From f456f1674d48932846eb7b5ec1df630ad67e7e3d Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Mon, 6 Apr 2026 17:24:36 +0200
Subject: kernel/acpi: discover local interrupt controllers

---
 kapi/include/kapi/acpi.hpp           | 91 +++++++++++++++++++++++++++---------
 kapi/include/kapi/devices/bus.hpp    |  2 +
 kapi/include/kapi/devices/device.hpp |  2 +
 3 files changed, 72 insertions(+), 23 deletions(-)

(limited to 'kapi')

diff --git a/kapi/include/kapi/acpi.hpp b/kapi/include/kapi/acpi.hpp
index 11068d1..5d55d08 100644
--- a/kapi/include/kapi/acpi.hpp
+++ b/kapi/include/kapi/acpi.hpp
@@ -1,8 +1,10 @@
 #ifndef TEACHOS_KAPI_ACPI_HPP
 #define TEACHOS_KAPI_ACPI_HPP
 
+#include "kapi/devices.hpp"
 #include "kapi/memory.hpp"
 
+#include <kstd/memory>
 #include <kstd/units>
 
 #include <array>
@@ -14,9 +16,38 @@
 namespace kapi::acpi
 {
 
-  //! @addtogroup kapi-acpi
+  //! @addtogroup kapi-acpi-kernel-defined
   //! @{
 
+  struct [[gnu::packed]] root_system_description_pointer
+  {
+    [[nodiscard]] auto oem_id() const noexcept -> std::string_view;
+    [[nodiscard]] auto revision() const noexcept -> std::uint8_t;
+    [[nodiscard]] auto signature() const noexcept -> std::string_view;
+    [[nodiscard]] auto table_address() const noexcept -> memory::physical_address;
+    [[nodiscard]] auto validate() const noexcept -> bool;
+
+  private:
+    std::array<char, 8> m_signature;
+    [[maybe_unused]] std::uint8_t m_checksum;
+    std::array<char, 6> m_oem_id;
+    std::uint8_t m_revision;
+    std::array<std::byte, 4> m_rsdt_address;
+  };
+
+  struct [[gnu::packed]] extended_system_description_pointer : root_system_description_pointer
+  {
+    [[nodiscard]] auto length() const noexcept -> kstd::units::bytes;
+    [[nodiscard]] auto table_address() const noexcept -> memory::physical_address;
+    [[nodiscard]] auto validate() const noexcept -> bool;
+
+  private:
+    std::uint32_t m_length;
+    std::array<std::byte, 8> m_xsdt_address;
+    [[maybe_unused]] std::uint8_t m_extended_checksum;
+    [[maybe_unused]] std::array<std::byte, 3> m_reserved;
+  };
+
   struct [[gnu::packed]] system_description_table_header
   {
     [[nodiscard]] auto checksum() const noexcept -> std::uint8_t;
@@ -41,38 +72,36 @@ namespace kapi::acpi
     std::uint32_t m_creator_revision;
   };
 
-  //! @}
+  struct [[gnu::packed]] madt_header : system_description_table_header
+  {
+    [[nodiscard]] auto local_interrupt_controller_address() const noexcept -> memory::physical_address;
+    [[nodiscard]] auto flags() const noexcept -> std::uint32_t;
 
-  //! @addtogroup kapi-acpi-kernel-defined
-  //! @{
+  private:
+    std::uint32_t m_local_interrupt_controller_address;
+    std::uint32_t m_flags;
+  };
 
