lkml.org 
[lkml]   [2003]   [Aug]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH][2.6][2/5]Support for HPET based timer
On Tue, Aug 19, 2003 at 05:18:50PM -0700, Pallipadi, Venkatesh wrote:

> Fixmap is for HPET memory map address access. As the timer
> initialization happen
> early in the boot sequence (before vm initialization), we need to have
> fixmap()
> and fix_to_virt() to access HPET memory map address.

Ahh, yes, you're right. You can't use ioremap at that time. Actually I
did the same on x86_64 not only because of vsyscalls.

> Yes. Most of the code is generic, and can run on other platforms. The
> only reason
> I have that check is because, I haven't got chance to test this patch on
> other
> platforms.
>
> Thanks,
> -Venkatesh
>
> > -----Original Message-----
> > From: Vojtech Pavlik [mailto:vojtech@suse.cz]
> > Sent: Tuesday, August 19, 2003 3:39 PM
> > To: Pallipadi, Venkatesh
> > Cc: linux-kernel@vger.kernel.org; torvalds@osdl.org;
> > Nakajima, Jun; Mallick, Asit K
> > Subject: Re: [PATCH][2.6][2/5]Support for HPET based timer
> >
> >
> > On Tue, Aug 19, 2003 at 12:20:02PM -0700, Pallipadi, Venkatesh wrote:
> >
> > > 2/5 - hpet2.patch - All the changes required to use HPET in place
> > > of PIT as the kernel base-timer at IRQ 0.
> >
> > What are you using the fixmap() for? i386 doesn't have vsyscalls ...
> >
> > Why are you limiting the HPET vendor ID to Intel? This code will
> > happily run on other vendor hardware as well ...
> >
> >
> > > diff -purN linux-2.6.0-test1/arch/i386/kernel/apic.c
> > linux-2.6.0-test1-hpet/arch/i386/kernel/apic.c
> > > --- linux-2.6.0-test1/arch/i386/kernel/apic.c
> > 2003-07-13 20:39:27.000000000 -0700
> > > +++ linux-2.6.0-test1-hpet/arch/i386/kernel/apic.c
> > 2003-08-13 11:36:24.000000000 -0700
> > > @@ -34,6 +34,7 @@
> > > #include <asm/pgalloc.h>
> > > #include <asm/desc.h>
> > > #include <asm/arch_hooks.h>
> > > +#include <asm/hpet.h>
> > >
> > > #include <mach_apic.h>
> > >
> > > @@ -749,7 +750,8 @@ static unsigned int __init get_8254_time
> > > return count;
> > > }
> > >
> > > -void __init wait_8254_wraparound(void)
> > > +/* next tick in 8254 can be caught by catching timer wraparound */
> > > +static void __init wait_8254_wraparound(void)
> > > {
> > > unsigned int curr_count, prev_count=~0;
> > > int delta;
> > > @@ -771,6 +773,12 @@ void __init wait_8254_wraparound(void)
> > > }
> > >
> > > /*
> > > + * Default initialization for 8254 timers. If we use other
> > timers like HPET,
> > > + * we override this later
> > > + */
> > > +void (*wait_timer_tick)(void) = wait_8254_wraparound;
> > > +
> > > +/*
> > > * This function sets up the local APIC timer, with a timeout of
> > > * 'clocks' APIC bus clock. During calibration we actually call
> > > * this function twice on the boot CPU, once with a bogus timeout
> > > @@ -811,7 +819,7 @@ static void setup_APIC_timer(unsigned in
> > > /*
> > > * Wait for IRQ0's slice:
> > > */
> > > - wait_8254_wraparound();
> > > + wait_timer_tick();
> > >
> > > __setup_APIC_LVTT(clocks);
> > >
> > > @@ -854,7 +862,7 @@ int __init calibrate_APIC_clock(void)
> > > * (the current tick might have been already half done)
> > > */
> > >
> > > - wait_8254_wraparound();
> > > + wait_timer_tick();
> > >
> > > /*
> > > * We wrapped around just now. Let's start:
> > > @@ -867,7 +875,7 @@ int __init calibrate_APIC_clock(void)
> > > * Let's wait LOOPS wraprounds:
> > > */
> > > for (i = 0; i < LOOPS; i++)
> > > - wait_8254_wraparound();
> > > + wait_timer_tick();
> > >
> > > tt2 = apic_read(APIC_TMCCT);
> > > if (cpu_has_tsc)
> > > diff -purN linux-2.6.0-test1/arch/i386/kernel/time.c
