Add default construction to the UltraScale configuration

The idea is to avoid reconfiguring the FPGA in already configured
devices

Author: lleoncr

include/cynq/hardware.hpp

@@ -208,5 +208,22 @@ class IHardware {
    */
   static std::shared_ptr<IHardware> Create(const HardwareArchitecture hw,
                                            const std::string &config);
+
+  /**
+   * @brief Create method
+   * Factory method to create a hardware-specific subclasses for accelerators
+   * and data movers. The configuration of the FPGA is not performed by using
+   * this constructor, since this assumes that there is none bitstream to load.
+   *
+   * @param hw One of the values in the HardwareArchitecture enum class
+   * present in the enums.hpp file that should correspond to the device being
+   * used.
+   *
+   * @return std::shared_ptr<IHardware>
+   * Returns an IAccelerator pointer with reference counting. It should be
+   * thread-safe.
+   *
+   */
+  static std::shared_ptr<IHardware> Create(const HardwareArchitecture hw);
 };
 }  // namespace cynq

include/cynq/ultrascale/hardware.hpp

@@ -86,9 +86,12 @@ class UltraScale : public IHardware {
    */
   UltraScale(const std::string &bitstream_file, const std::string &xclbin_file);
   /**
-   * No default constructor required
+   * @brief Construct a new UltraScale object
+   *
+   * Configure the hardware platform without loading a bitstream nor xclbin.
+   * This is useful for already configured FPGAs.
    */
-  UltraScale() = delete;
+  UltraScale();
   /**
    * @brief ~UltraScale destructor method
    * Destroy the UltraScale object.

src/cynq/hardware.cpp

@@ -38,6 +38,15 @@ std::shared_ptr<IHardware> IHardware::Create(const HardwareArchitecture hw,
   }
 }
 
+std::shared_ptr<IHardware> IHardware::Create(const HardwareArchitecture hw) {
+  switch (hw) {
+    case HardwareArchitecture::UltraScale:
+      return std::make_shared<UltraScale>();
+    default:
+      return nullptr;
+  }
+}
+
 std::shared_ptr<IExecutionGraph> IHardware::GetExecutionStream(
     const std::string& name, const IExecutionGraph::Type type,
     const std::shared_ptr<ExecutionGraphParameters> params) {

src/cynq/ultrascale/hardware.cpp

@@ -126,6 +126,23 @@ UltraScale::UltraScale(const std::string &bitstream_file,
   GetClocksInformation();
 }
 
+UltraScale::UltraScale()
+    : parameters_{std::make_shared<UltraScaleParameters>()} {
+  /* For the UltraScale, there is only a single device. It is possible to
+     load either a bitstream or a xclbin. */
+  Status st{};
+
+  /* Configure the buses accordingly to the default design */
+  st = LoadXclBin(EXAMPLE_KRIA_DEFAULT_XCLBIN_LOCATION);
+  if (st.code != Status::OK) {
+    std::string msg = "Error while configuring the buses: ";
+    msg += st.msg;
+    throw std::runtime_error(msg);
+  }
+
+  GetClocksInformation();
+}
+
 Status UltraScale::LoadBitstream(const std::string &bitstream_file) {
   /* FIXME: This is a temporal implementation while we are coding our own
      implementation. Use with caution */