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Commit a875c019 authored by Jacob Pan's avatar Jacob Pan Committed by H. Peter Anvin
Browse files

x86, mrst: add more timer config options 



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: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
LKML-Reference: <1274295685-6774-4-git-send-email-jacob.jun.pan@linux.intel.com>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent a0c173bd

arch/x86/include/asm/apb_timer.h

+0 −1
Original line number Diff line number Diff line
@@ -55,7 +55,6 @@ extern unsigned long apbt_quick_calibrate(void); 
extern int arch_setup_apbt_irqs(int irq, int trigger, int mask, int cpu);

extern void apbt_setup_secondary_clock(void);

extern unsigned int boot_cpu_id;

extern int disable_apbt_percpu;



extern struct sfi_timer_table_entry *sfi_get_mtmr(int hint);

extern void sfi_free_mtmr(struct sfi_timer_table_entry *mtmr);

arch/x86/include/asm/mrst.h

+1 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#define _ASM_X86_MRST_H

extern int pci_mrst_init(void);

extern int mrst_identify_cpu(void);

extern int mrst_timer_options __cpuinitdata;

int __init sfi_parse_mrtc(struct sfi_table_header *table);



/*

arch/x86/kernel/apb_timer.c

+8 −29
Original line number Diff line number Diff line
@@ -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;

	}

arch/x86/kernel/mrst.c

+63 −25
Original line number Diff line number Diff line
@@ -25,6 +25,29 @@ 
#include <asm/i8259.h>

#include <asm/apb_timer.h>



/*

 * the clockevent devices on Moorestown/Medfield can be APBT or LAPIC clock,

 * cmdline option x86_mrst_timer can be used to override the configuration

 * to prefer one or the other.

 * at runtime, there are basically three timer configurations:

 * 1. per cpu apbt clock only

 * 2. per cpu always-on lapic clocks only, this is Penwell/Medfield only

 * 3. per cpu lapic clock (C3STOP) and one apbt clock, with broadcast.

 *

 * by default (without cmdline option), platform code first detects cpu type

 * to see if we are on lincroft or penwell, then set up both lapic or apbt

 * clocks accordingly.

 * i.e. by default, medfield uses configuration #2, moorestown uses #1.

 * config #3 is supported but not recommended on medfield.

 *

 * rating and feature summary:

 * lapic (with C3STOP) --------- 100

 * apbt (always-on) ------------ 110

 * lapic (always-on,ARAT) ------ 150

 */



int mrst_timer_options __cpuinitdata;



static u32 sfi_mtimer_usage[SFI_MTMR_MAX_NUM];

static struct sfi_timer_table_entry sfi_mtimer_array[SFI_MTMR_MAX_NUM];

static int mrst_cpu_chip;
@@ -169,18 +192,6 @@ int __init sfi_parse_mrtc(struct sfi_table_header *table) 
	return 0;

}



/*

 * the secondary clock in Moorestown can be APBT or LAPIC clock, default to

 * APBT but cmdline option can also override it.

 */

static void __cpuinit mrst_setup_secondary_clock(void)

{

	/* restore default lapic clock if disabled by cmdline */

	if (disable_apbt_percpu)

		return setup_secondary_APIC_clock();

	apbt_setup_secondary_clock();

}



static unsigned long __init mrst_calibrate_tsc(void)

{

	unsigned long flags, fast_calibrate;
@@ -197,6 +208,21 @@ static unsigned long __init mrst_calibrate_tsc(void) 


void __init mrst_time_init(void)

{

	switch (mrst_timer_options) {

	case MRST_TIMER_APBT_ONLY:

		break;

	case MRST_TIMER_LAPIC_APBT:

		x86_init.timers.setup_percpu_clockev = setup_boot_APIC_clock;

		x86_cpuinit.setup_percpu_clockev = setup_secondary_APIC_clock;

		break;

	default:

		if (!boot_cpu_has(X86_FEATURE_ARAT))

			break;

		x86_init.timers.setup_percpu_clockev = setup_boot_APIC_clock;

		x86_cpuinit.setup_percpu_clockev = setup_secondary_APIC_clock;

		return;

	}

	/* we need at least one APB timer */

	sfi_table_parse(SFI_SIG_MTMR, NULL, NULL, sfi_parse_mtmr);

	pre_init_apic_IRQ0();

	apbt_time_init();
@@ -207,17 +233,6 @@ void __init mrst_rtc_init(void) 
	sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc);

}



/*

 * if we use per cpu apb timer, the bootclock already setup. if we use lapic

 * timer and one apbt timer for broadcast, we need to set up lapic boot clock.

 */

static void __init mrst_setup_boot_clock(void)

{

	pr_info("%s: per cpu apbt flag %d \n", __func__, disable_apbt_percpu);

	if (disable_apbt_percpu)

		setup_boot_APIC_clock();

};



int mrst_identify_cpu(void)

{

	return mrst_cpu_chip;
@@ -250,13 +265,13 @@ void __init x86_mrst_early_setup(void) 
	x86_init.resources.reserve_resources = x86_init_noop;



	x86_init.timers.timer_init = mrst_time_init;

	x86_init.timers.setup_percpu_clockev = mrst_setup_boot_clock;

	x86_init.timers.setup_percpu_clockev = x86_init_noop;



	x86_init.irqs.pre_vector_init = x86_init_noop;



	x86_init.oem.arch_setup = mrst_arch_setup;



	x86_cpuinit.setup_percpu_clockev = mrst_setup_secondary_clock;

	x86_cpuinit.setup_percpu_clockev = apbt_setup_secondary_clock;



	x86_platform.calibrate_tsc = mrst_calibrate_tsc;

	x86_init.pci.init = pci_mrst_init;
@@ -269,3 +284,26 @@ void __init x86_mrst_early_setup(void) 
	x86_init.mpparse.get_smp_config = x86_init_uint_noop;



}



/*

 * 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)

		mrst_timer_options = MRST_TIMER_APBT_ONLY;

	else if (strcmp("lapic_and_apbt", arg) == 0)

		mrst_timer_options = MRST_TIMER_LAPIC_APBT;

	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);