gpu : introduce notion of a device

The concept of a device is being introduced for the GPU, which enables a
more efficient and scalable approach to managing multiple sensors for a
single endpoint.

Refactoring of Entity-Manager Configuration and Endpoint Discovery To
support multiple sensors for an endpoint, the following changes are
being made:

Entity-Manager Configuration Discovery: This task will be moved out of
the GPU Temperature Sensor implementation.

Endpoint Discovery: Similarly, endpoint discovery will also be performed
outside of the GPU Temperature Sensor implementation.

Frequency of Task Execution: Both entity-manager configuration discovery
and endpoint discovery will be performed only once per endpoint, rather
than repeatedly for each sensor. This optimization will improve
performance and reduce redundancy.

Tested.

```
$ curl -k -u 'root:0penBmc' https://10.137.203.137/redfish/v1/Chassis/NVIDIA_GB200_1/Sensors/temperature_NVIDIA_GB200_GPU_TEMP_0
{
  "@odata.id": "/redfish/v1/Chassis/NVIDIA_GB200_1/Sensors/temperature_NVIDIA_GB200_GPU_TEMP_0",
  "@odata.type": "#Sensor.v1_2_0.Sensor",
  "Id": "temperature_NVIDIA_GB200_GPU_TEMP_0",
  "Name": "NVIDIA GB200 GPU TEMP 0",
  "Reading": 35.96875,
  "ReadingRangeMax": 127.0,
  "ReadingRangeMin": -128.0,
  "ReadingType": "Temperature",
  "ReadingUnits": "Cel",
  "Status": {
    "Health": "OK",
    "State": "Enabled"
  }
}%
```

Change-Id: Ie3dcd43caa031b4aaa61d8be3f5d71aefd53bc9a
Signed-off-by: Harshit Aghera <haghera@nvidia.com>
diff --git a/src/gpu/GpuSensor.hpp b/src/gpu/GpuSensor.hpp
index 7c70d55..2961404 100644
--- a/src/gpu/GpuSensor.hpp
+++ b/src/gpu/GpuSensor.hpp
@@ -7,34 +7,16 @@
 
 #include "MctpRequester.hpp"
 #include "Thresholds.hpp"
-#include "sensor.hpp"
+#include "UpdatableSensor.hpp"
 
-#include <boost/asio/io_context.hpp>
-#include <boost/asio/steady_timer.hpp>
-#include <boost/container/flat_map.hpp>
 #include <sdbusplus/asio/connection.hpp>
 #include <sdbusplus/asio/object_server.hpp>
-#include <sdbusplus/message.hpp>
 
-#include <chrono>
 #include <cstdint>
-#include <map>
 #include <memory>
 #include <string>
-#include <utility>
-#include <variant>
 #include <vector>
 
-constexpr const char* sensorPathPrefix = "/xyz/openbmc_project/sensors/";
-constexpr const char* sensorType = "NvidiaMctpVdm";
-
-using getSubTreeRet = std::vector<
-    std::pair<std::string,
-              std::vector<std::pair<std::string, std::vector<std::string>>>>>;
-using GpuSensorConfigMap =
-    std::map<std::string, std::variant<std::string, bool, uint32_t, uint8_t,
-                                       int64_t, std::vector<uint8_t>>>;
-
 /**
  * @struct DeviceInfo
  * @brief Contains information about a device
@@ -52,30 +34,27 @@
  * management via std::enable_shared_from_this
  */
 struct GpuTempSensor :
-    public Sensor,
+    public GpuSensor,
     public std::enable_shared_from_this<GpuTempSensor>
 {
   public:
     /**
      * @brief Constructor for GpuTempSensor
-     * @param conn D-Bus connection
-     * @param io Boost ASIO I/O context for asynchronous operations
+     * @param conn D-Bus connection for system communication
      * @param mctpRequester MCTP protocol requester for GPU communication
-     * @param name Name of the sensor
-     * @param sensorConfiguration Configuration string for the sensor
-     * @param objectServer D-Bus object server
-     * @param thresholdData Vector of threshold configurations
-     * @param pollRate How often to poll for new readings
-     * @param deviceInfo Information about the GPU device
-     * @param verbose Whether to enable verbose logging
+     * @param name Name of the sensor for identification in the system
+     * @param sensorConfiguration Configuration string for the sensor containing
+     * setup parameters
+     * @param eid EID of the device endpoint
+     * @param objectServer D-Bus object server for exposing sensor interfaces
+     * @param thresholdData Vector of threshold configurations for temperature
+     * monitoring
      */
     GpuTempSensor(std::shared_ptr<sdbusplus::asio::connection>& conn,
-                  boost::asio::io_context& io,
                   mctp::MctpRequester& mctpRequester, const std::string& name,
-                  const std::string& sensorConfiguration,
+                  const std::string& sensorConfiguration, uint8_t eid,
                   sdbusplus::asio::object_server& objectServer,
-                  std::vector<thresholds::Threshold>&& thresholdData,
-                  std::chrono::milliseconds pollRate);
+                  std::vector<thresholds::Threshold>&& thresholdData);
 
