*
* Copyright (C) 1991, 1992, 1995, 1999, 2000 Linus Torvalds
*
- * This file contains the PC-specific time handling details:
- * reading the RTC at bootup, etc..
- * 1994-07-02 Alan Modra
- * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
- * 1995-03-26 Markus Kuhn
- * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
- * precision CMOS clock update
+ * This file contains the clocksource time handling.
* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
* "A Kernel Model for Precision Timekeeping" by Dave Mills
* 1997-01-09 Adrian Sun
* 1999-04-16 Thorsten Kranzkowski (dl8bcu@gmx.net)
* fixed algorithm in do_gettimeofday() for calculating the precise time
* from processor cycle counter (now taking lost_ticks into account)
- * 2000-08-13 Jan-Benedict Glaw <jbglaw@lug-owl.de>
- * Fixed time_init to be aware of epoches != 1900. This prevents
- * booting up in 2048 for me;) Code is stolen from rtc.c.
* 2003-06-03 R. Scott Bailey <scott.bailey@eds.com>
* Tighten sanity in time_init from 1% (10,000 PPM) to 250 PPM
*/
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/hwrpb.h>
-#include <asm/rtc.h>
#include <linux/mc146818rtc.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/clocksource.h>
+#include <linux/clockchips.h>
#include "proto.h"
#include "irq_impl.h"
-static int set_rtc_mmss(unsigned long);
-
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
-#define TICK_SIZE (tick_nsec / 1000)
-
-/*
- * Shift amount by which scaled_ticks_per_cycle is scaled. Shifting
- * by 48 gives us 16 bits for HZ while keeping the accuracy good even
- * for large CPU clock rates.
- */
-#define FIX_SHIFT 48
-
-/* lump static variables together for more efficient access: */
-static struct {
- /* cycle counter last time it got invoked */
- __u32 last_time;
- /* ticks/cycle * 2^48 */
- unsigned long scaled_ticks_per_cycle;
- /* partial unused tick */
- unsigned long partial_tick;
-} state;
-
unsigned long est_cycle_freq;
#ifdef CONFIG_IRQ_WORK
return __builtin_alpha_rpcc();
}
-int update_persistent_clock(struct timespec now)
-{
- return set_rtc_mmss(now.tv_sec);
-}
-void read_persistent_clock(struct timespec *ts)
+\f
+/*
+ * The RTC as a clock_event_device primitive.
+ */
+
+static DEFINE_PER_CPU(struct clock_event_device, cpu_ce);
+
+irqreturn_t
+rtc_timer_interrupt(int irq, void *dev)
{
- unsigned int year, mon, day, hour, min, sec, epoch;
-
- sec = CMOS_READ(RTC_SECONDS);
- min = CMOS_READ(RTC_MINUTES);
- hour = CMOS_READ(RTC_HOURS);
- day = CMOS_READ(RTC_DAY_OF_MONTH);
- mon = CMOS_READ(RTC_MONTH);
- year = CMOS_READ(RTC_YEAR);
-
- if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
- sec = bcd2bin(sec);
- min = bcd2bin(min);
- hour = bcd2bin(hour);
- day = bcd2bin(day);
- mon = bcd2bin(mon);
- year = bcd2bin(year);
- }
+ int cpu = smp_processor_id();
+ struct clock_event_device *ce = &per_cpu(cpu_ce, cpu);
- /* PC-like is standard; used for year >= 70 */
- epoch = 1900;
- if (year < 20)
- epoch = 2000;
- else if (year >= 20 && year < 48)
- /* NT epoch */
- epoch = 1980;
- else if (year >= 48 && year < 70)
- /* Digital UNIX epoch */
- epoch = 1952;
+ /* Don't run the hook for UNUSED or SHUTDOWN. */
+ if (likely(ce->mode == CLOCK_EVT_MODE_PERIODIC))
+ ce->event_handler(ce);
- printk(KERN_INFO "Using epoch = %d\n", epoch);
+ if (test_irq_work_pending()) {
+ clear_irq_work_pending();
+ irq_work_run();
+ }
- if ((year += epoch) < 1970)
- year += 100;
+ return IRQ_HANDLED;
+}
- ts->tv_sec = mktime(year, mon, day, hour, min, sec);
- ts->tv_nsec = 0;
+static void
+rtc_ce_set_mode(enum clock_event_mode mode, struct clock_event_device *ce)
+{
+ /* The mode member of CE is updated in generic code.
