riscv: nx25: lib: Add relative lib funcs to support RISC-V

Add makefile, interrupts.c and boot.c,... functions
to support RISC-V arch.

Signed-off-by: Rick Chen <rick@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
Cc: Padmarao Begari <Padmarao.Begari@microsemi.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/arch/riscv/lib/interrupts.c b/arch/riscv/lib/interrupts.c
new file mode 100644
index 0000000000..075db8ba46
--- /dev/null
+++ b/arch/riscv/lib/interrupts.c
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2016-17 Microsemi Corporation.
+ * Padmarao Begari, Microsemi Corporation <padmarao.begari@microsemi.com>
+ *
+ * Copyright (C) 2017 Andes Technology Corporation
+ * Rick Chen, Andes Technology Corporation <rick@andestech.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/ptrace.h>
+#include <asm/system.h>
+#include <asm/encoding.h>
+
+static void _exit_trap(int code, uint epc, struct pt_regs *regs);
+
+int interrupt_init(void)
+{
+	return 0;
+}
+
+/*
+ * enable interrupts
+ */
+void enable_interrupts(void)
+{
+}
+
+/*
+ * disable interrupts
+ */
+int disable_interrupts(void)
+{
+	return 0;
+}
+
+uint handle_trap(uint mcause, uint epc, struct pt_regs *regs)
+{
+	uint is_int;
+
+	is_int = (mcause & MCAUSE_INT);
+	if ((is_int) && ((mcause & MCAUSE_CAUSE)  == IRQ_M_EXT))
+		external_interrupt(0);	/* handle_m_ext_interrupt */
+	else if ((is_int) && ((mcause & MCAUSE_CAUSE)  == IRQ_M_TIMER))
+		timer_interrupt(0);	/* handle_m_timer_interrupt */
+	else
+		_exit_trap(mcause, epc, regs);
+
+	return epc;
+}
+
+/*
+ *Entry Point for PLIC Interrupt Handler
+ */
+__attribute__((weak)) void external_interrupt(struct pt_regs *regs)
+{
+}
+
+__attribute__((weak)) void timer_interrupt(struct pt_regs *regs)
+{
+}
+
+static void _exit_trap(int code, uint epc, struct pt_regs *regs)
+{
+	static const char *exception_code[] = {
+		"Instruction address misaligned",
+		"Instruction access fault",
+		"Illegal instruction",
+		"Breakpoint",
+		"Load address misaligned"
+	};
+
+	printf("exception code: %d , %s , epc %08x , ra %08lx\n",
+		code, exception_code[code], epc, regs->ra);
+}