Set OccActive property on application start

Host sends OCC active status command just once as part
of power on operation and when that is sent, occ control
application binds the device. As part of bind, a sysfs
file gets created that would be used to communicate the
occ error status back to user.

If occ control application terminates and restarts, then
it needs some way to set OccActive property and this commit
adds that support.

Solution is to check if the device is already bound by checking
the presence of the OCC_HWMON_PATH/occ<number>-dev0 and set the
property if found

Fixes openbmc/openbmc#2238

Change-Id: I920b52e3970cc91af50b5bc68ead44c66eab8944
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>

3 files changed, 24 insertions, 3 deletions

diff --git a/occ_device.hpp b/occ_device.hpp
index a2b4e85..3f7dff4 100644
--- a/occ_device.hpp
+++ b/occ_device.hpp
@@ -6,7 +6,6 @@
 #include "occ_errors.hpp"
 #include "config.h"
 
-
 namespace open_power
 {
 namespace occ
@@ -61,6 +60,19 @@ class Device
            return write(unBindPath, config);
         }
 
+        /** @brief Returns if device is already bound.
+         *
+         *  On device bind, a soft link by the name $config
+         *  gets created in OCC_HWMON_PATH and gets removed
+         *  on unbind
+         *
+         *  @return true if bound, else false
+         */
+        inline bool bound() const
+        {
+            return fs::exists(OCC_HWMON_PATH + config);
+        }
+
         /** @brief Starts to monitor for errors */
         inline void addErrorWatch()
         {
diff --git a/occ_manager.hpp b/occ_manager.hpp
index 7bb1042..0d32241 100644
--- a/occ_manager.hpp
+++ b/occ_manager.hpp
@@ -48,6 +48,7 @@ struct Manager
             // I2C OCC status objects are initialized directly
             initStatusObjects();
 #else
+
             // Check if CPU inventory exists already.
             auto occs = open_power::occ::finder::get(bus);
             if (occs.empty())
@@ -75,6 +76,7 @@ struct Manager
 #endif
         }
 
+
     private:
         /** @brief Callback that responds to cpu creation in the inventory -
          *         by creating the needed objects.
diff --git a/occ_status.hpp b/occ_status.hpp
index c097908..a334a2b 100644
--- a/occ_status.hpp
+++ b/occ_status.hpp
@@ -55,7 +55,7 @@ class Status : public Interface
                EventPtr& event,
                const char* path,
                std::function<void(bool)> callBack = nullptr)
-            : Interface(bus, path),
+            : Interface(bus, path, true),
               bus(bus),
               path(path),
               callBack(callBack),
@@ -78,7 +78,14 @@ class Status : public Interface
                      std::bind(std::mem_fn(&Status::hostControlEvent),
                             this, std::placeholders::_1))
         {
-            // Nothing to do here
+            // Check to see if we have OCC already bound.  If so, just set it
+            if (device.bound())
+            {
+                this->occActive(true);
+            }
+
+            // Announce that we are ready
+            this->emit_object_added();
         }
 
         /** @brief Since we are overriding the setter-occActive but not the