+ Since we only support periodic events, nothing to do. */
+}
+
+static int
+rtc_ce_set_next_event(unsigned long evt, struct clock_event_device *ce)
+{
+ /* This hook is for oneshot mode, which we don't support. */
+ return -EINVAL;
}
+static void __init
+init_rtc_clockevent(void)
+{
+ int cpu = smp_processor_id();
+ struct clock_event_device *ce = &per_cpu(cpu_ce, cpu);
+
+ *ce = (struct clock_event_device){
+ .name = "rtc",
+ .features = CLOCK_EVT_FEAT_PERIODIC,
+ .rating = 100,
+ .cpumask = cpumask_of(cpu),
+ .set_mode = rtc_ce_set_mode,
+ .set_next_event = rtc_ce_set_next_event,
+ };
+ clockevents_config_and_register(ce, CONFIG_HZ, 0, 0);
+}
+\f
/*
- * timer_interrupt() needs to keep up the real-time clock,
- * as well as call the "xtime_update()" routine every clocktick
+ * The QEMU clock as a clocksource primitive.
*/
-irqreturn_t timer_interrupt(int irq, void *dev)
+
+static cycle_t
+qemu_cs_read(struct clocksource *cs)
{
- unsigned long delta;
- __u32 now;
- long nticks;
+ return qemu_get_vmtime();
+}
-#ifndef CONFIG_SMP
- /* Not SMP, do kernel PC profiling here. */
- profile_tick(CPU_PROFILING);
-#endif
+static struct clocksource qemu_cs = {
+ .name = "qemu",
+ .rating = 400,
+ .read = qemu_cs_read,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .max_idle_ns = LONG_MAX
+};
- /*
- * Calculate how many ticks have passed since the last update,
- * including any previous partial leftover. Save any resulting
- * fraction for the next pass.
- */
- now = rpcc();
- delta = now - state.last_time;
- state.last_time = now;
- delta = delta * state.scaled_ticks_per_cycle + state.partial_tick;
- state.partial_tick = delta & ((1UL << FIX_SHIFT) - 1);
- nticks = delta >> FIX_SHIFT;
- if (nticks)
- xtime_update(nticks);
+/*
+ * The QEMU alarm as a clock_event_device primitive.
+ */
- if (test_irq_work_pending()) {
- clear_irq_work_pending();
- irq_work_run();
- }
+static void
+qemu_ce_set_mode(enum clock_event_mode mode, struct clock_event_device *ce)
+{
+ /* The mode member of CE is updated for us in generic code.
+ Just make sure that the event is disabled. */
+ qemu_set_alarm_abs(0);
+}
-#ifndef CONFIG_SMP
- while (nticks--)
- update_process_times(user_mode(get_irq_regs()));
-#endif
+static int
+qemu_ce_set_next_event(unsigned long evt, struct clock_event_device *ce)
+{
+ qemu_set_alarm_rel(evt);
+ return 0;
+}
+static irqreturn_t
+qemu_timer_interrupt(int irq, void *dev)
+{
+ int cpu = smp_processor_id();
+ struct clock_event_device *ce = &per_cpu(cpu_ce, cpu);
+
+ ce->event_handler(ce);
return IRQ_HANDLED;
}
+static void __init
+init_qemu_clockevent(void)
+{
+ int cpu = smp_processor_id();
+ struct clock_event_device *ce = &per_cpu(cpu_ce, cpu);
+
+ *ce = (struct clock_event_device){
+ .name = "qemu",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .rating = 400,
+ .cpumask = cpumask_of(cpu),
+ .set_mode = qemu_ce_set_mode,
+ .set_next_event = qemu_ce_set_next_event,
+ };
+
+ clockevents_config_and_register(ce, NSEC_PER_SEC, 1000, LONG_MAX);
+}
+
+\f
void __init
common_init_rtc(void)
{
- unsigned char x;
+ unsigned char x, sel = 0;
/* Reset periodic interrupt frequency. */
- x = CMOS_READ(RTC_FREQ_SELECT) & 0x3f;
- /* Test includes known working values on various platforms
- where 0x26 is wrong; we refuse to change those. */
- if (x != 0x26 && x != 0x25 && x != 0x19 && x != 0x06) {
