diff options
author | Ingo Molnar <mingo@elte.hu> | 2009-03-06 16:44:14 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-03-06 16:45:01 +0100 |
commit | f0ef03985130287c6c84ebe69416cf790e6cc00e (patch) | |
tree | 3ecb04cc4d82e5fc3ae5f1747e6da172ae8cbcb7 /arch/x86/include/asm/mach_timer.h | |
parent | 16097439703bcd38e9fe5608c12add6dacb825ea (diff) | |
parent | 31bbed527e7039203920c51c9fb48c27aed0820c (diff) |
Merge branch 'x86/core' into tracing/textedit
Conflicts:
arch/x86/Kconfig
block/blktrace.c
kernel/irq/handle.c
Semantic conflict:
kernel/trace/blktrace.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/include/asm/mach_timer.h')
-rw-r--r-- | arch/x86/include/asm/mach_timer.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/x86/include/asm/mach_timer.h b/arch/x86/include/asm/mach_timer.h new file mode 100644 index 00000000000..853728519ae --- /dev/null +++ b/arch/x86/include/asm/mach_timer.h @@ -0,0 +1,48 @@ +/* + * Machine specific calibrate_tsc() for generic. + * Split out from timer_tsc.c by Osamu Tomita <tomita@cinet.co.jp> + */ +/* ------ Calibrate the TSC ------- + * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset(). + * Too much 64-bit arithmetic here to do this cleanly in C, and for + * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2) + * output busy loop as low as possible. We avoid reading the CTC registers + * directly because of the awkward 8-bit access mechanism of the 82C54 + * device. + */ +#ifndef _ASM_X86_MACH_DEFAULT_MACH_TIMER_H +#define _ASM_X86_MACH_DEFAULT_MACH_TIMER_H + +#define CALIBRATE_TIME_MSEC 30 /* 30 msecs */ +#define CALIBRATE_LATCH \ + ((CLOCK_TICK_RATE * CALIBRATE_TIME_MSEC + 1000/2)/1000) + +static inline void mach_prepare_counter(void) +{ + /* Set the Gate high, disable speaker */ + outb((inb(0x61) & ~0x02) | 0x01, 0x61); + + /* + * Now let's take care of CTC channel 2 + * + * Set the Gate high, program CTC channel 2 for mode 0, + * (interrupt on terminal count mode), binary count, + * load 5 * LATCH count, (LSB and MSB) to begin countdown. + * + * Some devices need a delay here. + */ + outb(0xb0, 0x43); /* binary, mode 0, LSB/MSB, Ch 2 */ + outb_p(CALIBRATE_LATCH & 0xff, 0x42); /* LSB of count */ + outb_p(CALIBRATE_LATCH >> 8, 0x42); /* MSB of count */ +} + +static inline void mach_countup(unsigned long *count_p) +{ + unsigned long count = 0; + do { + count++; + } while ((inb_p(0x61) & 0x20) == 0); + *count_p = count; +} + +#endif /* _ASM_X86_MACH_DEFAULT_MACH_TIMER_H */ |