5 files changed, 127 insertions, 1 deletions

diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt
index f283588..9868eb9 100644
--- a/kernel/CMakeLists.txt
+++ b/kernel/CMakeLists.txt
@@ -3,6 +3,7 @@ add_library("kernel_objs" OBJECT
     "kapi/boot_modules.cpp"
     "kapi/cio.cpp"
     "kapi/cpu.cpp"
+    "kapi/devices.cpp"
     "kapi/interrupts.cpp"
     "kapi/memory.cpp"
     "kapi/system.cpp"
@@ -17,6 +18,7 @@ add_library("kernel_objs" OBJECT
     "src/memory.cpp"
     "src/devices/block_device.cpp"
     "src/devices/block_device_utils.cpp"
+    "src/devices/root_bus.cpp"
     "src/devices/storage/controller.cpp"
     "src/devices/storage/management.cpp"
     "src/devices/storage/ram_disk/controller.cpp"
diff --git a/kernel/include/kernel/devices/root_bus.hpp b/kernel/include/kernel/devices/root_bus.hpp
new file mode 100644
index 0000000..660b715
--- /dev/null
+++ b/kernel/include/kernel/devices/root_bus.hpp
@@ -0,0 +1,16 @@
+#ifndef TEACHOS_KERNEL_DEVICES_ROOT_BUS_HPP
+#define TEACHOS_KERNEL_DEVICES_ROOT_BUS_HPP
+
+#include "kapi/devices/bus.hpp"
+
+namespace kernel::devices
+{
+
+  struct root_bus final : kapi::devices::bus
+  {
+    root_bus();
+  };
+
+}  // namespace kernel::devices
+
+#endif
\ No newline at end of file
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
diff --git a/kernel/src/devices/root_bus.cpp b/kernel/src/devices/root_bus.cpp
new file mode 100644
index 0000000..43a35bf
--- /dev/null
+++ b/kernel/src/devices/root_bus.cpp
@@ -0,0 +1,12 @@
+#include "kernel/devices/root_bus.hpp"
+
+#include "kapi/devices.hpp"
+
+namespace kernel::devices
+{
+
+  root_bus::root_bus()
+      : kapi::devices::bus{0, 0, "system"}
+  {}
+
+}  // namespace kernel::devices
\ No newline at end of file
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index 37b4c5b..2eaa2d8 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -1,6 +1,7 @@
 #include "kapi/boot_modules.hpp"
 #include "kapi/cio.hpp"
 #include "kapi/cpu.hpp"
+#include "kapi/devices.hpp"
 #include "kapi/interrupts.hpp"
 #include "kapi/memory.hpp"
 #include "kapi/system.hpp"
@@ -172,13 +173,21 @@ auto main() -> int
   kstd::println("[OS] IO subsystem initialized.");
 
   kapi::cpu::init();
-  kapi::interrupts::enable();
 
   kapi::memory::init();
   kernel::memory::init_heap(kapi::memory::heap_base);
   kstd::println("[OS] Memory subsystem initialized.");
   kapi::system::memory_initialized();
 
+  kapi::devices::init();
+  kstd::println("[OS] System root bus initialized.");
+
+  kapi::devices::init_platform_devices();
+  kstd::println("[OS] Platform devices initialized.");
+
+  kapi::interrupts::enable();
+  kstd::println("[OS] Interrupts enabled.");
+
   kapi::boot_modules::init();
   kstd::println("[OS] Boot module registry initialized.");