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-rw-r--r--arch/mips/kernel/time.c468
1 files changed, 69 insertions, 399 deletions
diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c
index 11aab6d6bfe..8d0170969e2 100644
--- a/arch/mips/kernel/time.c
+++ b/arch/mips/kernel/time.c
@@ -3,14 +3,15 @@
* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
* Copyright (c) 2003, 2004 Maciej W. Rozycki
*
- * Common time service routines for MIPS machines. See
- * Documentation/mips/time.README.
+ * Common time service routines for MIPS machines.
*
- * 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
+ * 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.
*/
+#include <linux/bug.h>
+#include <linux/clockchips.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
@@ -19,446 +20,115 @@
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/smp.h>
-#include <linux/kernel_stat.h>
#include <linux/spinlock.h>
-#include <linux/interrupt.h>
-#include <linux/module.h>
+#include <linux/export.h>
-#include <asm/bootinfo.h>
-#include <asm/cache.h>
-#include <asm/compiler.h>
-#include <asm/cpu.h>
#include <asm/cpu-features.h>
+#include <asm/cpu-type.h>
#include <asm/div64.h>
-#include <asm/sections.h>
#include <asm/time.h>
/*
- * The integer part of the number of usecs per jiffy is taken from tick,
- * but the fractional part is not recorded, so we calculate it using the
- * initial value of HZ. This aids systems where tick isn't really an
- * integer (e.g. for HZ = 128).
- */
-#define USECS_PER_JIFFY TICK_SIZE
-#define USECS_PER_JIFFY_FRAC ((unsigned long)(u32)((1000000ULL << 32) / HZ))
-
-#define TICK_SIZE (tick_nsec / 1000)
-
-/*
* forward reference
*/
DEFINE_SPINLOCK(rtc_lock);
+EXPORT_SYMBOL(rtc_lock);
-/*
- * By default we provide the null RTC ops
- */
-static unsigned long null_rtc_get_time(void)
-{
- return mktime(2000, 1, 1, 0, 0, 0);
-}
-
-static int null_rtc_set_time(unsigned long sec)
-{
- return 0;
-}
-
-unsigned long (*rtc_mips_get_time)(void) = null_rtc_get_time;
-int (*rtc_mips_set_time)(unsigned long) = null_rtc_set_time;
-int (*rtc_mips_set_mmss)(unsigned long);
-
-
-/* how many counter cycles in a jiffy */
-static unsigned long cycles_per_jiffy __read_mostly;
-
-/* expirelo is the count value for next CPU timer interrupt */
-static unsigned int expirelo;
-
-
-/*
- * Null timer ack for systems not needing one (e.g. i8254).
- */
-static void null_timer_ack(void) { /* nothing */ }
-
-/*
- * Null high precision timer functions for systems lacking one.
- */
-static cycle_t null_hpt_read(void)
+int __weak rtc_mips_set_time(unsigned long sec)
{
return 0;
}
-/*
- * Timer ack for an R4k-compatible timer of a known frequency.
- */
-static void c0_timer_ack(void)
+int __weak rtc_mips_set_mmss(unsigned long nowtime)
{
- unsigned int count;
-
-#ifndef CONFIG_SOC_PNX8550 /* pnx8550 resets to zero */
- /* Ack this timer interrupt and set the next one. */
- expirelo += cycles_per_jiffy;
-#endif
- write_c0_compare(expirelo);
-
- /* Check to see if we have missed any timer interrupts. */
- while (((count = read_c0_count()) - expirelo) < 0x7fffffff) {
- /* missed_timer_count++; */
- expirelo = count + cycles_per_jiffy;
- write_c0_compare(expirelo);
- }
+ return rtc_mips_set_time(nowtime);
}
-/*
- * High precision timer functions for a R4k-compatible timer.
- */
-static cycle_t c0_hpt_read(void)
+int update_persistent_clock(struct timespec now)
{
- return read_c0_count();
+ return rtc_mips_set_mmss(now.tv_sec);
}
-/* For use both as a high precision timer and an interrupt source. */
-static void __init c0_hpt_timer_init(void)
-{
- expirelo = read_c0_count() + cycles_per_jiffy;
- write_c0_compare(expirelo);
-}
-
-int (*mips_timer_state)(void);
-void (*mips_timer_ack)(void);
-
-/* last time when xtime and rtc are sync'ed up */
-static long last_rtc_update;
-
-/*
- * local_timer_interrupt() does profiling and process accounting
- * on a per-CPU basis.
