optional service to log info log on chassis poweron

This commit introduces a new service that will log an informational log
on every chassis power on.

This new informational error is being created for a couple of reasons:
- An easy eye catcher when reviewing logs to easily distinguish between
  major boots of the system (ones including a chassis power cycle)
- A mechanism for other OpenBMC software which utilizes the log to
  report back to the user when errors from the current boot need
  attention

This service needs to run before any of the power/vrm services run to
ensure any logs from those services can be correlated to running after
the current power on has started.

By default this service will not be installed but can be brought in via
a bbappend if desired.

Tested:
- Built new service into a flash image and confirmed
  - Info log was logged as expected during power on (prior to any vrm,
    power, or fan functions)
  - Info log was not logged when rebooting the BMC from a host running
    state

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: If78c076d86efabed6b0093e9f4116502a4d9da93

service_files/meson.build

@@ -20,7 +20,8 @@ unit_files = [
     'phosphor-set-host-transition-to-off@.service',
     'phosphor-set-host-transition-to-running@.service',
     'phosphor-chassis-check-power-status@.service',
-    'phosphor-bmc-security-check.service'
+    'phosphor-bmc-security-check.service',
+    'phosphor-create-chassis-poweron-log@.service'
 ]
 
 foreach u : unit_files

service_files/phosphor-create-chassis-poweron-log@.service

@@ -0,0 +1,20 @@
+[Unit]
+Description=Create info log indicating chassis%i poweron has started
+Wants=obmc-power-start-pre@%i.target
+Before=obmc-power-start-pre@%i.target
+Before=phosphor-regulators-config.service
+Conflicts=obmc-chassis-poweroff@%i.target
+ConditionPathExists=!/run/openbmc/chassis@%i-on
+
+[Service]
+Restart=no
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/bin/sh -c \
+  "busctl call xyz.openbmc_project.Logging /xyz/openbmc_project/logging \
+   xyz.openbmc_project.Logging.Create Create ssa{ss} \
+   xyz.openbmc_project.State.Info.ChassisPowerOnStarted \
+   xyz.openbmc_project.Logging.Entry.Level.Informational 1 CHASSIS_ID %i"
+
+[Install]
+WantedBy=obmc-chassis-poweron@%i.target