-  struct [[gnu::packed]] root_system_description_pointer
+  struct [[gnu::packed]] madt_subtable_header
   {
-    [[nodiscard]] auto oem_id() const noexcept -> std::string_view;
-    [[nodiscard]] auto revision() const noexcept -> std::uint8_t;
-    [[nodiscard]] auto signature() const noexcept -> std::string_view;
-    [[nodiscard]] auto table_address() const noexcept -> memory::physical_address;
-    [[nodiscard]] auto validate() const noexcept -> bool;
+    [[nodiscard]] auto type() const noexcept -> std::uint8_t;
+    [[nodiscard]] auto length() const noexcept -> std::size_t;
 
   private:
-    std::array<char, 8> m_signature;
-    [[maybe_unused]] std::uint8_t m_checksum;
-    std::array<char, 6> m_oem_id;
-    std::uint8_t m_revision;
-    std::array<std::byte, 4> m_rsdt_address;
+    std::uint8_t m_type;
+    std::uint8_t m_length;
   };
 
-  struct [[gnu::packed]] extended_system_description_pointer : root_system_description_pointer
+  struct [[gnu::packed]] madt_local_apic : madt_subtable_header
   {
-    [[nodiscard]] auto length() const noexcept -> kstd::units::bytes;
-    [[nodiscard]] auto table_address() const noexcept -> memory::physical_address;
-    [[nodiscard]] auto validate() const noexcept -> bool;
+    [[nodiscard]] auto apic_id() const noexcept -> std::uint8_t;
+    [[nodiscard]] auto flags() const noexcept -> std::uint32_t;
+    [[nodiscard]] auto processor_id() const noexcept -> std::uint32_t;
 
   private:
-    std::uint32_t m_length;
-    std::array<std::byte, 8> m_xsdt_address;
-    [[maybe_unused]] std::uint8_t m_extended_checksum;
-    [[maybe_unused]] std::array<std::byte, 3> m_reserved;
+    std::uint8_t m_processor_id;
+    std::uint8_t m_apic_id;
+    std::uint32_t m_flags;
   };
 
   //! Initialize the ACPI subsystem and discover the available tables.
@@ -86,6 +115,22 @@ namespace kapi::acpi
   //! @return true iff. the checksum is valid, false otherwise.
   auto validate_checksum(std::span<std::byte const> data) -> bool;
 
+  //! Get an ACPI table by its signature.
+  //!
+  //! @param signature The signature of the table to get.
+  //! @return A pointer to the table if found, nullptr otherwise.
+  auto get_table(std::string_view signature) -> kstd::observer_ptr<system_description_table_header const>;
+
+  //! @}
+
+  //! @addtogroup kapi-acpi-platform-defined
+  //! @{
+
+  auto get_root_pointer() -> kstd::observer_ptr<root_system_description_pointer const>;
+
+  auto create_local_interrupt_controller(std::size_t major, std::size_t minor, std::uint64_t hardware_id,
+                                         memory::physical_address address) -> kstd::unique_ptr<devices::device>;
+
   //! @}
 
 }  // namespace kapi::acpi
diff --git a/kapi/include/kapi/devices/bus.hpp b/kapi/include/kapi/devices/bus.hpp
index 052c062..a384291 100644
--- a/kapi/include/kapi/devices/bus.hpp
+++ b/kapi/include/kapi/devices/bus.hpp
@@ -1,6 +1,8 @@
 #ifndef TEACHOS_KAPI_DEVICES_BUS_HPP
 #define TEACHOS_KAPI_DEVICES_BUS_HPP
 
+// IWYU pragma: private, include "kapi/devices.hpp"
+
 #include "kapi/devices/device.hpp"
 #include "kapi/devices/manager.hpp"
 #include "kapi/system.hpp"
diff --git a/kapi/include/kapi/devices/device.hpp b/kapi/include/kapi/devices/device.hpp
index b7b6bba..ca5033e 100644
--- a/kapi/include/kapi/devices/device.hpp
+++ b/kapi/include/kapi/devices/device.hpp
@@ -1,6 +1,8 @@
 #ifndef TEACH_OS_KAPI_DEVICES_DEVICE_HPP
 #define TEACH_OS_KAPI_DEVICES_DEVICE_HPP
 
+// IWYU pragma: private, include "kapi/devices.hpp"
+
 #include <kstd/string>
 
 #include <cstddef>
-- 
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