From 36d8593ec74dc04d3bd7c1c897a7b7cfbd0b0dc6 Mon Sep 17 00:00:00 2001 From: Russell King - ARM Linux Date: Sat, 19 Feb 2011 15:34:50 +0000 Subject: Make clocksource name const As nothing should be writing to the clocksource name string, make the clocksource name pointer const. Build-tested on ARM Versatile Express. Signed-off-by: Russell King Signed-off-by: John Stultz --- include/linux/clocksource.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/clocksource.h') diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index c37b21ad5a3b..94c1f38e922a 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -161,7 +161,7 @@ struct clocksource { /* * First part of structure is read mostly */ - char *name; + const char *name; struct list_head list; int rating; cycle_t (*read)(struct clocksource *cs); -- cgit v1.2.3 From 8c414ff3f4dcdde228c6a668385218290d73a265 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 8 May 2011 18:50:20 +0100 Subject: clocksource: convert footbridge to generic i8253 clocksource Convert the footbridge isa-timer code to use generic i8253 clocksource. Acked-by: John Stultz Acked-by: Thomas Gleixner Signed-off-by: Russell King --- arch/arm/include/asm/i8253.h | 15 ++++++++++++ arch/arm/mach-footbridge/Kconfig | 2 ++ arch/arm/mach-footbridge/isa-timer.c | 45 ++++-------------------------------- include/linux/clocksource.h | 2 ++ 4 files changed, 23 insertions(+), 41 deletions(-) create mode 100644 arch/arm/include/asm/i8253.h (limited to 'include/linux/clocksource.h') diff --git a/arch/arm/include/asm/i8253.h b/arch/arm/include/asm/i8253.h new file mode 100644 index 000000000000..70656b69d5ce --- /dev/null +++ b/arch/arm/include/asm/i8253.h @@ -0,0 +1,15 @@ +#ifndef __ASMARM_I8253_H +#define __ASMARM_I8253_H + +/* i8253A PIT registers */ +#define PIT_MODE 0x43 +#define PIT_CH0 0x40 + +#define PIT_LATCH ((PIT_TICK_RATE + HZ / 2) / HZ) + +extern raw_spinlock_t i8253_lock; + +#define outb_pit outb_p +#define inb_pit inb_p + +#endif diff --git a/arch/arm/mach-footbridge/Kconfig b/arch/arm/mach-footbridge/Kconfig index bdd257921cfb..46adca068f2c 100644 --- a/arch/arm/mach-footbridge/Kconfig +++ b/arch/arm/mach-footbridge/Kconfig @@ -4,6 +4,7 @@ menu "Footbridge Implementations" config ARCH_CATS bool "CATS" + select CLKSRC_I8253 select FOOTBRIDGE_HOST select ISA select ISA_DMA @@ -59,6 +60,7 @@ config ARCH_EBSA285_HOST config ARCH_NETWINDER bool "NetWinder" + select CLKSRC_I8253 select FOOTBRIDGE_HOST select ISA select ISA_DMA diff --git a/arch/arm/mach-footbridge/isa-timer.c b/arch/arm/mach-footbridge/isa-timer.c index 441c6ce0d555..7020f1a3feca 100644 --- a/arch/arm/mach-footbridge/isa-timer.c +++ b/arch/arm/mach-footbridge/isa-timer.c @@ -10,53 +10,16 @@ #include #include #include +#include #include #include - +#include #include #include "common.h" -#define PIT_MODE 0x43 -#define PIT_CH0 0x40 - -#define PIT_LATCH ((PIT_TICK_RATE + HZ / 2) / HZ) - -static cycle_t pit_read(struct clocksource *cs) -{ - unsigned long flags; - static int old_count; - static u32 old_jifs; - int count; - u32 jifs; - - raw_local_irq_save(flags); - - jifs = jiffies; - outb_p(0x00, PIT_MODE); /* latch the count */ - count = inb_p(PIT_CH0); /* read the latched count */ - count |= inb_p(PIT_CH0) << 8; - - if (count > old_count && jifs == old_jifs) - count = old_count; - - old_count = count; - old_jifs = jifs; - - raw_local_irq_restore(flags); - - count = (PIT_LATCH - 1) - count; - - return (cycle_t)(jifs * PIT_LATCH) + count; -} - -static struct clocksource pit_cs = { - .name = "pit", - .rating = 110, - .read = pit_read, - .mask = CLOCKSOURCE_MASK(32), -}; +DEFINE_RAW_SPINLOCK(i8253_lock); static void pit_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) @@ -121,7 +84,7 @@ static void __init isa_timer_init(void) pit_ce.max_delta_ns = clockevent_delta2ns(0x7fff, &pit_ce); pit_ce.min_delta_ns = clockevent_delta2ns(0x000f, &pit_ce); - clocksource_register_hz(&pit_cs, PIT_TICK_RATE); + clocksource_i8253_init(); setup_irq(pit_ce.irq, &pit_timer_irq); clockevents_register_device(&pit_ce); diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index c37b21ad5a3b..f13469b3df86 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -341,4 +341,6 @@ static inline void update_vsyscall_tz(void) extern void timekeeping_notify(struct clocksource *clock); +extern int clocksource_i8253_init(void); + #endif /* _LINUX_CLOCKSOURCE_H */ -- cgit v1.2.3 From 369db4c9524b7487faf1ff89646eee396c1363e1 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 May 2011 21:33:40 +0000 Subject: clocksource: Restructure clocksource struct members Group the hot path members of struct clocksource together so we have a better cache line footprint. Make it cacheline aligned. Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Eric Dumazet Reviewed-by: Ingo Molnar Link: http://lkml.kernel.org/r/%3C20110518210136.003081882%40linutronix.de%3E --- include/linux/clocksource.h | 32 ++++++++++++++------------------ 1 file changed, 14 insertions(+), 18 deletions(-) (limited to 'include/linux/clocksource.h') diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 0fb0b7e79394..c918fbd33ee5 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -159,42 +159,38 @@ extern u64 timecounter_cyc2time(struct timecounter *tc, */ struct clocksource { /* - * First part of structure is read mostly + * Hotpath data, fits in a single cache line when the + * clocksource itself is cacheline aligned. */ - const char *name; - struct list_head list; - int rating; cycle_t (*read)(struct clocksource *cs); - int (*enable)(struct clocksource *cs); - void (*disable)(struct clocksource *cs); + cycle_t cycle_last; cycle_t mask; u32 mult; u32 shift; u64 max_idle_ns; - unsigned long flags; - cycle_t (*vread)(void); - void (*suspend)(struct clocksource *cs); - void (*resume)(struct clocksource *cs); + #ifdef CONFIG_IA64 void *fsys_mmio; /* used by fsyscall asm code */ #define CLKSRC_FSYS_MMIO_SET(mmio, addr) ((mmio) = (addr)) #else #define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0) #endif - - /* - * Second part is written at each timer interrupt - * Keep it in a different cache line to dirty no - * more than one cache line. - */ - cycle_t cycle_last ____cacheline_aligned_in_smp; + const char *name; + struct list_head list; + int rating; + cycle_t (*vread)(void); + int (*enable)(struct clocksource *cs); + void (*disable)(struct clocksource *cs); + unsigned long flags; + void (*suspend)(struct clocksource *cs); + void (*resume)(struct clocksource *cs); #ifdef CONFIG_CLOCKSOURCE_WATCHDOG /* Watchdog related data, used by the framework */ struct list_head wd_list; cycle_t wd_last; #endif -}; +} ____cacheline_aligned; /* * Clock source flags bits:: -- cgit v1.2.3