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x86, mrst: add more timer config options

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Always-on local APIC timer (ARAT) has been introduced to Medfield, along
with the platform APB timers we have more timer configuration options
between Moorestown and Medfield.

This patch adds run-time detection of avaiable timer features so that
we can treat Medfield as a variant of Moorestown and set up the optimal
timer options for each platform. i.e.

Medfield: per cpu always-on local APIC timer
Moorestown: per cpu APB timer

Manual override is possible via cmdline option x86_mrst_timer.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
LKML-Reference: <1274295685-6774-4-git-send-email-jacob.jun.pan@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Jacob Pan
2010-05-19 12:01:25 -07:00
committed by H. Peter Anvin
parent a0c173bd8a
commit a875c01944
4 changed files with 72 additions and 55 deletions
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37
arch/x86/kernel/apb_timer.c
View File

@@ -43,10 +43,11 @@
#include <asm/fixmap.h>
#include <asm/apb_timer.h>
#include <asm/mrst.h>
#define APBT_MASK CLOCKSOURCE_MASK(32)
#define APBT_SHIFT 22
#define APBT_CLOCKEVENT_RATING 150
#define APBT_CLOCKEVENT_RATING 110
#define APBT_CLOCKSOURCE_RATING 250
#define APBT_MIN_DELTA_USEC 200
@@ -83,8 +84,6 @@ struct apbt_dev {
char name[10];
};
int disable_apbt_percpu __cpuinitdata;
static DEFINE_PER_CPU(struct apbt_dev, cpu_apbt_dev);
#ifdef CONFIG_SMP
@@ -194,29 +193,6 @@ static struct clock_event_device apbt_clockevent = {
.rating = APBT_CLOCKEVENT_RATING,
};
/*
* if user does not want to use per CPU apb timer, just give it a lower rating
* than local apic timer and skip the late per cpu timer init.
*/
static inline int __init setup_x86_mrst_timer(char *arg)
{
if (!arg)
return -EINVAL;
if (strcmp("apbt_only", arg) == 0)
disable_apbt_percpu = 0;
else if (strcmp("lapic_and_apbt", arg) == 0)
disable_apbt_percpu = 1;
else {
pr_warning("X86 MRST timer option %s not recognised"
" use x86_mrst_timer=apbt_only or lapic_and_apbt\n",
arg);
return -EINVAL;
}
return 0;
}
__setup("x86_mrst_timer=", setup_x86_mrst_timer);
/*
* start count down from 0xffff_ffff. this is done by toggling the enable bit
* then load initial load count to ~0.
@@ -335,7 +311,7 @@ static int __init apbt_clockevent_register(void)
adev->num = smp_processor_id();
memcpy(&adev->evt, &apbt_clockevent, sizeof(struct clock_event_device));
if (disable_apbt_percpu) {
if (mrst_timer_options == MRST_TIMER_LAPIC_APBT) {
apbt_clockevent.rating = APBT_CLOCKEVENT_RATING - 100;
global_clock_event = &adev->evt;
printk(KERN_DEBUG "%s clockevent registered as global\n",
@@ -429,7 +405,8 @@ static int apbt_cpuhp_notify(struct notifier_block *n,
static __init int apbt_late_init(void)
{
if (disable_apbt_percpu || !apb_timer_block_enabled)
if (mrst_timer_options == MRST_TIMER_LAPIC_APBT ||
!apb_timer_block_enabled)
return 0;
/* This notifier should be called after workqueue is ready */
hotcpu_notifier(apbt_cpuhp_notify, -20);
@@ -450,6 +427,8 @@ static void apbt_set_mode(enum clock_event_mode mode,
int timer_num;
struct apbt_dev *adev = EVT_TO_APBT_DEV(evt);
BUG_ON(!apbt_virt_address);
timer_num = adev->num;
pr_debug("%s CPU %d timer %d mode=%d\n",
__func__, first_cpu(*evt->cpumask), timer_num, mode);
@@ -676,7 +655,7 @@ void __init apbt_time_init(void)
}
#ifdef CONFIG_SMP
/* kernel cmdline disable apb timer, so we will use lapic timers */
if (disable_apbt_percpu) {
if (mrst_timer_options == MRST_TIMER_LAPIC_APBT) {
printk(KERN_INFO "apbt: disabled per cpu timer\n");
return;
}