base/arch/i386/hal/rtc.c

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/*
 * Copyright (C) 2005-2008  Paolo Mantegazza  (mantegazza@aero.polimi.it)
 * (RTC specific part with) Giuseppe Quaranta (quaranta@aero.polimi.it)
 *
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */


#ifdef INCLUDED_BY_HAL_C

#include <linux/mc146818rtc.h>
static inline unsigned char RT_CMOS_READ(unsigned char addr)
{
    outb_p(addr, RTC_PORT(0));
    return inb_p(RTC_PORT(1));
}

//#define TEST_RTC
#define MIN_RTC_FREQ  2
#define MAX_RTC_FREQ  8192
#define RTC_FREQ      MAX_RTC_FREQ

static void rt_broadcast_rtc_interrupt(void)
{
#ifdef CONFIG_SMP
    apic_wait_icr_idle();
    apic_write_around(APIC_ICR, APIC_DM_FIXED | APIC_DEST_ALLBUT | RTAI_APIC_TIMER_VECTOR | APIC_DEST_LOGICAL);
    ((void (*)(void))rtai_realtime_irq[RTAI_APIC_TIMER_IPI].handler)();
#endif
}

static void (*usr_rtc_handler)(void);

#if CONFIG_RTAI_DONT_DISPATCH_CORE_IRQS

int _rtai_rtc_timer_handler(void)
{
    unsigned long cpuid = rtai_cpuid();
    unsigned long sflags;

    HAL_LOCK_LINUX();
    rt_mask_and_ack_irq(RTC_IRQ);
    RTAI_SCHED_ISR_LOCK();

    RT_CMOS_READ(RTC_INTR_FLAGS); // CMOS_READ(RTC_INTR_FLAGS);
    rt_enable_irq(RTC_IRQ);
    usr_rtc_handler();

    RTAI_SCHED_ISR_UNLOCK();
    HAL_UNLOCK_LINUX();

    if (!test_bit(IPIPE_STALL_FLAG, ROOT_STATUS_ADR(cpuid))) {
        rtai_sti();
        hal_fast_flush_pipeline(cpuid);
#if defined(CONFIG_SMP) &&  LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,32)
        __set_bit(IPIPE_STALL_FLAG, ROOT_STATUS_ADR(cpuid));
#endif
        return 1;
    }

    return 0;
}

void rtai_rtc_timer_handler(void);
DEFINE_VECTORED_ISR(rtai_rtc_timer_handler, _rtai_rtc_timer_handler);

static struct desc_struct rtai_rtc_timer_sysvec;

#endif /* CONFIG_RTAI_DONT_DISPATCH_CORE_IRQS */

/* 
 * NOTE FOR USE IN RTAI_TRIOSS.
 * "rtc_freq" must be a power of 2 & (MIN_RTC_FREQ <= rtc_freq <= MAX_RTC_FREQ).
 * So the best thing to do is to load this module and your skin of choice 
 * setting "rtc_freq" in this module and "rtc_freq" in the skin specific module
 * to the very same power of 2 that best fits your needs.
 */ 

static void rtc_handler(int irq, int rtc_freq)
{
#ifdef TEST_RTC
    static int stp, cnt;
    if (++cnt == rtc_freq) {
        rt_printk("<> IRQ %d, %d: CNT %d <>\n", irq, ++stp, cnt);
        cnt = 0;
    }
#endif
    RT_CMOS_READ(RTC_INTR_FLAGS); // CMOS_READ(RTC_INTR_FLAGS);
    rt_enable_irq(RTC_IRQ);
    if (usr_rtc_handler) {
        usr_rtc_handler();
    }
}

int fusion_timer_running;
#ifdef RTAI_TRIOSS
static void fusion_rtc_handler(void)
{
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/apic.h>
#include <mach_ipi.h>
    int cpuid;
    for (cpuid = 0; cpuid < num_online_cpus(); cpuid++) {
        hal_pend_domain_uncond(RTAI_APIC_TIMER_VECTOR, fusion_domain, cpuid);
    }
#ifdef CONFIG_SMP
    send_IPI_allbutself(RESCHEDULE_VECTOR);  // any unharmful ipi suffices 
#endif
#else 
    hal_pend_domain_uncond(RTAI_TIMER_8254_IRQ, fusion_domain, rtai_cpuid());
#endif
}
EXPORT_SYMBOL(fusion_timer_running);
#endif

void rt_request_rtc(long rtc_freq, void *handler)
{
    int pwr2;

    if (rtc_freq <= 0) {
        rtc_freq = RTC_FREQ;
    }
    if (rtc_freq > MAX_RTC_FREQ) {
        rtc_freq = MAX_RTC_FREQ;
    } else if (rtc_freq < MIN_RTC_FREQ) {
        rtc_freq = MIN_RTC_FREQ;
    }
    pwr2 = 1;
    if (rtc_freq > MIN_RTC_FREQ) {
        while (rtc_freq > (1 << pwr2)) {
            pwr2++;
        }
        if (rtc_freq <= ((3*(1 << (pwr2 - 1)) + 1)>>1)) {
            pwr2--;
        }
    }

    rt_disable_irq(RTC_IRQ);
    rt_release_irq(RTC_IRQ);
    rtai_cli();
    CMOS_WRITE(CMOS_READ(RTC_FREQ_SELECT), RTC_FREQ_SELECT);
    CMOS_WRITE(CMOS_READ(RTC_CONTROL),     RTC_CONTROL);
    CMOS_WRITE(RTC_REF_CLCK_32KHZ | (16 - pwr2),          RTC_FREQ_SELECT);
    CMOS_WRITE((CMOS_READ(RTC_CONTROL) & 0x8F) | RTC_PIE, RTC_CONTROL);
    rtai_sti();
#ifdef RTAI_TRIOSS
    usr_rtc_handler = fusion_rtc_handler;
#else
    usr_rtc_handler = handler ? handler : rt_broadcast_rtc_interrupt;
#endif
    SET_FUSION_TIMER_RUNNING();
#ifdef TEST_RTC
    rt_printk("<%s>\n", fusion_timer_running ? "FUSION TIMER RUNNING" : "");
#endif
    rt_request_irq(RTC_IRQ, (void *)rtc_handler, (void *)rtc_freq, 0);
    SET_INTR_GATE(ext_irq_vector(RTC_IRQ), rtai_rtc_timer_handler, rtai_rtc_timer_sysvec);
    rt_enable_irq(RTC_IRQ);
    CMOS_READ(RTC_INTR_FLAGS);
    return;
}

void rt_release_rtc(void)
{
    rt_disable_irq(RTC_IRQ);
    usr_rtc_handler = NULL;
    CLEAR_FUSION_TIMER_RUNNING();
    RESET_INTR_GATE(ext_irq_vector(RTC_IRQ), rtai_rtc_timer_sysvec);
    rt_release_irq(RTC_IRQ);
    rtai_cli();
    CMOS_WRITE(CMOS_READ(RTC_FREQ_SELECT), RTC_FREQ_SELECT);
    CMOS_WRITE(CMOS_READ(RTC_CONTROL),     RTC_CONTROL);
    rtai_sti();
    return;
}

EXPORT_SYMBOL(rt_request_rtc);
EXPORT_SYMBOL(rt_release_rtc);

#endif /* INCLUDED_BY_HAL_C */

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