From: Thomas Gleixner Add clockevent drivers for i386: lapic (local) and PIT (global). Update the timer IRQ to call into the PIT driver's event handler and the lapic-timer IRQ to call into the lapic clockevent driver. The assignement of timer functionality is delegated to the core framework code and replaces the compile and runtime evalution in do_timer_interrupt_hook() Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar -- arch/i386/Kconfig | 4 + arch/i386/kernel/apic.c | 117 ++++++++++++++++++++++++++----- arch/i386/kernel/i8253.c | 94 ++++++++++++++++++++++-- arch/i386/kernel/time.c | 45 ----------- include/asm-i386/i8253.h | 18 ++++ include/asm-i386/mach-default/do_timer.h | 27 +------ include/asm-i386/mach-visws/do_timer.h | 2 include/asm-i386/mach-voyager/do_timer.h | 15 ++- 8 files changed, 225 insertions(+), 97 deletions(-) Index: linux-2.6.18-mm2/arch/i386/Kconfig =================================================================== --- linux-2.6.18-mm2.orig/arch/i386/Kconfig 2006-10-02 00:55:46.000000000 +0200 +++ linux-2.6.18-mm2/arch/i386/Kconfig 2006-10-02 00:55:53.000000000 +0200 @@ -18,6 +18,10 @@ config GENERIC_TIME bool default y +config GENERIC_CLOCKEVENTS + bool + default y + config LOCKDEP_SUPPORT bool default y Index: linux-2.6.18-mm2/arch/i386/kernel/apic.c =================================================================== --- linux-2.6.18-mm2.orig/arch/i386/kernel/apic.c 2006-10-02 00:55:46.000000000 +0200 +++ linux-2.6.18-mm2/arch/i386/kernel/apic.c 2006-10-02 00:55:53.000000000 +0200 @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -70,6 +71,25 @@ static inline void lapic_enable(void) */ int apic_verbosity; +static unsigned int calibration_result; + +static void lapic_next_event(unsigned long delta, + struct clock_event_device *evt); +static void lapic_timer_setup(enum clock_event_mode mode, + struct clock_event_device *evt); + +/* + * The local apic timer can be used for any function which is CPU local. + */ +static struct clock_event_device lapic_clockevent = { + .name = "lapic", + .capabilities = CLOCK_CAP_NEXTEVT | CLOCK_CAP_PROFILE + | CLOCK_CAP_UPDATE, + .shift = 32, + .set_mode = lapic_timer_setup, + .set_next_event = lapic_next_event, +}; +static DEFINE_PER_CPU(struct clock_event_device, lapic_events); static void apic_pm_activate(void); @@ -919,6 +939,11 @@ fake_ioapic_page: */ /* + * FIXME: Move this to i8253.h. There is no need to keep the access to + * the PIT scattered all around the place -tglx + */ + +/* * The timer chip is already set up at HZ interrupts per second here, * but we do not accept timer interrupts yet. We only allow the BP * to calibrate. @@ -976,13 +1001,15 @@ void (*wait_timer_tick)(void) __devinitd #define APIC_DIVISOR 16 -static void __setup_APIC_LVTT(unsigned int clocks) +static void __setup_APIC_LVTT(unsigned int clocks, int oneshot) { unsigned int lvtt_value, tmp_value, ver; int cpu = smp_processor_id(); ver = GET_APIC_VERSION(apic_read(APIC_LVR)); - lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR; + lvtt_value = LOCAL_TIMER_VECTOR; + if (!oneshot) + lvtt_value |= APIC_LVT_TIMER_PERIODIC; if (!APIC_INTEGRATED(ver)) lvtt_value |= SET_APIC_TIMER_BASE(APIC_TIMER_BASE_DIV); @@ -999,23 +1026,43 @@ static void __setup_APIC_LVTT(unsigned i & ~(APIC_TDR_DIV_1 | APIC_TDR_DIV_TMBASE)) | APIC_TDR_DIV_16); - apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR); + if (!oneshot) + apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR); } -static void __devinit setup_APIC_timer(unsigned int clocks) +static void lapic_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + apic_write_around(APIC_TMICT, delta); +} + +static void lapic_timer_setup(enum clock_event_mode mode, + struct clock_event_device *evt) { unsigned long flags; local_irq_save(flags); + if (CLOCK_EVT_PERIODIC) { + /* + * Wait for IRQ0's slice: + */ + wait_timer_tick(); + } + __setup_APIC_LVTT(calibration_result, mode != CLOCK_EVT_PERIODIC); + local_irq_restore(flags); +} - /* - * Wait for IRQ0's slice: - */ - wait_timer_tick(); +/* + * Setup the