root / Whitix / branches / hybrid / arch / i386 / kernel / init.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
 *
 */

#include <i386/i386.h>
#include <i386/pit.h>
#include <i386/smp.h>
#include <i386/cpuid.h>
#include <i386/virtual.h>
#include <i386/idt.h>
#include <i386/ioports.h>
#include <i386/pic.h>
#include <time.h>
#include <vmm.h>

#define rdtsc(low,high) \
        asm volatile("rdtsc" : "=a"(low), "=d"(high))

#define CALIBRATE_LATCH (5*LATCH)
#define CALIBRATE_TIME  (5*1000020/HZ)

static DWORD CalibrateTsc()
{
        DWORD startLow,startHigh,endLow,endHigh,count;

        /* Set the gate high and disable the speaker */
        outb(0x61,(inb(0x61) & ~0x02) | 0x01);
        /* Use the PIT to countdown */
        outb(0x43,0xB0);
        outb(0x42,CALIBRATE_LATCH & 0xFF);
        outb(0x42,CALIBRATE_LATCH >> 8);

        rdtsc(startLow,startHigh);
        count=0;
        do
        {
                ++count;
        }while (!(inb(0x61) & 0x20));

        rdtsc(endLow,endHigh);

        /* Do a 64-bit subtract */
        asm("subl %2,%0 \n\t"
                "sbbl %3,%1" : "=a"(endLow),"=d"(endHigh)
                : "g"(startLow),"g"(startHigh),"g"(endLow),"1"(endHigh));

        asm("divl %2" : "=a"(endLow),"=d"(endHigh) : "r"(endLow),"g"(0),"1"(CALIBRATE_TIME));
        return endLow;
}

/* Could probably be moved into pit.c */
static void CalcCpuSpeed()
{
        /* Adapted from Linux, which seems to have a pretty accurate CPU speed calculator. */
        if (CpuIdSupports(CPU_FEATURE_TSC))
        {
                DWORD tscQ=CalibrateTsc();
                DWORD eax=0,edx=1000,cpuKhz;
                asm("divl %2" : "=a"(cpuKhz),"=d"(edx):"r"(tscQ),"g"(eax),"1"(edx));

                KePrint("CPU: Detected a %lu.%03lu MHz processor.\n",cpuKhz/1000,cpuKhz % 1000);
        }
}

int ArchInit()
{
        KePrint("Whitix x86 v0.1.5. Built on %s at %s\n",__DATE__,__TIME__);
        PhysInit();
        VirtEarlyInit();
        CpuIdInit();
        CalcCpuSpeed();

        SmpInit();
        PicRemap(0x20,0x28);
        IrqInit();
        IdtInit();
        IdtLoad();

        PitInit();

        return 0;
}