/*      $OpenBSD: smpprobe.c,v 1.6 2004/03/09 19:12:13 tom Exp $        */

/*
 * Copyright (c) 1997 Tobias Weingartner
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/param.h>
#include <machine/biosvar.h>
#include "libsa.h"

extern int debug;

extern u_int cnvmem, extmem;
#define MP_FLOAT_SIG    0x5F504D5F      /* _MP_ */
#define MP_CONF_SIG     0x504D4350      /* PCMP */

typedef struct _mp_float {
        u_int32_t signature;
        u_int32_t conf_addr;
        u_int8_t length;
        u_int8_t spec_rev;
        u_int8_t checksum;
        u_int8_t feature[5];
} mp_float_t;


static __inline int
mp_checksum(u_int8_t *ptr, int len)
{
        register int i, sum = 0;

#ifdef DEBUG
        printf("Checksum %p for %d\n", ptr, len);
#endif

        for (i = 0; i < len; i++)
                sum += *(ptr + i);

        return (!(sum & 0xff));
}


static mp_float_t *
mp_probefloat(u_int8_t *ptr, int len)
{
        mp_float_t *mpp = NULL;
        int i;

#ifdef DEBUG
        if (debug)
                printf("Checking %p for %d\n", ptr, len);
#endif
        for (i = 0; i < 1024; i++) {
                mp_float_t *tmp = (mp_float_t*)(ptr + i);

                if (tmp->signature == MP_FLOAT_SIG) {
                        printf("Found possible MP signature at: %p\n", ptr);

                        mpp = tmp;
                        break;
                }
                if ((tmp->signature == MP_FLOAT_SIG) &&
                    mp_checksum((u_int8_t *)tmp, tmp->length*16)) {
#ifdef DEBUG
                        if (debug)
                                printf("Found valid MP signature at: %p\n",
                                    ptr);
#endif
                        mpp = tmp;
                        break;
                }
        }

        return mpp;
}


void
smpprobe(void)
{
        mp_float_t *mp = NULL;

        /* Check EBDA */
        if (!(mp = mp_probefloat((void *)((*((u_int32_t*)0x4e)) * 16), 1024)) &&
                /* Check BIOS ROM 0xE0000 - 0xFFFFF */
            !(mp = mp_probefloat((void *)(0xE0000), 0x1FFFF)) &&
                /* Check last 1K of base RAM */
            !(mp = mp_probefloat((void *)(cnvmem * 1024), 1024)) &&
                /* Check last 1K of extended RAM XXX */
            !(mp = mp_probefloat((void *)(extmem * 1024 - 1024), 1024))) {
                /* No valid MP signature found */
#if DEBUG
                if (debug)
                        printf("No valid MP signature found.\n");
#endif
                return;
        }

        /* Valid MP signature found */
        printf(" smp");

#if DEBUG
        if (debug)
                printf("Floating Structure:\n"
                    "\tSignature: %x\n"
                    "\tConfig at: %x\n"
                    "\tLength: %d\n"
                    "\tRev: 1.%d\n"
                    "\tFeature: %x %x %x %x %x\n",
                    mp->signature, mp->conf_addr, mp->length, mp->spec_rev,
                    mp->feature[0], mp->feature[1], mp->feature[2],
                    mp->feature[3], mp->feature[4]);
#endif
}