local APIC timer for this CPU. Copy the initilized values + * of the boot CPU and register the clock event in the framework. + */ +static void __devinit setup_APIC_timer(void) +{ + struct clock_event_device *levt = &__get_cpu_var(lapic_events); - __setup_APIC_LVTT(clocks); + memcpy(levt, &lapic_clockevent, sizeof(*levt)); - local_irq_restore(flags); + register_local_clockevent(levt); } /* @@ -1024,6 +1071,8 @@ static void __devinit setup_APIC_timer(u * to calibrate, since some later bootup code depends on getting * the first irq? Ugh. * + * TODO: Fix this rather than saying "Ugh" -tglx + * * We want to do the calibration only once since we * want to have local timer irqs syncron. CPUs connected * by the same APIC bus have the very same bus frequency. @@ -1046,7 +1095,7 @@ static int __init calibrate_APIC_clock(v * value into the APIC clock, we just want to get the * counter running for calibration. */ - __setup_APIC_LVTT(1000000000); + __setup_APIC_LVTT(1000000000, 0); /* * The timer chip counts down to zero. Let's wait @@ -1083,6 +1132,14 @@ static int __init calibrate_APIC_clock(v result = (tt1-tt2)*APIC_DIVISOR/LOOPS; + /* Calculate the scaled math multiplication factor */ + lapic_clockevent.mult = div_sc(tt1-tt2, TICK_NSEC * LOOPS, 32); + lapic_clockevent.max_delta_ns = + clockevent_delta2ns(0x7FFFFF, &lapic_clockevent); + printk("lapic max_delta_ns: %ld\n", lapic_clockevent.max_delta_ns); + lapic_clockevent.min_delta_ns = + clockevent_delta2ns(0xF, &lapic_clockevent); + if (cpu_has_tsc) apic_printk(APIC_VERBOSE, "..... CPU clock speed is " "%ld.%04ld MHz.\n", @@ -1097,8 +1154,6 @@ static int __init calibrate_APIC_clock(v return result; } -static unsigned int calibration_result; - void __init setup_boot_APIC_clock(void) { unsigned long flags; @@ -1111,14 +1166,14 @@ void __init setup_boot_APIC_clock(void) /* * Now set up the timer for real. */ - setup_APIC_timer(calibration_result); + setup_APIC_timer(); local_irq_restore(flags); } void __devinit setup_secondary_APIC_clock(void) { - setup_APIC_timer(calibration_result); + setup_APIC_timer(); } void disable_APIC_timer(void) @@ -1164,6 +1219,35 @@ void switch_APIC_timer_to_ipi(void *cpum !cpu_isset(cpu, timer_bcast_ipi)) { disable_APIC_timer(); cpu_set(cpu, timer_bcast_ipi); +#ifdef CONFIG_HIGH_RES_TIMERS + /* + * C3 stops the local apic timer. We can not make high + * resolution timers and dynamic ticks work with one global + * timer. Disable the NEXTEVT capability, so high resolution / + * dyntick mode gets disabled too. + * + * There is a solution for this problem, but this is beyond the + * scope of this initial patchset: + * + * When the local apic timer is unusable in C3, then we can + * utilize the PIT to provide a global wakeup, which can be + * directed to the CPU which has the earliest wakeup + * point. Once the CPU is up again, the local apic is resumed + * and can be used for the per cpu clock events again. It's not + * hard to provide the infrastructure, but I need more insight + * into the ACPI code to get it right. + * + * Disable the highres/dyntick feature in this case for now, + * until somebody beats the ACPI clue into me. :) + * + * tglx + */ + printk("Disabling NO_HZ and high resolution timers " + "due to timer broadcasting (C3 stops local apic)\n"); + for_each_possible_cpu(cpu) + per_cpu(lapic_events, cpu).capabilities &= + ~CLOCK_CAP_NEXTEVT; +#endif } } EXPORT_SYMBOL(switch_APIC_timer_to_ipi); @@ -1224,6 +1308,7 @@ inline void smp_local_timer_interrupt(st fastcall void smp_apic_timer_interrupt(struct pt_regs *regs) { int cpu = smp_processor_id(); + struct clock_event_device *evt = &per_cpu(lapic_events, cpu); /* * the NMI deadlock-detector uses this. @@ -1241,7 +1326,7 @@ fastcall void smp_apic_timer_interrupt(s * interrupt lock, which is the WrongThing (tm) to do. */ irq_enter(); - smp_local_timer_interrupt(regs); + evt->event_handler(regs); irq_exit(); } Index: linux-2.6.18-mm2/arch/i386/kernel/i8253.c =================================================================== --- linux-2.6.18-mm2.orig/arch/i386/kernel/i8253.c 