x86_64: port legacy PIT driver to new architecture

5 files changed, 184 insertions, 23 deletions

diff --git a/arch/x86_64/arch/bus/isa.cpp b/arch/x86_64/arch/bus/isa.cpp
index dd248f76..573feb72 100644
--- a/arch/x86_64/arch/bus/isa.cpp
+++ b/arch/x86_64/arch/bus/isa.cpp
@@ -2,6 +2,11 @@
 
 #include <kapi/devices.hpp>
 
+#include <kstd/result.hpp>
+
+#include <algorithm>
+#include <cstdint>
+
 namespace arch::bus
 {
 
@@ -9,4 +14,28 @@ namespace arch::bus
       : kapi::devices::bus{"isa"}
   {}
 
+  auto isa::enumerate(kapi::devices::bus &) -> void
+  {
+    // NOTE: ISA does not support enumeration, but we need to fulfill the interface.
+  }
+
+  auto isa::match(kapi::devices::device const & device, kapi::devices::driver const & driver) const
+      -> kstd::result<std::uint32_t>
+  {
+    auto identification = device.as<isa_identification>();
+    auto claims = driver.as<isa_driver_identification>();
+
+    if (!identification || !claims || !std::ranges::contains(claims->supported_names(), identification->isa_name()))
+    {
+      return kstd::failure(kapi::devices::driver_match_errc::no_match);
+    }
+
+    return 0u;
+  }
+
+  auto isa::protocol() -> kapi::devices::bus_protocol *
+  {
+    return this;
+  }
+
 }  // namespace arch::bus
\ No newline at end of file
diff --git a/arch/x86_64/arch/bus/isa.hpp b/arch/x86_64/arch/bus/isa.hpp
index 5741a640..a09127dd 100644
--- a/arch/x86_64/arch/bus/isa.hpp
+++ b/arch/x86_64/arch/bus/isa.hpp
@@ -1,14 +1,45 @@
 #ifndef TEACHOS_X86_64_BUS_ISA_HPP
 #define TEACHOS_X86_64_BUS_ISA_HPP
 
-#include <kapi/devices/bus.hpp>
+#include <kapi/devices.hpp>
+
+#include <kstd/result.hpp>
+
+#include <cstdint>
+#include <span>
+#include <string_view>
 
 namespace arch::bus
 {
 
-  struct isa final : public kapi::devices::bus
+  struct isa_identification
+  {
+    constexpr auto static id = kapi::devices::interface{"isa_identification"};
+
+    virtual ~isa_identification() = default;
+
+    [[nodiscard]] virtual auto isa_name() const -> std::string_view = 0;
+  };
+
+  struct isa_driver_identification
+  {
+    constexpr auto static id = kapi::devices::interface{"isa_driver_identification"};
+
+    virtual ~isa_driver_identification() = default;
+
+    [[nodiscard]] virtual auto supported_names() const -> std::span<std::string_view const> = 0;
+  };
+
+  struct isa final : public kapi::devices::bus, kapi::devices::bus_protocol
   {
     isa();
+
+    auto enumerate(kapi::devices::bus & self) -> void override;
+
+    [[nodiscard]] auto match(kapi::devices::device const & device, kapi::devices::driver const & driver) const
+        -> kstd::result<std::uint32_t> override;
+
+    [[nodiscard]] auto protocol() -> kapi::devices::bus_protocol * override;
   };
 
 }  // namespace arch::bus
diff --git a/arch/x86_64/arch/devices/init.cpp b/arch/x86_64/arch/devices/init.cpp
index 2c4fb3c3..f6adcbcf 100644
--- a/arch/x86_64/arch/devices/init.cpp
+++ b/arch/x86_64/arch/devices/init.cpp
@@ -7,6 +7,7 @@
 #include <kapi/acpi.hpp>
 #include <kapi/cpu.hpp>
 #include <kapi/devices.hpp>
+#include <kapi/devices/driver_registry.hpp>
 
