Delay opening OCC device until bind

Fixes openbmc/openbmc#2118

Change-Id: If9e2610fe7443daa2196b0e5989f81bc544266b2
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>

3 files changed, 80 insertions, 18 deletions

diff --git a/configure.ac b/configure.ac
index 098a0eb..24191c8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -101,6 +101,10 @@ AC_ARG_VAR(FSI_SCAN_FILE, [The File to write for initiating FSI rescan])
 AS_IF([test "x$FSI_SCAN_FILE" == "x"], [FSI_SCAN_FILE="/sys/devices/platform/gpio-fsi/fsi0/slave@00:00/00:00:00:0a/fsi1/rescan"])
 AC_DEFINE_UNQUOTED([FSI_SCAN_FILE], ["$FSI_SCAN_FILE"], [The File to write for initiating FSI rescan])
 
+AC_ARG_VAR(OCC_DEV_PATH, [The OCC device path in /dev])
+AS_IF([test "x$OCC_DEV_PATH" == "x"], [OCC_DEV_PATH="/dev/occ"])
+AC_DEFINE_UNQUOTED([OCC_DEV_PATH], ["$OCC_DEV_PATH"], [The OCC device path in /dev])
+
 AC_ARG_VAR(PS_DERATING_FACTOR, [The power supply derating factor])
 AS_IF([test "x$PS_DERATING_FACTOR" == "x"], [PS_DERATING_FACTOR=90])
 AC_DEFINE_UNQUOTED([PS_DERATING_FACTOR], [$PS_DERATING_FACTOR], [The power supply derating factor])
diff --git a/occ_pass_through.cpp b/occ_pass_through.cpp
index 2846dda..4a7057b 100644
--- a/occ_pass_through.cpp
+++ b/occ_pass_through.cpp
@@ -2,11 +2,14 @@
 #include <algorithm>
 #include <fcntl.h>
 #include <errno.h>
+#include <string>
+#include <unistd.h>
 #include <phosphor-logging/log.hpp>
 #include <phosphor-logging/elog.hpp>
 #include <org/open_power/OCC/Device/error.hpp>
 #include "occ_pass_through.hpp"
 #include "elog-errors.hpp"
+#include "config.h"
 namespace open_power
 {
 namespace occ
@@ -17,20 +20,22 @@ PassThrough::PassThrough(
     const char* path) :
     Iface(bus, path),
     path(path),
-    fd(openDevice())
+    devicePath(OCC_DEV_PATH + std::to_string((this->path.back() - '0') + 1)),
+    activeStatusSignal(
+            bus,
+            sdbusRule::propertiesChanged(path, "org.open_power.OCC.Status"),
+            std::bind(std::mem_fn(&PassThrough::activeStatusEvent),
+                this, std::placeholders::_1))
 {
     // Nothing to do.
 }
 
-int PassThrough::openDevice()
+void PassThrough::openDevice()
 {
     using namespace phosphor::logging;
     using namespace sdbusplus::org::open_power::OCC::Device::Error;
 
-    // Device instance number starts from 1.
-    devicePath.append(std::to_string((this->path.back() - '0') + 1));
-
-    int fd = open(devicePath.c_str(), O_RDWR | O_NONBLOCK);
+    fd = open(devicePath.c_str(), O_RDWR | O_NONBLOCK);
     if (fd < 0)
     {
         // This would log and terminate since its not handled.
@@ -40,7 +45,15 @@ int PassThrough::openDevice()
             phosphor::logging::org::open_power::OCC::Device::
                 OpenFailure::CALLOUT_DEVICE_PATH(devicePath.c_str()));
     }
-    return fd;
+    return;
+}
+
+void PassThrough::closeDevice()
+{
+    if (fd >= 0)
+    {
+        close(fd);
+    }
 }
 
 std::vector<int32_t> PassThrough::send(std::vector<int32_t> command)
@@ -60,7 +73,7 @@ std::vector<int32_t> PassThrough::send(std::vector<int32_t> command)
             [](decltype(cmdInBytes)::value_type x){return x;});
 