- printk("Setting RTC_FREQ to 1024 Hz (%x)\n", x);
- CMOS_WRITE(0x26, RTC_FREQ_SELECT);
+#if CONFIG_HZ == 1024 || CONFIG_HZ == 1200
+ x = CMOS_READ(RTC_FREQ_SELECT) & 0x3f;
+ /* Test includes known working values on various platforms
+ where 0x26 is wrong; we refuse to change those. */
+ if (x != 0x26 && x != 0x25 && x != 0x19 && x != 0x06) {
+ sel = RTC_REF_CLCK_32KHZ + 6;
}
+#elif CONFIG_HZ == 256 || CONFIG_HZ == 128 || CONFIG_HZ == 64 || CONFIG_HZ == 32
+ sel = RTC_REF_CLCK_32KHZ + __builtin_ffs(32768 / CONFIG_HZ);
+#else
+# error "Unknown HZ from arch/alpha/Kconfig"
+#endif
+ if (sel) {
+ printk(KERN_INFO "Setting RTC_FREQ to %d Hz (%x)\n",
+ CONFIG_HZ, sel);
+ CMOS_WRITE(sel, RTC_FREQ_SELECT);
+ }
/* Turn on periodic interrupts. */
x = CMOS_READ(RTC_CONTROL);
init_rtc_irq();
}
-unsigned int common_get_rtc_time(struct rtc_time *time)
-{
- return __get_rtc_time(time);
-}
+\f
+#ifndef CONFIG_ALPHA_WTINT
+/*
+ * The RPCC as a clocksource primitive.
+ *
+ * While we have free-running timecounters running on all CPUs, and we make
+ * a half-hearted attempt in init_rtc_rpcc_info to sync the timecounter
+ * with the wall clock, that initialization isn't kept up-to-date across
+ * different time counters in SMP mode. Therefore we can only use this
+ * method when there's only one CPU enabled.
+ *
+ * When using the WTINT PALcall, the RPCC may shift to a lower frequency,
+ * or stop altogether, while waiting for the interrupt. Therefore we cannot
+ * use this method when WTINT is in use.
+ */
-int common_set_rtc_time(struct rtc_time *time)
+static cycle_t read_rpcc(struct clocksource *cs)
{
- return __set_rtc_time(time);
+ return rpcc();
}
+static struct clocksource clocksource_rpcc = {
+ .name = "rpcc",
+ .rating = 300,
+ .read = read_rpcc,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS
+};
+#endif /* ALPHA_WTINT */
+
+\f
/* Validate a computed cycle counter result against the known bounds for
the given processor core. There's too much brokenness in the way of
timing hardware for any one method to work everywhere. :-(
return rpcc();
}
-#ifndef CONFIG_SMP
-/* Until and unless we figure out how to get cpu cycle counters
- in sync and keep them there, we can't use the rpcc. */
-static cycle_t read_rpcc(struct clocksource *cs)
-{
- cycle_t ret = (cycle_t)rpcc();
- return ret;
-}
-
-static struct clocksource clocksource_rpcc = {
- .name = "rpcc",
- .rating = 300,
- .read = read_rpcc,
- .mask = CLOCKSOURCE_MASK(32),
- .flags = CLOCK_SOURCE_IS_CONTINUOUS
-};
-
-static inline void register_rpcc_clocksource(long cycle_freq)
-{
- clocksource_register_hz(&clocksource_rpcc, cycle_freq);
-}
-#else /* !CONFIG_SMP */
-static inline void register_rpcc_clocksource(long cycle_freq)
-{
-}
-#endif /* !CONFIG_SMP */
-
void __init
time_init(void)
{
unsigned long cycle_freq, tolerance;
long diff;
+ if (alpha_using_qemu) {
+ clocksource_register_hz(&qemu_cs, NSEC_PER_SEC);
+ init_qemu_clockevent();
+
+ timer_irqaction.handler = qemu_timer_interrupt;
+ init_rtc_irq();
+ return;
+ }
+
/* Calibrate CPU clock -- attempt #1. */
if (!est_cycle_freq)
est_cycle_freq = validate_cc_value(calibrate_cc_with_pit());
"and unable to estimate a proper value!\n");
}
- /* From John Bowman <bowman@math.ualberta.ca>: allow the values
- to settle, as the Update-In-Progress bit going low isn't good
- enough on some hardware. 2ms is our guess; we haven't found