- *
- * In UP mode, it is invoked from the (global) timer_interrupt.
- *
- * In SMP mode, it might invoked by per-CPU timer interrupt, or
- * a broadcasted inter-processor interrupt which itself is triggered
- * by the global timer interrupt.
- */
-void local_timer_interrupt(int irq, void *dev_id)
-{
- profile_tick(CPU_PROFILING);
- update_process_times(user_mode(get_irq_regs()));
-}
-
-/*
- * High-level timer interrupt service routines. This function
- * is set as irqaction->handler and is invoked through do_IRQ.
- */
-irqreturn_t timer_interrupt(int irq, void *dev_id)
-{
- write_seqlock(&xtime_lock);
-
- mips_timer_ack();
-
- /*
- * call the generic timer interrupt handling
- */
- do_timer(1);
-
- /*
- * If we have an externally synchronized Linux clock, then update
- * CMOS clock accordingly every ~11 minutes. rtc_mips_set_time() has to be
- * called as close as possible to 500 ms before the new second starts.
- */
- if (ntp_synced() &&
- xtime.tv_sec > last_rtc_update + 660 &&
- (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
- (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
- if (rtc_mips_set_mmss(xtime.tv_sec) == 0) {
- last_rtc_update = xtime.tv_sec;
- } else {
- /* do it again in 60 s */
- last_rtc_update = xtime.tv_sec - 600;
- }
- }
-
- write_sequnlock(&xtime_lock);
-
- /*
- * In UP mode, we call local_timer_interrupt() to do profiling
- * and process accouting.
- *
- * In SMP mode, local_timer_interrupt() is invoked by appropriate
- * low-level local timer interrupt handler.
- */
- local_timer_interrupt(irq, dev_id);
-
- return IRQ_HANDLED;
-}
-
-int null_perf_irq(void)
+static int null_perf_irq(void)
{
return 0;
}
int (*perf_irq)(void) = null_perf_irq;
-EXPORT_SYMBOL(null_perf_irq);
EXPORT_SYMBOL(perf_irq);
-asmlinkage void ll_timer_interrupt(int irq)
-{
- int r2 = cpu_has_mips_r2;
-
- irq_enter();
- kstat_this_cpu.irqs[irq]++;
-
- /*
- * Suckage alert:
- * Before R2 of the architecture there was no way to see if a
- * performance counter interrupt was pending, so we have to run the
- * performance counter interrupt handler anyway.
- */
- if (!r2 || (read_c0_cause() & (1 << 26)))
- if (perf_irq())
- goto out;
-
- /* we keep interrupt disabled all the time */
- if (!r2 || (read_c0_cause() & (1 << 30)))
- timer_interrupt(irq, NULL);
-
-out:
- irq_exit();
-}
-
-asmlinkage void ll_local_timer_interrupt(int irq)
-{
- irq_enter();
- if (smp_processor_id() != 0)
- kstat_this_cpu.irqs[irq]++;
-
- /* we keep interrupt disabled all the time */
- local_timer_interrupt(irq, NULL);
-
- irq_exit();
-}
-
/*
* time_init() - it does the following things.
*
- * 1) board_time_init() -
- * a) (optional) set up RTC routines,
- * b) (optional) calibrate and set the mips_hpt_frequency
+ * 1) plat_time_init() -
+ * a) (optional) set up RTC routines,
+ * b) (optional) calibrate and set the mips_hpt_frequency
* (only needed if you intended to use cpu counter as timer interrupt
* source)
- * 2) setup xtime based on rtc_mips_get_time().
- * 3) calculate a couple of cached variables for later usage
- * 4) plat_timer_setup() -
- * a) (optional) over-write any choices made above by time_init().
- * b) machine specific code should setup the timer irqaction.
