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    Subject[PATCH] PC-9800 subarch. support for 2.5.64-ac3 (20/20) timer
    This is the patch to support NEC PC-9800 subarchitecture
    against 2.5.64-ac3. (20/20)

    Support difference of timer, using mach-* scheme.
    - Change CLOCK_TICK_RATE from constant to variable.
    Some PC98 can select base clock at boottime.
    - Replace calibrate_tsc function using anoter time counter on PC98.
    Because PIT channel2 on notebook PC98 is stopped.

    Regards,
    Osamu Tomita


    diff -Nru linux-2.5.63/arch/i386/kernel/timers/timer_pit.c linux98-2.5.63/arch/i386/kernel/timers/timer_pit.c
    --- linux-2.5.63/arch/i386/kernel/timers/timer_pit.c 2003-02-25 04:05:41.000000000 +0900
    +++ linux98-2.5.63/arch/i386/kernel/timers/timer_pit.c 2003-03-04 14:58:59.000000000 +0900
    @@ -16,9 +16,13 @@
    extern spinlock_t i8259A_lock;
    extern spinlock_t i8253_lock;
    #include "do_timer.h"
    +#include "io_ports.h"
    +
    +static int count_p; /* counter in get_offset_pit() */

    static int init_pit(void)
    {
    + count_p = LATCH;
    return 0;
    }

    @@ -77,7 +81,6 @@
    {
    int count;
    unsigned long flags;
    - static int count_p = LATCH; /* for the first call after boot */
    static unsigned long jiffies_p = 0;

    /*
    @@ -87,9 +90,9 @@

    spin_lock_irqsave(&i8253_lock, flags);
    /* timer count may underflow right here */
    - outb_p(0x00, 0x43); /* latch the count ASAP */
    + outb_p(0x00, PIT_MODE); /* latch the count ASAP */

    - count = inb_p(0x40); /* read the latched count */
    + count = inb_p(PIT_CH0); /* read the latched count */

    /*
    * We do this guaranteed double memory access instead of a _p
    @@ -97,13 +100,13 @@
    */
    jiffies_t = jiffies;

    - count |= inb_p(0x40) << 8;
    + count |= inb_p(PIT_CH0) << 8;

    /* VIA686a test code... reset the latch if count > max + 1 */
    if (count > LATCH) {
    - outb_p(0x34, 0x43);
    - outb_p(LATCH & 0xff, 0x40);
    - outb(LATCH >> 8, 0x40);
    + outb_p(0x34, PIT_MODE);
    + outb_p(LATCH & 0xff, PIT_CH0);
    + outb(LATCH >> 8, PIT_CH0);
    count = LATCH - 1;
    }

    diff -Nru linux-2.5.63/arch/i386/kernel/timers/timer_tsc.c linux98-2.5.63/arch/i386/kernel/timers/timer_tsc.c
    --- linux-2.5.63/arch/i386/kernel/timers/timer_tsc.c 2003-02-25 04:05:37.000000000 +0900
    +++ linux98-2.5.63/arch/i386/kernel/timers/timer_tsc.c 2003-03-04 14:39:42.000000000 +0900
    @@ -14,6 +14,9 @@
    /* processor.h for distable_tsc flag */
    #include <asm/processor.h>

    +#include "io_ports.h"
    +#include "mach_timer.h"
    +
    int tsc_disable __initdata = 0;

    extern spinlock_t i8253_lock;
    @@ -24,6 +27,8 @@

    static unsigned long last_tsc_low; /* lsb 32 bits of Time Stamp Counter */

    +static int count2; /* counter for mark_offset_tsc() */
    +
    /* Cached *multiplier* to convert TSC counts to microseconds.
    * (see the equation below).
    * Equal to 2^32 * (1 / (clocks per usec) ).
    @@ -64,7 +69,7 @@
    {
    int count;
    int countmp;
    - static int count1=0, count2=LATCH;
    + static int count1 = 0;
    /*
    * It is important that these two operations happen almost at
    * the same time. We do the RDTSC stuff first, since it's
    @@ -82,10 +87,10 @@
    rdtscl(last_tsc_low);

    spin_lock(&i8253_lock);
    - outb_p(0x00, 0x43); /* latch the count ASAP */
    + outb_p(0x00, PIT_MODE); /* latch the count ASAP */

    - count = inb_p(0x40); /* read the latched count */
    - count |= inb(0x40) << 8;
    + count = inb_p(PIT_CH0); /* read the latched count */
    + count |= inb(PIT_CH0) << 8;
    spin_unlock(&i8253_lock);

    if (pit_latch_buggy) {
    @@ -127,26 +132,11 @@
    * device.
    */

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

    unsigned long __init calibrate_tsc(void)
    {
    - /* Set the Gate high, disable speaker */
    - outb((inb(0x61) & ~0x02) | 0x01, 0x61);
    -
    - /*
    - * Now let's take care of CTC channel 2
    - *
    - * Set the Gate high, program CTC channel 2 for mode 0,
    - * (interrupt on terminal count mode), binary count,
    - * load 5 * LATCH count, (LSB and MSB) to begin countdown.
    - *
    - * Some devices need a delay here.
    - */
    - outb(0xb0, 0x43); /* binary, mode 0, LSB/MSB, Ch 2 */
    - outb_p(CALIBRATE_LATCH & 0xff, 0x42); /* LSB of count */
    - outb_p(CALIBRATE_LATCH >> 8, 0x42); /* MSB of count */
    + mach_prepare_counter();

