1 files changed, 91 insertions, 0 deletions
diff --git a/riscv/mmio_plugin.h b/riscv/mmio_plugin.h
new file mode 100644
index 0000000..f14470b
--- /dev/null
+++ b/riscv/mmio_plugin.h
@@ -0,0 +1,91 @@
+#ifndef _RISCV_MMIO_PLUGIN_H
+#define _RISCV_MMIO_PLUGIN_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+typedef uint64_t reg_t;
+
+typedef struct {
+  // Allocate user data for an instance of the plugin. The parameter is a simple
+  // c-string containing arguments used to construct the plugin. It returns a
+  // void* to the allocated data.
+  void* (*alloc)(const char*);
+
+  // Load a memory address of the MMIO plugin. The parameters are the user_data
+  // (void*), memory offset (reg_t), number of bytes to load (size_t), and the
+  // buffer into which the loaded data should be written (uint8_t*). Return true
+  // if the load is successful and false otherwise.
+  bool (*load)(void*, reg_t, size_t, uint8_t*);
+
+  // Store some bytes to a memory address of the MMIO plugin. The parameters are
+  // the user_data (void*), memory offset (reg_t), number of bytes to store
+  // (size_t), and the buffer containing the data to be stored (const uint8_t*).
+  // Return true if the store is successful and false otherwise.
+  bool (*store)(void*, reg_t, size_t, const uint8_t*);
+
+  // Deallocate the data allocated during the call to alloc. The parameter is a
+  // pointer to the user data allocated during the call to alloc.
+  void (*dealloc)(void*);
+} mmio_plugin_t;
+
+// Register an mmio plugin with the application. This should be called by
+// plugins as part of their loading process.
+extern void register_mmio_plugin(const char* name_cstr,
+                                 const mmio_plugin_t* mmio_plugin);
+
+#ifdef __cplusplus
+}
+
+#include <string>
+
+// Wrapper around the C plugin API that makes registering a C++ class with
+// correctly formed constructor, load, and store functions easier. The template
+// type should be the type that implements the MMIO plugin interface. Simply
+// make a global mmio_plugin_registration_t and your plugin should register
+// itself with the application when it is loaded because the
+// mmio_plugin_registration_t constructor will be called.
+template <typename T>
+struct mmio_plugin_registration_t
+{
+  static void* alloc(const char* args)
+  {
+    return reinterpret_cast<void*>(new T(std::string(args)));
+  }
+
+  static bool load(void* self, reg_t addr, size_t len, uint8_t* bytes)
+  {
+    return reinterpret_cast<T*>(self)->load(addr, len, bytes);
+  }
+
+  static bool store(void* self, reg_t addr, size_t len, const uint8_t* bytes)
+  {
+    return reinterpret_cast<T*>(self)->store(addr, len, bytes);
+  }
+
+  static void dealloc(void* self)
+  {
+    delete reinterpret_cast<T*>(self);
+  }
+
+  mmio_plugin_registration_t(const std::string& name)
+  {
+    mmio_plugin_t plugin = {
+      mmio_plugin_registration_t<T>::alloc,
+      mmio_plugin_registration_t<T>::load,
+      mmio_plugin_registration_t<T>::store,
+      mmio_plugin_registration_t<T>::dealloc,
+    };
+
+    register_mmio_plugin(name.c_str(), &plugin);
+  }
+};
+#endif // __cplusplus
+
+#endif