- * c) enable the timer interrupt
+ * 2) calculate a couple of cached variables for later usage
*/
-void (*board_time_init)(void);
-
unsigned int mips_hpt_frequency;
-static struct irqaction timer_irqaction = {
- .handler = timer_interrupt,
- .flags = IRQF_DISABLED,
- .name = "timer",
-};
-
-static unsigned int __init calibrate_hpt(void)
-{
- cycle_t frequency, hpt_start, hpt_end, hpt_count, hz;
-
- const int loops = HZ / 10;
- int log_2_loops = 0;
- int i;
-
- /*
- * We want to calibrate for 0.1s, but to avoid a 64-bit
- * division we round the number of loops up to the nearest
- * power of 2.
- */
- while (loops > 1 << log_2_loops)
- log_2_loops++;
- i = 1 << log_2_loops;
-
- /*
- * Wait for a rising edge of the timer interrupt.
- */
- while (mips_timer_state());
- while (!mips_timer_state());
-
- /*
- * Now see how many high precision timer ticks happen
- * during the calculated number of periods between timer
- * interrupts.
- */
- hpt_start = clocksource_mips.read();
- do {
- while (mips_timer_state());
- while (!mips_timer_state());
- } while (--i);
- hpt_end = clocksource_mips.read();
-
- hpt_count = (hpt_end - hpt_start) & clocksource_mips.mask;
- hz = HZ;
- frequency = hpt_count * hz;
-
- return frequency >> log_2_loops;
-}
-
-struct clocksource clocksource_mips = {
- .name = "MIPS",
- .mask = 0xffffffff,
- .is_continuous = 1,
-};
-
-static void __init init_mips_clocksource(void)
-{
- u64 temp;
- u32 shift;
-
- if (!mips_hpt_frequency || clocksource_mips.read == null_hpt_read)
- return;
-
- /* Calclate a somewhat reasonable rating value */
- clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
- /* Find a shift value */
- for (shift = 32; shift > 0; shift--) {
- temp = (u64) NSEC_PER_SEC << shift;
- do_div(temp, mips_hpt_frequency);
- if ((temp >> 32) == 0)
- break;
+/*
+ * This function exists in order to cause an error due to a duplicate
+ * definition if platform code should have its own implementation. The hook
+ * to use instead is plat_time_init. plat_time_init does not receive the
+ * irqaction pointer argument anymore. This is because any function which
+ * initializes an interrupt timer now takes care of its own request_irq rsp.
+ * setup_irq calls and each clock_event_device should use its own
+ * struct irqrequest.
+ */
+void __init plat_timer_setup(void)
+{
+ BUG();
+}
+
+static __init int cpu_has_mfc0_count_bug(void)
+{
+ switch (current_cpu_type()) {
+ case CPU_R4000PC:
+ case CPU_R4000SC:
+ case CPU_R4000MC:
+ /*
+ * V3.0 is documented as suffering from the mfc0 from count bug.
+ * Afaik this is the last version of the R4000. Later versions
+ * were marketed as R4400.
+ */
+ return 1;
+
+ case CPU_R4400PC:
+ case CPU_R4400SC:
+ case CPU_R4400MC:
+ /*
+ * The published errata for the R4400 up to 3.0 say the CPU
+ * has the mfc0 from count bug.
+ */
+ if ((current_cpu_data.processor_id & 0xff) <= 0x30)
+ return 1;
+
+ /*
+ * we assume newer revisions are ok
+ */
+ return 0;
}
- clocksource_mips.shift = shift;
- clocksource_mips.mult = (u32)temp;
- clocksource_register(&clocksource_mips);
+ return 0;
}
void __init time_init(void)
{
- if (board_time_init)
- board_time_init();
-
- if (!rtc_mips_set_mmss)
- rtc_mips_set_mmss = rtc_mips_set_time;
-
- xtime.tv_sec = rtc_mips_get_time();
- xtime.tv_nsec = 0;
-
- set_normalized_timespec(&wall_to_monotonic,
- -xtime.tv_sec, -xtime.tv_nsec);
-
- /* Choose appropriate high precision timer routines. */
- if (!cpu_has_counter && !clocksource_mips.read)
- /* No high precision timer -- sorry. */
- clocksource_mips.read = null_hpt_read;
- else if (!mips_hpt_frequency && !mips_timer_state) {
- /* A high precision timer of unknown frequency. */
- if (!clocksource_mips.read)
- /* No external high precision timer -- use R4k. */
- clocksource_mips.read = c0_hpt_read;
- } else {
- /* We know counter frequency. Or we can get it. */
- if (!clocksource_mips.read) {
- /* No external high precision timer -- use R4k. */
- clocksource_mips.read = c0_hpt_read;
-
- if (!mips_timer_state) {
- /* No external timer interrupt -- use R4k. */
- mips_timer_ack = c0_timer_ack;
- /* Calculate cache parameters. */
- cycles_per_jiffy =
- (mips_hpt_frequency + HZ / 2) / HZ;
- /*
- * This sets up the high precision
- * timer for the first interrupt.
