1 files changed, 87 insertions, 0 deletions
diff --git a/kernel/kapi/devices.cpp b/kernel/kapi/devices.cpp
new file mode 100644
index 0000000..031f2c9
--- /dev/null
+++ b/kernel/kapi/devices.cpp
@@ -0,0 +1,87 @@
+#include "kapi/devices.hpp"
+
+#include "kapi/system.hpp"
+
+#include "kernel/devices/root_bus.hpp"
+
+#include <kstd/flat_map>
+#include <kstd/memory>
+#include <kstd/print>
+
+#include <atomic>
+#include <cstddef>
+#include <optional>
+#include <string_view>
+#include <utility>
+
+namespace kapi::devices
+{
+
+  namespace
+  {
+    auto constinit next_major_number = std::atomic_size_t{1};
+    auto constinit root_bus = std::optional<kernel::devices::root_bus>{};
+    auto constinit device_tree = kstd::flat_map<std::pair<std::size_t, std::size_t>, kstd::observer_ptr<device>>{};
+  }  // namespace
+
+  auto init() -> void
+  {
+    auto static is_initialized = std::atomic_flag{};
+    if (is_initialized.test_and_set())
+    {
+      return;
+    }
+
+    auto & bus = root_bus.emplace();
+    register_device(bus);
+    bus.init();
+  }
+
+  auto get_root_bus() -> bus &
+  {
+    if (!root_bus.has_value())
+    {
+      kapi::system::panic("[OS:DEV] Root bus not initialized!");
+    }
+    return *root_bus;
+  }
+
+  auto allocate_major_number() -> std::size_t
+  {
+    return next_major_number++;
+  }
+
+  auto register_device(device & device) -> bool
+  {
+    kstd::println("[OS:DEV] Registering device {}@{}:{}", device.name(), device.major(), device.minor());
+    return device_tree.emplace(std::pair{device.major(), device.minor()}, &device).second;
+  }
+
+  auto unregister_device(device &) -> bool
+  {
+    kstd::println("[OS:DEV] TODO: implement device deregistration");
+    return false;
+  }
+
+  auto find_device(std::size_t major, std::size_t minor) -> kstd::observer_ptr<device>
+  {
+    if (device_tree.contains(std::pair{major, minor}))
+    {
+      return device_tree.at(std::pair{major, minor});
+    }
+    return nullptr;
+  }
+
+  auto find_device(std::string_view name) -> kstd::observer_ptr<device>
+  {
+    for (auto const & [key, value] : device_tree)
+    {
+      if (value->name() == name)
+      {
+        return value;
+      }
+    }
+    return nullptr;
+  }
+
+}  // namespace kapi::devices
+\ No newline at end of file