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>

5 files changed, 130 insertions, 58 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;
+}
diff --git a/hw/fsp/fsp-rtc.c b/hw/fsp/fsp-rtc.c
index bafcc33..eff2c84 100644
--- a/hw/fsp/fsp-rtc.c
+++ b/hw/fsp/fsp-rtc.c
@@ -52,12 +52,16 @@
  * of the two has a pending event to signal.
  */
 
+#include <rtc.h>
+
 enum {
 	RTC_TOD_VALID,
 	RTC_TOD_INVALID,
 	RTC_TOD_PERMANENT_ERROR,
 } rtc_tod_state = RTC_TOD_INVALID;
 
+bool rtc_tod_cache_dirty = false;
+
 static struct lock rtc_lock;
 static struct fsp_msg *rtc_read_msg;
 static struct fsp_msg *rtc_write_msg;
@@ -67,13 +71,6 @@ static struct fsp_msg *rtc_write_msg;
  */
 static bool fsp_in_reset = false;
 
-/* last synchonisation point */
-static struct {
-	struct tm	tm;
-	unsigned long	tb;
-	bool		dirty;
-} rtc_tod_cache;
-
 struct opal_tpo_data {
 	uint64_t tpo_async_token;
 	uint32_t *year_month_day;
@@ -95,16 +92,6 @@ DEFINE_LOG_ENTRY(OPAL_RC_RTC_READ, OPAL_PLATFORM_ERR_EVT, OPAL_RTC,
 			OPAL_PLATFORM_FIRMWARE, OPAL_INFO,
 			OPAL_NA, NULL);
 
-static void tm_add(struct tm *in, struct tm *out, unsigned long secs)
-{
-	assert(in);
-	assert(out);
-
-	*out = *in;
-	out->tm_sec += secs;
-	mktime(out);
-}
-
 static void fsp_tpo_req_complete(struct fsp_msg *read_resp)
 {
 	 struct opal_tpo_data *attr = read_resp->user_data;
@@ -154,6 +141,7 @@ static void fsp_tpo_req_complete(struct fsp_msg *read_resp)
 static void fsp_rtc_process_read(struct fsp_msg *read_resp)
 {
 	int val = (read_resp->word1 >> 8) & 0xff;
+	struct tm tm;
 
 	switch (val) {
 	case FSP_STATUS_TOD_RESET:
@@ -171,9 +159,8 @@ static void fsp_rtc_process_read(struct fsp_msg *read_resp)
 	case FSP_STATUS_SUCCESS:
 		/* Save the read RTC value in our cache */
 		datetime_to_tm(read_resp->data.words[0],
-			       (u64) read_resp->data.words[1] << 32, &rtc_tod_cache.tm);
-		rtc_tod_cache.tb = mftb();
-		rtc_tod_state = RTC_TOD_VALID;
+			       (u64) read_resp->data.words[1] << 32, &tm);
+		rtc_cache_update(&tm);
 		break;
 
 	default:
@@ -230,32 +217,6 @@ static int64_t fsp_rtc_send_read_request(void)
 	return OPAL_BUSY_EVENT;
 }
 
-static void encode_cached_tod(uint32_t *year_month_day,
-		uint64_t *hour_minute_second_millisecond)
-{
-	unsigned long cache_age_sec;
-	struct tm tm;
-
-	cache_age_sec = tb_to_msecs(mftb() - rtc_tod_cache.tb) / 1000;
-
-	tm_add(&rtc_tod_cache.tm, &tm, cache_age_sec);
-
-	/* Format to OPAL API values */
-	tm_to_datetime(&tm, year_month_day, hour_minute_second_millisecond);
-}
-
-int fsp_rtc_get_cached_tod(uint32_t *year_month_day,
-		uint64_t *hour_minute_second_millisecond)
-{
-
-	if (rtc_tod_state != RTC_TOD_VALID)
-		return -1;
-
-	encode_cached_tod(year_month_day,
-			hour_minute_second_millisecond);
-	return 0;
-}
-
 static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
 				 uint64_t *hour_minute_second_millisecond)
 {
@@ -268,7 +229,7 @@ static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
 	lock(&rtc_lock);
 	/* During R/R of FSP, read cached TOD */
 	if (fsp_in_reset) {
-		fsp_rtc_get_cached_tod(year_month_day,
+		rtc_cache_get_datetime(year_month_day,
 				hour_minute_second_millisecond);
 		rc = OPAL_SUCCESS;
 		goto out;
@@ -299,7 +260,7 @@ static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
 		fsp_freemsg(msg);
 
