From: Thomas Gleixner Date: Thu, 11 Oct 2007 09:11:50 +0000 (+0200) Subject: i386: prepare shared kernel/i8253.c X-Git-Tag: v2.6.24-rc1~1707 X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=d07ec74041a48f2ce47aa254e716e1e2c17a1191;p=~shefty%2Frdma-dev.git i386: prepare shared kernel/i8253.c Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index a0bd5aa66e1..0d09d881223 100644 --- a/arch/i386/kernel/Makefile +++ b/arch/i386/kernel/Makefile @@ -7,7 +7,7 @@ extra-y := head.o init_task.o vmlinux.lds obj-y := process.o signal.o entry.o traps_32.o irq.o \ ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_i386.o \ pci-dma.o i386_ksyms.o i387.o bootflag.o e820.o\ - quirks.o i8237.o topology.o alternative.o i8253.o tsc.o + quirks.o i8237.o topology.o alternative.o i8253_32.o tsc.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-y += cpu/ diff --git a/arch/i386/kernel/i8253.c b/arch/i386/kernel/i8253.c deleted file mode 100644 index 6d839f2f1b1..00000000000 --- a/arch/i386/kernel/i8253.c +++ /dev/null @@ -1,206 +0,0 @@ -/* - * i8253.c 8253/PIT functions - * - */ -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include -#include - -DEFINE_SPINLOCK(i8253_lock); -EXPORT_SYMBOL(i8253_lock); - -/* - * HPET replaces the PIT, when enabled. So we need to know, which of - * the two timers is used - */ -struct clock_event_device *global_clock_event; - -/* - * 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) -{ - unsigned long flags; - - spin_lock_irqsave(&i8253_lock, flags); - - 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_irqrestore(&i8253_lock, flags); -} - -/* - * 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) -{ - unsigned long flags; - - spin_lock_irqsave(&i8253_lock, flags); - outb_p(delta & 0xff , PIT_CH0); /* LSB */ - outb(delta >> 8 , PIT_CH0); /* MSB */ - spin_unlock_irqrestore(&i8253_lock, flags); - - 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() - */ -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, - .shift = 32, - .irq = 0, -}; - -/* - * 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) -{ - /* - * Start pit with the boot cpu mask and make it global after the - * IO_APIC has been initialized. - */ - pit_clockevent.cpumask = cpumask_of_cpu(smp_processor_id()); - pit_clockevent.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, 32); - pit_clockevent.max_delta_ns = - clockevent_delta2ns(0x7FFF, &pit_clockevent); - pit_clockevent.min_delta_ns = - clockevent_delta2ns(0xF, &pit_clockevent); - clockevents_register_device(&pit_clockevent); - global_clock_event = &pit_clockevent; -} - -/* - * 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(void) -{ - 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); -} -arch_initcall(init_pit_clocksource); diff --git a/arch/i386/kernel/i8253_32.c b/arch/i386/kernel/i8253_32.c new file mode 100644 index 00000000000..6d839f2f1b1 --- /dev/null +++ b/arch/i386/kernel/i8253_32.c @@ -0,0 +1,206 @@ +/* + * i8253.c 8253/PIT functions + * + */ +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +DEFINE_SPINLOCK(i8253_lock); +EXPORT_SYMBOL(i8253_lock); + +/* + * HPET replaces the PIT, when enabled. So we need to know, which of + * the two timers is used + */ +struct clock_event_device *global_clock_event; + +/* + * 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) +{ + unsigned long flags; + + spin_lock_irqsave(&i8253_lock, flags); + + 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_irqrestore(&i8253_lock, flags); +} + +/* + * 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) +{ + unsigned long flags; + + spin_lock_irqsave(&i8253_lock, flags); + outb_p(delta & 0xff , PIT_CH0); /* LSB */ + outb(delta >> 8 , PIT_CH0); /* MSB */ + spin_unlock_irqrestore(&i8253_lock, flags); + + 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() + */ +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, + .shift = 32, + .irq = 0, +}; + +/* + * 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) +{ + /* + * Start pit with the boot cpu mask and make it global after the + * IO_APIC has been initialized. + */ + pit_clockevent.cpumask = cpumask_of_cpu(smp_processor_id()); + pit_clockevent.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, 32); + pit_clockevent.max_delta_ns = + clockevent_delta2ns(0x7FFF, &pit_clockevent); + pit_clockevent.min_delta_ns = + clockevent_delta2ns(0xF, &pit_clockevent); + clockevents_register_device(&pit_clockevent); + global_clock_event = &pit_clockevent; +} + +/* + * 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(void) +{ + 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); +} +arch_initcall(init_pit_clocksource);