Witherspoon AVS Bus Control

Perform an AVS bus workaround on the VRMs attached
to the processor.  The AVS bus is how the processor
talks to the VRMs.

After the workaround, this also provides services to
disable the AVS bus so a VRM override can be run, and
then enable it again afterwards.

Change-Id: I68c48ffaafe5d7125556aa9d36cf11bf55ca93ac
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/chassis/avsbus-control/avsbus-enable@.service b/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/chassis/avsbus-control/avsbus-enable@.service
new file mode 100644
index 0000000..9032f68
--- /dev/null
+++ b/meta-openbmc-machines/meta-openpower/meta-ibm/meta-witherspoon/recipes-phosphor/chassis/avsbus-control/avsbus-enable@.service
@@ -0,0 +1,14 @@
+[Unit]
+Description=Enable the AVS bus on VRMs
+Wants=vrm-control@%i.service
+After=vrm-control@%i.service
+Before=vcs_off@%i.service
+Conflicts=obmc-chassis-stop@%i.target
+
+[Service]
+ExecStart={bindir}/avsbus-enable.sh
+Type=oneshot
+RemainAfterExit=yes
+
+[Install]
+WantedBy=obmc-chassis-start@%i.target