path: root/isys/smp.c

/*
[_Anarchy_(alan@lightning.swansea.uk.linux.org)] you should do one check
   though - if the board seems to be SMP and the CPU in /proc/cpuinfo is non
   intel dont install an SMP kernel - thats a dual pentium board with a cyrix
   or similar single cpu in it
*/


#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <string.h>
#include <errno.h>

#ifdef __alpha__
int alphaDetectSMP(void)
{
    int issmp = 0;
    FILE *f;
    
    f = fopen("/proc/cpuinfo", "r");
    if (f) {     
	char buff[1024];
	
	while (fgets (buff, 1024, f) != NULL) {
	    if (!strncmp (buff, "cpus detected\t\t: ", 17)) {
		if (strtoul (buff + 17, NULL, 0) > 1)
		    issmp = 1;
		break;
	    }
	}
	fclose(f);
    } else
	return -1;
    
    return issmp;
}
#endif /* __alpha__ */

#ifdef __sparc__
int sparcDetectSMP(void)
{
    int issmp = 0;
    FILE *f;
    
    f = fopen("/proc/cpuinfo", "r");
    if (f) {     
	char buff[1024];
	
	while (fgets (buff, 1024, f) != NULL) {
	    if (!strncmp (buff, "ncpus probed\t: ", 15)) {
		if (strtoul (buff + 15, NULL, 0) > 1)
		    issmp = 1;
		break;
	    }
	}
	fclose(f);
    } else
	return -1;
    
    return issmp;
}
#endif /* __sparc__ */

#ifdef __i386__
/*
 * Copyright (c) 1996, by Steve Passe
 * 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. The name of the developer may NOT be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR 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.
 *
 *      $Id$
 */

/*
 * mptable.c
 */

#define VMAJOR                  2
#define VMINOR                  0
#define VDELTA                  12

/*
 * this will cause the raw mp table to be dumped to /tmp/mpdump
 *
#define RAW_DUMP
 */

#define MP_SIG                  0x5f504d5f      /* _MP_ */
#define EXTENDED_PROCESSING_READY
#define OEM_PROCESSING_READY_NOT

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>

#define LINUX 1
#if LINUX
typedef unsigned int vm_offset_t;
#else
#include <machine/types.h>
#endif

/* EBDA is @ 40:0e in real-mode terms */
#define EBDA_POINTER            0x040e          /* location of EBDA pointer */

/* CMOS 'top of mem' is @ 40:13 in real-mode terms */
#define TOPOFMEM_POINTER        0x0413          /* BIOS: base memory size */

#define DEFAULT_TOPOFMEM        0xa0000

#define BIOS_BASE               0xf0000
#define BIOS_BASE2              0xe0000
#define BIOS_SIZE               0x10000
#define ONE_KBYTE               1024

#define GROPE_AREA1             0x80000
#define GROPE_AREA2             0x90000
#define GROPE_SIZE              0x10000

/* MP Floating Pointer Structure */
typedef struct MPFPS {
    char        signature[ 4 ];
    void*       pap;
    u_char      length;
    u_char      spec_rev;
    u_char      checksum;
    u_char      mpfb1;
    u_char      mpfb2;
    u_char      mpfb3;
    u_char      mpfb4;
    u_char      mpfb5;
} mpfps_t;

static void seekEntry( vm_offset_t addr );
static void apic_probe( vm_offset_t* paddr, int* where );
static void readEntry( void* entry, int size );

/* global data */
static int     pfd;            /* physical /dev/mem fd */
static int     verbose = 0;
static int     grope = 0;

static int intelDetectSMP(void)
{
  vm_offset_t paddr;
  int         where;

    /* open physical memory for access to MP structures */
    if ( (pfd = open( "/dev/mem", O_RDONLY )) < 0 ) {
	return 0;
    }

    /* probe for MP structures */
    apic_probe( &paddr, &where );
    close (pfd);

    if ( where <= 0 )
	return 0;

    return 1;
}

/*
 * set PHYSICAL address of MP floating pointer structure
 */
#define NEXT(X)         ((X) += 4)
static void
apic_probe( vm_offset_t* paddr, int* where )
{
    /*
     * c rewrite of apic_probe() by Jack F. Vogel
     */

    int         x;
    u_short     segment;
    vm_offset_t target;
    u_int       buffer[ BIOS_SIZE / sizeof( int ) ];

    if ( verbose )
        printf( "\n" );

    /* search Extended Bios Data Area, if present */
    if ( verbose )
        printf( " looking for EBDA pointer @ 0x%04x, ", EBDA_POINTER );
    seekEntry( (vm_offset_t)EBDA_POINTER );
    readEntry( &segment, 2 );
    if ( segment ) {                /* search EBDA */
        target = (vm_offset_t)segment << 4;
        if ( verbose )
            printf( "found, searching EBDA @ 0x%08x\n", target );
        seekEntry( target );
        readEntry( buffer, ONE_KBYTE );

        for ( x = 0; x < ONE_KBYTE / sizeof ( unsigned int ); NEXT(x) ) {
            if ( buffer[ x ] == MP_SIG ) {
                *where = 1;
                *paddr = (x * sizeof( unsigned int )) + target;
                return;
            }
        }
    }
    else {
        if ( verbose )
            printf( "NOT found\n" );
    }