    {
    unsigned long startlow, starthigh;
    @@ -154,10 +144,7 @@
    unsigned long count;

    rdtsc(startlow,starthigh);
    - count = 0;
    - do {
    - count++;
    - } while ((inb(0x61) & 0x20) == 0);
    + mach_countup(&count);
    rdtsc(endlow,endhigh);

    last_tsc_low = endlow;
    @@ -273,6 +260,8 @@
    cpufreq_register_notifier(&time_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
    #endif

    + count2 = LATCH; /* initialize counter for mark_offset_tsc() */
    +
    if (cpu_has_tsc) {
    unsigned long tsc_quotient = calibrate_tsc();
    if (tsc_quotient) {
    diff -Nru linux/include/asm-i386/mach-default/mach_timer.h linux98/include/asm-i386/mach-default/mach_timer.h
    --- linux/include/asm-i386/mach-default/mach_timer.h 1970-01-01 09:00:00.000000000 +0900
    +++ linux98/include/asm-i386/mach-default/mach_timer.h 2003-03-04 15:39:44.000000000 +0900
    @@ -0,0 +1,46 @@
    +/*
    + * include/asm-i386/mach-default/mach_timer.h
    + *
    + * Machine specific calibrate_tsc() for generic.
    + * Split out from timer_tsc.c by Osamu Tomita <tomita@cinet.co.jp>
    + */
    +/* ------ Calibrate the TSC -------
    + * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset().
    + * Too much 64-bit arithmetic here to do this cleanly in C, and for
    + * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2)
    + * output busy loop as low as possible. We avoid reading the CTC registers
    + * directly because of the awkward 8-bit access mechanism of the 82C54
    + * device.
    + */
    +#ifndef _MACH_TIMER_H
    +#define _MACH_TIMER_H
    +
    +#define CALIBRATE_LATCH (5 * LATCH)
    +
    +static inline void mach_prepare_counter(void)
    +{
    + /* Set the Gate high, disable speaker */
    + outb((inb(0x61) & ~0x02) | 0x01, 0x61);
    +
    + /*
    + * Now let's take care of CTC channel 2
    + *
    + * Set the Gate high, program CTC channel 2 for mode 0,
    + * (interrupt on terminal count mode), binary count,
    + * load 5 * LATCH count, (LSB and MSB) to begin countdown.
    + *
    + * Some devices need a delay here.
    + */
    + outb(0xb0, 0x43); /* binary, mode 0, LSB/MSB, Ch 2 */
    + outb_p(CALIBRATE_LATCH & 0xff, 0x42); /* LSB of count */
    + outb_p(CALIBRATE_LATCH >> 8, 0x42); /* MSB of count */
    +}
    +
    +static inline void mach_countup(unsigned long *count)
    +{
    + do {
    + *count++;
    + } while ((inb(0x61) & 0x20) == 0);
    +}
    +
    +#endif /* !_MACH_TIMER_H */
    diff -Nru linux-2.5.64/include/asm-i386/mach-pc9800/do_timer.h linux98-2.5.64/include/asm-i386/mach-pc9800/do_timer.h
    --- linux-2.5.64/include/asm-i386/mach-pc9800/do_timer.h 1970-01-01 09:00:00.000000000 +0900
    +++ linux98-2.5.64/include/asm-i386/mach-pc9800/do_timer.h 2003-03-05 13:37:30.000000000 +0900
    @@ -0,0 +1,82 @@
    +/* defines for inline arch setup functions */
    +
    +#include <asm/apic.h>
    +
    +/**
    + * do_timer_interrupt_hook - hook into timer tick
    + * @regs: standard registers from interrupt
    + *
    + * Description:
    + * This hook is called immediately after the timer interrupt is ack'd.
    + * It's primary purpose is to allow architectures that don't possess
    + * individual per CPU clocks (like the CPU APICs supply) to broadcast the
    + * timer interrupt as a means of triggering reschedules etc.
    + **/
    +
    +static inline void do_timer_interrupt_hook(struct pt_regs *regs)
    +{
    + do_timer(regs);
    +/*
    + * In the SMP case we use the local APIC timer interrupt to do the
    + * profiling, except when we simulate SMP mode on a uniprocessor
    + * system, in that case we have to call the local interrupt handler.
    + */
    +#ifndef CONFIG_X86_LOCAL_APIC
    + x86_do_profile(regs);
    +#else
    + if (!using_apic_timer)
    + smp_local_timer_interrupt(regs);
    +#endif
    +}
    +
    +
    +/* you can safely undefine this if you don't have the Neptune chipset */
    +
    +#define BUGGY_NEPTUN_TIMER
    +
    +/**
    + * do_timer_overflow - process a detected timer overflow condition
    + * @count: hardware timer interrupt count on overflow
    + *
    + * Description:
    + * This call is invoked when the jiffies count has not incremented but
    + * the hardware timer interrupt has. It means that a timer tick interrupt
    + * came along while the previous one was pending, thus a tick was missed
    + **/
    +static inline int do_timer_overflow(int count)
    +{
    + int i;
    +
    + spin_lock(&i8259A_lock);
    + /*
    + * This is tricky when I/O APICs are used;
    + * see do_timer_interrupt().
    + */
    + i = inb(0x00);
    + spin_unlock(&i8259A_lock);
    +
    + /* assumption about timer being IRQ0 */
    + if (i & 0x01) {
    + /*
    + * We cannot detect lost timer interrupts ...
    + * well, that's why we call them lost, don't we? :)
    + * [hmm, on the Pentium and Alpha we can ... sort of]
    + */
    + count -= LATCH;
    + } else {
    +#ifdef BUGGY_NEPTUN_TIMER
    + /*
    + * for the Neptun bug we know that the 'latch'
    + * command doesn't latch the high and low value
    + * of the counter atomically. Thus we have to
    + * substract 256 from the counter
    + * ... funny, isnt it? :)
    + */
    +
    + count -= 256;
    +#else
    + printk("do_slow_gettimeoffset(): hardware timer problem?\n");
    +#endif
    + }
    + return count;
    +}
    diff -Nru linux/include/asm-i386/mach-pc9800/mach_timer.h linux98/include/asm-i386/mach-pc9800/mach_timer.h
    --- linux/include/asm-i386/mach-pc9800/mach_timer.h 1970-01-01 09:00:00.000000000 +0900
    +++ linux98/include/asm-i386/mach-pc9800/mach_timer.h 2003-03-04 15:43:29.000000000 +0900
    @@ -0,0 +1,31 @@
    +/*
    + * include/asm-i386/mach-pc9800/mach_timer.h
    + *
    + * Machine specific calibrate_tsc() for PC-9800.
    + * Written by Osamu Tomita <tomita@cinet.co.jp>
    + */
    +/* ------ Calibrate the TSC -------
    + * PC-9800:
    + * CTC cannot be used because some models (especially
    + * note-machines) may disable clock to speaker channel (#1)
    + * unless speaker is enabled. We use ARTIC instead.
    + */
    +#ifndef _MACH_TIMER_H
    +#define _MACH_TIMER_H
    +
    +#define CALIBRATE_LATCH (5 * 307200/HZ) /* 0.050sec * 307200Hz = 15360 */
    +
    +static inline void mach_prepare_counter(void)
    +{
    + /* ARTIC can't be stopped nor reset. So we wait roundup. */
    + while (inw(0x5c));
    +}
    +
    +static inline void mach_countup(unsigned long *count)
    +{
    + do {
    + *count = inw(0x5c);
    + } while (*count < CALIBRATE_LATCH);
    +}
    +
    +#endif /* !_MACH_TIMER_H */
    diff -Nru linux/include/asm-i386/timex.h linux98/include/asm-i386/timex.h
    --- linux/include/asm-i386/timex.h 2002-02-14 18:09:15.000000000 +0900
    +++ linux98/include/asm-i386/timex.h 2002-02-14 23:58:57.000000000 +0900
    @@ -9,11 +9,15 @@
    #include <linux/config.h>
    #include <asm/msr.h>

