pseq: Standard pgood fault detection algorithm

Create a StandardDevice class for the phosphor-power-sequencer
application.  This class implements the standard pgood (power good)
fault detection algorithm.

When adding support for a new power sequencer device type, a sub-class
of StandardDevice should be created if possible.  This will ensure that
pgood fault detection works consistently across device types.

Tested:
* Verified all new and existing gtests ran successfully

Change-Id: I80c0b36429f1d84fa1e317889803429927797fdc
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/src/meson.build b/phosphor-power-sequencer/src/meson.build
index db8112f..2d14caf 100644
--- a/phosphor-power-sequencer/src/meson.build
+++ b/phosphor-power-sequencer/src/meson.build
@@ -8,6 +8,7 @@
     'config_file_parser.cpp',
     'rail.cpp',
     'services.cpp',
+    'standard_device.cpp',
     implicit_include_directories: false,
     dependencies: [
         nlohmann_json_dep,
diff --git a/phosphor-power-sequencer/src/power_sequencer_device.hpp b/phosphor-power-sequencer/src/power_sequencer_device.hpp
index f6ebb48..7a8c1b3 100644
--- a/phosphor-power-sequencer/src/power_sequencer_device.hpp
+++ b/phosphor-power-sequencer/src/power_sequencer_device.hpp
@@ -129,9 +129,13 @@
     virtual double getVoutUVFaultLimit(uint8_t page) = 0;
 
     /**
-     * Returns whether a pgood fault has occurred on one of the rails being
+     * Checks whether a pgood fault has occurred on one of the rails being
      * monitored by this device.
      *
+     * If a pgood fault was found, this method returns a string containing the
+     * error that should be logged.  If no fault was found, an empty string is
+     * returned.
+     *
      * Throws an exception if an error occurs while trying to obtain the status
      * of the rails.
      *
@@ -141,16 +145,14 @@
      *                         supply error occurred.  This error may be the
      *                         root cause if a pgood fault occurred on a power
      *                         supply rail monitored by this device.
-     * @param error Error that should be logged if this method returns true.
      * @param additionalData Additional data to include in the error log if
-     *                       this method returns true.
-     * @return true if a pgood fault was found on a rail monitored by this
-     *         device, false otherwise
+     *                       a pgood fault was found
+     * @return error that should be logged if a pgood fault was found, or an
+     *         empty string if no pgood fault was found
      */
-    virtual bool
-        hasPgoodFault(Services& services, const std::string& powerSupplyError,
-                      std::string& error,
-                      std::map<std::string, std::string>& additionalData) = 0;
+    virtual std::string
+        findPgoodFault(Services& services, const std::string& powerSupplyError,
+                       std::map<std::string, std::string>& additionalData) = 0;
 };
 
