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linux/include/asm-x86_64/hpet.h
Jordan Hargrave b20367a6c2 [PATCH] x86_64: Fix drift with HPET timer enabled
If the HPET timer is enabled, the clock can drift by ~3 seconds a day.
This is due to the HPET timer not being initialized with the correct
setting (still using PIT count).

If HZ changes, this drift can become even more pronounced.

HPET patch initializes tick_nsec with correct tick_nsec settings for
HPET timer.

Vojtech comments:

  "It's not entirely correct (it assumes the HPET ticks totally
   exactly), but it's significantly better than assuming the PIT error
   there."

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:53 -07:00

72 lines
2.0 KiB
C

#ifndef _ASM_X8664_HPET_H
#define _ASM_X8664_HPET_H 1
/*
* Documentation on HPET can be found at:
* http://www.intel.com/ial/home/sp/pcmmspec.htm
* ftp://download.intel.com/ial/home/sp/mmts098.pdf
*/
#define HPET_MMAP_SIZE 1024
#define HPET_ID 0x000
#define HPET_PERIOD 0x004
#define HPET_CFG 0x010
#define HPET_STATUS 0x020
#define HPET_COUNTER 0x0f0
#define HPET_Tn_OFFSET 0x20
#define HPET_Tn_CFG(n) (0x100 + (n) * HPET_Tn_OFFSET)
#define HPET_Tn_ROUTE(n) (0x104 + (n) * HPET_Tn_OFFSET)
#define HPET_Tn_CMP(n) (0x108 + (n) * HPET_Tn_OFFSET)
#define HPET_T0_CFG HPET_Tn_CFG(0)
#define HPET_T0_CMP HPET_Tn_CMP(0)
#define HPET_T1_CFG HPET_Tn_CFG(1)
#define HPET_T1_CMP HPET_Tn_CMP(1)
#define HPET_ID_VENDOR 0xffff0000
#define HPET_ID_LEGSUP 0x00008000
#define HPET_ID_64BIT 0x00002000
#define HPET_ID_NUMBER 0x00001f00
#define HPET_ID_REV 0x000000ff
#define HPET_ID_NUMBER_SHIFT 8
#define HPET_ID_VENDOR_SHIFT 16
#define HPET_ID_VENDOR_8086 0x8086
#define HPET_CFG_ENABLE 0x001
#define HPET_CFG_LEGACY 0x002
#define HPET_LEGACY_8254 2
#define HPET_LEGACY_RTC 8
#define HPET_TN_LEVEL 0x0002
#define HPET_TN_ENABLE 0x0004
#define HPET_TN_PERIODIC 0x0008
#define HPET_TN_PERIODIC_CAP 0x0010
#define HPET_TN_64BIT_CAP 0x0020
#define HPET_TN_SETVAL 0x0040
#define HPET_TN_32BIT 0x0100
#define HPET_TN_ROUTE 0x3e00
#define HPET_TN_FSB 0x4000
#define HPET_TN_FSB_CAP 0x8000
#define HPET_TN_ROUTE_SHIFT 9
#define HPET_TICK_RATE (HZ * 100000UL)
extern int is_hpet_enabled(void);
extern int hpet_rtc_timer_init(void);
extern int oem_force_hpet_timer(void);
extern int hpet_use_timer;
#ifdef CONFIG_HPET_EMULATE_RTC
extern int hpet_mask_rtc_irq_bit(unsigned long bit_mask);
extern int hpet_set_rtc_irq_bit(unsigned long bit_mask);
extern int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec);
extern int hpet_set_periodic_freq(unsigned long freq);
extern int hpet_rtc_dropped_irq(void);
extern int hpet_rtc_timer_init(void);
#endif /* CONFIG_HPET_EMULATE_RTC */
#endif