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/* Project:     OSLib
 * Description: The OS Construction Kit
 * Date:                1.6.2000
 * Idea by:             Luca Abeni & Gerardo Lamastra
 *
 * OSLib is an SO project aimed at developing a common, easy-to-use
 * low-level infrastructure for developing OS kernels and Embedded
 * Applications; it partially derives from the HARTIK project but it
 * currently is independently developed.
 *
 * OSLib is distributed under GPL License, and some of its code has
 * been derived from the Linux kernel source; also some important
 * ideas come from studying the DJGPP go32 extender.
 *
 * We acknowledge the Linux Community, Free Software Foundation,
 * D.J. Delorie and all the other developers who believe in the
 * freedom of software and ideas.
 *
 * For legalese, check out the included GPL license.
 */


/*      Advanced Timer Managment
 *      Author: Giacomo Guidi <giacomo@gandalf.sssup.it>
 */


#include <ll/i386/stdlib.h>
#include <ll/i386/error.h>
#include <ll/sys/ll/ll-data.h>
#include <ll/sys/ll/ll-func.h>
#include <ll/i386/pic.h>
#include <ll/i386/apic.h>
#include <ll/i386/64bit.h>
#include <ll/sys/ll/event.h>
#include <ll/sys/ll/time.h>
#include <ll/i386/advtimer.h>

#define CALIBRATE_USING_CMOS

unsigned long long init_tsc;
unsigned long long * ptr_init_tsc = &init_tsc;

struct timespec init_time;
struct timespec * ptr_init_time = &init_time;

unsigned int clk_per_msec = 0;
unsigned int apic_clk_per_msec = 0;
unsigned int apic_set_limit = 0;

/* Precalcolated const
   used in ll_read_timer */

unsigned int clk_opt_0 = 0;
unsigned int clk_opt_1 = 0;
unsigned int clk_opt_2 = 0;
unsigned int clk_opt_3 = 0;
unsigned int clk_opt_4 = 0;
unsigned int clk_opt_5 = 0;

unsigned char save_CMOS_regA;
unsigned char save_CMOS_regB;

unsigned char X86_tsc = 0;
unsigned char X86_apic = 0;
unsigned char use_tsc = 0;
unsigned char use_apic = 0;

#ifdef CONFIG_MELAN
#  define CLOCK_TICK_RATE 1189200 /* AMD Elan has different frequency! */
#else
#  define CLOCK_TICK_RATE 1193182 /* Underlying HZ */
#endif

#define COUNTER_END 100

#define barrier() __asm__ __volatile__("" ::: "memory");

//TSC Calibration (idea from the linux kernel code)
void ll_calibrate_tsc(void)
{

        unsigned long long start;
        unsigned long long end;
        unsigned long long dtsc;
       
        unsigned int start_8253, end_8253, delta_8253;

        outp(0x61, (inp(0x61) & ~0x02) | 0x01);

        outp(0x43,0xB0);                        /* binary, mode 0, LSB/MSB, Ch 2 */
        outp(0x42,0xFF);                        /* LSB of count */
        outp(0x42,0xFF);                        /* MSB of count */
       
        barrier();
        rdtscll(start);
        barrier();
        outp(0x43,0x00);
        start_8253 = inp(0x42);
        start_8253 |= inp(0x42) << 8;
        barrier();
        rdtscll(start);
        barrier();
 
        do {
            outp(0x43,0x00);
            end_8253 = inp(0x42);
            end_8253 |= inp(0x42) << 8;
        } while (end_8253 > COUNTER_END);

        barrier();
        rdtscll(end);
        barrier();
        outp(0x43,0x00);
        end_8253 = inp(0x42);
        end_8253 |= inp(0x42) << 8;
        barrier();
        rdtscll(end);
        barrier();

        //Delta TSC
        dtsc = end - start;

        //Delta PIT
        delta_8253 = start_8253 - end_8253;

        if (delta_8253 > 0x20000) {
                message("Error calculating Delta PIT\n");
                ll_abort(10);
        }

        message("Delta TSC               = %10d\n",(int)dtsc);

        message("Delta PIT               = %10d\n",delta_8253);

        clk_per_msec = dtsc * CLOCK_TICK_RATE / delta_8253 / 1000;
       
        message("Calibrated Clk_per_msec = %10d\n",clk_per_msec);
}

#define CMOS_INIT  0
#define CMOS_BEGIN 1
#define CMOS_START 2
#define CMOS_END   3

int cmos_calibrate_status = CMOS_INIT;
unsigned long long irq8_start;
unsigned long long irq8_end;

void calibrate_tsc_IRQ8(void *p)
{
        unsigned char set;

        CMOS_READ(0x0C,set);

        barrier();
        rdtscll(irq8_end);
        barrier();

        if (cmos_calibrate_status == CMOS_START) {
                cmos_calibrate_status = CMOS_END;
        }

        if (cmos_calibrate_status == CMOS_BEGIN) {
                irq8_start = irq8_end;
                cmos_calibrate_status = CMOS_START;
        }

        if (cmos_calibrate_status == CMOS_INIT) {
                cmos_calibrate_status = CMOS_BEGIN;
        }
}

//TSC Calibration using RTC
void ll_calibrate_tsc_cmos(void)
{
        unsigned long long dtsc;

        irq_bind(8, calibrate_tsc_IRQ8, INT_FORCE);

        CMOS_READ(0x0A,save_CMOS_regA);
        CMOS_READ(0x0B,save_CMOS_regB);
   
        CMOS_WRITE(0x0A,0x2F); // Set 2 Hz Periodic Interrupt
        CMOS_WRITE(0x0B,0x42); // Enable Interrupt

        irq_unmask(8);
 
        sti();

        while (cmos_calibrate_status != CMOS_END) {
                barrier();
        }
 
        cli();

        dtsc = irq8_end - irq8_start;

        clk_per_msec = dtsc / 500;
        clk_opt_0 = (unsigned int)(dtsc);
        clk_opt_1 = (unsigned int)((unsigned long long)(dtsc << 1));
        clk_opt_2 = (unsigned int)((unsigned long long)(dtsc << 33) / 1000000000L);
        clk_opt_3 = (unsigned int)((unsigned long long)(dtsc << 32) / 1000000000L);
        clk_opt_4 = (unsigned int)((unsigned long long)(dtsc << 31) / 1000000000L);
        clk_opt_5 = (unsigned int)((unsigned long long)(dtsc << 30) / 1000000000L);

        message("Calibrated CPU Clk/msec  = %10u\n",clk_per_msec);

#ifdef __O1000__
        if (clk_per_msec < 1000000) {
                message("Timer Optimization CPU < 1 GHz\n");
        } else {
                message("Bad Timer Optimization\n");
                ll_abort(66);
        }
#endif

#ifdef __O2000__
        if (clk_per_msec < 2000000 && clk_per_msec >= 1000000) {
                message("Timer Optimization 1 GHz < CPU < 2 GHz\n");
        } else {
                message("Bad Timer Optimization\n");
                ll_abort(66);
        }
#endif

#ifdef __O4000__
        if (clk_per_msec < 4000000 && clk_per_msec >= 2000000) {
                message("Timer Optimization 2 GHz < CPU < 4 GHz\n");
        } else {
                message("Bad Timer Optimization\n");
                ll_abort(66);
        }
#endif

        irq_mask(8);

        CMOS_WRITE(0x0A,save_CMOS_regA);
        CMOS_WRITE(0x0B,save_CMOS_regB);
}

int apic_get_maxlvt(void)
{
        unsigned int v, ver, maxlvt;

        v = apic_read(APIC_LVR);
        ver = GET_APIC_VERSION(v);
        /* 82489DXs do not report # of LVT entries. */
        maxlvt = APIC_INTEGRATED(ver) ? GET_APIC_MAXLVT(v) : 2;
        return maxlvt;
}

/* Clear local APIC, from Linux kernel */
void clear_local_APIC(void)
{
        int maxlvt;
        unsigned long v;

        maxlvt = apic_get_maxlvt();

