Add fake RTC to generic platform

Adds a fake RTC that can be initialized via a named reserve in the
device tree that may, at some point, be on NVRAM.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 70 insertions, 1 deletions

diff --git a/hw/Makefile.inc b/hw/Makefile.inc
index 14bf8e78..f1ffe55c 100644
--- a/hw/Makefile.inc
+++ b/hw/Makefile.inc
@@ -4,7 +4,7 @@ SUBDIRS += hw
 HW_OBJS  = xscom.o chiptod.o gx.o cec.o lpc.o lpc-uart.o psi.o
 HW_OBJS += homer.o slw.o occ.o nx.o fsi-master.o centaur.o
 HW_OBJS += p7ioc.o p7ioc-inits.o p7ioc-phb.o p5ioc2.o p5ioc2-phb.o
-HW_OBJS += phb3.o sfc-ctrl.o
+HW_OBJS += phb3.o sfc-ctrl.o fake-rtc.o
 HW=hw/built-in.o
 
 include $(SRC)/hw/fsp/Makefile.inc
diff --git a/hw/fake-rtc.c b/hw/fake-rtc.c
new file mode 100644
index 00000000..2aadfa09
--- /dev/null
+++ b/hw/fake-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 <opal.h>
+#include <mem_region.h>
+
+//#define DBG(fmt...)	printf("FAKERTC: " fmt)
+#define DBG(fmt...)	do { } while(0)
+
+uint32_t *fake_ymd;
+uint64_t *fake_hmsm;
+
+static int64_t fake_rtc_write(uint32_t ymd, uint64_t hmsm)
+{
+	*fake_ymd = ymd;
+	*fake_hmsm = hmsm;
+
+	return OPAL_SUCCESS;
+}
+
+static int64_t fake_rtc_read(uint32_t *ymd, uint64_t *hmsm)
+{
+	if (!ymd || !hmsm)
+		return OPAL_PARAMETER;
+
+	*ymd = *fake_ymd;
+	*hmsm = *fake_hmsm;
+
+	return OPAL_SUCCESS;
+}
+
+void fake_rtc_init(void)
+{
+	struct mem_region *rtc_region = NULL;
+	uint32_t *rtc = NULL;
+
+	/* Read initial values from reserved memory */
+	rtc_region = find_mem_region("ibm,fake-rtc");
+
+	/* Should we register anyway? */
+	if (!rtc_region) {
+		DBG("No initial RTC value found\n");
+		return;
+	}
+
+	rtc = (uint32_t *) rtc_region->start;
+
+	fake_ymd = rtc;
+	fake_hmsm = ((uint64_t *) &rtc[1]);
+
+	DBG("Init fake RTC to 0x%x 0x%llx\n", *fake_ymd, *fake_hmsm);
+
+	opal_register(OPAL_RTC_READ, fake_rtc_read, 2);
+	opal_register(OPAL_RTC_WRITE, fake_rtc_write, 2);
+}