From 6dc1cf6f932bb0ea4d8f5e913a0a401ecacd2f03 Mon Sep 17 00:00:00 2001
From: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Date: Fri, 19 May 2017 15:35:09 +0530
Subject: [PATCH] rtc: opal: Handle disabled TPO in opal_get_tpo_time()
References: bsc#1055122
Patch-mainline: v4.13-rc1
Git-commit: 6dc1cf6f932bb0ea4d8f5e913a0a401ecacd2f03
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 <vaibhav@linux.vnet.ibm.com>
Reported-by: Steve Best <sbest@redhat.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
drivers/rtc/rtc-opal.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/rtc/rtc-opal.c b/drivers/rtc/rtc-opal.c
index ea20f627dabe..2d84e2a28772 100644
--- a/drivers/rtc/rtc-opal.c
+++ b/drivers/rtc/rtc-opal.c
@@ -142,6 +142,16 @@ static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
y_m_d = be32_to_cpu(__y_m_d);
h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32);
+
+ /* check if no alarm is set */
+ if (y_m_d == 0 && h_m_s_ms == 0) {
+ pr_debug("No alarm is set\n");
+ rc = -ENOENT;
+ goto exit;
+ } else {
+ pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
+ }
+
opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
exit:
--
2.10.2