> > linux-2.6.0-test1-hpet/arch/i386/kernel/time.c
> > > --- linux-2.6.0-test1/arch/i386/kernel/time.c
> > 2003-07-13 20:34:29.000000000 -0700
> > > +++ linux-2.6.0-test1-hpet/arch/i386/kernel/time.c
> > 2003-08-18 12:36:25.000000000 -0700
> > > @@ -60,6 +60,8 @@
> > > #include <linux/timex.h>
> > > #include <linux/config.h>
> > >
> > > +#include <asm/hpet.h>
> > > +
> > > #include <asm/arch_hooks.h>
> > >
> > > #include "io_ports.h"
> > > @@ -298,6 +300,12 @@ void __init time_init(void)
> > > xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
> > > wall_to_monotonic.tv_nsec = -xtime.tv_nsec;
> > >
> > > +#ifdef CONFIG_HPET_TIMER
> > > + if (hpet_enable() >= 0) {
> > > + printk("Using HPET for base-timer\n");
> > > + }
> > > +#endif
> > > +
> > > cur_timer = select_timer();
> > > time_init_hook();
> > > }
> > > diff -purN linux-2.6.0-test1/arch/i386/kernel/time_hpet.c
> > linux-2.6.0-test1-hpet/arch/i386/kernel/time_hpet.c
> > > --- linux-2.6.0-test1/arch/i386/kernel/time_hpet.c
> > 1969-12-31 16:00:00.000000000 -0800
> > > +++ linux-2.6.0-test1-hpet/arch/i386/kernel/time_hpet.c
> > 2003-08-18 20:22:06.000000000 -0700
> > > @@ -0,0 +1,153 @@
> > > +/*
> > > + * linux/arch/i386/kernel/time_hpet.c
> > > + * This code largely copied from arch/x86_64/kernel/time.c
> > > + * See that file for credits.
> > > + *
> > > + * 2003-06-30 Venkatesh Pallipadi - Additional changes
> > for HPET support
> > > + */
> > > +
> > > +#include <linux/errno.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/param.h>
> > > +#include <linux/string.h>
> > > +#include <linux/init.h>
> > > +#include <linux/smp.h>
> > > +
> > > +#include <asm/timer.h>
> > > +#include <asm/fixmap.h>
> > > +#include <asm/apic.h>
> > > +
> > > +#include <linux/timex.h>
> > > +#include <linux/config.h>
> > > +
> > > +#include <asm/hpet.h>
> > > +
> > > +unsigned long hpet_period; /* fsecs / HPET clock */
> > > +unsigned long hpet_tick; /* hpet clks count per tick */
> > > +unsigned long hpet_address; /* hpet memory map address */
> > > +
> > > +static int use_hpet; /* can be used for
> > runtime check of hpet */
> > > +static int boot_hpet_disable; /* boottime override
> > for HPET timer */
> > > +
> > > +#define FSEC_TO_USEC (1000000000UL)
> > > +
> > > +#ifdef CONFIG_X86_LOCAL_APIC
> > > +/*
> > > + * HPET counters dont wrap around on every tick. They just
> > change the
> > > + * comparator value and continue. Next tick can be caught
> > by checking
> > > + * for a change in the comparator value. Used in apic.c.
> > > + */
> > > +void __init wait_hpet_tick(void)
> > > +{
> > > + unsigned int start_cmp_val, end_cmp_val;
> > > +
> > > + start_cmp_val = hpet_readl(HPET_T0_CMP);
> > > + do {
> > > + end_cmp_val = hpet_readl(HPET_T0_CMP);
> > > + } while (start_cmp_val == end_cmp_val);
> > > +}
> > > +#endif
> > > +
> > > +/*
> > > + * Check whether HPET was found by ACPI boot parse. If yes
> > setup HPET
> > > + * counter 0 for kernel base timer.
> > > + */
> > > +int __init hpet_enable(void)
> > > +{
> > > + unsigned int cfg, id;
> > > + unsigned long tick_fsec_low, tick_fsec_high; /* tick in
> > femto sec */
> > > + unsigned long hpet_tick_rem;
> > > +
> > > + if (boot_hpet_disable)
> > > + return -1;
> > > +
> > > + if (!hpet_address) {
> > > + return -1;
> > > + }
> > > + set_fixmap_nocache(FIX_HPET_BASE, hpet_address);
> > > + printk(KERN_INFO "HPET enabled at %#lx\n", hpet_address);
> > > +
> > > + /*
> > > + * Read the period, compute tick and quotient.
> > > + */
> > > + id = hpet_readl(HPET_ID);
> > > +
> > > + /*
> > > + * We are checking for value '1' or more in number field.