 		if (rtc_tod_state == RTC_TOD_VALID) {
-			encode_cached_tod(year_month_day,
+			rtc_cache_get_datetime(year_month_day,
 					hour_minute_second_millisecond);
 			rc = OPAL_SUCCESS;
 		} else
@@ -310,7 +271,7 @@ static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
 	} else if (mftb() > read_req_tb + msecs_to_tb(rtc_read_timeout_ms)) {
 		prlog(PR_TRACE, "RTC read timed out\n");
 
-		encode_cached_tod(year_month_day,
+		rtc_cache_get_datetime(year_month_day,
 				hour_minute_second_millisecond);
 		rc = OPAL_SUCCESS;
 
@@ -329,6 +290,7 @@ static int64_t fsp_opal_rtc_write(uint32_t year_month_day,
 	struct fsp_msg *msg;
 	uint32_t w0, w1, w2;
 	int64_t rc;
+	struct tm tm;
 
 	lock(&rtc_lock);
 	if (rtc_tod_state == RTC_TOD_PERMANENT_ERROR) {
@@ -386,9 +348,9 @@ static int64_t fsp_opal_rtc_write(uint32_t year_month_day,
 
 	if (fsp_in_reset) {
 		datetime_to_tm(rtc_write_msg->data.words[0],
-			       (u64) rtc_write_msg->data.words[1] << 32,  &rtc_tod_cache.tm);
-		rtc_tod_cache.tb = mftb();
-		rtc_tod_cache.dirty = true;
+			       (u64) rtc_write_msg->data.words[1] << 32,  &tm);
+		rtc_cache_update(&tm);
+		rtc_tod_cache_dirty = true;
 		fsp_freemsg(rtc_write_msg);
 		rtc_write_msg = NULL;
 		rc = OPAL_SUCCESS;
@@ -491,7 +453,7 @@ static void rtc_flush_cached_tod(void)
 	uint64_t h_m_s_m;
 	uint32_t y_m_d;
 
-	if (fsp_rtc_get_cached_tod(&y_m_d, &h_m_s_m))
+	if (rtc_cache_get_datetime(&y_m_d, &h_m_s_m))
 		return;
 	msg = fsp_mkmsg(FSP_CMD_WRITE_TOD, 3, y_m_d,
 			(h_m_s_m >> 32) & 0xffffff00, 0);
@@ -515,9 +477,9 @@ static bool fsp_rtc_msg_rr(u32 cmd_sub_mod, struct fsp_msg *msg)
 	case FSP_RELOAD_COMPLETE:
 		lock(&rtc_lock);
 		fsp_in_reset = false;
-		if (rtc_tod_cache.dirty) {
+		if (rtc_tod_cache_dirty) {
 			rtc_flush_cached_tod();
-			rtc_tod_cache.dirty = false;
+			rtc_tod_cache_dirty = false;
 		}
 		unlock(&rtc_lock);
 		rc = true;
diff --git a/include/rtc.h b/include/rtc.h
new file mode 100644
index 0000000..a993fd4
--- /dev/null
+++ b/include/rtc.h
@@ -0,0 +1,40 @@
+/* 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.
+ */
+
+#ifndef __RTC_H
+#define __RTC_H
+
+#include <time-utils.h>
+
+/*
+ * Update the cache to the current time as specified by tm.
+ */
+void rtc_cache_update(struct tm *tm);
+
+/*
+ * Get the current time based on the cache. If the cache is valid the result
+ * is returned in tm and the function returns 0. Otherwise returns -1.
+ */
+int rtc_cache_get(struct tm *tm);
+
+/*
+ * Same as the previous function except the result is returned as an OPAL
+ * datetime.
+ */
+int rtc_cache_get_datetime(uint32_t *year_month_day,
+			   uint64_t *hour_minute_second_millisecond);
+
+#endif