- bogomips yet, but this is close on a 500Mhz box. */
- __delay(1000000);
-
-
- if (HZ > (1<<16)) {
- extern void __you_loose (void);
- __you_loose();
- }
-
- register_rpcc_clocksource(cycle_freq);
-
- state.last_time = cc1;
- state.scaled_ticks_per_cycle
- = ((unsigned long) HZ << FIX_SHIFT) / cycle_freq;
- state.partial_tick = 0L;
+ /* See above for restrictions on using clocksource_rpcc. */
+#ifndef CONFIG_ALPHA_WTINT
+ if (hwrpb->nr_processors == 1)
+ clocksource_register_hz(&clocksource_rpcc, cycle_freq);
+#endif
/* Startup the timer source. */
alpha_mv.init_rtc();
+ init_rtc_clockevent();
}
-/*
- * In order to set the CMOS clock precisely, set_rtc_mmss has to be
- * called 500 ms after the second nowtime has started, because when
- * nowtime is written into the registers of the CMOS clock, it will
- * jump to the next second precisely 500 ms later. Check the Motorola
- * MC146818A or Dallas DS12887 data sheet for details.
- *
- * BUG: This routine does not handle hour overflow properly; it just
- * sets the minutes. Usually you won't notice until after reboot!
- */
-
-
-static int
-set_rtc_mmss(unsigned long nowtime)
+/* Initialize the clock_event_device for secondary cpus. */
+#ifdef CONFIG_SMP
+void __init
+init_clockevent(void)
{
- int retval = 0;
- int real_seconds, real_minutes, cmos_minutes;
- unsigned char save_control, save_freq_select;
-
- /* irq are locally disabled here */
- spin_lock(&rtc_lock);
- /* Tell the clock it's being set */
- save_control = CMOS_READ(RTC_CONTROL);
- CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
-
- /* Stop and reset prescaler */
- save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
- CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
-
- cmos_minutes = CMOS_READ(RTC_MINUTES);
- if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
- cmos_minutes = bcd2bin(cmos_minutes);
-
- /*
- * since we're only adjusting minutes and seconds,
- * don't interfere with hour overflow. This avoids
- * messing with unknown time zones but requires your
- * RTC not to be off by more than 15 minutes
- */
- real_seconds = nowtime % 60;
- real_minutes = nowtime / 60;
- if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) {
- /* correct for half hour time zone */
- real_minutes += 30;
- }
- real_minutes %= 60;
-
- if (abs(real_minutes - cmos_minutes) < 30) {
- if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
- real_seconds = bin2bcd(real_seconds);
- real_minutes = bin2bcd(real_minutes);
- }
- CMOS_WRITE(real_seconds,RTC_SECONDS);
- CMOS_WRITE(real_minutes,RTC_MINUTES);
- } else {
- printk_once(KERN_NOTICE
- "set_rtc_mmss: can't update from %d to %d\n",
- cmos_minutes, real_minutes);
- retval = -1;
- }
-
- /* The following flags have to be released exactly in this order,
- * otherwise the DS12887 (popular MC146818A clone with integrated
- * battery and quartz) will not reset the oscillator and will not
- * update precisely 500 ms later. You won't find this mentioned in
- * the Dallas Semiconductor data sheets, but who believes data
- * sheets anyway ... -- Markus Kuhn
- */
- CMOS_WRITE(save_control, RTC_CONTROL);
- CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
- spin_unlock(&rtc_lock);
-
- return retval;
+ if (alpha_using_qemu)
+ init_qemu_clockevent();
+ else
+ init_rtc_clockevent();
}
+#endif
projects / linux-drm-fsl-dcu.git / blobdiff