2006-10-02 00:55:46.000000000 +0200 +++ linux-2.6.18-mm2/arch/i386/kernel/i8253.c 2006-10-02 00:55:53.000000000 +0200 @@ -2,7 +2,7 @@ * i8253.c 8253/PIT functions * */ -#include +#include #include #include #include @@ -19,20 +19,98 @@ DEFINE_SPINLOCK(i8253_lock); EXPORT_SYMBOL(i8253_lock); -void setup_pit_timer(void) +#ifdef CONFIG_HPET_TIMER +/* + * 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; +#endif + +/* + * 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_PERIODIC: + /* binary, mode 2, LSB/MSB, ch 0 */ + outb_p(0x34, PIT_MODE); + udelay(10); + outb_p(LATCH & 0xff , PIT_CH0); /* LSB */ + outb(LATCH >> 8 , PIT_CH0); /* MSB */ + break; + + case CLOCK_EVT_ONESHOT: + case CLOCK_EVT_SHUTDOWN: + /* One shot setup */ + outb_p(0x38, PIT_MODE); + udelay(10); + break; + } + spin_unlock_irqrestore(&i8253_lock, flags); +} + +/* + * Program the next event in oneshot mode + * + * Delta is given in PIT ticks + */ +static void pit_next_event(unsigned long delta, struct clock_event_device *evt) { unsigned long flags; spin_lock_irqsave(&i8253_lock, flags); - outb_p(0x34,PIT_MODE); /* binary, mode 2, LSB/MSB, ch 0 */ - udelay(10); - outb_p(LATCH & 0xff , PIT_CH0); /* LSB */ - udelay(10); - outb(LATCH >> 8 , PIT_CH0); /* MSB */ + outb_p(delta & 0xff , PIT_CH0); /* LSB */ + outb(delta >> 8 , PIT_CH0); /* MSB */ spin_unlock_irqrestore(&i8253_lock, flags); } /* + * 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", + .capabilities = CLOCK_CAP_TICK | CLOCK_CAP_PROFILE | CLOCK_CAP_UPDATE +#ifndef CONFIG_SMP + | CLOCK_CAP_NEXTEVT +#endif + , + .set_mode = init_pit_timer, + .set_next_event = pit_next_event, + .shift = 32, +}; + +/* + * 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) +{ + 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); + register_global_clockevent(&pit_clockevent); +#ifdef CONFIG_HPET_TIMER + global_clock_event = &pit_clockevent; +#endif +} + +/* * Since the PIT overflows every tick, its not very useful * to just read by itself. So use jiffies to emulate a free * running counter: @@ -46,7 +124,7 @@ static cycle_t pit_read(void) 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 Index: linux-2.6.18-mm2/arch/i386/kernel/time.c =================================================================== --- linux-2.6.18-mm2.orig/arch/i386/kernel/time.c 2006-10-02 00:55:50.000000000 +0200 +++ linux-2.6.18-mm2/arch/i386/kernel/time.c 2006-10-02 00:55:53.000000000 +0200 @@ -163,15 +163,6 @@ EXPORT_SYMBOL(profile_pc); */ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) { - /* - * Here we are in the timer irq handler. We just have irqs locally - * disabled but we don't know if the timer_bh is running on the other - * CPU. We need to avoid to SMP race with it. NOTE: we don' t need - * the irq version of write_lock because as just said we have irq - * locally disabled. -arca - */ - write_seqlock(&xtime_lock); - #ifdef CONFIG_X86_IO_APIC if (timer_ack) { /* @@ -190,7 +181,6 @@ irqreturn_t timer_interrupt(int irq, voi do_timer_interrupt_hook(regs); - if (MCA_bus) { /* The PS/2 uses level-triggered interrupts. You can't turn them off, nor would you want to (any attempt to @@ -205,8 +195,6 @@ irqreturn_t timer_interrupt(int irq, voi outb_p( irq|0x80, 0x61 ); /* reset the IRQ */ } - write_sequnlock(&xtime_lock); - #ifdef CONFIG_X86_LOCAL_APIC if (using_apic_timer) smp_send_timer_broadcast_ipi(regs); @@ -283,39 +271,6 @@ void notify_arch_cmos_timer(void) mod_timer(&sync_cmos_timer, jiffies + 1); } -static int timer_resume(struct sys_device *dev) -{ -#ifdef CONFIG_HPET_TIMER - if (is_hpet_enabled()) - hpet_reenable(); -#endif - setup_pit_timer(); - - return 0; -} - -static struct sysdev_class timer_sysclass = { - .resume = timer_resume, - set_kset_name("timer"), -}; - - -/* XXX this driverfs stuff should probably go elsewhere later -john */ -static struct sys_device device_timer = { - .id = 0, - .cls = &timer_sysclass, -}; - -static int time_init_device(void) -{ - int error = sysdev_class_register(&timer_sysclass); - if (!error) - error = sysdev_register(&device_timer); - return error; -} - -device_initcall(time_init_device); - #ifdef CONFIG_HPET_TIMER extern void (*late_time_init)(void); /* Duplicate of time_init() below, with hpet_enable part added */ Index: linux-2.6.18-mm2/include/asm-i386/i8253.h =================================================================== --- linux-2.6.18-mm2.orig/include/asm-i386/i8253.h 2006-10-02 00:55:46.000000000 +0200 +++ linux-2.6.18-mm2/include/asm-i386/i8253.h 2006-10-02 00:55:53.000000000 +0200 @@ -3,4 +3,22 @@ extern spinlock_t i8253_lock; +#ifdef CONFIG_HPET_TIMER +extern struct clock_event_device *global_clock_event; +#else +extern struct clock_event_device pit_clockevent; +# define global_clock_event (&pit_clockevent) +#endif + +/** + * pit_interrupt_hook - hook into timer tick + * @regs: standard registers from interrupt + * + * Call the global clock event handler. + **/ +static inline void pit_interrupt_hook(struct pt_regs *regs) +{ + global_clock_event->event_handler(regs); +} + #endif /* __ASM_I8253_H__ */ Index: linux-2.6.18-mm2/include/asm-i386/mach-default/do_timer.h =================================================================== --- linux-2.6.18-mm2.orig/include/asm-i386/mach-default/do_timer.h 2006-10-02 00:55:46.000000000 +0200 +++ linux-2.6.18-mm2/include/asm-i386/mach-default/do_timer.h 2006-10-02 00:55:53.000000000 +0200 @@ -1,39 +1,20 @@ /* defines for inline arch setup functions */ +#include -#include #include +#include /** * do_timer_interrupt_hook - hook into timer tick * @regs: standard registers from interrupt * - * Description: - * This hook is called immediately after the timer interrupt is ack'd. - * It's primary purpose is to allow architectures that don't possess - * individual per CPU clocks (like the CPU APICs supply) to broadcast the - * timer interrupt as a means of triggering reschedules etc. + * Call the pit clock event handler. see asm/i8253.h **/ - static inline void do_timer_interrupt_hook(struct pt_regs *regs) { - do_timer(1); -#ifndef CONFIG_SMP - update_process_times(user_mode_vm(regs)); -#endif -/* - * In the SMP case we use the local APIC timer interrupt to do the - * profiling, except when we simulate SMP mode on a uniprocessor - * system, in that case we have to call the local interrupt handler. - */ -#ifndef CONFIG_X86_LOCAL_APIC - profile_tick(CPU_PROFILING, regs); -#else - if (!using_apic_timer) - smp_local_timer_interrupt(regs); -#endif + pit_interrupt_hook(regs); } - /* you can safely undefine this if you don't have the Neptune chipset */ #define BUGGY_NEPTUN_TIMER Index: linux-2.6.18-mm2/include/asm-i386/mach-visws/do_timer.h =================================================================== --- linux-2.6.18-mm2.orig/include/asm-i386/mach-visws/do_timer.h 2006-10-02 00:55:46.000000000 +0200 +++ linux-2.6.18-mm2/include/asm-i386/mach-visws/do_timer.h 2006-10-02 00:55:53.000000000 +0200 @@ -9,7 +9,9 @@ static inline void do_timer_interrupt_ho /* Clear the interrupt */ co_cpu_write(CO_CPU_STAT,co_cpu_read(CO_CPU_STAT) & ~CO_STAT_TIMEINTR); + write_seqlock(&xtime_lock); do_timer(1); + write_sequnlock(&xtime_lock); #ifndef CONFIG_SMP update_process_times(user_mode_vm(regs)); #endif Index: linux-2.6.18-mm2/include/asm-i386/mach-voyager/do_timer.h =================================================================== --- linux-2.6.18-mm2.orig/include/asm-i386/mach-voyager/do_timer.h 2006-10-02 00:55:46.000000000 +0200 +++ linux-2.6.18-mm2/include/asm-i386/mach-voyager/do_timer.h 2006-10-02 00:55:53.000000000 +0200 @@ -1,13 +1,18 @@ /* defines for inline arch setup functions */ +#include + #include +#include +/** + * do_timer_interrupt_hook - hook into timer tick + * @regs: standard registers from interrupt + * + * Call the pit clock event handler. see asm/i8253.h + **/ static inline void do_timer_interrupt_hook(struct pt_regs *regs) { - do_timer(1); -#ifndef CONFIG_SMP - update_process_times(user_mode_vm(regs)); -#endif - + pit_interrupt_hook(regs); voyager_timer_interrupt(regs); } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/