| /* |
| * arch/xtensa/kernel/time.c |
| * |
| * Timer and clock support. |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file "COPYING" in the main directory of this archive |
| * for more details. |
| * |
| * Copyright (C) 2005 Tensilica Inc. |
| * |
| * Chris Zankel <chris@zankel.net> |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/errno.h> |
| #include <linux/time.h> |
| #include <linux/timex.h> |
| #include <linux/interrupt.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/irq.h> |
| #include <linux/profile.h> |
| #include <linux/delay.h> |
| |
| #include <asm/timex.h> |
| #include <asm/platform.h> |
| |
| |
| extern volatile unsigned long wall_jiffies; |
| |
| spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED; |
| EXPORT_SYMBOL(rtc_lock); |
| |
| |
| #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT |
| unsigned long ccount_per_jiffy; /* per 1/HZ */ |
| unsigned long ccount_nsec; /* nsec per ccount increment */ |
| #endif |
| |
| unsigned int last_ccount_stamp; |
| static long last_rtc_update = 0; |
| |
| /* |
| * Scheduler clock - returns current tim in nanosec units. |
| */ |
| |
| unsigned long long sched_clock(void) |
| { |
| return (unsigned long long)jiffies * (1000000000 / HZ); |
| } |
| |
| static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs); |
| static struct irqaction timer_irqaction = { |
| .handler = timer_interrupt, |
| .flags = SA_INTERRUPT, |
| .name = "timer", |
| }; |
| |
| void __init time_init(void) |
| { |
| time_t sec_o, sec_n = 0; |
| |
| /* The platform must provide a function to calibrate the processor |
| * speed for the CALIBRATE. |
| */ |
| |
| #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT |
| printk("Calibrating CPU frequency "); |
| platform_calibrate_ccount(); |
| printk("%d.%02d MHz\n", (int)ccount_per_jiffy/(1000000/HZ), |
| (int)(ccount_per_jiffy/(10000/HZ))%100); |
| #endif |
| |
| /* Set time from RTC (if provided) */ |
| |
| if (platform_get_rtc_time(&sec_o) == 0) |
| while (platform_get_rtc_time(&sec_n)) |
| if (sec_o != sec_n) |
| break; |
| |
| xtime.tv_nsec = 0; |
| last_rtc_update = xtime.tv_sec = sec_n; |
| last_ccount_stamp = get_ccount(); |
| |
| set_normalized_timespec(&wall_to_monotonic, |
| -xtime.tv_sec, -xtime.tv_nsec); |
| |
| /* Initialize the linux timer interrupt. */ |
| |
| setup_irq(LINUX_TIMER_INT, &timer_irqaction); |
| set_linux_timer(get_ccount() + CCOUNT_PER_JIFFY); |
| } |
| |
| |
| int do_settimeofday(struct timespec *tv) |
| { |
| time_t wtm_sec, sec = tv->tv_sec; |
| long wtm_nsec, nsec = tv->tv_nsec; |
| unsigned long ccount; |
| |
| if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) |
| return -EINVAL; |
| |
| write_seqlock_irq(&xtime_lock); |
| |
| /* This is revolting. We need to set "xtime" correctly. However, the |
| * value in this location is the value at the most recent update of |
| * wall time. Discover what correction gettimeofday() would have |
| * made, and then undo it! |
| */ |
| ccount = get_ccount(); |
| nsec -= (ccount - last_ccount_stamp) * CCOUNT_NSEC; |
| nsec -= (jiffies - wall_jiffies) * CCOUNT_PER_JIFFY * CCOUNT_NSEC; |
| |
| wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); |
| wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); |
| |
| set_normalized_timespec(&xtime, sec, nsec); |
| set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); |
| |
| ntp_clear(); |
| write_sequnlock_irq(&xtime_lock); |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(do_settimeofday); |
| |
| |
| void do_gettimeofday(struct timeval *tv) |
| { |
| unsigned long flags; |
| unsigned long sec, usec, delta, lost, seq; |
| |
| do { |
| seq = read_seqbegin_irqsave(&xtime_lock, flags); |
| |
| delta = get_ccount() - last_ccount_stamp; |
| sec = xtime.tv_sec; |
| usec = (xtime.tv_nsec / NSEC_PER_USEC); |
| |
| lost = jiffies - wall_jiffies; |
| |
| } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); |
| |
| usec += lost * (1000000UL/HZ) + (delta * CCOUNT_NSEC) / NSEC_PER_USEC; |
| for (; usec >= 1000000; sec++, usec -= 1000000) |
| ; |
| |
| tv->tv_sec = sec; |
| tv->tv_usec = usec; |
| } |
| |
| EXPORT_SYMBOL(do_gettimeofday); |
| |
| /* |
| * The timer interrupt is called HZ times per second. |
| */ |
| |
| irqreturn_t timer_interrupt (int irq, void *dev_id, struct pt_regs *regs) |
| { |
| |
| unsigned long next; |
| |
| next = get_linux_timer(); |
| |
| again: |
| while ((signed long)(get_ccount() - next) > 0) { |
| |
| profile_tick(CPU_PROFILING, regs); |
| #ifndef CONFIG_SMP |
| update_process_times(user_mode(regs)); |
| #endif |
| |
| write_seqlock(&xtime_lock); |
| |
| last_ccount_stamp = next; |
| next += CCOUNT_PER_JIFFY; |
| do_timer (regs); /* Linux handler in kernel/timer.c */ |
| |
| if (ntp_synced() && |
| xtime.tv_sec - last_rtc_update >= 659 && |
| abs((xtime.tv_nsec/1000)-(1000000-1000000/HZ))<5000000/HZ && |
| jiffies - wall_jiffies == 1) { |
| |
| if (platform_set_rtc_time(xtime.tv_sec+1) == 0) |
| last_rtc_update = xtime.tv_sec+1; |
| else |
| /* Do it again in 60 s */ |
| last_rtc_update += 60; |
| } |
| write_sequnlock(&xtime_lock); |
| } |
| |
| /* NOTE: writing CCOMPAREn clears the interrupt. */ |
| |
| set_linux_timer (next); |
| |
| /* Make sure we didn't miss any tick... */ |
| |
| if ((signed long)(get_ccount() - next) > 0) |
| goto again; |
| |
| /* Allow platform to do something usefull (Wdog). */ |
| |
| platform_heartbeat(); |
| |
| return IRQ_HANDLED; |
| } |
| |
| #ifndef CONFIG_GENERIC_CALIBRATE_DELAY |
| void __devinit calibrate_delay(void) |
| { |
| loops_per_jiffy = CCOUNT_PER_JIFFY; |
| printk("Calibrating delay loop (skipped)... " |
| "%lu.%02lu BogoMIPS preset\n", |
| loops_per_jiffy/(1000000/HZ), |
| (loops_per_jiffy/(10000/HZ)) % 100); |
| } |
| #endif |
| |