Add PEL related methods

This adds 2 methods to retrieve PEL data:
1) GetPEL - This will be for use by the PLDM handler in order to
   get a PEL from the logging daemon when the host asks for one
   based on the PEL ID.  It returns a file descriptor to the PEL
   data, which is a lot faster than returning the whole PEL (up
   to 16KB) over D-Bus.

2) GetPELFromOBMCID - This will be mostly for debug using REST/curl
   before the full Redfish event log implementation is available,
   so one can get PEL data off of the BMC when only the OpenBMC
   event log ID is known.

   A use case could be:  Enumerate /xyz/openbmc_project/logging/entry,
   and then call GetPELFromOBMCID on every event that comes back.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I92ac36cffed7fbee4f25205123c484007cbe9d63
diff --git a/org/open_power/Logging/PEL.interface.yaml b/org/open_power/Logging/PEL.interface.yaml
new file mode 100644
index 0000000..d51e999
--- /dev/null
+++ b/org/open_power/Logging/PEL.interface.yaml
@@ -0,0 +1,36 @@
+description: >
+  Provides D-Bus access to OpenPower Platform Event Logs
+methods:
+  - name: GetPEL
+    description: >
+      Returns a file desciptor to a PEL.
+    parameters:
+      - name: pelID
+        type: int32
+        description: >
+          The PEL log ID of the PEL to retrieve.
+    returns:
+      - name: data
+        type: unixfd
+        description: >
+          A file descriptor for a file that contains the PEL.
+    errors:
+       - xyz.openbmc_project.Common.Error.InternalFailure
+       - xyz.openbmc_project.Common.Error.InvalidArgument
+
+  - name: GetPELFromOBMCID
+    description: >
+      Returns PEL data based on the OpenBMC event log ID.
+    parameters:
+      - name: obmcLogID
+        type: int32
+        description: >
+          The OpenBMC event log ID of the PEL to retrieve.
+    returns:
+      - name: data
+        type: array[byte]
+        description: >
+          The PEL data
+    errors:
+       - xyz.openbmc_project.Common.Error.InternalFailure
+       - xyz.openbmc_project.Common.Error.InvalidArgument