        /*
         * Masking an LVT entry on a P6 can trigger a local APIC error
         * if the vector is zero. Mask LVTERR first to prevent this.
         */

        if (maxlvt >= 3) {
                v = 0xFF; /* any non-zero vector will do */
                apic_write_around(APIC_LVTERR, v | APIC_LVT_MASKED);
        }
        /*
         * Careful: we have to set masks only first to deassert
         * any level-triggered sources.
         */

        v = apic_read(APIC_LVTT);
        apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
        v = apic_read(APIC_LVT0);
        apic_write_around(APIC_LVT0, v | APIC_LVT_MASKED);
        v = apic_read(APIC_LVT1);
        apic_write_around(APIC_LVT1, v | APIC_LVT_MASKED);
        if (maxlvt >= 4) {
                v = apic_read(APIC_LVTPC);
                apic_write_around(APIC_LVTPC, v | APIC_LVT_MASKED);
        }

        /*
         * Clean APIC state for other OSs:
         */

        apic_write_around(APIC_LVTT, APIC_LVT_MASKED);
        apic_write_around(APIC_LVT0, APIC_LVT_MASKED);
        apic_write_around(APIC_LVT1, APIC_LVT_MASKED);
        if (maxlvt >= 3)
                apic_write_around(APIC_LVTERR, APIC_LVT_MASKED);
        if (maxlvt >= 4)
                apic_write_around(APIC_LVTPC, APIC_LVT_MASKED);
        v = GET_APIC_VERSION(apic_read(APIC_LVR));
        if (APIC_INTEGRATED(v)) {       /* !82489DX */
                if (maxlvt > 3)
                        apic_write(APIC_ESR, 0);
                apic_read(APIC_ESR);
        }
}

void disable_local_APIC(void)
{
        unsigned long value;

        clear_local_APIC();

        /*
         * Disable APIC (implies clearing of registers
         * for 82489DX!).
         */

        value = apic_read(APIC_SPIV);
        value &= ~APIC_SPIV_APIC_ENABLED;
        apic_write_around(APIC_SPIV, value);
}

#define SPURIOUS_APIC_VECTOR 0xFF

/*
 * Setup the local APIC, minimal code to run P6 APIC
 */

void setup_local_APIC (void)
{
        unsigned long value;

        /* Pound the ESR really hard over the head with a big hammer - mbligh */

        apic_write(APIC_ESR, 0);
        apic_write(APIC_ESR, 0);
        apic_write(APIC_ESR, 0);
        apic_write(APIC_ESR, 0);

        value = APIC_SPIV_FOCUS_DISABLED | APIC_SPIV_APIC_ENABLED | SPURIOUS_APIC_VECTOR;
        apic_write_around(APIC_SPIV, value);

        value = APIC_DM_EXTINT | APIC_LVT_LEVEL_TRIGGER;
        apic_write_around(APIC_LVT0, value);

        value = APIC_DM_NMI;
        apic_write_around(APIC_LVT1, value);

        apic_write(APIC_ESR, 0);
}

void disable_APIC_timer(void)
{
        unsigned long v;
                                                                                                                             
        v = apic_read(APIC_LVTT);
        apic_write_around(APIC_LVTT, v | APIC_LVT_MASKED);
}
                                                                                                                             
void enable_APIC_timer(void)
{
        unsigned long v;
                                                                                                                             
        v = apic_read(APIC_LVTT);
        apic_write_around(APIC_LVTT, v & ~APIC_LVT_MASKED);
}

#define LOCAL_TIMER_VECTOR 0x39

/* Set APIC Timer... from Linux kernel */
void setup_APIC_timer()
{
        unsigned int lvtt1_value;

        lvtt1_value = SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV) |
                        APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
        apic_write_around(APIC_LVTT, lvtt1_value);

        /*
        * Divide PICLK by 1
        */

        apic_write_around(APIC_TDCR, APIC_TDR_DIV_1);

        apic_write_around(APIC_TMICT, MAX_DWORD);

        disable_APIC_timer();                                                                                                                            
}

