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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; //Wraparound 292 years

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;

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;

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

  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

}