diff options
Diffstat (limited to 'arch/mn10300/kernel/time.c')
| -rw-r--r-- | arch/mn10300/kernel/time.c | 111 |
1 files changed, 52 insertions, 59 deletions
diff --git a/arch/mn10300/kernel/time.c b/arch/mn10300/kernel/time.c index babb7c2ac37..67c6416a58f 100644 --- a/arch/mn10300/kernel/time.c +++ b/arch/mn10300/kernel/time.c @@ -1,6 +1,6 @@ /* MN10300 Low level time management * - * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2007-2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - Derived from arch/i386/kernel/time.c * @@ -16,29 +16,20 @@ #include <linux/init.h> #include <linux/smp.h> #include <linux/profile.h> +#include <linux/cnt32_to_63.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> #include <asm/irq.h> #include <asm/div64.h> #include <asm/processor.h> #include <asm/intctl-regs.h> #include <asm/rtc.h> - -#ifdef CONFIG_MN10300_RTC -unsigned long mn10300_ioclk; /* system I/O clock frequency */ -unsigned long mn10300_iobclk; /* system I/O clock frequency */ -unsigned long mn10300_tsc_per_HZ; /* number of ioclks per jiffy */ -#endif /* CONFIG_MN10300_RTC */ +#include "internal.h" static unsigned long mn10300_last_tsc; /* time-stamp counter at last time * interrupt occurred */ -static irqreturn_t timer_interrupt(int irq, void *dev_id); - -static struct irqaction timer_irq = { - .handler = timer_interrupt, - .flags = IRQF_DISABLED | IRQF_SHARED | IRQF_TIMER, - .mask = CPU_MASK_NONE, - .name = "timer", -}; +static unsigned long sched_clock_multiplier; /* * scheduler clock - returns current time in nanosec units. @@ -46,51 +37,59 @@ static struct irqaction timer_irq = { unsigned long long sched_clock(void) { union { - unsigned long long l; - u32 w[2]; - } quot; + unsigned long long ll; + unsigned l[2]; + } tsc64, result; + unsigned long tmp; + unsigned product[3]; /* 96-bit intermediate value */ + + /* cnt32_to_63() is not safe with preemption */ + preempt_disable(); + + /* expand the tsc to 64-bits. + * - sched_clock() must be called once a minute or better or the + * following will go horribly wrong - see cnt32_to_63() + */ + tsc64.ll = cnt32_to_63(get_cycles()) & 0x7fffffffffffffffULL; - quot.w[0] = mn10300_last_tsc - get_cycles(); - quot.w[1] = 1000000000; + preempt_enable(); - asm("mulu %2,%3,%0,%1" - : "=r"(quot.w[1]), "=r"(quot.w[0]) - : "0"(quot.w[1]), "1"(quot.w[0]) + /* scale the 64-bit TSC value to a nanosecond value via a 96-bit + * intermediate + */ + asm("mulu %2,%0,%3,%0 \n" /* LSW * mult -> 0:%3:%0 */ + "mulu %2,%1,%2,%1 \n" /* MSW * mult -> %2:%1:0 */ + "add %3,%1 \n" + "addc 0,%2 \n" /* result in %2:%1:%0 */ + : "=r"(product[0]), "=r"(product[1]), "=r"(product[2]), "=r"(tmp) + : "0"(tsc64.l[0]), "1"(tsc64.l[1]), "2"(sched_clock_multiplier) : "cc"); - do_div(quot.l, MN10300_TSCCLK); + result.l[0] = product[1] << 16 | product[0] >> 16; + result.l[1] = product[2] << 16 | product[1] >> 16; - return quot.l; + return result.ll; } /* - * advance the kernel's time keeping clocks (xtime and jiffies) - * - we use Timer 0 & 1 cascaded as a clock to nudge us the next time - * there's a need to update + * initialise the scheduler clock */ -static irqreturn_t timer_interrupt(int irq, void *dev_id) +static void __init mn10300_sched_clock_init(void) { - unsigned tsc, elapse; - - write_seqlock(&xtime_lock); - - while (tsc = get_cycles(), - elapse = mn10300_last_tsc - tsc, /* time elapsed since last - * tick */ - elapse > MN10300_TSC_PER_HZ - ) { - mn10300_last_tsc -= MN10300_TSC_PER_HZ; - - /* advance the kernel's time tracking system */ - profile_tick(CPU_PROFILING); - do_timer(1); - check_rtc_time(); - } - - write_sequnlock(&xtime_lock); + sched_clock_multiplier = + __muldiv64u(NSEC_PER_SEC, 1 << 16, MN10300_TSCCLK); +} +/** + * local_timer_interrupt - Local timer interrupt handler + * + * Handle local timer interrupts for this CPU. They may have been propagated + * to this CPU from the CPU that actually gets them by way of an IPI. + */ +irqreturn_t local_timer_interrupt(void) +{ + profile_tick(CPU_PROFILING); update_process_times(user_mode(get_irq_regs())); - return IRQ_HANDLED; } @@ -105,27 +104,21 @@ void __init time_init(void) */ TMPSCNT |= TMPSCNT_ENABLE; - startup_timestamp_counter(); + init_clocksource(); printk(KERN_INFO "timestamp counter I/O clock running at %lu.%02lu" " (calibrated against RTC)\n", MN10300_TSCCLK / 1000000, (MN10300_TSCCLK / 10000) % 100); - xtime.tv_sec = get_initial_rtc_time(); - xtime.tv_nsec = 0; + mn10300_last_tsc = read_timestamp_counter(); - mn10300_last_tsc = TMTSCBC; - - /* use timer 0 & 1 cascaded to tick at as close to HZ as possible */ - setup_irq(TMJCIRQ, &timer_irq); - - set_intr_level(TMJCIRQ, TMJCICR_LEVEL); - - startup_jiffies_counter(); + init_clockevents(); #ifdef CONFIG_MN10300_WD_TIMER /* start the watchdog timer */ watchdog_go(); #endif + + mn10300_sched_clock_init(); } |