[PATCH 1/5] Implement {read,update}_persistent_clock.
Tony Breeds
tony at bakeyournoodle.com
Wed Sep 19 16:49:46 EST 2007
With these functions implemented we cooperate better with the generic
timekeeping code. This obsoletes the need for the timer sysdev as a bonus.
Signed-off-by: Tony Breeds <tony at bakeyournoodle.com>
---
* Compile tested for arch/powerpc/configs/*_defconfig
* Booted on pSeries, iSeries, Cell and PS3
arch/powerpc/Kconfig | 3 +
arch/powerpc/kernel/time.c | 85 ++++++++++-------------------------
arch/powerpc/sysdev/Makefile | 5 --
arch/powerpc/sysdev/timer.c | 81 ---------------------------------
4 files changed, 29 insertions(+), 145 deletions(-)
Index: working/arch/powerpc/Kconfig
===================================================================
--- working.orig/arch/powerpc/Kconfig
+++ working/arch/powerpc/Kconfig
@@ -21,6 +21,9 @@ config MMU
bool
default y
+config GENERIC_CMOS_UPDATE
+ def_bool y
+
config GENERIC_HARDIRQS
bool
default y
Index: working/arch/powerpc/kernel/time.c
===================================================================
--- working.orig/arch/powerpc/kernel/time.c
+++ working/arch/powerpc/kernel/time.c
@@ -74,16 +74,11 @@
#endif
#include <asm/smp.h>
-/* keep track of when we need to update the rtc */
-time_t last_rtc_update;
#ifdef CONFIG_PPC_ISERIES
static unsigned long __initdata iSeries_recal_titan;
static signed long __initdata iSeries_recal_tb;
#endif
-/* The decrementer counts down by 128 every 128ns on a 601. */
-#define DECREMENTER_COUNT_601 (1000000000 / HZ)
-
#define XSEC_PER_SEC (1024*1024)
#ifdef CONFIG_PPC64
@@ -349,39 +344,6 @@ void udelay(unsigned long usecs)
}
EXPORT_SYMBOL(udelay);
-static __inline__ void timer_check_rtc(void)
-{
- /*
- * update the rtc when needed, this should be performed on the
- * right fraction of a second. Half or full second ?
- * Full second works on mk48t59 clocks, others need testing.
- * Note that this update is basically only used through
- * the adjtimex system calls. Setting the HW clock in
- * any other way is a /dev/rtc and userland business.
- * This is still wrong by -0.5/+1.5 jiffies because of the
- * timer interrupt resolution and possible delay, but here we
- * hit a quantization limit which can only be solved by higher
- * resolution timers and decoupling time management from timer
- * interrupts. This is also wrong on the clocks
- * which require being written at the half second boundary.
- * We should have an rtc call that only sets the minutes and
- * seconds like on Intel to avoid problems with non UTC clocks.
- */
- if (ppc_md.set_rtc_time && ntp_synced() &&
- xtime.tv_sec - last_rtc_update >= 659 &&
- abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) {
- struct rtc_time tm;
- to_tm(xtime.tv_sec + 1 + timezone_offset, &tm);
- tm.tm_year -= 1900;
- tm.tm_mon -= 1;
- if (ppc_md.set_rtc_time(&tm) == 0)
- last_rtc_update = xtime.tv_sec + 1;
- else
- /* Try again one minute later */
- last_rtc_update += 60;
- }
-}
-
/*
* This version of gettimeofday has microsecond resolution.
*/
@@ -690,7 +652,6 @@ void timer_interrupt(struct pt_regs * re
tb_last_jiffy = tb_next_jiffy;
do_timer(1);
timer_recalc_offset(tb_last_jiffy);
- timer_check_rtc();
}
write_sequnlock(&xtime_lock);
}
@@ -802,11 +763,6 @@ int do_settimeofday(struct timespec *tv)
set_normalized_timespec(&xtime, new_sec, new_nsec);
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
- /* In case of a large backwards jump in time with NTP, we want the
- * clock to be updated as soon as the PLL is again in lock.
