rtc: Add a generic rtc cache

Some of the generic skiboot code needs access to the rtc (for example
the pel logging code). Currently this is accessed via a call to fsp
specific code which implements an rtc cache. Obviously this wont work
on systems without a fsp.

This patch makes the rtc cache generic so that we can get the time on
other platforms (assuming they have some kind of rtc).

Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

3 files changed, 73 insertions, 3 deletions

diff --git a/core/Makefile.inc b/core/Makefile.inc
index 615b27b..8540695 100644
--- a/core/Makefile.inc
+++ b/core/Makefile.inc
@@ -7,7 +7,7 @@ CORE_OBJS += timebase.o opal-msg.o pci.o pci-opal.o fast-reboot.o
 CORE_OBJS += device.o exceptions.o trace.o affinity.o vpd.o
 CORE_OBJS += hostservices.o platform.o nvram.o flash-nvram.o hmi.o
 CORE_OBJS += console-log.o ipmi.o time-utils.o pel.o pool.o errorlog.o
-CORE_OBJS += timer.o i2c.o
+CORE_OBJS += timer.o i2c.o rtc.o
 CORE=core/built-in.o
 
 CFLAGS_SKIP_core/relocate.o = -pg -fstack-protector-all
diff --git a/core/pel.c b/core/pel.c
index 5cbb3f1..faa622b 100644
--- a/core/pel.c
+++ b/core/pel.c
@@ -3,6 +3,7 @@
 #include <device.h>
 #include <fsp.h>
 #include <pel.h>
+#include <rtc.h>
 
 /* Create MTMS section for sapphire log */
 static void create_mtms_section(struct errorlog *elog_data,
@@ -56,7 +57,7 @@ static void create_extended_header_section(struct errorlog *elog_data,
 	memset(extdhdr->opal_subsys_version, 0x00,
 				sizeof(extdhdr->opal_subsys_version));
 
-	fsp_rtc_get_cached_tod(&extdhdr->extended_header_date, &extd_time);
+	rtc_cache_get_datetime(&extdhdr->extended_header_date, &extd_time);
 	extdhdr->extended_header_time = extd_time >> 32;
 	extdhdr->opal_symid_len = 0;
 
@@ -159,7 +160,7 @@ static void create_private_header_section(struct errorlog *elog_data,
 	privhdr->v6header.component_id = elog_data->component_id;
 	privhdr->plid = elog_data->plid;
 
-	fsp_rtc_get_cached_tod(&privhdr->create_date, &ctime);
+	rtc_cache_get_datetime(&privhdr->create_date, &ctime);
 	privhdr->create_time = ctime >> 32;
 	privhdr->section_count = 5;
 
diff --git a/core/rtc.c b/core/rtc.c
new file mode 100644
index 0000000..60d2d85
--- /dev/null
+++ b/core/rtc.c
@@ -0,0 +1,69 @@
+/* Copyright 2013-2014 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * 	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <skiboot.h>
+#include <lock.h>
+#include <rtc.h>
+#include <timebase.h>
+
+static struct lock rtc_tod_lock = LOCK_UNLOCKED;
+
+static struct {
+	struct tm	tm;
+	unsigned long	tb;
+	bool		valid;
+} rtc_tod_cache;
+
+void rtc_cache_update(struct tm *tm)
+{
+	lock(&rtc_tod_lock);
+	rtc_tod_cache.tb = mftb();
+	rtc_tod_cache.tm = *tm;
+	rtc_tod_cache.valid = true;
+	unlock(&rtc_tod_lock);
+}
+
+int rtc_cache_get(struct tm *tm)
+{
+	unsigned long cache_age_sec;
+
+	lock(&rtc_tod_lock);
+	if (!rtc_tod_cache.valid)
+		return -1;
+
+	cache_age_sec = tb_to_msecs(mftb() - rtc_tod_cache.tb) / 1000;
+	*tm = rtc_tod_cache.tm;
+	unlock(&rtc_tod_lock);
+
+	tm->tm_sec += cache_age_sec;
+	mktime(tm);
+
+	return 0;
+}
+
+int rtc_cache_get_datetime(uint32_t *year_month_day,
+		uint64_t *hour_minute_second_millisecond)
+{
+	struct tm tm;
+
+	if (rtc_cache_get(&tm) < 0)
+		return -1;
+
+	tm_to_datetime(&tm, year_month_day, hour_minute_second_millisecond);
+
+	return 0;
+}