root / Whitix / branches / hybrid / arch / i386 / kernel / smp.c

/*  This file is part of Whitix.
 *
 *  Whitix 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.
 *
 *  Whitix 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 Whitix; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

/* Just detects whether the system is or is not a SMP system */

#include <console.h>
#include <i386/smp.h>
#include <typedefs.h>

#define MP_FPS_SIG   (('_' << 24) | ('P' << 16) | ('M' << 8) | ('_'))

struct MpConfig;

struct MpFloating
{
        char sig[4];
        struct MpConfig* config;
        BYTE length; /* In 16 byte paragraphs */
        BYTE version; /* 1 = 1.1, 4 = 1.4 */
        BYTE checkSum; /* Should be zero */
        BYTE mpFeatures1;
        BYTE mpFeatures2;
        BYTE reserved[3];
};

struct MpConfig
{
        char sig[4];
        WORD length;
        BYTE version,checkSum;
        char oemId[8];
        char productId[12];
        DWORD tablePointer,tableSize;
        BYTE entryCount;
        DWORD apicAddress;
        WORD extTableLength;
        BYTE extTableCheckSum;
};

/* SmpDetectStruct - Searches an area of memory for the "_MP_" signature */
DWORD SmpDetectStruct(DWORD addr,DWORD length)
{
        DWORD* i;
        for (i=(DWORD*)addr; i<(DWORD*)(addr+length); i+=4)
                if (*i == MP_FPS_SIG)
                        return (DWORD)i;

        return 0;
}

int SmpInit()
{
        DWORD addr;
        extern DWORD ebdaAddr;

        KePrint("Detecting SMP...");

        /* 
         * The The MP Floating Pointer Structure is in one of four memory areas: 
         * (1) The first kilobyte of the Extended BIOS Data Area (EBDA). 
         * (2) The last kilobyte of base memory (639-640k). 
         * (3) The BIOS ROM address space (0xF0000-0xFFFFF). 
         * (4) The first kilobyte of memory.
         * The OS should search for the ASCII string "_MP_" in these four areas
         */

//      if ((addr=SmpDetectStruct(0x0, 0x400)))
//              goto found;

        if ((addr=SmpDetectStruct(0x9FC00,0x400)))
                goto found;

        if ((addr=SmpDetectStruct(0xF0000,0xFFFF)))
                goto found;

        if (ebdaAddr && (addr=SmpDetectStruct(ebdaAddr,0x400)))
                goto found;

        KePrint("Not found\n");
        return 0;

found:
        KePrint("Found at %#X\n",addr);
        return 0;
}