PEL: Add API to get the PLDM instance ID

In order to send a PLDM command, one must get the instance ID parameter
to use for that command from the PLDM daemon via a D-Bus method.

Implement this API in the DataInterface class, though leave the body of
it stubbed out until the PLDM daemon switches to using async D-Bus
operations as right now the logging daemon and PLDM daemon can deadlock
with each calling into the other.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I592e7bad922c725edee67003e9957388df5f195c

2 files changed, 47 insertions, 2 deletions

diff --git a/extensions/openpower-pels/data_interface.cpp b/extensions/openpower-pels/data_interface.cpp
index 7342dc0..6ad8b6e 100644
--- a/extensions/openpower-pels/data_interface.cpp
+++ b/extensions/openpower-pels/data_interface.cpp
@@ -35,6 +35,7 @@ namespace object_path
 constexpr auto objectMapper = "/xyz/openbmc_project/object_mapper";
 constexpr auto systemInv = "/xyz/openbmc_project/inventory/system";
 constexpr auto hostState = "/xyz/openbmc_project/state/host0";
+constexpr auto pldm = "/xyz/openbmc_project/pldm";
 } // namespace object_path
 
 namespace interface
@@ -43,6 +44,7 @@ constexpr auto dbusProperty = "org.freedesktop.DBus.Properties";
 constexpr auto objectMapper = "xyz.openbmc_project.ObjectMapper";
 constexpr auto invAsset = "xyz.openbmc_project.Inventory.Decorator.Asset";
 constexpr auto osStatus = "xyz.openbmc_project.State.OperatingSystem.Status";
+constexpr auto pldmRequester = "xyz.openbmc_project.PLDM.Requester";
 } // namespace interface
 
 using namespace sdbusplus::xyz::openbmc_project::State::OperatingSystem::server;
@@ -140,7 +142,7 @@ void DataInterface::getProperty(const std::string& service,
 }
 
 DBusService DataInterface::getService(const std::string& objectPath,
-                                      const std::string& interface)
+                                      const std::string& interface) const
 {
     auto method = _bus.new_method_call(service_name::objectMapper,
                                        object_path::objectMapper,
@@ -222,6 +224,26 @@ void DataInterface::osStatePropChanged(sdbusplus::message::message& msg)
     }
 }
 
+uint8_t DataInterface::getPLDMInstanceID(uint8_t eid) const
+{
+    return 0;
+// Don't use until PLDM switches to async D-Bus.
+#if 0
+    auto service = getService(object_path::pldm, interface::pldmRequester);
+
+    auto method =
+        _bus.new_method_call(service.c_str(), object_path::pldm,
+                             interface::pldmRequester, "GetInstanceId");
+    method.append(eid);
+    auto reply = _bus.call(method);
+
+    uint8_t instanceID = 0;
+    reply.read(instanceID);
+
+    return instanceID;
+#endif
+}
+
 void DataInterface::readBMCFWVersion()
 {
     std::ifstream versionFile{BMC_VERSION_FILE};
diff --git a/extensions/openpower-pels/data_interface.hpp b/extensions/openpower-pels/data_interface.hpp
index ff0aa75..35e220c 100644
--- a/extensions/openpower-pels/data_interface.hpp
+++ b/extensions/openpower-pels/data_interface.hpp
@@ -63,6 +63,20 @@ class DataInterfaceBase
         return _hostUp;
     }
 
+    /**
+     * @brief Returns the PLDM instance ID to use for PLDM commands
+     *
+     * The base class implementation just returns zero.
+     *
+     * @param[in] eid - The PLDM EID
+     *
+     * @return uint8_t - The instance ID
+     */
+    virtual uint8_t getPLDMInstanceID(uint8_t eid) const
+    {
+        return 0;
+    }
+
     using HostStateChangeFunc = std::function<void(bool)>;
 
     /**
@@ -192,6 +206,15 @@ class DataInterface : public DataInterfaceBase
      */
     explicit DataInterface(sdbusplus::bus::bus& bus);
 
+    /**
+     * @brief Returns the PLDM instance ID to use for PLDM commands
+     *
+     * @param[in] eid - The PLDM EID
+     *
+     * @return uint8_t - The instance ID
+     */
+    uint8_t getPLDMInstanceID(uint8_t eid) const override;
+
   private:
     /**
      * @brief Reads the machine type/model and SN from D-Bus.
@@ -236,7 +259,7 @@ class DataInterface : public DataInterfaceBase
      * @param[in] interface - The D-Bus interface
      */
     DBusService getService(const std::string& objectPath,
-                           const std::string& interface);
+                           const std::string& interface) const;
     /**
      * @brief Wrapper for the 'GetAll' properties method call
      *