#define APIC_LIMIT 0xFF000000
#define APIC_SET_LIMIT 10

void ll_calibrate_apic(void)
{
        unsigned int apic_start = 0, apic_end = 0, dapic;
        unsigned long long tsc_start = 0, tsc_end = 0, dtsc;
        unsigned int tmp_value;

        tmp_value = SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV) | LOCAL_TIMER_VECTOR;
        apic_write_around(APIC_LVTT, tmp_value);

        apic_write_around(APIC_TDCR, APIC_TDR_DIV_1);

        apic_write(APIC_TMICT, MAX_DWORD);

        enable_APIC_timer();

        barrier();
        rdtscll(tsc_start);
        barrier();
        apic_start = apic_read(APIC_TMCCT);
        barrier();            

        while (apic_read(APIC_TMCCT) > APIC_LIMIT) {
                barrier();
                rdtscll(tsc_end);
        }

        barrier();
        rdtscll(tsc_end);
        barrier();
        apic_end = apic_read(APIC_TMCCT);
        barrier();    

        disable_APIC_timer();

        dtsc = tsc_end - tsc_start;
        dapic = apic_start - apic_end;
       
        apic_clk_per_msec = (unsigned long long)(clk_per_msec) * (unsigned long long)(dapic) / dtsc;
        apic_set_limit = ((apic_clk_per_msec / 100) != 0) ? (apic_clk_per_msec/100) : APIC_SET_LIMIT;  

        message("Calibrated APIC Clk/msec = %10d\n",apic_clk_per_msec);
}

void ll_init_advtimer()
{
        unsigned long msr_low_orig, tmp;

#ifdef __APIC__
        use_apic = X86_apic;
#endif

#ifdef __TSC__
        use_tsc = X86_tsc;
#endif

        if (use_tsc) {
 
#ifdef CALIBRATE_USING_CMOS
                ll_calibrate_tsc_cmos();
#else
                ll_calibrate_tsc();
#endif 

                rdtscll(init_tsc); // Read start TSC
                init_time.tv_sec = 0;
                init_time.tv_nsec = 0;

                if (use_apic) {
                        rdmsr(APIC_BASE_MSR, msr_low_orig, tmp);
                        wrmsr(APIC_BASE_MSR, msr_low_orig|(1<<11), 0);

                        clear_local_APIC();

                        ll_calibrate_apic();

                        setup_local_APIC();
       
                        setup_APIC_timer();
                }
        }
}

void ll_restore_adv()
{
        SYS_FLAGS f;

        /* Disable APIC */
        if (use_apic) {
                unsigned int msr_low_orig, tmp;

                f = ll_fsave();

                disable_APIC_timer();

                rdmsr(APIC_BASE_MSR, msr_low_orig, tmp);
                wrmsr(APIC_BASE_MSR, msr_low_orig&~(1<<11), 0);

                ll_frestore(f);
        }
}

void ll_scale_advtimer(unsigned int old_f, unsigned int new_f)
{
        unsigned long long dtsc;
        unsigned long temp;
        SYS_FLAGS f;

        if (use_tsc) {
                f = ll_fsave();

                rdtscll(init_tsc);              // Set new start TSC
                ll_read_timespec(&init_time);   // Set new start TimeSpec
       
                mul32div32to32(clk_per_msec,new_f,old_f,temp);
                clk_per_msec = temp;
                dtsc = (unsigned long long)(clk_per_msec) * 500;
                clk_opt_0 = (unsigned int)(dtsc);
                clk_opt_1 = (unsigned int)((unsigned long long)(dtsc << 1));
                clk_opt_2 = (unsigned int)((unsigned long long)(dtsc << 33) / 1000000000L);
                clk_opt_3 = (unsigned int)((unsigned long long)(dtsc << 32) / 1000000000L);
                clk_opt_4 = (unsigned int)((unsigned long long)(dtsc << 31) / 1000000000L);
                clk_opt_5 = (unsigned int)((unsigned long long)(dtsc << 30) / 1000000000L);

                ll_frestore(f);
        }
}