putc,
+	.console_getc		= sifive_uart_getc,
+	.console_init		= ux600_console_init,
+	.irqchip_init		= ux600_irqchip_init,
+	.ipi_send		= clint_ipi_send,
+	.ipi_clear		= clint_ipi_clear,
+	.ipi_init		= ux600_ipi_init,
+	.timer_value		= clint_timer_value,
+	.timer_event_stop	= clint_timer_event_stop,
+	.timer_event_start	= clint_timer_event_start,
+	.timer_init		= ux600_timer_init,
+	.system_reset		= ux600_system_reset
+};
+
+const struct sbi_platform platform = {
+	.opensbi_version	= OPENSBI_VERSION,
+	.platform_version	= SBI_PLATFORM_VERSION(0x0U, 0x01U),
+	.name			= "Nuclei UX600",
+	.features		= SBI_PLATFORM_DEFAULT_FEATURES,
+	.hart_count		= UX600_HART_COUNT,
+	.hart_stack_size	= SBI_PLATFORM_DEFAULT_HART_STACK_SIZE,
+	.platform_ops_addr	= (unsigned long)&platform_ops
+};