> > > + * So, we are OK with HPET_EMULATE_RTC part too, where we need
> > > + * to have atleast 2 timers.
> > > + */
> > > + if (!(id & HPET_ID_NUMBER) ||
> > > + !(id & HPET_ID_LEGSUP))
> > > + return -1;
> > > +
> > > + if (((id & HPET_ID_VENDOR) >> HPET_ID_VENDOR_SHIFT) !=
> > > + HPET_ID_VENDOR_8086)
> > > + return -1;
> > > +
> > > + hpet_period = hpet_readl(HPET_PERIOD);
> > > + if ((hpet_period < HPET_MIN_PERIOD) || (hpet_period >
> > HPET_MAX_PERIOD))
> > > + return -1;
> > > +
> > > + /*
> > > + * 64 bit math
> > > + * First changing tick into fsec
> > > + * Then 64 bit div to find number of hpet clk per tick
> > > + */
> > > + ASM_MUL64_REG(tick_fsec_low, tick_fsec_high,
> > > + KERNEL_TICK_USEC, FSEC_TO_USEC);
> > > + ASM_DIV64_REG(hpet_tick, hpet_tick_rem,
> > > + hpet_period, tick_fsec_low, tick_fsec_high);
> > > +
> > > + if (hpet_tick_rem > (hpet_period >> 1))
> > > + hpet_tick++; /* rounding the result */
> > > +
> > > + /*
> > > + * Stop the timers and reset the main counter.
> > > + */
> > > + cfg = hpet_readl(HPET_CFG);
> > > + cfg &= ~HPET_CFG_ENABLE;
> > > + hpet_writel(cfg, HPET_CFG);
> > > + hpet_writel(0, HPET_COUNTER);
> > > + hpet_writel(0, HPET_COUNTER + 4);
> > > +
> > > + /*
> > > + * Set up timer 0, as periodic with first interrupt to
> > happen at
> > > + * hpet_tick, and period also hpet_tick.
> > > + */
> > > + cfg = hpet_readl(HPET_T0_CFG);
> > > + cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
> > > + HPET_TN_SETVAL | HPET_TN_32BIT;
> > > + hpet_writel(cfg, HPET_T0_CFG);
> > > + hpet_writel(hpet_tick, HPET_T0_CMP);
> > > +
> > > + /*
> > > + * Go!
> > > + */
> > > + cfg = hpet_readl(HPET_CFG);
> > > + cfg |= HPET_CFG_ENABLE | HPET_CFG_LEGACY;
> > > + hpet_writel(cfg, HPET_CFG);
> > > +
> > > + use_hpet = 1;
> > > +#ifdef CONFIG_X86_LOCAL_APIC
> > > + wait_timer_tick = wait_hpet_tick;
> > > +#endif
> > > + return 0;
> > > +}
> > > +
> > > +int is_hpet_enabled(void)
> > > +{
> > > + return use_hpet;
> > > +}
> > > +
> > > +static int __init hpet_setup(char* str)
> > > +{
> > > + if (str) {
> > > + if (!strncmp("disable", str, 7))
> > > + boot_hpet_disable = 1;
> > > + }
> > > + return 1;
> > > +}
> > > +
> > > +__setup("hpet=", hpet_setup);
> > > +
> > > diff -purN linux-2.6.0-test1/include/asm-i386/apic.h
> > linux-2.6.0-test1-hpet/include/asm-i386/apic.h
> > > --- linux-2.6.0-test1/include/asm-i386/apic.h
> > 2003-07-13 20:38:53.000000000 -0700
> > > +++ linux-2.6.0-test1-hpet/include/asm-i386/apic.h
> > 2003-08-13 11:34:37.000000000 -0700
> > > @@ -64,6 +64,8 @@ static inline void ack_APIC_irq(void)
> > > apic_write_around(APIC_EOI, 0);
> > > }
> > >
> > > +extern void (*wait_timer_tick)(void);
> > > +
> > > extern int get_maxlvt(void);
> > > extern void clear_local_APIC(void);
> > > extern void connect_bsp_APIC (void);
> > > diff -purN linux-2.6.0-test1/include/asm-i386/fixmap.h
> > linux-2.6.0-test1-hpet/include/asm-i386/fixmap.h
> > > --- linux-2.6.0-test1/include/asm-i386/fixmap.h
> > 2003-07-13 20:29:30.000000000 -0700
> > > +++ linux-2.6.0-test1-hpet/include/asm-i386/fixmap.h
> > 2003-08-14 13:10:31.000000000 -0700
> > > @@ -44,6 +44,9 @@
> > > enum fixed_addresses {
> > > FIX_HOLE,
> > > FIX_VSYSCALL,
> > > +#ifdef CONFIG_HPET_TIMER
