Re: [PATCH v2 1/4] Implement {read,update}_persistent_clock.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello.

Tony Breeds wrote:

With these functions implemented we cooperate better with the generic
timekeeping code.  This obsoletes the need for the timer sysdev as a bonus.

Aha, I'm seeing it's not merged to mainline yet! And this can't be merged to -rt patch either, beucase -rt alsready has read_persistent_clock() implemented since around 2.6.18-rt...

Signed-off-by: Tony Breeds <tony@xxxxxxxxxxxxxxxxxx>

---

Patch set updated to powerpc/for-2.6.24

* 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
@@ -881,12 +837,35 @@ 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;
+	}

   This looks incomplete.

@@ -898,14 +877,10 @@ 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;
@@ -980,19 +955,14 @@ 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);

Is there any sense of grabbing xtime_lock in time_init() when you've implemented read_persistent_clock()?

/* 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;

Huh? The 'xtime' should now be set by the *generic* timekeeping code using read_persistent_clock() -- or else what's the point to implement the function? :-/

@@ -1010,9 +980,6 @@ 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);

   That 'xtime_lock' grabbing should be gone with this patch, and is not. NAK.

WBR, Sergei
-
To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [RT Stable]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]

  Powered by Linux