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/*
* arch/blackfin/kernel/time.c
*
* This file contains the Blackfin-specific time handling details.
* Most of the stuff is located in the machine specific files.
*
* Copyright 2004-2008 Analog Devices Inc.
* Licensed under the GPL-2 or later.
*/
#include <linux/module.h>
#include <linux/profile.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <asm/blackfin.h>
#include <asm/time.h>
#include <asm/gptimers.h>
/* This is an NTP setting */
#define TICK_SIZE (tick_nsec / 1000)
static struct irqaction bfin_timer_irq = {
.name = "Blackfin Timer Tick",
.flags = IRQF_DISABLED
};
#if defined(CONFIG_IPIPE)
void __init setup_system_timer0(void)
{
/* Power down the core timer, just to play safe. */
bfin_write_TCNTL(0);
disable_gptimers(TIMER0bit);
set_gptimer_status(0, TIMER_STATUS_TRUN0);
while (get_gptimer_status(0) & TIMER_STATUS_TRUN0)
udelay(10);
set_gptimer_config(0, 0x59); /* IRQ enable, periodic, PWM_OUT, SCLKed, OUT PAD disabled */
set_gptimer_period(TIMER0_id, get_sclk() / HZ);
set_gptimer_pwidth(TIMER0_id, 1);
SSYNC();
enable_gptimers(TIMER0bit);
}
#else
void __init setup_core_timer(void)
{
u32 tcount;
/* power up the timer, but don't enable it just yet */
bfin_write_TCNTL(1);
CSYNC();
/* the TSCALE prescaler counter */
bfin_write_TSCALE(TIME_SCALE - 1);
tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1);
bfin_write_TPERIOD(tcount);
bfin_write_TCOUNT(tcount);
/* now enable the timer */
CSYNC();
bfin_write_TCNTL(7);
}
#endif
static void __init
time_sched_init(irqreturn_t(*timer_routine) (int, void *))
{
#if defined(CONFIG_IPIPE)
setup_system_timer0();
bfin_timer_irq.handler = timer_routine;
setup_irq(IRQ_TIMER0, &bfin_timer_irq);
#else
setup_core_timer();
bfin_timer_irq.handler = timer_routine;
setup_irq(IRQ_CORETMR, &bfin_timer_irq);
#endif
}
#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
/*
* Should return useconds since last timer tick
*/
u32 arch_gettimeoffset(void)
{
unsigned long offset;
unsigned long clocks_per_jiffy;
#if defined(CONFIG_IPIPE)
clocks_per_jiffy = bfin_read_TIMER0_PERIOD();
offset = bfin_read_TIMER0_COUNTER() / \
(((clocks_per_jiffy + 1) * HZ) / USEC_PER_SEC);
if ((get_gptimer_status(0) & TIMER_STATUS_TIMIL0) && offset < (100000 / HZ / 2))
offset += (USEC_PER_SEC / HZ);
#else
clocks_per_jiffy = bfin_read_TPERIOD();
offset = (clocks_per_jiffy - bfin_read_TCOUNT()) / \
(((clocks_per_jiffy + 1) * HZ) / USEC_PER_SEC);
/* Check if we just wrapped the counters and maybe missed a tick */
if ((bfin_read_ILAT() & (1 << IRQ_CORETMR))
&& (offset < (100000 / HZ / 2)))
offset += (USEC_PER_SEC / HZ);
#endif
return offset;
}
#endif
static inline int set_rtc_mmss(unsigned long nowtime)
{
return 0;
}
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*/
#ifdef CONFIG_CORE_TIMER_IRQ_L1
__attribute__((l1_text))
#endif
irqreturn_t timer_interrupt(int irq, void *dummy)
{
/* last time the cmos clock got updated */
static long last_rtc_update;
write_seqlock(&xtime_lock);
do_timer(1);
/*
* If we have an externally synchronized Linux clock, then update
* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() 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 / NSEC_PER_USEC) >=
500000 - ((unsigned)TICK_SIZE) / 2
&& (xtime.tv_nsec / NSEC_PER_USEC) <=
500000 + ((unsigned)TICK_SIZE) / 2) {
if (set_rtc_mmss(xtime.tv_sec) == 0)
last_rtc_update = xtime.tv_sec;
else
/* Do it again in 60s. */
last_rtc_update = xtime.tv_sec - 600;
}
write_sequnlock(&xtime_lock);
#ifdef CONFIG_IPIPE
update_root_process_times(get_irq_regs());
#else
update_process_times(user_mode(get_irq_regs()));
#endif
profile_tick(CPU_PROFILING);
return IRQ_HANDLED;
}
void __init time_init(void)
{
time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */
#ifdef CONFIG_RTC_DRV_BFIN
/* [#2663] hack to filter junk RTC values that would cause
* userspace to have to deal with time values greater than
* 2^31 seconds (which uClibc cannot cope with yet)
*/
if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n");
bfin_write_RTC_STAT(0);
}
#endif
/* Initialize xtime. From now on, xtime is updated with timer interrupts */
xtime.tv_sec = secs_since_1970;
xtime.tv_nsec = 0;
wall_to_monotonic.tv_sec = -xtime.tv_sec;
time_sched_init(timer_interrupt);
}
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