- */
- c0_hpt_timer_init();
- }
- }
- if (!mips_hpt_frequency)
- mips_hpt_frequency = calibrate_hpt();
-
- /* Report the high precision timer rate for a reference. */
- printk("Using %u.%03u MHz high precision timer.\n",
- ((mips_hpt_frequency + 500) / 1000) / 1000,
- ((mips_hpt_frequency + 500) / 1000) % 1000);
- }
-
- if (!mips_timer_ack)
- /* No timer interrupt ack (e.g. i8254). */
- mips_timer_ack = null_timer_ack;
+ plat_time_init();
/*
- * Call board specific timer interrupt setup.
- *
- * this pointer must be setup in machine setup routine.
- *
- * Even if a machine chooses to use a low-level timer interrupt,
- * it still needs to setup the timer_irqaction.
- * In that case, it might be better to set timer_irqaction.handler
- * to be NULL function so that we are sure the high-level code
- * is not invoked accidentally.
+ * The use of the R4k timer as a clock event takes precedence;
+ * if reading the Count register might interfere with the timer
+ * interrupt, then we don't use the timer as a clock source.
+ * We may still use the timer as a clock source though if the
+ * timer interrupt isn't reliable; the interference doesn't
+ * matter then, because we don't use the interrupt.
*/
- plat_timer_setup(&timer_irqaction);
-
- init_mips_clocksource();
-}
-
-#define FEBRUARY 2
-#define STARTOFTIME 1970
-#define SECDAY 86400L
-#define SECYR (SECDAY * 365)
-#define leapyear(y) ((!((y) % 4) && ((y) % 100)) || !((y) % 400))
-#define days_in_year(y) (leapyear(y) ? 366 : 365)
-#define days_in_month(m) (month_days[(m) - 1])
-
-static int month_days[12] = {
- 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
-};
-
-void to_tm(unsigned long tim, struct rtc_time *tm)
-{
- long hms, day, gday;
- int i;
-
- gday = day = tim / SECDAY;
- hms = tim % SECDAY;
-
- /* Hours, minutes, seconds are easy */
- tm->tm_hour = hms / 3600;
- tm->tm_min = (hms % 3600) / 60;
- tm->tm_sec = (hms % 3600) % 60;
-
- /* Number of years in days */
- for (i = STARTOFTIME; day >= days_in_year(i); i++)
- day -= days_in_year(i);
- tm->tm_year = i;
-
- /* Number of months in days left */
- if (leapyear(tm->tm_year))
- days_in_month(FEBRUARY) = 29;
- for (i = 1; day >= days_in_month(i); i++)
- day -= days_in_month(i);
- days_in_month(FEBRUARY) = 28;
- tm->tm_mon = i - 1; /* tm_mon starts from 0 to 11 */
-
- /* Days are what is left over (+1) from all that. */
- tm->tm_mday = day + 1;
-
- /*
- * Determine the day of week
- */
- tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */
-}
-
-EXPORT_SYMBOL(rtc_lock);
-EXPORT_SYMBOL(to_tm);
-EXPORT_SYMBOL(rtc_mips_set_time);
-EXPORT_SYMBOL(rtc_mips_get_time);
-
-unsigned long long sched_clock(void)
-{
- return (unsigned long long)jiffies*(1000000000/HZ);
+ if (mips_clockevent_init() != 0 || !cpu_has_mfc0_count_bug())
+ init_mips_clocksource();
}
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