service: device-tree node vpd to d-bus hw id data
A daemon for transferring Viable Product Data (VPD) from device-tree
nodes to D-Bus as described in the design doc @
https://gerrit.openbmc.org/c/openbmc/docs/+/66369
and discussed in this Technical Oversight Forum topic @
https://github.com/openbmc/technical-oversight-forum/issues/38
Tested:
Ensure 'model' and/or 'serial-number' nodes are populated in
/proc/device-tree. Can be hardcoded into platform DTS via
linux-kernel recipe if needed.
'''
After OBMC boot, calling
> busctl introspect xyz.openbmc_project.MachineContext /xyz/openbmc_project/MachineContext
produces the following output:
NAME TYPE SIGNATURE RESULT/VALUE FLAGS
...
xyz.openbmc_project.Inventory.Decorator.Asset interface - - -
.BuildDate property s "" emits-change writable
.Manufacturer property s "" emits-change writable
.Model property s "hpe,dl360" emits-change writable
.PartNumber property s "" emits-change writable
.SerialNumber property s "t5texpl" emits-change writable
...
Note: Writing to one of these properties will update the property on D-Bus without affecting the
underlying device-tree node. An 'updated' event will be fired, so Entity-Manager probes monitoring
a given property would recognize the new value and key off it.
'''
Change-Id: Id52d1fc3b26010c864c7e64d3dfdf0a2b5de9294
Signed-off-by: Chris Sides <Christopher.Sides@hpe.com>
diff --git a/src/devicetree_vpd_parser.cpp b/src/devicetree_vpd_parser.cpp
new file mode 100644
index 0000000..87bd2d7
--- /dev/null
+++ b/src/devicetree_vpd_parser.cpp
@@ -0,0 +1,44 @@
+#include "machine_context.hpp"
+
+#include <memory>
+
+int main()
+{
+ static constexpr auto reqDBusPath = "/xyz/openbmc_project/MachineContext";
+ static constexpr auto reqDBusName = "xyz.openbmc_project.MachineContext";
+
+ /*Note: OpenBMC convention typically has service name = bus name,
+ where the bus name is representative of the underlying hardware.
+
+ In the case of MachineContext, the BMC is not gathering data from
+ specific hardware, but is instead parsing device-tree nodes for
+ context about the hardware OpenBMC is running on.
+
+ Because the VPD data being parsed is coming from device-tree,
+ the daemon and matching service name reflect that.
+
+ Because the parsed data represents 'machine context' data,
+ the bus name and associated path the daemon writes to
+ reflects that instead.
+ */
+
+ sdbusplus::async::context ctx;
+ sdbusplus::server::manager_t manager{ctx, reqDBusPath};
+
+ std::unique_ptr<MachineContext> mc = nullptr;
+ if (MachineContext::keyNodeExists())
+ {
+ mc = std::make_unique<MachineContext>(ctx, reqDBusPath);
+ mc->populateFromDeviceTree();
+ }
+
+ // NOLINTNEXTLINE(readability-static-accessed-through-instance)
+ ctx.spawn([](sdbusplus::async::context& ctx) -> sdbusplus::async::task<> {
+ ctx.request_name(reqDBusName);
+ co_return;
+ }(ctx));
+
+ ctx.run();
+
+ return 0;
+};