/*
 * 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;
}