linux-stable.git/drivers/rtc/rtc-opal.c, branch v4.4.121 Linux kernel stable tree rtc-opal: Fix handling of firmware error codes, prevent busy loops 2018-02-22T14:44:59+00:00 Stewart Smith stewart@linux.vnet.ibm.com 2016-08-02T01:50:16+00:00 99863c1bfdbf08d9a9001ac2c7c4d4e66fcdab6d commit 5b8b58063029f02da573120ef4dc9079822e3cda upstream. According to the OPAL docs: skiboot-5.2.5/doc/opal-api/opal-rtc-read-3.txt skiboot-5.2.5/doc/opal-api/opal-rtc-write-4.txt OPAL_HARDWARE may be returned from OPAL_RTC_READ or OPAL_RTC_WRITE and this indicates either a transient or permanent error. Prior to this patch, Linux was not dealing with OPAL_HARDWARE being a permanent error particularly well, in that you could end up in a busy loop. This was not too hard to trigger on an AMI BMC based OpenPOWER machine doing a continuous "ipmitool mc reset cold" to the BMC, the result of that being that we'd get stuck in an infinite loop in opal_get_rtc_time(). We now retry a few times before returning the error higher up the stack. Fixes: 16b1d26e77b1 ("rtc/tpo: Driver to support rtc and wakeup on PowerNV platform") Cc: stable@vger.kernel.org # v3.19+ Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5b8b58063029f02da573120ef4dc9079822e3cda upstream.

According to the OPAL docs:
  skiboot-5.2.5/doc/opal-api/opal-rtc-read-3.txt
  skiboot-5.2.5/doc/opal-api/opal-rtc-write-4.txt

OPAL_HARDWARE may be returned from OPAL_RTC_READ or OPAL_RTC_WRITE and
this indicates either a transient or permanent error.

Prior to this patch, Linux was not dealing with OPAL_HARDWARE being a
permanent error particularly well, in that you could end up in a busy
loop.

This was not too hard to trigger on an AMI BMC based OpenPOWER machine
doing a continuous "ipmitool mc reset cold" to the BMC, the result of
that being that we'd get stuck in an infinite loop in
opal_get_rtc_time().

We now retry a few times before returning the error higher up the
stack.

Fixes: 16b1d26e77b1 ("rtc/tpo: Driver to support rtc and wakeup on PowerNV platform")
Cc: stable@vger.kernel.org # v3.19+
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtc: opal: enable support for the stardard "wakeup-source" property 2015-11-08T13:12:30+00:00 Sudeep Holla Sudeep.Holla@arm.com 2015-10-21T10:10:00+00:00 347e40f0302c7e817e64256284b9e69a8b2711d2 Though the opal rtc driver should and will continue to support the legacy "has-tpo" property to enable RTC as the wakeup source, we need to add support for the new standard property "wakeup-source" This patch adds support for "wakeup-source" property in addition to the existing "has-tpo" property. Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com> Cc: rtc-linux@googlegroups.com Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> 
Though the opal rtc driver should and will continue to support the legacy
"has-tpo" property to enable RTC as the wakeup source, we need to add
support for the new standard property "wakeup-source"

This patch adds support for "wakeup-source" property in addition to the
existing "has-tpo" property.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
rtc: opal: fix type of token 2015-11-08T13:12:24+00:00 Andrzej Hajda a.hajda@samsung.com 2015-09-21T13:33:56+00:00 c35300941656508d37315625d276c5a104823505 The variable can take signed values. The problem has been detected using proposed semantic patch scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1]. [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576 Signed-off-by: Andrzej Hajda <a.hajda@samsung.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> 
The variable can take signed values.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2038576

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
rtc: opal: Enable alarms only when opal supports tpo 2015-09-05T11:19:06+00:00 Vaibhav Jain vaibhav@linux.vnet.ibm.com 2015-07-14T07:58:28+00:00 f4a2eecb3ff9f51b179b213e7cc3766f920f2dc5 rtc-opal driver provides support for rtc alarms via timed-power-on(tpo). However some Power platforms like BML use a fake rtc clock and don't support tpo. Such platforms are indicated by the missing 'has-tpo' property in the device tree. Current implementation however enables callback for rtc_class_ops.read/set alarm irrespective of the tpo support from the platform. This results in a failed opal call when kernel tries to read an existing alarms via opal_get_tpo_time during rtc device registration. This patch fixes this issue by setting opal_rtc_ops.read/set_alarm callback pointers only when tpo is supported. Acked-by: Michael Neuling <mikey@neuling.org> Acked-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com> Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> 
rtc-opal driver provides support for rtc alarms via
timed-power-on(tpo). However some Power platforms like BML use a fake
rtc clock and don't support tpo. Such platforms are indicated by the
missing 'has-tpo' property in the device tree.

Current implementation however enables callback for
rtc_class_ops.read/set alarm irrespective of the tpo support from the
platform. This results in a failed opal call when kernel tries to read
an existing alarms via opal_get_tpo_time during rtc device registration.

This patch fixes this issue by setting opal_rtc_ops.read/set_alarm
callback pointers only when tpo is supported.

Acked-by: Michael Neuling <mikey@neuling.org>
Acked-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
rtc: Drop owner assignment from platform_driver 2015-09-05T11:19:06+00:00 Krzysztof Kozlowski k.kozlowski@samsung.com 2015-07-10T06:39:51+00:00 045c6fdd37a01d950c0f5ca64733b53b184fe91b platform_driver does not need to set an owner because platform_driver_register() will set it. Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> 
platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
rtc: use more standard kernel logging styles 2015-04-17T13:04:02+00:00 Joe Perches joe@perches.com 2015-04-16T19:46:14+00:00 a737e835e5769ef22897179ed7f82b1fc50bfa58 Neaten the logging a bit by adding #define pr_fmt Miscellanea: o Remove __FILE__/__func__ uses o Coalesce formats adding missing spaces o Align arguments o (rtc-cmos) Integrated 2 consecutive messages Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Joshua Kinard <kumba@gentoo.org> Cc: Chanwoo Choi <cw00.choi@samsung.com> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Cc: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Neaten the logging a bit by adding #define pr_fmt

Miscellanea:

o Remove __FILE__/__func__ uses
o Coalesce formats adding missing spaces
o Align arguments
o (rtc-cmos) Integrated 2 consecutive messages

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
rtc/tpo: Driver to support rtc and wakeup on PowerNV platform 2014-11-17T07:04:01+00:00 Neelesh Gupta neelegup@linux.vnet.ibm.com 2014-10-14T08:38:36+00:00 16b1d26e77b142546e2b9b6dc3b5aa5c44ae3b77 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> 
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>