/*
 * File      : mips_excpt.c
 * This file is part of RT-Thread RTOS
 * COPYRIGHT (C) 2008 - 2012, RT-Thread Development Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Change Logs:
 * Date           Author       Notes
 * 2016年9月7日     Urey         the first version
 */

#include <rtthread.h>
#include <rthw.h>
#include <stdio.h>

#include "mips.h"
#include "mips_excpt.h"

extern int backtrace(void);
int backtrace_ctx(mips_reg_ctx *ctx);

extern long list_thread(void);

const static char *regstr[] = {
	"$0  zero", "$1  at", "$2  v0", "$3  v1", "$4  a0", "$5  a1", "$6  a2", "$7  a3",
	"$8  t0", "$9  t1", "$10 t2", "$11 t3", "$12 t4", "$13 t5", "$14 t6", "$15 t7",
	"$16 s0", "$17 s1", "$18 s2", "$19 s3", "$20 s4", "$21 s5", "$22 s6", "$23 s7",
	"$24 t8", "$25 t9", "$26 k0", "$27 k1", "$28 gp", "$29 sp", "$30 fp", "$31 ra"
};

static const char *cause_strings[32] =
{
  /*  0 */ "Int",
  /*  1 */ "TLB Mods",
  /*  2 */ "TLB Load",
  /*  3 */ "TLB Store",
  /*  4 */ "Address Load",
  /*  5 */ "Address Store",
  /*  6 */ "Instruction Bus Error",
  /*  7 */ "Data Bus Error",
  /*  8 */ "Syscall",
  /*  9 */ "Breakpoint",
  /* 10 */ "Reserved Instruction",
  /* 11 */ "Coprocessor Unuseable",
  /* 12 */ "Overflow",
  /* 13 */ "Trap",
  /* 14 */ "Instruction Virtual Coherency Error",
  /* 15 */ "FP Exception",
  /* 16 */ "Reserved 16",
  /* 17 */ "Reserved 17",
  /* 18 */ "Reserved 18",
  /* 19 */ "Reserved 19",
  /* 20 */ "Reserved 20",
  /* 21 */ "Reserved 21",
  /* 22 */ "Reserved 22",
  /* 23 */ "Watch",
  /* 24 */ "Reserved 24",
  /* 25 */ "Reserved 25",
  /* 26 */ "Reserved 26",
  /* 27 */ "Reserved 27",
  /* 28 */ "Reserved 28",
  /* 29 */ "Reserved 29",
  /* 30 */ "Reserved 30",
  /* 31 */ "Data Virtual Coherency Error"
};


/**
 * exception handle table
 */
exception_func_t sys_exception_handlers[32];

static void mod_handler(mips_reg_ctx *regs)
{
    rt_kprintf("tlb modification exception\n");
    rt_kprintf("exception happens, epc: 0x%08x\n", read_c0_epc());
    rt_kprintf("                 cause: 0x%08x\n", read_c0_cause());

    list_thread();

    printf("-----------------------------------------------------\n");
    printf("BACKTRACE:\n");
    backtrace();
    printf("-----------------------------------------------------\n");

    rt_hw_cpu_shutdown();
}

static void tlbl_handler(mips_reg_ctx *regs)
{
    rt_kprintf("tlb exception: load\n");
    rt_kprintf("exception happens, epc: 0x%08x\n", read_c0_epc());
    rt_kprintf("                 cause: 0x%08x\n", read_c0_cause());

    list_thread();

    printf("-----------------------------------------------------\n");
    printf("BACKTRACE:\n");
    backtrace();
    printf("-----------------------------------------------------\n");

    rt_hw_cpu_shutdown();
}

static void tlbs_handler(mips_reg_ctx *regs)
{
    rt_kprintf("tlb exception: store\n");
    rt_kprintf("exception happens, epc: 0x%08x\n", read_c0_epc());
    rt_kprintf("                 cause: 0x%08x\n", read_c0_cause());

    list_thread();

    printf("-----------------------------------------------------\n");
    printf("BACKTRACE:\n");
    backtrace();
    printf("-----------------------------------------------------\n");