> > > + FIX_HPET_BASE,
> > > +#endif
> > > #ifdef CONFIG_X86_LOCAL_APIC
> > > FIX_APIC_BASE, /* local (CPU) APIC) -- required for
> > SMP or not */
> > > #endif
> > > diff -purN linux-2.6.0-test1/include/asm-i386/hpet.h
> > linux-2.6.0-test1-hpet/include/asm-i386/hpet.h
> > > --- linux-2.6.0-test1/include/asm-i386/hpet.h
> > 1969-12-31 16:00:00.000000000 -0800
> > > +++ linux-2.6.0-test1-hpet/include/asm-i386/hpet.h
> > 2003-08-18 20:22:40.000000000 -0700
> > > @@ -0,0 +1,104 @@
> > > +
> > > +#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_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_VENDOR 0xffff0000
> > > +#define HPET_ID_LEGSUP 0x00008000
> > > +#define HPET_ID_NUMBER 0x00001f00
> > > +#define HPET_ID_REV 0x000000ff
> > > +
> > > +#define HPET_ID_VENDOR_SHIFT 16
> > > +#define HPET_ID_VENDOR_8086 0x8086
> > > +
> > > +#define HPET_CFG_ENABLE 0x001
> > > +#define HPET_CFG_LEGACY 0x002
> > > +
> > > +#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 hpet_readl(a)
> > readl(fix_to_virt(FIX_HPET_BASE) + a)
> > > +#define hpet_writel(d,a) writel(d,
> > fix_to_virt(FIX_HPET_BASE) + a)
> > > +
> > > +#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_period; /* fsecs / HPET clock */
> > > +extern unsigned long hpet_tick; /* hpet clks count per tick */
> > > +extern unsigned long hpet_address; /* hpet memory map address */
> > > +extern unsigned long hpet_virt_address; /* hpet kernel
> > virtual address */
> > > +
> > > +extern int hpet_enable(void);
> > > +extern int is_hpet_enabled(void);
> > > +
> > > +#endif /* CONFIG_HPET_TIMER */
> > > +#endif /* _I386_HPET_H */
> > > diff -purN linux-2.6.0-test1/include/asm-i386/mc146818rtc.h
> > linux-2.6.0-test1-hpet/include/asm-i386/mc146818rtc.h
> > > --- linux-2.6.0-test1/include/asm-i386/mc146818rtc.h
> > 2003-07-13 20:36:37.000000000 -0700
> > > +++ linux-2.6.0-test1-hpet/include/asm-i386/mc146818rtc.h
> > 2003-08-18 20:23:43.000000000 -0700
> > > @@ -24,6 +24,10 @@ outb_p((addr),RTC_PORT(0)); \
> > > outb_p((val),RTC_PORT(1)); \
> > > })
> > >
> > > +#ifdef CONFIG_HPET_TIMER
> > > +#define RTC_IRQ 0
> > > +#else
> > > #define RTC_IRQ 8
> > > +#endif
> > >
> > > #endif /* _ASM_MC146818RTC_H */
> > > diff -purN
> > linux-2.6.0-test1/Documentation/kernel-parameters.txt
> > linux-2.6.0-test1-hpet/Documentation/kernel-parameters.txt
> > > --- linux-2.6.0-test1/Documentation/kernel-parameters.txt
> > 2003-07-13 20:39:36.000000000 -0700
> > > +++
> > linux-2.6.0-test1-hpet/Documentation/kernel-parameters.txt
> > 2003-08-18 20:37:41.000000000 -0700
> > > @@ -212,7 +212,10 @@ running once the system is up.
> > > when calculating gettimeofday(). If
> > specicified timesource
> > > is not avalible, it defaults to PIT.
> > > Format: { pit | tsc | cyclone | ... }
> > > -
> > > +
> > > + hpet= [IA-32,HPET] option to disable HPET and use PIT.
> > > + Format: disable
> > > +
> > > cm206= [HW,CD]
> > > Format: { auto | [<io>,][<irq>] }
> > >
> > >
> > >
> >
> >
> >
> > --
> > Vojtech Pavlik
> > SuSE Labs, SuSE CR
> >
>

--
Vojtech Pavlik
SuSE Labs, SuSE CR
-
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/

\
 
 \ /
  Last update: 2005-03-22 13:47    [W:0.044 / U:0.368 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site