Implement part of BmcEpoch

Add BmcEpoch which inherits EpochBase and will handle times for BMC,
it is partly implemented.

Add unit test cases to test basic functions.

Change-Id: Ia5e4d0f884156d238f3f84df490a2efbce43e89a
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/Makefile.am b/Makefile.am
index 4b4cf02..3eef41a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -5,7 +5,8 @@
 noinst_LTLIBRARIES = libtimemanager.la
 
 libtimemanager_la_SOURCES = \
-	epoch_base.cpp
+	epoch_base.cpp \
+	bmc_epoch.cpp
 
 phosphor_timemanager_SOURCES = \
 	main.cpp
diff --git a/bmc_epoch.cpp b/bmc_epoch.cpp
new file mode 100644
index 0000000..c17ddf5
--- /dev/null
+++ b/bmc_epoch.cpp
@@ -0,0 +1,50 @@
+#include "bmc_epoch.hpp"
+
+#include <phosphor-logging/log.hpp>
+
+namespace phosphor
+{
+namespace time
+{
+namespace server = sdbusplus::xyz::openbmc_project::Time::server;
+using namespace phosphor::logging;
+
+BmcEpoch::BmcEpoch(sdbusplus::bus::bus& bus,
+                   const char* objPath)
+    : EpochBase(bus, objPath)
+{
+    // Empty
+}
+
+uint64_t BmcEpoch::elapsed() const
+{
+    // It does not needs to check owner when getting time
+    return getTime().count();
+}
+
+uint64_t BmcEpoch::elapsed(uint64_t value)
+{
+    // TODO: set time based on current time mode and owner
+    auto time = std::chrono::microseconds(value);
+    switch (timeOwner)
+    {
+        case Owner::BMC:
+        {
+            setTime(time);
+            break;
+        }
+        // TODO: below cases are to be implemented
+        case Owner::HOST:
+            break;
+        case Owner::SPLIT:
+            break;
+        case Owner::BOTH:
+            break;
+    }
+    server::EpochTime::elapsed(value);
+    return value;
+}
+
+}
+}
+
diff --git a/bmc_epoch.hpp b/bmc_epoch.hpp
new file mode 100644
index 0000000..56d78e9
--- /dev/null
+++ b/bmc_epoch.hpp
@@ -0,0 +1,39 @@
+#pragma once
+
+#include "epoch_base.hpp"
+
+namespace phosphor
+{
+namespace time
+{
+
+/** @class BmcEpoch
+ *  @brief OpenBMC BMC EpochTime implementation.
+ *  @details A concrete implementation for xyz.openbmc_project.Time.EpochTime
+ *  DBus API for BMC's epoch time.
+ */
+class BmcEpoch : public EpochBase
+{
+    public:
+        friend class TestBmcEpoch;
+        BmcEpoch(sdbusplus::bus::bus& bus,
+                 const char* objPath);
+
+        /**
+         * @brief Get value of Elapsed property
+         *
+         * @return The elapsed microseconds since UTC
+         **/
+        uint64_t elapsed() const override;
+
+        /**
+         * @brief Set value of Elapsed property
+         *
+         * @param[in] value - The microseconds since UTC to set
+         * @return The updated elapsed microseconds since UTC
+         **/
+        uint64_t elapsed(uint64_t value) override;
+};
+
+}
+}
diff --git a/main.cpp b/main.cpp
index 0cf2807..05ac453 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,10 +1,12 @@
 #include <sdbusplus/bus.hpp>
 
 #include "config.h"
+#include "bmc_epoch.hpp"
 
 int main()
 {
     auto bus = sdbusplus::bus::new_default();
+    phosphor::time::BmcEpoch bmc(bus, OBJPATH_BMC);
 
     bus.request_name(BUSNAME);
 
diff --git a/test/Makefile.am b/test/Makefile.am
index 66e1ae5..26c4c15 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -6,7 +6,8 @@
 check_PROGRAMS += test
 
 test_SOURCES = \
-    TestEpochBase.cpp
+    TestEpochBase.cpp \
+    TestBmcEpoch.cpp
 
 test_LDADD = $(top_builddir)/libtimemanager.la
 
diff --git a/test/TestBmcEpoch.cpp b/test/TestBmcEpoch.cpp
new file mode 100644
index 0000000..67f89bb
--- /dev/null
+++ b/test/TestBmcEpoch.cpp
@@ -0,0 +1,55 @@
+#include <sdbusplus/bus.hpp>
+#include <gtest/gtest.h>
+
+#include "bmc_epoch.hpp"
+#include "config.h"
+
+namespace phosphor
+{
+namespace time
+{
+
+class TestBmcEpoch : public testing::Test
+{
+    public:
+        using Mode = EpochBase::Mode;
+        using Owner = EpochBase::Owner;
+
+        sdbusplus::bus::bus bus;
+        BmcEpoch bmcEpoch;
+
+        TestBmcEpoch()
+            : bus(sdbusplus::bus::new_default()),
+              bmcEpoch(bus, OBJPATH_BMC)
+        {
+            // Empty
+        }
+
+        // Proxies for BmcEpoch's private members and functions
+        Mode getTimeMode()
+        {
+            return bmcEpoch.timeMode;
+        }
+        Owner getTimeOwner()
+        {
+            return bmcEpoch.timeOwner;
+        }
+};
+
+TEST_F(TestBmcEpoch, empty)
+{
+    EXPECT_EQ(Mode::NTP, getTimeMode());
+    EXPECT_EQ(Owner::BMC, getTimeOwner());
+}
+
+TEST_F(TestBmcEpoch, getElapsed)
+{
+    auto t1 = bmcEpoch.elapsed();
+    EXPECT_NE(0, t1);
+    auto t2 = bmcEpoch.elapsed();
+    EXPECT_GE(t2, t1);
+}
+
+
+}
+}