    rt_hw_cpu_shutdown();
}

static void adel_handler(mips_reg_ctx *regs)
{
    rt_kprintf("address error exception: load\n");
    rt_kprintf("exception happens, epc: 0x%08x\n", read_c0_epc());
    rt_kprintf("                 cause: 0x%08x\n", read_c0_cause());

    list_thread();
    rt_kprintf("current thread: %.*s\n", RT_NAME_MAX, rt_thread_self()->name);

    printf("-----------------------------------------------------\n");
    printf("BACKTRACE:\n");
    backtrace();
    printf("-----------------------------------------------------\n");

    rt_hw_cpu_shutdown();
}

static void ades_handler(mips_reg_ctx *regs)
{
    rt_kprintf("address error exception: store\n");
    rt_kprintf("exception happens, epc: 0x%08x\n", read_c0_epc());
    rt_kprintf("                 cause: 0x%08x\n", read_c0_cause());

    list_thread();

    printf("-----------------------------------------------------\n");
    printf("BACKTRACE:\n");
    backtrace();
    printf("-----------------------------------------------------\n");

    rt_hw_cpu_shutdown();
}

static void fpe_handler(mips_reg_ctx *regs)
{
    rt_kprintf("floating point exception\n");
    rt_kprintf("exception happens, epc: 0x%08x\n", read_c0_epc());
    rt_kprintf("                 cause: 0x%08x\n", read_c0_cause());

    list_thread();

    printf("-----------------------------------------------------\n");
    printf("BACKTRACE:\n");
    backtrace();
    printf("-----------------------------------------------------\n");

    rt_hw_cpu_shutdown();
}


static void unhandled_exception_handle(mips_reg_ctx *regs)
{
	int i;
	unsigned int cause = read_c0_cause();
	unsigned int exc = (cause >> 2) & 0x1f;

	rt_kprintf("exception happens, epc: 0x%08x\n", regs->CP0EPC);
	rt_kprintf("                 cause: 0x%08x\n", regs->CP0Cause);

	for (i = 0; i < 32; i++)
	{
		if (i % 4 == 0)
			printf("\n");
		printf("%8s %08x ", regstr[i], regs->regs[i]);
	}
	printf("\n");

	list_thread();
	rt_hw_cpu_shutdown();
}

static void install_default_exception_handler(void)
{
    int i;

    for (i=0; i<sizeof(sys_exception_handlers)/sizeof(sys_exception_handlers[0]); i++)
        sys_exception_handlers[i] = (exception_func_t)unhandled_exception_handle;

    sys_exception_handlers[EX_MOD]  = mod_handler;
    sys_exception_handlers[EX_TLBL] = tlbl_handler;
    sys_exception_handlers[EX_TLBS] = tlbs_handler;
    sys_exception_handlers[EX_ADEL] = adel_handler;
    sys_exception_handlers[EX_ADES] = ades_handler;
    sys_exception_handlers[EX_FPE]  = fpe_handler;
}

int rt_hw_exception_init(void)
{
    /* install the default exception handler */
    install_default_exception_handler();

    return RT_EOK;
}

/**
 * setup the exception handle
 */
exception_func_t rt_set_except_vector(int n, exception_func_t func)
{
    exception_func_t old_handler = sys_exception_handlers[n];

    if ((n == 0) || (n > 32) || (!func))
    {
        return 0;
    }

    sys_exception_handlers[n] = func;

    return old_handler;
}

void mips_exception_handler(mips_reg_ctx *ctx)
{
	static int read_epc_count = 0;
	static int epc_save = 0;
	int 	i;
	unsigned int epc;