    +#ifdef CONFIG_X86_PC9800
    + extern int CLOCK_TICK_RATE;
    +#else
    #ifdef CONFIG_MELAN
    # define CLOCK_TICK_RATE 1189200 /* AMD Elan has different frequency! */
    #else
    # define CLOCK_TICK_RATE 1193180 /* Underlying HZ */
    #endif
    +#endif

    #define CLOCK_TICK_FACTOR 20 /* Factor of both 1000000 and CLOCK_TICK_RATE */
    #define FINETUNE ((((((long)LATCH * HZ - CLOCK_TICK_RATE) << SHIFT_HZ) * \
    diff -Nru linux-2.5.63/kernel/timer.c linux98-2.5.63/kernel/timer.c
    --- linux-2.5.63/kernel/timer.c 2003-02-25 04:05:41.000000000 +0900
    +++ linux98-2.5.63/kernel/timer.c 2003-03-04 15:13:37.000000000 +0900
    @@ -437,8 +437,13 @@
    /*
    * Timekeeping variables
    */
    +#ifdef CONFIG_X86_PC9800
    +unsigned long tick_usec; /* ACTHZ period (usec) */
    +unsigned long tick_nsec; /* USER_HZ period (nsec) */
    +#else
    unsigned long tick_usec = TICK_USEC; /* ACTHZ period (usec) */
    unsigned long tick_nsec = TICK_NSEC(TICK_USEC); /* USER_HZ period (nsec) */
    +#endif

    /* The current time */
    struct timespec xtime __attribute__ ((aligned (16)));
    -
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