The OPAL RTC driver does not sleep in case it gets OPAL_BUSY or
OPAL_BUSY_EVENT from firmware, which causes large scheduling
latencies, up to 50 seconds have been observed here when RTC stops
responding (BMC reboot can do it).
Fix this by converting it to the standard form OPAL_BUSY loop that
sleeps.
Fixes: 628daa8d5a ("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks")
Cc: stable@vger.kernel.org # v3.2+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Only delay opal_rtc_read() when busy and are going to retry.
This has the advantage of possibly saving a massive 10ms off booting!
Kudos to Stewart for noticing.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
GregorianDay() is supposed to calculate the day of the week
(tm->tm_wday) for a given day/month/year. In that calcuation it
indexed into an array called MonthOffset using tm->tm_mon-1. However
tm_mon is zero-based, not one-based, so this is off-by-one. It also
means that every January, GregoiranDay() will access element -1 of
the MonthOffset array.
It also doesn't appear to be a correct algorithm either: see in
contrast kernel/time/timeconv.c's time_to_tm function.
It's been broken forever, which suggests no-one in userland uses
this. It looks like no-one in the kernel uses tm->tm_wday either
(see e.g. drivers/rtc/rtc-ds1305.c:319).
tm->tm_wday is conventionally set to -1 when not available in
hardware so we can simply set it to -1 and drop the function.
(There are over a dozen other drivers in drivers/rtc that do
this.)
Found using UBSAN.
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrew Morton <akpm@linux-foundation.org> # as an example of what UBSan finds.
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The patch implements the OPAL rtc driver that binds with the rtc
driver subsystem. The driver uses the platform device infrastructure
to probe the rtc device and register it to rtc class framework. The
'wakeup' is supported depending upon the property 'has-tpo' present
in the OF node. It provides a way to load the generic rtc driver in
in the absence of an OPAL driver.
The patch also moves the existing OPAL rtc get/set time interfaces to the
new driver and exposes the necessary OPAL calls using EXPORT_SYMBOL_GPL.
Test results:
-------------
Host:
[root@tul169p1 ~]# ls -l /sys/class/rtc/
total 0
lrwxrwxrwx 1 root root 0 Oct 14 03:07 rtc0 -> ../../devices/opal-rtc/rtc/rtc0
[root@tul169p1 ~]# cat /sys/devices/opal-rtc/rtc/rtc0/time
08:10:07
[root@tul169p1 ~]# echo `date '+%s' -d '+ 2 minutes'` > /sys/class/rtc/rtc0/wakealarm
[root@tul169p1 ~]# cat /sys/class/rtc/rtc0/wakealarm
1413274345
[root@tul169p1 ~]#
FSP:
$ smgr mfgState
standby
$ rtim timeofday
System time is valid: 2014/10/14 08:12:04.225115
$ smgr mfgState
ipling
$
CC: devicetree@vger.kernel.org
CC: tglx@linutronix.de
CC: rtc-linux@googlegroups.com
CC: a.zummo@towertech.it
Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Check that the OPAL_RTC_READ token exists before we use the OPAL RTC.
Refactors the code a little to merge error paths.
This avoids littering the OPAL console with:
"OPAL: Called with bad token 3".
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently we continue to poll get/set_rtc_time even when we know they
are not working.
This changes it so that if it fails at boot time we remove the ppc_md
get/set_rtc_time hooks so that we don't end up polling known broken
calls.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Sparse caught an issue where opal_set_rtc_time was incorrectly
byteswapping. Also fix a number of sparse warnings.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Implements OPAL RTC and NVRAM support and wire all that up to
the powernv platform.
We use RTAS for RTC as a fallback if available. Using RTAS for nvram
is not supported yet, pending some rework/cleanup and generalization
of the pSeries & CHRP code. We also use RTAS fallbacks for power off
and reboot
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