	//如果 read_epc_count>0 说明 c_except_handler 在读 epc 时重入了，即读 epc 导致了一个新的异常
	if (read_epc_count > 0)
	{
		printf("ERROR: read epc fail when except handle\n");
		epc = epc_save;
		read_epc_count = 0;
	}
	else
	{
		read_epc_count++;
		epc_save 	= 0;
		epc 		= read_c0_epc();
		epc_save 	= epc;

		if (epc != 0)
		{
			printf("-----------------------------------------------------\n");
			for (i = 0; i < 4; i++)
			{
				printf("%08x:\t%08x\n",
				       (epc - 4 * 4 + i * 4),
				       *(unsigned int *) ((epc - 4 * 4 + i * 4) | 0xa0000000));
			}
			for (i = 0; i < 4; i++)
			{
				printf("%08x:\t%08x\n",
				       (epc + i * 4),
				       *(unsigned int *) ((epc + i * 4) | 0xa0000000));
			}
			printf("-----------------------------------------------------\n");
		}

		read_epc_count--;
	}

	printf("-----------------------------------------------------\n");
	unsigned int cause = read_c0_cause();
	unsigned int exc = (cause >> 2) & 0x1f;
	printf("CAUSE=%08x --> %s\n", cause, cause_strings[exc]);
	printf("EPC=%08x\n", epc);

	for (i = 0; i < 32; i++)
	{
		if ((i != 0) && (i % 4 == 0))
			printf("\n");
		printf("%8s %08x ", regstr[i], ctx->regs[i]);
	}
	printf("\n-----------------------------------------------------\n");
	printf("%s: \t %8x\n","CP0Status  ",	ctx->CP0Status);
	printf("%s: \t %8x\n","CP0DataHI  ",	ctx->CP0DataHI);
	printf("%s: \t %8x\n","CP0DataLO  ",	ctx->CP0DataLO);
	printf("%s: \t %8x\n","CP0BadVAddr",	ctx->CP0BadVAddr);
	printf("%s: \t %8x\n","CP0Cause   ",	ctx->CP0Cause);
	printf("%s: \t %8x\n","CP0EPC     ",	ctx->CP0EPC);
	printf("-----------------------------------------------------\n");

#if 0
	switch (exc)
	{
	case EX_MOD:
	 /*  TLB modified                */
		break;

    case EX_TLBL:                                                       /*  TLB exc(load or ifetch)     */
    case EX_TLBS:                                                       /*  TLB exception (store)       */

    	break;

    case EX_ADEL:                                                       /*  Address err(load or ifetch) */
    case EX_ADES:                                                       /*  Address error (store)       */

    	break;

    case EX_IBE:                                                        /*  Instruction Bus Error       */
    case EX_DBE:                                                        /*  Data Bus Error              */

    	break;

    case EX_SYS:                                                        /*  Syscall                     */

    	break;

    case EX_BP:                                                         /*  Breakpoint                  */
    case EX_TR:                                                         /*  Trap instruction            */

    	break;
    case EX_RI:                                                         /*  Reserved instruction        */

    	break;
    case EX_FPE:                                                        /*  floating point exception    */
    	break;

    case EX_CPU:                                                        /*  CoProcessor Unusable        */

    	break;
    case EX_OV:                                                         /*  OVerflow                    */
    case EX_C2E:                                                        /*  COP2 exception              */
    case EX_MDMX:                                                       /*  MDMX exception              */
    case EX_WATCH:                                                      /*  Watch exception             */
    case EX_MCHECK:                                                     /*  Machine check exception     */
    case EX_CacheErr:                                                   /*  Cache error caused re-entry */
                                                                        /*  to Debug Mode               */

    	break;
    default:
    	rt_kprintf("Unknow exception: %d\r\n", exc);
    	break;
	}
#else
	sys_exception_handlers[exc](ctx);
#endif

	rt_hw_cpu_shutdown();
}


void mips_cache_error_handler (unsigned int  Addr)
{
	rt_kprintf("cache exception happens, epc: 0x%08x\n", read_c0_epc());
	list_thread();
	rt_hw_cpu_shutdown();
}

void mips_tlb_refill_handler(void)
{
	rt_kprintf("tlb-miss happens, epc: 0x%08x\n", read_c0_epc());
	rt_kprintf("                cause: 0x%08x\n", read_c0_cause());
	list_thread();
	rt_kprintf("current thread: %s\n", rt_thread_self()->name);
	rt_hw_cpu_shutdown();
}