regulators: Complete PresenceDetection class
Complete implementation of the PresenceDetection class. Implement the
execute() method that executes one or more actions to determine if a
device is present.
Cache the results so that subsequent calls to execute() will return the
cached value. Executing the actions may be expensive, requiring one or
more D-Bus calls.
Provide a clearCache() method to be called on each boot to clear the
cached value.
Signed-off-by: Bob King <Bob_King@wistron.com>
Change-Id: Ie0e3dfde10f2df8ca8b56ec14ce723f356e97dfc
diff --git a/phosphor-regulators/src/meson.build b/phosphor-regulators/src/meson.build
index 8238d93..7b852bb 100644
--- a/phosphor-regulators/src/meson.build
+++ b/phosphor-regulators/src/meson.build
@@ -15,6 +15,7 @@
'id_map.cpp',
'journal.cpp',
'pmbus_utils.cpp',
+ 'presence_detection.cpp',
'presence_service.cpp',
'rail.cpp',
'sensor_monitoring.cpp',
diff --git a/phosphor-regulators/src/presence_detection.cpp b/phosphor-regulators/src/presence_detection.cpp
new file mode 100644
index 0000000..3ed5350
--- /dev/null
+++ b/phosphor-regulators/src/presence_detection.cpp
@@ -0,0 +1,64 @@
+/**
+ * Copyright © 2020 IBM Corporation
+ *
+ * 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 "presence_detection.hpp"
+
+#include "action_environment.hpp"
+#include "action_utils.hpp"
+#include "chassis.hpp"
+#include "device.hpp"
+#include "exception_utils.hpp"
+#include "system.hpp"
+
+#include <exception>
+
+namespace phosphor::power::regulators
+{
+
+bool PresenceDetection::execute(Services& services, System& system,
+ Chassis& /*chassis*/, Device& device)
+{
+ // If no presence value is cached
+ if (!isPresent.has_value())
+ {
+ // Initially assume device is present
+ isPresent = true;
+
+ // Execute actions to find device presence
+ try
+ {
+ // Create ActionEnvironment
+ ActionEnvironment environment{system.getIDMap(), device.getID(),
+ services};
+
+ // Execute the actions and cache resulting value
+ isPresent = action_utils::execute(actions, environment);
+ }
+ catch (const std::exception& e)
+ {
+ // Log error messages in journal
+ services.getJournal().logError(exception_utils::getMessages(e));
+ services.getJournal().logError("Unable to determine presence of " +
+ device.getID());
+
+ // TODO: Create error log entry
+ }
+ }
+
+ return isPresent.value();
+}
+
+} // namespace phosphor::power::regulators
diff --git a/phosphor-regulators/src/presence_detection.hpp b/phosphor-regulators/src/presence_detection.hpp
index 23f416c..0574003 100644
--- a/phosphor-regulators/src/presence_detection.hpp
+++ b/phosphor-regulators/src/presence_detection.hpp
@@ -16,14 +16,21 @@
#pragma once
#include "action.hpp"
+#include "services.hpp"
#include <memory>
+#include <optional>
#include <utility>
#include <vector>
namespace phosphor::power::regulators
{
+// Forward declarations to avoid circular dependencies
+class Chassis;
+class Device;
+class System;
+
/**
* @class PresenceDetection
*
@@ -69,20 +76,30 @@
}
/**
+ * Clears the cached presence value.
+ */
+ void clearCache(void)
+ {
+ isPresent.reset();
+ }
+
+ /**
* Executes the actions to detect whether the device is present.
*
* The return value of the last action indicates whether the device is
* present. A return value of true means the device is present; false means
* the device is missing.
*
+ * Caches the resulting presence value. Subsequent calls to execute() will
+ * return the cached value rather than re-executing the actions. This
+ * provides a performance improvement since the actions may be expensive to
+ * execute, such as I2C reads or D-Bus method calls. The cached value can
+ * be cleared by calling clearCache().
+ *
* @return true if device is present, false otherwise
*/
- bool execute()
- {
- // TODO: Create ActionEnvironment, execute actions, catch and handle any
- // exceptions
- return true;
- }
+ bool execute(Services& services, System& system, Chassis& chassis,
+ Device& device);
/**
* Returns the actions that detect whether the device is present.
@@ -94,11 +111,26 @@
return actions;
}
+ /**
+ * Returns the cached presence value, if any.
+ *
+ * @return cached presence value
+ */
+ std::optional<bool> getCachedPresence() const
+ {
+ return isPresent;
+ }
+
private:
/**
* Actions that detect whether the device is present.
*/
std::vector<std::unique_ptr<Action>> actions{};
+
+ /**
+ * Cached presence value. Initially has no value.
+ */
+ std::optional<bool> isPresent{};
};
} // namespace phosphor::power::regulators