diff options
Diffstat (limited to 'arch/mips/kernel/i8253.c')
| -rw-r--r-- | arch/mips/kernel/i8253.c | 185 |
1 files changed, 7 insertions, 178 deletions
diff --git a/arch/mips/kernel/i8253.c b/arch/mips/kernel/i8253.c index ed5c441615e..c5bc344fc74 100644 --- a/arch/mips/kernel/i8253.c +++ b/arch/mips/kernel/i8253.c @@ -3,208 +3,37 @@ * */ #include <linux/clockchips.h> -#include <linux/init.h> -#include <linux/interrupt.h> -#include <linux/jiffies.h> -#include <linux/module.h> +#include <linux/i8253.h> +#include <linux/export.h> #include <linux/smp.h> -#include <linux/spinlock.h> +#include <linux/irq.h> -#include <asm/delay.h> -#include <asm/i8253.h> -#include <asm/io.h> #include <asm/time.h> -DEFINE_SPINLOCK(i8253_lock); -EXPORT_SYMBOL(i8253_lock); - -/* - * Initialize the PIT timer. - * - * This is also called after resume to bring the PIT into operation again. - */ -static void init_pit_timer(enum clock_event_mode mode, - struct clock_event_device *evt) -{ - spin_lock(&i8253_lock); - - switch(mode) { - case CLOCK_EVT_MODE_PERIODIC: - /* binary, mode 2, LSB/MSB, ch 0 */ - outb_p(0x34, PIT_MODE); - outb_p(LATCH & 0xff , PIT_CH0); /* LSB */ - outb(LATCH >> 8 , PIT_CH0); /* MSB */ - break; - - case CLOCK_EVT_MODE_SHUTDOWN: - case CLOCK_EVT_MODE_UNUSED: - if (evt->mode == CLOCK_EVT_MODE_PERIODIC || - evt->mode == CLOCK_EVT_MODE_ONESHOT) { - outb_p(0x30, PIT_MODE); - outb_p(0, PIT_CH0); - outb_p(0, PIT_CH0); - } - break; - - case CLOCK_EVT_MODE_ONESHOT: - /* One shot setup */ - outb_p(0x38, PIT_MODE); - break; - - case CLOCK_EVT_MODE_RESUME: - /* Nothing to do here */ - break; - } - spin_unlock(&i8253_lock); -} - -/* - * Program the next event in oneshot mode - * - * Delta is given in PIT ticks - */ -static int pit_next_event(unsigned long delta, struct clock_event_device *evt) -{ - spin_lock(&i8253_lock); - outb_p(delta & 0xff , PIT_CH0); /* LSB */ - outb(delta >> 8 , PIT_CH0); /* MSB */ - spin_unlock(&i8253_lock); - - return 0; -} - -/* - * On UP the PIT can serve all of the possible timer functions. On SMP systems - * it can be solely used for the global tick. - * - * The profiling and update capabilites are switched off once the local apic is - * registered. This mechanism replaces the previous #ifdef LOCAL_APIC - - * !using_apic_timer decisions in do_timer_interrupt_hook() - */ -static struct clock_event_device pit_clockevent = { - .name = "pit", - .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, - .set_mode = init_pit_timer, - .set_next_event = pit_next_event, - .irq = 0, -}; - static irqreturn_t timer_interrupt(int irq, void *dev_id) { - pit_clockevent.event_handler(&pit_clockevent); + i8253_clockevent.event_handler(&i8253_clockevent); return IRQ_HANDLED; } static struct irqaction irq0 = { .handler = timer_interrupt, - .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_TIMER, + .flags = IRQF_NOBALANCING | IRQF_TIMER, .name = "timer" }; -/* - * Initialize the conversion factor and the min/max deltas of the clock event - * structure and register the clock event source with the framework. - */ void __init setup_pit_timer(void) { - struct clock_event_device *cd = &pit_clockevent; - unsigned int cpu = smp_processor_id(); - - /* - * Start pit with the boot cpu mask and make it global after the - * IO_APIC has been initialized. - */ - cd->cpumask = cpumask_of(cpu); - clockevent_set_clock(cd, CLOCK_TICK_RATE); - cd->max_delta_ns = clockevent_delta2ns(0x7FFF, cd); - cd->min_delta_ns = clockevent_delta2ns(0xF, cd); - clockevents_register_device(cd); - + clockevent_i8253_init(true); setup_irq(0, &irq0); } -/* - * Since the PIT overflows every tick, its not very useful - * to just read by itself. So use jiffies to emulate a free - * running counter: - */ -static cycle_t pit_read(struct clocksource *cs) -{ - unsigned long flags; - int count; - u32 jifs; - static int old_count; - static u32 old_jifs; - - spin_lock_irqsave(&i8253_lock, flags); - /* - * Although our caller may have the read side of xtime_lock, - * this is now a seqlock, and we are cheating in this routine - * by having side effects on state that we cannot undo if - * there is a collision on the seqlock and our caller has to - * retry. (Namely, old_jifs and old_count.) So we must treat - * jiffies as volatile despite the lock. We read jiffies - * before latching the timer count to guarantee that although - * the jiffies value might be older than the count (that is, - * the counter may underflow between the last point where - * jiffies was incremented and the point where we latch the - * count), it cannot be newer. - */ - jifs = jiffies; - outb_p(0x00, PIT_MODE); /* latch the count ASAP */ - count = inb_p(PIT_CH0); /* read the latched count */ - count |= inb_p(PIT_CH0) << 8; - - /* VIA686a test code... reset the latch if count > max + 1 */ - if (count > LATCH) { - outb_p(0x34, PIT_MODE); - outb_p(LATCH & 0xff, PIT_CH0); - outb(LATCH >> 8, PIT_CH0); - count = LATCH - 1; - } - - /* - * It's possible for count to appear to go the wrong way for a - * couple of reasons: - * - * 1. The timer counter underflows, but we haven't handled the - * resulting interrupt and incremented jiffies yet. - * 2. Hardware problem with the timer, not giving us continuous time, - * the counter does small "jumps" upwards on some Pentium systems, - * (see c't 95/10 page 335 for Neptun bug.) - * - * Previous attempts to handle these cases intelligently were - * buggy, so we just do the simple thing now. - */ - if (count > old_count && jifs == old_jifs) { - count = old_count; - } - old_count = count; - old_jifs = jifs; - - spin_unlock_irqrestore(&i8253_lock, flags); - - count = (LATCH - 1) - count; - - return (cycle_t)(jifs * LATCH) + count; -} - -static struct clocksource clocksource_pit = { - .name = "pit", - .rating = 110, - .read = pit_read, - .mask = CLOCKSOURCE_MASK(32), - .mult = 0, - .shift = 20, -}; - static int __init init_pit_clocksource(void) { if (num_possible_cpus() > 1) /* PIT does not scale! */ return 0; - clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20); - return clocksource_register(&clocksource_pit); + return clocksource_i8253_init(); } arch_initcall(init_pit_clocksource); |