     /**
      * @brief Destructor
@@ -91,47 +70,9 @@
 
   private:
     /**
-     * @brief Read the current temperature value from the GPU
-     */
-    void read();
-
-    /**
-     * @brief Initialize the sensor
-     */
-    void init();
-
-    /**
      * @brief Update the sensor reading
      */
-    void update();
-
-    /**
-     * @brief Discover available GPUs on the system
-     */
-    void discoverGpus();
-
-    /**
-     * @brief Process MCTP endpoints discovered on the system
-     *
-     * @param[in] ec Error code from the D-Bus method call
-     * @param[in] ret Object tree results containing MCTP endpoint information
-     */
-    void processMctpEndpoints(const boost::system::error_code& ec,
-                              const getSubTreeRet& ret);
-
-    /**
-     * @brief Process configuration properties for MCTP endpoints
-     *
-     * @param[in] ec Error code from the D-Bus properties method call
-     * @param[in] configs Map of configuration properties for the endpoint
-     */
-    void processEndpointConfigs(const boost::system::error_code& ec,
-                                const GpuSensorConfigMap& configs);
-    /**
-     * @brief Process a discovered GPU endpoint
-     * @param eid The endpoint ID of the discovered GPU
-     */
-    void processGpuEndpoint(uint8_t eid);
+    void update() final;
 
     /**
      * @brief MCTP endpoint ID
@@ -144,52 +85,12 @@
     uint8_t sensorId;
 
     /**
-     * @brief How often to poll the sensor in milliseconds
-     */
-    std::chrono::milliseconds sensorPollMs;
-
-    /**
-     * @brief Timer for scheduling sensor reads
-     */
-    boost::asio::steady_timer waitTimer;
-
-    /**
      * @brief Reference to the MCTP requester for communication
      */
     mctp::MctpRequester& mctpRequester;
 
     /**
-     * @brief D-Bus connection
-     */
-    std::shared_ptr<sdbusplus::asio::connection> conn;
-
-    /**
      * @brief D-Bus object server
      */
     sdbusplus::asio::object_server& objectServer;
 };
-
-/**
- * @brief Create GPU temperature sensors
- * @param io Boost ASIO I/O context
- * @param objectServer D-Bus object server
- * @param sensors Map to store created sensors
- * @param dbusConnection D-Bus connection
- * @param mctpRequester MCTP requester for GPU communication
- */
-void createSensors(
-    boost::asio::io_context& io, sdbusplus::asio::object_server& objectServer,
-    boost::container::flat_map<std::string, std::shared_ptr<GpuTempSensor>>&
-        sensors,
-    std::shared_ptr<sdbusplus::asio::connection>& dbusConnection,
-    mctp::MctpRequester& mctpRequester);
-
-/**
- * @brief Handle D-Bus interface removal events
- * @param message D-Bus message containing interface removal information
- * @param sensors Map of GPU temperature sensors to check for removal
- */
-void interfaceRemoved(
-    sdbusplus::message_t& message,
-    boost::container::flat_map<std::string, std::shared_ptr<GpuTempSensor>>&
-        sensors);