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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;

unsigned long long init_nsec;
unsigned long long * ptr_init_nsec = &init_nsec;

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;

#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()
{
    #ifdef __APIC__
      unsigned long msr_low_orig, tmp;
    #endif

    #ifdef __TSC__
 
        #ifdef CALIBRATE_USING_CMOS
          ll_calibrate_tsc_cmos();
        #else
          ll_calibrate_tsc();
        #endif 

        rdtscll(init_tsc); // Read start TSC
        init_nsec = 0;

        #ifdef __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();

        #endif

    #endif

}

void ll_restore_adv()
{
        /* Disable APIC */
        #ifdef __APIC__
                unsigned int msr_low_orig, tmp;

                cli();

                disable_APIC_timer();

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

                sti();

        #endif
   
}