[patch 08/46] i386: use GTOD persistent clock support

Thomas Gleixner
2007-01-23T22:13:49Z

[-- Attachment #1: gtod-persistent-clock-support-i386.patch --]
[-- Type: text/plain, Size: 6021 bytes --]

From: John Stultz <johnstul@us.ibm.com>

Persistent clock support: do proper timekeeping across suspend/resume, i386
arch support.

[ cleanup from Adrian Bunk <bunk@stusta.de> ]

Build-fixes-from: Andrew Morton <akpm@osdl.org>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

arch/i386/kernel/apm.c | 44 ---------------------------------------
arch/i386/kernel/time.c | 54 ------------------------------------------------
2 files changed, 1 insertion(+), 97 deletions(-)

Index: linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/apm.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/arch/i386/kernel/apm.c
+++ linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/apm.c
@@ -236,7 +236,6 @@

#include "io_ports.h"

-extern unsigned long get_cmos_time(void);
extern void machine_real_restart(unsigned char *, int);

#if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
@@ -1176,28 +1175,6 @@ out:
spin_unlock(&user_list_lock);
}

-static void set_time(void)
-{
- struct timespec ts;
- if (got_clock_diff) { /* Must know time zone in order to set clock */
- ts.tv_sec = get_cmos_time() + clock_cmos_diff;
- ts.tv_nsec = 0;
- do_settimeofday(&ts);
- }
-}
-
-static void get_time_diff(void)
-{
-#ifndef CONFIG_APM_RTC_IS_GMT
- /*
- * Estimate time zone so that set_time can update the clock
- */
- clock_cmos_diff = -get_cmos_time();
- clock_cmos_diff += get_seconds();
- got_clock_diff = 1;
-#endif
-}
-
static void reinit_timer(void)
{
#ifdef INIT_TIMER_AFTER_SUSPEND
@@ -1237,19 +1214,6 @@ static int suspend(int vetoable)
local_irq_disable();
device_power_down(PMSG_SUSPEND);

- /* serialize with the timer interrupt */
- write_seqlock(&xtime_lock);
-
- /* protect against access to timer chip registers */
- spin_lock(&i8253_lock);
-
- get_time_diff();
- /*
- * Irq spinlock must be dropped around set_system_power_state.
- * We'll undo any timer changes due to interrupts below.
- */
- spin_unlock(&i8253_lock);
- write_sequnlock(&xtime_lock);
local_irq_enable();

save_processor_state();
@@ -1258,7 +1222,6 @@ static int suspend(int vetoable)
restore_processor_state();

local_irq_disable();
- set_time();
reinit_timer();

if (err == APM_NO_ERROR)
@@ -1288,11 +1251,6 @@ static void standby(void)

local_irq_disable();
device_power_down(PMSG_SUSPEND);
- /* serialize with the timer interrupt */
- write_seqlock(&xtime_lock);
- /* If needed, notify drivers here */
- get_time_diff();
- write_sequnlock(&xtime_lock);
local_irq_enable();

err = set_system_power_state(APM_STATE_STANDBY);
@@ -1386,7 +1344,6 @@ static void check_events(void)
ignore_bounce = 1;
if ((event != APM_NORMAL_RESUME)
|| (ignore_normal_resume == 0)) {
- set_time();
device_resume();
pm_send_all(PM_RESUME, (void *)0);
queue_event(event, NULL);
@@ -1402,7 +1359,6 @@ static void check_events(void)
break;

case APM_UPDATE_TIME:
- set_time();
break;

case APM_CRITICAL_SUSPEND:
Index: linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/time.c
===================================================================
--- linux-2.6.20-rc4-mm1-bo.orig/arch/i386/kernel/time.c
+++ linux-2.6.20-rc4-mm1-bo/arch/i386/kernel/time.c
@@ -214,7 +214,7 @@ irqreturn_t timer_interrupt(int irq, voi
}

/* not static: needed by APM */
-unsigned long get_cmos_time(void)
+unsigned long read_persistent_clock(void)
{
unsigned long retval;
unsigned long flags;
@@ -227,7 +227,6 @@ unsigned long get_cmos_time(void)

return retval;
}
-EXPORT_SYMBOL(get_cmos_time);

static void sync_cmos_clock(unsigned long dummy);

@@ -280,58 +279,19 @@ void notify_arch_cmos_timer(void)
mod_timer(&sync_cmos_timer, jiffies + 1);
}

-static long clock_cmos_diff;
-static unsigned long sleep_start;
-
-static int timer_suspend(struct sys_device *dev, pm_message_t state)
-{
- /*
- * Estimate time zone so that set_time can update the clock
- */
- unsigned long ctime = get_cmos_time();
-
- clock_cmos_diff = -ctime;
- clock_cmos_diff += get_seconds();
- sleep_start = ctime;
- return 0;
-}
-
static int timer_resume(struct sys_device *dev)
{
- unsigned long flags;
- unsigned long sec;
- unsigned long ctime = get_cmos_time();
- long sleep_length = (ctime - sleep_start) * HZ;
- struct timespec ts;
-
- if (sleep_length < 0) {
- printk(KERN_WARNING "CMOS clock skew detected in timer resume!\n");
- /* The time after the resume must not be earlier than the time
- * before the suspend or some nasty things will happen
- */
- sleep_length = 0;
- ctime = sleep_start;
- }
#ifdef CONFIG_HPET_TIMER
if (is_hpet_enabled())
hpet_reenable();
#endif
setup_pit_timer();
-
- sec = ctime + clock_cmos_diff;
- ts.tv_sec = sec;
- ts.tv_nsec = 0;
- do_settimeofday(&ts);
- write_seqlock_irqsave(&xtime_lock, flags);
- jiffies_64 += sleep_length;
- write_sequnlock_irqrestore(&xtime_lock, flags);
touch_softlockup_watchdog();
return 0;
}

static struct sysdev_class timer_sysclass = {
.resume = timer_resume,
- .suspend = timer_suspend,
set_kset_name("timer"),
};

@@ -357,12 +317,6 @@ extern void (*late_time_init)(void);
/* Duplicate of time_init() below, with hpet_enable part added */
static void __init hpet_time_init(void)
{
- struct timespec ts;
- ts.tv_sec = get_cmos_time();
- ts.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
-
- do_settimeofday(&ts);
-
if ((hpet_enable() >= 0) && hpet_use_timer) {
printk("Using HPET for base-timer\n");
}
@@ -373,7 +327,6 @@ static void __init hpet_time_init(void)

void __init time_init(void)
{
- struct timespec ts;
#ifdef CONFIG_HPET_TIMER
if (is_hpet_capable()) {
/*
@@ -384,10 +337,5 @@ void __init time_init(void)
return;
}
#endif
- ts.tv_sec = get_cmos_time();
- ts.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
-
- do_settimeofday(&ts);
-
do_time_init();
}

--