 #include <acpi/acpi.hpp>
 
@@ -14,7 +15,6 @@
 #include <kstd/print.hpp>
 
 #include <cstdint>
-#include <utility>
 
 namespace arch::devices
 {
@@ -63,12 +63,12 @@ namespace arch::devices
     kstd::println("[x86_64:DEV] Initializing ISA bus...");
 
     auto isa_bus = kstd::make_shared<arch::bus::isa>();
+    auto root_bus = kapi::devices::get_root_bus();
 
-    auto pit = kstd::make_shared<arch::devices::legacy_pit>(pit_frequency_in_hz);
-    isa_bus->add_child(std::move(pit));
+    root_bus->add_child(isa_bus);
 
-    auto root_bus = kapi::devices::get_root_bus();
-    root_bus->add_child(std::move(isa_bus));
+    kapi::devices::driver_registry::get().add(kstd::make_shared<pit_driver>(pit_frequency_in_hz));
+    isa_bus->add_child(kstd::make_shared<pit_device>());
   }
 
 }  // namespace arch::devices
diff --git a/arch/x86_64/arch/devices/legacy_pit.cpp b/arch/x86_64/arch/devices/legacy_pit.cpp
index d93b38fd..5e968a6b 100644
--- a/arch/x86_64/arch/devices/legacy_pit.cpp
+++ b/arch/x86_64/arch/devices/legacy_pit.cpp
@@ -1,16 +1,25 @@
 #include <arch/devices/legacy_pit.hpp>
 
+#include <arch/bus/isa.hpp>
 #include <arch/device_io/port_io.hpp>
 
 #include <kapi/devices.hpp>
 #include <kapi/devices/device.hpp>
 #include <kapi/interrupts.hpp>
 
+#include <kstd/memory.hpp>
+#include <kstd/result.hpp>
+
+#include <array>
 #include <cstdint>
+#include <span>
+#include <string_view>
 
 namespace arch::devices
 {
 
+  using namespace std::string_view_literals;
+
   namespace
   {
     using command_port = io::port<0x43, std::uint8_t, io::port_write>;
@@ -20,19 +29,46 @@ namespace arch::devices
 
     constexpr auto base_frequency = 1'193'182u;
     constexpr auto square_wave_mode = 0x36;
+
+    constexpr auto pit_names = std::array{"pit"sv};
   }  // namespace
 
-  legacy_pit::legacy_pit(std::uint32_t frequency_in_hz)
-      : kapi::devices::device{"legacy_pit"}
-      , m_irq_number{0}
-      , m_frequency_in_hz{frequency_in_hz}
+  pit_device::pit_device()
+      : device{"legacy_pit"}
+  {}
+
+  auto pit_device::isa_name() const -> std::string_view
+  {
+    return "pit";
+  }
+
+  auto pit_device::init() -> bool
+  {
+    return true;
+  }
+
+  auto pit_device::query_interface(kapi::devices::interface interface) -> void *
+  {
+    if (interface == arch::bus::isa_identification::id)
+    {
+      return static_cast<arch::bus::isa_identification *>(this);
+    }
+
+    return kapi::devices::device::query_interface(interface);
+  }
+
+  pit_driver::pit_driver(std::uint32_t frequency_in_hz)
+      : m_frequency_in_hz{frequency_in_hz}
   {}
 
-  auto legacy_pit::init() -> bool
+  auto pit_driver::probe(kapi::devices::device & device) -> kstd::result<void>
   {
-    auto divisor = static_cast<std::uint16_t>(base_frequency / m_frequency_in_hz);
+    auto data = kstd::make_shared<driver_data>(0, m_frequency_in_hz, 0);
+    device.set_driver_data(data);
 
-    kapi::interrupts::register_handler(m_irq_number, *this);
+    auto divisor = static_cast<std::uint16_t>(base_frequency / data->frequency_in_hz);
+
+    kapi::interrupts::register_handler(data->irq_number, *this);
 
     command_port::write<std::uint8_t>(square_wave_mode);
     io::wait();
@@ -41,19 +77,46 @@ namespace arch::devices
     channel_0_port::write<std::uint8_t>(divisor >> 8 & 0xff);
     io::wait();
 