 } // namespace phosphor::power::sequencer
diff --git a/phosphor-power-sequencer/src/standard_device.cpp b/phosphor-power-sequencer/src/standard_device.cpp
new file mode 100644
index 0000000..cc999c5
--- /dev/null
+++ b/phosphor-power-sequencer/src/standard_device.cpp
@@ -0,0 +1,105 @@
+/**
+ * Copyright © 2024 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 "standard_device.hpp"
+
+#include "format_utils.hpp"
+
+#include <exception>
+#include <format>
+#include <span>
+#include <stdexcept>
+
+namespace phosphor::power::sequencer
+{
+
+std::string StandardDevice::findPgoodFault(
+    Services& services, const std::string& powerSupplyError,
+    std::map<std::string, std::string>& additionalData)
+{
+    std::string error{};
+    try
+    {
+        prepareForPgoodFaultDetection(services);
+
+        // Get all GPIO values (if possible) from device.  They may be slow to
+        // obtain, so obtain them once and then pass values to each Rail object.
+        std::vector<int> gpioValues = getGPIOValuesIfPossible();
+
+        // Loop through all the rails checking if any detected a pgood fault.
+        // The rails are in power-on-sequence order.
+        for (std::unique_ptr<Rail>& rail : rails)
+        {
+            if (rail->hasPgoodFault(*this, services, gpioValues,
+                                    additionalData))
+            {
+                services.logErrorMsg(std::format(
+                    "Pgood fault found in rail monitored by device {}", name));
+
+                // If this is a PSU rail and a PSU error was previously detected
+                if (rail->isPowerSupplyRail() && !powerSupplyError.empty())
+                {
+                    // Return power supply error as root cause
+                    error = powerSupplyError;
+                }
+                else
+                {
+                    // Return pgood fault as root cause
+                    error =
+                        "xyz.openbmc_project.Power.Error.PowerSequencerVoltageFault";
+                }
+
+                storePgoodFaultDebugData(services, gpioValues, additionalData);
+                break;
+            }
+        }
+    }
+    catch (const std::exception& e)
+    {
+        throw std::runtime_error{std::format(
+            "Unable to determine if a pgood fault occurred in device {}: {}",
+            name, e.what())};
+    }
+    return error;
+}
+
+std::vector<int> StandardDevice::getGPIOValuesIfPossible()
+{
+    std::vector<int> values{};
+    try
+    {
+        values = getGPIOValues();
+    }
+    catch (...)
+    {}
+    return values;
+}
+
+void StandardDevice::storePgoodFaultDebugData(
+    Services& services, const std::vector<int>& gpioValues,
+    std::map<std::string, std::string>& additionalData)
+{
+    additionalData.emplace("DEVICE_NAME", name);
+    if (!gpioValues.empty())
+    {
+        std::string valuesStr = format_utils::toString(std::span(gpioValues));
+        services.logInfoMsg(
+            std::format("Device {} GPIO values: {}", name, valuesStr));
+        additionalData.emplace("GPIO_VALUES", valuesStr);
+    }
+}
+
+} // namespace phosphor::power::sequencer
diff --git a/phosphor-power-sequencer/src/standard_device.hpp b/phosphor-power-sequencer/src/standard_device.hpp
new file mode 100644
index 0000000..3dbba2f
--- /dev/null
+++ b/phosphor-power-sequencer/src/standard_device.hpp
@@ -0,0 +1,143 @@
+/**
+ * Copyright © 2024 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.
+ */
+#pragma once
+
+#include "power_sequencer_device.hpp"
+#include "rail.hpp"
+#include "services.hpp"
+
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace phosphor::power::sequencer
+{
+
+/**
+ * @class StandardDevice
+ *
+ * PowerSequencerDevice sub-class that implements the standard pgood fault
+ * detection algorithm.
+ *
+ * When adding support for a new power sequencer device type, create a sub-class
+ * of StandardDevice if possible.  This will ensure that pgood fault detection
+ * works consistently across device types.
+ */
+class StandardDevice : public PowerSequencerDevice
+{
+  public:
+    // Specify which compiler-generated methods we want
+    StandardDevice() = delete;
+    StandardDevice(const StandardDevice&) = delete;
+    StandardDevice(StandardDevice&&) = delete;
+    StandardDevice& operator=(const StandardDevice&) = delete;
+    StandardDevice& operator=(StandardDevice&&) = delete;
+    virtual ~StandardDevice() = default;
+
+    /**
+     * Constructor.
+     *
+     * @param name device name
+     * @param rails voltage rails that are enabled and monitored by this device
+     */
+    explicit StandardDevice(const std::string& name,
+                            std::vector<std::unique_ptr<Rail>> rails) :
+        name{name},
+        rails{std::move(rails)}
+    {}
+
+    /** @copydoc PowerSequencerDevice::getName() */
+    virtual const std::string& getName() const override
+    {
+        return name;
+    }
+
+    /** @copydoc PowerSequencerDevice::getRails() */
+    virtual const std::vector<std::unique_ptr<Rail>>& getRails() const override
+    {
+        return rails;
+    }
+
+    /** @copydoc PowerSequencerDevice::findPgoodFault()
+     *
+     * Calls prepareForPgoodFaultDetection() before starting detection.  If a
+     * pgood fault is detected, calls storePgoodFaultDebugData().
+     */
+    virtual std::string findPgoodFault(
+        Services& services, const std::string& powerSupplyError,
+        std::map<std::string, std::string>& additionalData) override;
+
+  protected:
+    /**
+     * Prepare for pgood fault detection.
+     *
+     * Perform any actions that are necessary to prepare for fault detection.
+     * For example, cache information that is slow to obtain and is used
+     * multiple times during detection.
+     *
+     * Default implementation does nothing.  Override in sub-classes if needed.
+     *
+     * @param services System services like hardware presence and the journal
+     */
+    virtual void
+        prepareForPgoodFaultDetection([[maybe_unused]] Services& services)
+    {}
+
+    /**
+     * Returns the GPIO values that can be read from the device, if possible.
+     *
+     * If the device does not support reading GPIO values or an error occurs, an
+     * empty vector is returned.
+     *
+     * @return GPIO values, or empty vector if values could not be read
+     */
+    virtual std::vector<int> getGPIOValuesIfPossible();
+
+    /**
+     * Store pgood fault debug data in the specified additional data map.
+     *
+     * The default implementation stores the device name and all the GPIO
+     * values.  The GPIO values are stored as a simple list of integers.
+     *
+     * Sub-classes should override if needed to store device-specific data
+     * and/or a formatted representation of the GPIO values.
+     *
+     * This method should NOT throw exceptions.  If debug data cannot be
+     * obtained, the error should be caught and ignored so that pgood error
+     * handling can continue.
+     *
+     * @param services System services like hardware presence and the journal
+     * @param gpioValues GPIO values obtained from the device (if any)
+     * @param additionalData Additional data to include in an error log
+     */
+    virtual void storePgoodFaultDebugData(
+        Services& services, const std::vector<int>& gpioValues,
+        std::map<std::string, std::string>& additionalData);
+
+    /**
+     * Device name.
+     */
+    std::string name{};
+
+    /**
+     * Voltage rails that are enabled and monitored by this device.
+     */
+    std::vector<std::unique_ptr<Rail>> rails{};
+};
+
+} // namespace phosphor::power::sequencer