• john stultz's avatar
    [PATCH] i386: fix hpet for systems that don't support legacy replacement · 35492df5
    john stultz authored
    Currently the i386 HPET code assumes the entire HPET implementation from
    the spec is present.  This breaks on boxes that do not implement the
    optional legacy timer replacement functionality portion of the spec.
    
    This patch, which is very similar to my x86-64 patch for the same issue,
    fixes the problem allowing i386 systems that cannot use the HPET for the
    timer interrupt and RTC to still use the HPET as a time source.  I've
    tested this patch on a system systems without HPET, with HPET but without
    legacy timer replacement, as well as HPET with legacy timer replacement.
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    35492df5
hpet.h 3.19 KB

#ifndef _I386_HPET_H
#define _I386_HPET_H

#ifdef CONFIG_HPET_TIMER

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp.h>

#include <asm/io.h>
#include <asm/smp.h>
#include <asm/irq.h>
#include <asm/msr.h>
#include <asm/delay.h>
#include <asm/mpspec.h>
#include <asm/uaccess.h>
#include <asm/processor.h>

#include <linux/timex.h>
#include <linux/config.h>

#include <asm/fixmap.h>

/*
 * 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_T0_CFG	0x100
#define HPET_T0_CMP	0x108
#define HPET_T0_ROUTE	0x110
#define HPET_T1_CFG	0x120
#define HPET_T1_CMP	0x128
#define HPET_T1_ROUTE	0x130
#define HPET_T2_CFG	0x140
#define HPET_T2_CMP	0x148
#define HPET_T2_ROUTE	0x150

#define HPET_ID_LEGSUP	0x00008000
#define HPET_ID_NUMBER	0x00001f00
#define HPET_ID_REV	0x000000ff
#define	HPET_ID_NUMBER_SHIFT	8

#define HPET_CFG_ENABLE	0x001
#define HPET_CFG_LEGACY	0x002
#define	HPET_LEGACY_8254	2
#define	HPET_LEGACY_RTC		8

#define HPET_TN_ENABLE		0x004
#define HPET_TN_PERIODIC	0x008
#define HPET_TN_PERIODIC_CAP	0x010
#define HPET_TN_SETVAL		0x040
#define HPET_TN_32BIT		0x100

/* Use our own asm for 64 bit multiply/divide */
#define ASM_MUL64_REG(eax_out,edx_out,reg_in,eax_in) 			\
		__asm__ __volatile__("mull %2" 				\
				:"=a" (eax_out), "=d" (edx_out) 	\
				:"r" (reg_in), "0" (eax_in))

#define ASM_DIV64_REG(eax_out,edx_out,reg_in,eax_in,edx_in) 		\
		__asm__ __volatile__("divl %2" 				\
				:"=a" (eax_out), "=d" (edx_out) 	\
				:"r" (reg_in), "0" (eax_in), "1" (edx_in))

#define KERNEL_TICK_USEC 	(1000000UL/HZ)	/* tick value in microsec */
/* Max HPET Period is 10^8 femto sec as in HPET spec */
#define HPET_MAX_PERIOD (100000000UL)
/*
 * Min HPET period is 10^5 femto sec just for safety. If it is less than this,
 * then 32 bit HPET counter wrapsaround in less than 0.5 sec.
 */
#define HPET_MIN_PERIOD (100000UL)

extern unsigned long hpet_tick;  	/* hpet clks count per tick */
extern unsigned long hpet_address;	/* hpet memory map physical address */
extern int hpet_use_timer;

extern int hpet_rtc_timer_init(void);
extern int hpet_enable(void);
extern int hpet_reenable(void);
extern int is_hpet_enabled(void);
extern int is_hpet_capable(void);
extern int hpet_readl(unsigned long a);

#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);
extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs);
#endif /* CONFIG_HPET_EMULATE_RTC */
#endif /* CONFIG_HPET_TIMER */
#endif /* _I386_HPET_H */