get AMD GPUs in plugin

src/plugins/AMD.cpp

@@ -1,22 +1,56 @@
 #include <Plugin.hpp>
 
+#include <errno.h>
+#include <fcntl.h>
+#include <filesystem>
+#include <functional>
 #include <iostream>
+#include <libdrm/amdgpu.h>
+#include <libdrm/amdgpu_drm.h>
+#include <unistd.h>
+#include <xf86drm.h>
+
+extern int errno;
+
+#ifndef DRM_RENDER_MINOR_NAME
+	#define DRM_RENDER_MINOR_NAME "renderD"
+#endif
+
+#define _HWMON_NAME "hwmon"
+#define _AMDGPU_NAME "amdgpu"
+#define DEVICE_FILE_PREFIX DRM_DIR_NAME "/" DRM_RENDER_MINOR_NAME
+#define RENDERD_OFFSET 128
 
 using namespace TuxClocker::Plugin;
 using namespace TuxClocker::Device;
 using namespace TuxClocker;
 
+namespace fs = std::filesystem;
+
+struct AMDAssignableInfo {
+	// Thus is Linux only
+	std::optional<std::string> hwmonPath;
+	amdgpu_device_handle devHandle;
+};
+
 class AMDPlugin : public DevicePlugin {
 public:
 	AMDPlugin();
 	std::optional<InitializationError> initializationError() {return std::nullopt;}
 	void foo() {std::cout << "hi from AMD plugin\n";}
 	TreeNode<DeviceNode> deviceRootNode();
-	~AMDPlugin() {}
+	~AMDPlugin();
 private:
 	TreeNode<DeviceNode> m_rootNode;
+	std::vector<AMDAssignableInfo> m_assignableInfoVec;
 };
 
+AMDPlugin::~AMDPlugin() {
+	for (auto info : m_assignableInfoVec) {
+		amdgpu_device_deinitialize(info.devHandle);
+	}
+}
+
 AMDPlugin::AMDPlugin() {
 	/*Assignable a([](auto arg) {
 		return std::nullopt;
@@ -24,6 +58,51 @@ AMDPlugin::AMDPlugin() {
 	
 	DeviceNode root{"AMD", a};
 	m_rootNode.appendChild(root);*/
+	
+	struct FSInfo {
+		std::string path;
+		std::string filename;
+	};
+	
+	std::vector<FSInfo> infoVec;
+	// Iterate through files in GPU device folder and find which ones have amdgpu loaded
+	for (const auto &entry : fs::directory_iterator(DRM_DIR_NAME)) {
+		// Check if entry is renderD file
+		if (entry.path().string().find(DRM_RENDER_MINOR_NAME) != std::string::npos) {
+			infoVec.push_back(FSInfo{entry.path().string(), entry.path().filename().string()});
+		}
+	}
+	
+	for (const auto &info : infoVec) {
+		auto fd = open(info.path.c_str(), O_RDONLY);
+		auto v_ptr = drmGetVersion(fd);
+		amdgpu_device_handle dev;
+		uint32_t m, n;
+		if (fd > 0 &&
+		    v_ptr &&
+		    amdgpu_device_initialize(fd, &m, &n, &dev) == 0 &&
+		    std::string(v_ptr->name).find(_AMDGPU_NAME) != std::string::npos) {
+				// Device uses amdgpu
+				// Find hwmon path if available
+				std::ostringstream stream;
+				stream << "/sys/class/drm/" << info.filename << "/device/hwmon";
+			
+				std::optional<std::string> hwmonPath = std::nullopt;
+				try {
+					for (const auto &entry : fs::directory_iterator(stream.str())) {
+						if (entry.path().filename().string().find("hwmon") != std::string::npos) {
+							hwmonPath = entry.path().string();
+							break;
+						}
+					}
+				}
+				// This exception is only abnormal to get on Linux
+				catch (fs::filesystem_error &e) {}
+				m_assignableInfoVec.push_back(AMDAssignableInfo{hwmonPath, dev});
+		}
+		close(fd);
+		drmFreeVersion(v_ptr);
+	}
 }
 
 TreeNode<DeviceNode> AMDPlugin::deviceRootNode() {

src/plugins/meson.build

@@ -1,5 +1,11 @@
-shared_library('amd', 'AMD.cpp',
-	override_options : ['cpp_std=c++17'],
-	include_directories : incdir,
-	install_dir : get_option('libdir') / 'tuxclocker' / 'plugins',
-	install : true)
+libdrm_amdgpu = cppc.find_library('libdrm_amdgpu', required : false)
+libdrm_dep = dependency('libdrm', required : false)
+
+if libdrm_dep.found() and libdrm_amdgpu.found()
+	shared_library('amd', 'AMD.cpp',
+		override_options : ['cpp_std=c++17'],
+		include_directories : incdir,
+		dependencies : [libdrm_amdgpu, libdrm_dep],
+		install_dir : get_option('libdir') / 'tuxclocker' / 'plugins',
+		install : true)
+endif