     ssize_t size = cmdInBytes.size() * sizeof(decltype(cmdInBytes)::value_type);
-    auto rc = write((fd)(), cmdInBytes.data(), size);
+    auto rc = write(fd, cmdInBytes.data(), size);
     if (rc < 0 || (rc != size))
     {
         // This would log and terminate since its not handled.
@@ -75,7 +88,7 @@ std::vector<int32_t> PassThrough::send(std::vector<int32_t> command)
     while(1)
     {
         uint8_t data {};
-        auto len = read((fd)(), &data, sizeof(data));
+        auto len = read(fd, &data, sizeof(data));
         if (len > 0)
         {
             response.emplace_back(data);
@@ -105,5 +118,28 @@ std::vector<int32_t> PassThrough::send(std::vector<int32_t> command)
     return response;
 }
 
+// Called at OCC Status change signal
+void PassThrough::activeStatusEvent(sdbusplus::message::message& msg)
+{
+    std::string statusInterface;
+    std::map<std::string, sdbusplus::message::variant<bool>> msgData;
+    msg.read(statusInterface, msgData);
+
+    auto propertyMap = msgData.find("OccActive");
+    if (propertyMap != msgData.end())
+    {
+        // Extract the OccActive property
+        if (sdbusplus::message::variant_ns::get<bool>(propertyMap->second))
+        {
+            this->openDevice();
+        }
+        else
+        {
+            this->closeDevice();
+        }
+    }
+    return;
+}
+
 } // namespace occ
 } // namespace open_power
diff --git a/occ_pass_through.hpp b/occ_pass_through.hpp
index f2f78c7..205fc04 100644
--- a/occ_pass_through.hpp
+++ b/occ_pass_through.hpp
@@ -4,7 +4,6 @@
 #include <sdbusplus/bus.hpp>
 #include <sdbusplus/server/object.hpp>
 #include <org/open_power/OCC/PassThrough/server.hpp>
-#include "file.hpp"
 
 namespace open_power
 {
@@ -14,6 +13,9 @@ namespace occ
 using Iface = sdbusplus::server::object::object<
     sdbusplus::org::open_power::OCC::server::PassThrough>;
 
+// For waiting on signals
+namespace sdbusRule = sdbusplus::bus::match::rules;
+
 /** @class PassThrough
  *  @brief Implements org.open_power.OCC.PassThrough
  */
@@ -21,7 +23,6 @@ class PassThrough : public Iface
 {
     public:
         PassThrough() = delete;
-        ~PassThrough() = default;
         PassThrough(const PassThrough&) = delete;
         PassThrough& operator=(const PassThrough&) = delete;
         PassThrough(PassThrough&&) = default;
@@ -34,6 +35,11 @@ class PassThrough : public Iface
         PassThrough(sdbusplus::bus::bus& bus,
                     const char* path);
 
+        ~PassThrough()
+        {
+            closeDevice();
+        }
+
         /** @brief Pass through command to OCC
          *  @param[in] command - command to pass-through
          *  @returns OCC response as an array
@@ -48,17 +54,33 @@ class PassThrough : public Iface
         /** @brief OCC device path
          *  For now, here is the hard-coded mapping until
          *  the udev rule is in.
-         *  occ0 --> /dev/occfifo1
-         *  occ1 --> /dev/occfifo2
+         *  occ0 --> /dev/occ1
+         *  occ1 --> /dev/occ2
          *  ...
          */
-        std::string devicePath = "/dev/occ";
+        std::string devicePath;
 
-        /** @brief File descriptor manager */
-        FileDescriptor fd;
+        /** brief file descriptor associated with occ device */
+        int fd = -1;
+
+        /** @brief Subscribe to OCC Status signal
+         *
+         *  Once the OCC status gets to active, only then we will get /dev/occ2
+         *  populated and hence need to wait on that before opening that
+         */
+        sdbusplus::bus::match_t activeStatusSignal;
 
-        /** Opens devicePath and returns file descritor */
-        int openDevice();
+        /** Opens devicePath and populates file descritor */
+        void openDevice();
+
+        /** Closed the fd associated with opened device */
+        void closeDevice();
+
+        /** @brief Callback function on OCC Status change signals
+         *
+         *  @param[in]  msg - Data associated with subscribed signal
+         */
+        void activeStatusEvent(sdbusplus::message::message& msg);
 };
 
 } // namespace occ