- */
- last_rtc_update = new_sec - 658;
-
ntp_clear();
new_xsec = xtime.tv_nsec;
@@ -882,12 +838,35 @@ void __init generic_calibrate_decr(void)
#endif
}
-unsigned long get_boot_time(void)
+int update_persistent_clock(struct timespec now)
{
struct rtc_time tm;
- if (ppc_md.get_boot_time)
- return ppc_md.get_boot_time();
+ if (!ppc_md.set_rtc_time)
+ return 0;
+
+ to_tm(now.tv_sec + 1 + timezone_offset, &tm);
+ tm.tm_year -= 1900;
+ tm.tm_mon -= 1;
+
+ return ppc_md.set_rtc_time(&tm);
+}
+
+unsigned long read_persistent_clock(void)
+{
+ struct rtc_time tm;
+ static int first = 1;
+
+ /* XXX this is a litle fragile but will work okay in the short term */
+ if (first) {
+ first = 0;
+ if (ppc_md.time_init)
+ timezone_offset = ppc_md.time_init();
+
+ /* get_boot_time() isn't guaranteed to be safe to call late */
+ if (ppc_md.get_boot_time)
+ return ppc_md.get_boot_time() -timezone_offset;
+ }
if (!ppc_md.get_rtc_time)
return 0;
ppc_md.get_rtc_time(&tm);
@@ -899,14 +878,10 @@ unsigned long get_boot_time(void)
void __init time_init(void)
{
unsigned long flags;
- unsigned long tm = 0;
struct div_result res;
u64 scale, x;
unsigned shift;
- if (ppc_md.time_init != NULL)
- timezone_offset = ppc_md.time_init();
-
if (__USE_RTC()) {
/* 601 processor: dec counts down by 128 every 128ns */
ppc_tb_freq = 1000000000;
@@ -981,19 +956,14 @@ void __init time_init(void)
/* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
boot_tb = get_tb_or_rtc();
- tm = get_boot_time();
-
write_seqlock_irqsave(&xtime_lock, flags);
/* If platform provided a timezone (pmac), we correct the time */
if (timezone_offset) {
sys_tz.tz_minuteswest = -timezone_offset / 60;
sys_tz.tz_dsttime = 0;
- tm -= timezone_offset;
}
- xtime.tv_sec = tm;
- xtime.tv_nsec = 0;
do_gtod.varp = &do_gtod.vars[0];
do_gtod.var_idx = 0;
do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
@@ -1011,9 +981,6 @@ void __init time_init(void)
time_freq = 0;
- last_rtc_update = xtime.tv_sec;
- set_normalized_timespec(&wall_to_monotonic,
- -xtime.tv_sec, -xtime.tv_nsec);
write_sequnlock_irqrestore(&xtime_lock, flags);
/* Not exact, but the timer interrupt takes care of this */
Index: working/arch/powerpc/sysdev/Makefile
===================================================================
--- working.orig/arch/powerpc/sysdev/Makefile
+++ working/arch/powerpc/sysdev/Makefile
@@ -20,11 +20,6 @@ obj-$(CONFIG_MV64X60) += $(mv64x60-y) m
obj-$(CONFIG_RTC_DRV_CMOS) += rtc_cmos_setup.o
obj-$(CONFIG_AXON_RAM) += axonram.o
-# contains only the suspend handler for time
-ifeq ($(CONFIG_RTC_CLASS),)
-obj-$(CONFIG_PM) += timer.o
-endif
-
ifeq ($(CONFIG_PPC_MERGE),y)
obj-$(CONFIG_PPC_INDIRECT_PCI) += indirect_pci.o
obj-$(CONFIG_PPC_I8259) += i8259.o
Index: working/arch/powerpc/sysdev/timer.c
===================================================================
--- working.orig/arch/powerpc/sysdev/timer.c
+++ /dev/null
@@ -1,81 +0,0 @@
-/*
- * Common code to keep time when machine suspends.
- *
- * Copyright 2007 Johannes Berg <johannes at sipsolutions.net>
- *
- * GPLv2
- */
-
-#include <linux/time.h>
-#include <linux/sysdev.h>
-#include <asm/rtc.h>
-
-static unsigned long suspend_rtc_time;
-
-/*
- * Reset the time after a sleep.
- */
-static int timer_resume(struct sys_device *dev)
-{
- struct timeval tv;
- struct timespec ts;
- struct rtc_time cur_rtc_tm;
- unsigned long cur_rtc_time, diff;
-
- /* get current RTC time and convert to seconds */
- get_rtc_time(&cur_rtc_tm);
- cur_rtc_time = mktime(cur_rtc_tm.tm_year + 1900,
- cur_rtc_tm.tm_mon + 1,
- cur_rtc_tm.tm_mday,
- cur_rtc_tm.tm_hour,
- cur_rtc_tm.tm_min,
- cur_rtc_tm.tm_sec);
-
- diff = cur_rtc_time - suspend_rtc_time;
-
- /* adjust time of day by seconds that elapsed while
- * we were suspended */
- do_gettimeofday(&tv);
- ts.tv_sec = tv.tv_sec + diff;
- ts.tv_nsec = tv.tv_usec * NSEC_PER_USEC;
- do_settimeofday(&ts);
-
- return 0;
-}
-
-static int timer_suspend(struct sys_device *dev, pm_message_t state)
-{
- struct rtc_time suspend_rtc_tm;
- WARN_ON(!ppc_md.get_rtc_time);
-
- get_rtc_time(&suspend_rtc_tm);
- suspend_rtc_time = mktime(suspend_rtc_tm.tm_year + 1900,
- suspend_rtc_tm.tm_mon + 1,
- suspend_rtc_tm.tm_mday,
- suspend_rtc_tm.tm_hour,
- suspend_rtc_tm.tm_min,
- suspend_rtc_tm.tm_sec);
-
- return 0;
-}
-
-static struct sysdev_class timer_sysclass = {
- .resume = timer_resume,
- .suspend = timer_suspend,
- set_kset_name("timer"),
-};
-
-static struct sys_device device_timer = {
- .id = 0,
- .cls = &timer_sysclass,
-};
-
-static int time_init_device(void)
-{
- int error = sysdev_class_register(&timer_sysclass);
- if (!error)
- error = sysdev_register(&device_timer);
- return error;
-}
-
-device_initcall(time_init_device);
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