[RFC/PATCH] Implement {read,update}_persistent_clock.
Tony Breeds
tony at bakeyournoodle.com
Tue Sep 11 17:49:17 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
* Really needs booting on powermac and a quad G5 (hint hint)
* Should remove arch/powerpc/sysdev/timer.c at the same time.
arch/powerpc/Kconfig | 3 +
arch/powerpc/kernel/time.c | 58 ++++++++++-------------------------
arch/powerpc/sysdev/Makefile | 5 ---
3 files changed, 20 insertions(+), 46 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
@@ -349,38 +344,7 @@ 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.
@@ -688,7 +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);
}
@@ -800,11 +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;
@@ -880,12 +838,36 @@ 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;
+ unsigned long time = 0;
+
+ 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 (system_state != SYSTEM_RUNNING && 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);
@@ -897,14 +879,10 @@ 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;
@@ -979,19 +957,14 @@ void __init time_init(void)
/* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
boot_tb = get_tb();
- 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;
@@ -1009,9 +982,6 @@ 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
Yours Tony
linux.conf.au http://linux.conf.au/ || http://lca2008.linux.org.au/
Jan 28 - Feb 02 2008 The Australian Linux Technical Conference!
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