-    return true;
+    return kstd::success();
   }
 
-  auto legacy_pit::handle_interrupt(std::uint32_t irq_number) -> kapi::interrupts::status
+  auto pit_driver::unbind(kapi::devices::device & device) -> void
   {
-    if (irq_number != m_irq_number)
+    auto data = static_pointer_cast<driver_data>(device.driver_data());
+
+    kapi::interrupts::unregister_handler(data->irq_number, *this);
+
+    device.set_driver_data(nullptr);
+  }
+
+  auto pit_driver::supported_names() const -> std::span<std::string_view const>
+  {
+    return pit_names;
+  }
+
+  auto pit_driver::handle_interrupt(std::uint32_t irq_number) -> kapi::interrupts::status
+  {
+    // auto data = static_pointer_cast<driver_data>(device.driver_data());
+
+    if (irq_number != 0)
     {
       return kapi::interrupts::status::unhandled;
     }
 
-    ++m_ticks;
+    // TODO: upgrade kapi interrupts to gain access to the device.
+    // ++m_ticks;
 
     return kapi::interrupts::status::handled;
   }
 
+  auto pit_driver::query_interface(kapi::devices::interface interface) -> void *
+  {
+    if (interface == arch::bus::isa_driver_identification::id)
+    {
+      return static_cast<arch::bus::isa_driver_identification *>(this);
+    }
+
+    return kapi::devices::driver::query_interface(interface);
+  }
+
 }  // namespace arch::devices
\ No newline at end of file
diff --git a/arch/x86_64/arch/devices/legacy_pit.hpp b/arch/x86_64/arch/devices/legacy_pit.hpp
index 7a74144e..1bb41e2b 100644
--- a/arch/x86_64/arch/devices/legacy_pit.hpp
+++ b/arch/x86_64/arch/devices/legacy_pit.hpp
@@ -1,26 +1,64 @@
 #ifndef TEACHOS_ARCH_X86_64_DEVICES_LEGACY_PIT_HPP
 #define TEACHOS_ARCH_X86_64_DEVICES_LEGACY_PIT_HPP
 
-#include <kapi/devices/device.hpp>
+#include <arch/bus/isa.hpp>
+
+#include <kapi/devices.hpp>
 #include <kapi/interrupts.hpp>
 
+#include <kstd/result.hpp>
+
 #include <cstdint>
+#include <span>
+#include <string_view>
 
 namespace arch::devices
 {
 
-  struct legacy_pit : kapi::devices::device, kapi::interrupts::handler
+  //! The ISA device for the legacy Programmable Interrupt Timer.
+  //!
+  //! This type identifies the PIT device node to the driver, so the driver can be matched successfully.
+  struct pit_device final : kapi::devices::device, arch::bus::isa_identification
   {
-    explicit legacy_pit(std::uint32_t frequency_in_hz);
+    pit_device();
 
+    // TODO: remove
     auto init() -> bool override;
 
+    //! Get the synthetic ISA identifier for this device.
+    //!
+    //! @return the string "pit"
+    [[nodiscard]] auto isa_name() const -> std::string_view override;
+
+  protected:
+    auto query_interface(kapi::devices::interface interface) -> void * override;
+  };
+
+  //! The driver for the legacy, ISA-connected Programmable Interrupt Timer.
+  struct pit_driver final : kapi::devices::driver, arch::bus::isa_driver_identification, kapi::interrupts::handler
+  {
+    explicit pit_driver(std::uint32_t frequency_in_hz);
+
+    [[nodiscard]] auto probe(kapi::devices::device & device) -> kstd::result<void> override;
+
+    auto unbind(kapi::devices::device & device) -> void override;
+
+    [[nodiscard]] auto supported_names() const -> std::span<std::string_view const> override;
+
     auto handle_interrupt(std::uint32_t irq_number) -> kapi::interrupts::status override;
 
+  protected:
+    auto query_interface(kapi::devices::interface interface) -> void * override;
+
   private:
-    std::uint32_t m_irq_number{};
+    struct driver_data
+    {
+      std::uint32_t irq_number{};
+      std::uint32_t frequency_in_hz{};
+      std::uint64_t ticks{};
+    };
+
     std::uint32_t m_frequency_in_hz{};
-    std::uint64_t m_ticks{};
   };
 
 }  // namespace arch::devices