linux-toradex.git/drivers/rtc/rtc-opal.c, branch v4.16-rc6

rtc-opal: Fix handling of firmware error codes, prevent busy loops

2018-01-27T10:15:59+00:00

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 
Signed-off-by: Michael Ellerman

rtc: opal: Implement rtc_class_ops.alarm_irq_enable callback

2017-06-24T05:48:30+00:00

Provide an implementation of the callback
rtc_class_ops.alarm_irq_enable for rtc-opal driver. This callback is
called when the wake alarm is disabled via the command:

'echo 0 > /sys/class/rtc/rtc0/wakealarm'

Without this the Timed-Power-On(TPO) config remains set even when its
disabled by the above command and FSP will still force machine
boot at previously configured alarm time.

The callback is implemented as function opal_tpo_alarm_irq_enable()
which calls opal_set_tpo_time() with alarm.enabled == 0. A branch is
added to opal_set_tpo_time() to handle this case by passing y_m_d ==
h_m_s_ms == 0 to opal as arguments for opal_tpo_write() call.

Signed-off-by: Vaibhav Jain 
Signed-off-by: Alexandre Belloni

rtc: opal: Handle disabled TPO in opal_get_tpo_time()

2017-05-31T10:57:37+00:00

On PowerNV platform when Timed-Power-On(TPO) is disabled, read of
stored TPO yields value with all date components set to '0' inside
opal_get_tpo_time(). The function opal_to_tm() then converts it to an
offset from year 1900 yielding alarm-time == "1900-00-01
00:00:00". This causes problems with __rtc_read_alarm() that
expecting an offset from "1970-00-01 00:00:00" and returned alarm-time
results in a -ve value for time64_t. Which ultimately results in this
error reported in kernel logs with a seemingly garbage value:

"rtc rtc0: invalid alarm value: -2-1--1041528741
2005511117:71582844:32"

We fix this by explicitly handling the case of all alarm date-time
components being '0' inside opal_get_tpo_time() and returning -ENOENT
in such a case. This signals generic rtc that no alarm is set and it
bails out from the alarm initialization flow without reporting the
above error.

Signed-off-by: Vaibhav Jain 
Reported-by: Steve Best 
Signed-off-by: Alexandre Belloni

powerpc/opal: Add inline function to get rc from an ASYNC_COMP opal_msg

2016-06-29T07:33:18+00:00

An opal_msg of type OPAL_MSG_ASYNC_COMP contains the return code in the
params[1] struct member. However this isn't intuitive or obvious when
reading the code and requires that a user look at the skiboot
documentation or opal-api.h to verify this.

Add an inline function to get the return code from an opal_msg and update
call sites accordingly.

Signed-off-by: Suraj Jitindar Singh 
Signed-off-by: Michael Ellerman

powerpc: Remove broken GregorianDay()

2015-12-16T01:54:04+00:00

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 
Cc: Andrew Morton  # as an example of what UBSan finds.
Cc: Alessandro Zummo 
Cc: Alexandre Belloni 
Cc: rtc-linux@googlegroups.com
Signed-off-by: Daniel Axtens 
Acked-by: Alexandre Belloni 
Signed-off-by: Michael Ellerman

rtc: opal: enable support for the stardard "wakeup-source" property

2015-11-08T13:12:30+00:00

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 
Cc: Alexandre Belloni 
Cc: rtc-linux@googlegroups.com
Signed-off-by: Sudeep Holla 
Signed-off-by: Alexandre Belloni

rtc: opal: fix type of token

2015-11-08T13:12:24+00:00

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 
Signed-off-by: Alexandre Belloni

rtc: opal: Enable alarms only when opal supports tpo

2015-09-05T11:19:06+00:00

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 
Acked-by: Neelesh Gupta 
Signed-off-by: Vaibhav Jain 
Acked-by: Stewart Smith 
Signed-off-by: Alexandre Belloni

rtc: Drop owner assignment from platform_driver

2015-09-05T11:19:06+00:00

platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Alexandre Belloni

rtc: use more standard kernel logging styles

2015-04-17T13:04:02+00:00

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 
Acked-by: Alexandre Belloni 
Cc: Alessandro Zummo 
Cc: Joshua Kinard 
Cc: Chanwoo Choi 
Reviewed-by: Krzysztof Kozlowski 
Tested-by: Krzysztof Kozlowski 
Cc: Aaro Koskinen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds