/*
 * linux/arch/ppc/kernel/traps.c
 *
 * Copyright (C) 1995-1996  Gary Thomas (gdt@linuxppc.org)
 *
 * Modified by Cort Dougan (cort@cs.nmt.edu)
 * and Paul Mackerras (paulus@cs.anu.edu.au)
 * fixed Machine Check Reasons by Reinhard Meyer (r.meyer@emk-elektronik.de)
 *
 * (C) Copyright 2000-2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

/*
 * This file handles the architecture-dependent parts of hardware exceptions
 */

#include <common.h>
#include <command.h>
#include <asm/processor.h>

#if defined(CONFIG_CMD_KGDB)
int (*debugger_exception_handler) (struct pt_regs *) = 0;
#endif

/* Returns 0 if exception not found and fixup otherwise.  */
extern unsigned long search_exception_table (unsigned long);

/* THIS NEEDS CHANGING to use the board info structure.
*/
#define END_OF_MEM      0x02000000

/*
 * Trap & Exception support
 */

void print_backtrace (unsigned long *sp)
{
	int cnt = 0;
	unsigned long i;

	printf ("Call backtrace: ");
	while (sp) {
		if ((uint) sp > END_OF_MEM)
			break;

		i = sp[1];
		if (cnt++ % 7 == 0)
			printf ("\n");
		printf ("%08lX ", i);
		if (cnt > 32)
			break;
		sp = (unsigned long *) *sp;
	}
	printf ("\n");
}

void show_regs (struct pt_regs *regs)
{
	int i;

	printf ("NIP: %08lX XER: %08lX LR: %08lX REGS: %p TRAP: %04lx DAR: %08lX\n",
		regs->nip, regs->xer, regs->link, regs, regs->trap, regs->dar);
	printf ("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n",
		regs->msr,
		regs->msr & MSR_EE ? 1 : 0, regs->msr & MSR_PR ? 1 : 0,
		regs->msr & MSR_FP ? 1 : 0, regs->msr & MSR_ME ? 1 : 0,
		regs->msr & MSR_IR ? 1 : 0, regs->msr & MSR_DR ? 1 : 0);

	printf ("\n");
	for (i = 0; i < 32; i++) {
		if ((i % 8) == 0) {
			printf ("GPR%02d: ", i);
		}

		printf ("%08lX ", regs->gpr[i]);
		if ((i % 8) == 7) {
			printf ("\n");
		}
	}
}


void _exception (int signr, struct pt_regs *regs)
{
	show_regs (regs);
	print_backtrace ((unsigned long *) regs->gpr[1]);
	panic ("Exception in kernel pc %lx signal %d", regs->nip, signr);
}

void MachineCheckException (struct pt_regs *regs)
{
	unsigned long fixup;

	/* Probing PCI using config cycles cause this exception
	 * when a device is not present.  Catch it and return to
	 * the PCI exception handler.
	 */
	if ((fixup = search_exception_table (regs->nip)) != 0) {
		regs->nip = fixup;
		return;
	}
#if defined(CONFIG_CMD_KGDB)
	if (debugger_exception_handler
	    && (*debugger_exception_handler) (regs))
		return;
#endif

	printf ("Machine check in kernel mode.\n");
	printf ("Caused by (from msr): ");
	printf ("regs %p ", regs);
	/* refer to 603e Manual (MPC603EUM/AD), chapter 4.5.2.1 */
	switch (regs->msr & 0x000F0000) {
	case (0x80000000 >> 12):
		printf ("Machine check signal - probably due to mm fault\n"
			"with mmu off\n");
		break;
	case (0x80000000 >> 13):
		printf ("Transfer error ack signal\n");
		break;
	case (0x80000000 >> 14):
		printf ("Data parity signal\n");
		break;
	case (0x80000000 >> 15):
		printf ("Address parity signal\n");
		break;
	default:
		printf ("Unknown values in msr\n");
	}
	show_regs (regs);
	print_backtrace ((unsigned long *) regs->gpr[1]);
	panic ("machine check");
}

void AlignmentException (struct pt_regs *regs)
{
#if defined(CONFIG_CMD_KGDB)
	if (debugger_exception_handler
	    && (*debugger_exception_handler) (regs))
		return;
#endif
	show_regs (regs);
	print_backtrace ((unsigned long *) regs->gpr[1]);
	panic ("Alignment Exception");
}

void ProgramCheckException (struct pt_regs *regs)
{
#if defined(CONFIG_CMD_KGDB)
	if (debugger_exception_handler
	    && (*debugger_exception_handler) (regs))
		return;
#endif
	show_regs (regs);
	print_backtrace ((unsigned long *) regs->gpr[1]);
	panic ("Program Check Exception");
}

void SoftEmuException (struct pt_regs *regs)
{
#if defined(CONFIG_CMD_KGDB)
	if (debugger_exception_handler
	    && (*debugger_exception_handler) (regs))
		return;
#endif
	show_regs (regs);
	print_backtrace ((unsigned long *) regs->gpr[1]);
	panic ("Software Emulation Exception");
}


void UnknownException (struct pt_regs *regs)
{
#if defined(CONFIG_CMD_KGDB)
	if (debugger_exception_handler
	    && (*debugger_exception_handler) (regs))
		return;
#endif
	printf ("Bad trap at PC: %lx, SR: %lx, vector=%lx\n",
		regs->nip, regs->msr, regs->trap);
	_exception (0, regs);
}

#if defined(CONFIG_CMD_BEDBUG)
extern void do_bedbug_breakpoint (struct pt_regs *);
#endif

void DebugException (struct pt_regs *regs)
{

	printf ("Debugger trap at @ %lx\n", regs->nip);
	show_regs (regs);
#if defined(CONFIG_CMD_BEDBUG)
	do_bedbug_breakpoint (regs);
#endif
}

/* Probe an address by reading.  If not present, return -1, otherwise
 * return 0.
 */
int addr_probe (uint * addr)
{
#if 0
	int retval;

	__asm__ __volatile__ ("1: lwz %0,0(%1)\n"
			      "   eieio\n"
			      "   li %0,0\n"
			      "2:\n"
			      ".section .fixup,\"ax\"\n"
			      "3: li %0,-1\n"
			      "   b 2b\n"
			      ".section __ex_table,\"a\"\n"
			      "   .align 2\n"
			      "   .long 1b,3b\n"
			      ".text":"=r" (retval):"r" (addr));

	return (retval);
#endif
	return 0;
}