u-boot/arch/riscv/lib/interrupts.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * 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>
 */

#include <common.h>
#include <irq_func.h>
#include <asm/ptrace.h>
#include <asm/system.h>
#include <asm/encoding.h>

static void _exit_trap(ulong code, ulong epc, struct pt_regs *regs)
{
	static const char * const exception_code[] = {
		"Instruction address misaligned",
		"Instruction access fault",
		"Illegal instruction",
		"Breakpoint",
		"Load address misaligned",
		"Load access fault",
		"Store/AMO address misaligned",
		"Store/AMO access fault",
		"Environment call from U-mode",
		"Environment call from S-mode",
		"Reserved",
		"Environment call from M-mode",
		"Instruction page fault",
		"Load page fault",
		"Reserved",
		"Store/AMO page fault",
	};

	if (code < ARRAY_SIZE(exception_code)) {
		printf("exception code: %ld , %s , epc %lx , ra %lx\n",
		       code, exception_code[code], epc, regs->ra);
	} else {
		printf("reserved exception code: %ld , epc %lx , ra %lx\n",
		       code, epc, regs->ra);
	}

	hang();
}

int interrupt_init(void)
{
	return 0;
}

/*
 * enable interrupts
 */
void enable_interrupts(void)
{
}

/*
 * disable interrupts
 */
int disable_interrupts(void)
{
	return 0;
}

ulong handle_trap(ulong cause, ulong epc, struct pt_regs *regs)
{
	ulong is_irq, irq;

	is_irq = (cause & MCAUSE_INT);
	irq = (cause & ~MCAUSE_INT);

	if (is_irq) {
		switch (irq) {
		case IRQ_M_EXT:
		case IRQ_S_EXT:
			external_interrupt(0);	/* handle external interrupt */
			break;
		case IRQ_M_TIMER:
		case IRQ_S_TIMER:
			timer_interrupt(0);	/* handle timer interrupt */
			break;
		default:
			_exit_trap(cause, epc, regs);
			break;
		};
	} else {
		_exit_trap(cause, 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)
{
}