    /* read CMOS for real top of mem */
    seekEntry( (vm_offset_t)TOPOFMEM_POINTER );
    readEntry( &segment, 2 );
    --segment;                                          /* less ONE_KBYTE */
    target = segment * 1024;
    if ( verbose )
        printf( " searching CMOS 'top of mem' @ 0x%08x (%dK)\n",
                target, segment );
    seekEntry( target );
    readEntry( buffer, ONE_KBYTE );

    for ( x = 0; x < ONE_KBYTE / sizeof ( unsigned int ); NEXT(x) ) {
        if ( buffer[ x ] == MP_SIG ) {
            *where = 2;
            *paddr = (x * sizeof( unsigned int )) + target;
            return;
        }
    }

    /* we don't necessarily believe CMOS, check base of the last 1K of 640K */
    if ( target != (DEFAULT_TOPOFMEM - 1024)) {
        target = (DEFAULT_TOPOFMEM - 1024);
        if ( verbose )
            printf( " searching default 'top of mem' @ 0x%08x (%dK)\n",
                    target, (target / 1024) );
        seekEntry( target );
        readEntry( buffer, ONE_KBYTE );

        for ( x = 0; x < ONE_KBYTE / sizeof ( unsigned int ); NEXT(x) ) {
            if ( buffer[ x ] == MP_SIG ) {
                *where = 3;
                *paddr = (x * sizeof( unsigned int )) + target;
                return;
            }
        }
    }

    /* search the BIOS */
    if ( verbose )
        printf( " searching BIOS @ 0x%08x\n", BIOS_BASE );
    seekEntry( BIOS_BASE );
    readEntry( buffer, BIOS_SIZE );

    for ( x = 0; x < BIOS_SIZE / sizeof( unsigned int ); NEXT(x) ) {
        if ( buffer[ x ] == MP_SIG ) {
            *where = 4;
            *paddr = (x * sizeof( unsigned int )) + BIOS_BASE;
            return;
        }
    }

    /* search the extended BIOS */
    if ( verbose )
        printf( " searching extended BIOS @ 0x%08x\n", BIOS_BASE2 );
    seekEntry( BIOS_BASE2 );
    readEntry( buffer, BIOS_SIZE );

    for ( x = 0; x < BIOS_SIZE / sizeof( unsigned int ); NEXT(x) ) {
        if ( buffer[ x ] == MP_SIG ) {
            *where = 5;
            *paddr = (x * sizeof( unsigned int )) + BIOS_BASE2;
            return;
        }
    }

    if ( grope ) {
        /* search additional memory */
        target = GROPE_AREA1;
        if ( verbose )
            printf( " groping memory @ 0x%08x\n", target );
        seekEntry( target );
        readEntry( buffer, GROPE_SIZE );

        for ( x = 0; x < GROPE_SIZE / sizeof( unsigned int ); NEXT(x) ) {
            if ( buffer[ x ] == MP_SIG ) {
                *where = 6;
                *paddr = (x * sizeof( unsigned int )) + GROPE_AREA1;
                return;
            }
        }

        target = GROPE_AREA2;
        if ( verbose )
            printf( " groping memory @ 0x%08x\n", target );
        seekEntry( target );
        readEntry( buffer, GROPE_SIZE );

        for ( x = 0; x < GROPE_SIZE / sizeof( unsigned int ); NEXT(x) ) {
            if ( buffer[ x ] == MP_SIG ) {
                *where = 7;
                *paddr = (x * sizeof( unsigned int )) + GROPE_AREA2;
                return;
            }
        }
    }

    *where = 0;
    *paddr = (vm_offset_t)0;
}


/*
 *
 */
static void
seekEntry( vm_offset_t addr )
{
    if ( lseek( pfd, (off_t)addr, SEEK_SET ) < 0 ) {
        return;
        perror( "/dev/mem seek" );
        exit( 1 );
    }
}


/*
 *
 */
static void
readEntry( void* entry, int size )
{
    if ( read( pfd, entry, size ) != size ) {
        return;
        perror( "readEntry" );
        exit( 1 );
    }
}


#endif /* __i386__ */

int detectSMP(void)
{
    static int isSMP = -1;

    if (isSMP != -1)
	return isSMP;

#ifdef __i386__
    return isSMP = intelDetectSMP();
#elif __sparc__
    return isSMP = sparcDetectSMP();
#elif __alpha__
    return isSMP = alphaDetectSMP();
#elif __ia64__
    return isSMP = 1;
#else
    #error unknown architecture
#endif
}