kapi: add driver registry

4 files changed, 186 insertions, 2 deletions

diff --git a/kernel/kapi/devices.cpp b/kernel/kapi/devices.cpp
index 8f3011fe..5eed1b87 100644
--- a/kernel/kapi/devices.cpp
+++ b/kernel/kapi/devices.cpp
@@ -2,6 +2,7 @@
 
 #include <kernel/devices/root_bus.hpp>
 
+#include <kapi/devices/driver_registry.hpp>
 #include <kapi/system.hpp>
 #include <kapi/test_support/devices.hpp>
 
@@ -9,6 +10,7 @@
 #include <kstd/memory.hpp>
 #include <kstd/print.hpp>
 #include <kstd/string.hpp>
+#include <kstd/vector.hpp>
 
 #include <string_view>
 #include <utility>
@@ -29,6 +31,7 @@ namespace kapi::devices
     }
 
     interface_registry::init();
+    driver_registry::init();
 
     root_bus = kstd::make_shared<kernel::devices::root_bus>();
     register_device(root_bus);
@@ -85,6 +88,21 @@ namespace kapi::devices
     return found->second.lock();
   }
 
+  auto all() -> kstd::vector<kstd::shared_ptr<device>>
+  {
+    auto result = kstd::vector<kstd::shared_ptr<device>>{};
+
+    for (auto const & [name, weak_device] : device_tree)
+    {
+      if (auto device = weak_device.lock())
+      {
+        result.push_back(std::move(device));
+      }
+    }
+
+    return result;
+  }
+
 }  // namespace kapi::devices
 
 namespace kapi::test_support::devices
@@ -92,6 +110,7 @@ namespace kapi::test_support::devices
   auto deinit() -> void
   {
     deinit_interface_registry();
+    deinit_driver_registry();
 
     kapi::devices::root_bus.reset();
   }
diff --git a/kernel/kapi/devices/bus.cpp b/kernel/kapi/devices/bus.cpp
index 179a04a8..6c659ef5 100644
--- a/kernel/kapi/devices/bus.cpp
+++ b/kernel/kapi/devices/bus.cpp
@@ -68,6 +68,11 @@ namespace kapi::devices
     return {m_devices.data(), m_devices.size()};
   }
 
+  auto bus::protocol() -> struct bus_protocol *
+  {
+    return nullptr;
+  }
+
   auto bus::enumerate() -> bool
   {
     return true;
diff --git a/kernel/kapi/devices/device.cpp b/kernel/kapi/devices/device.cpp
index 540d37b7..cbbd5405 100644
--- a/kernel/kapi/devices/device.cpp
+++ b/kernel/kapi/devices/device.cpp
@@ -22,9 +22,29 @@ namespace kapi::devices
     return m_parent.lock();
   }
 
-  auto device::set_parent(kstd::weak_ptr<bus> parent) -> void
+  auto device::state() const noexcept -> enum state
   {
-    m_parent = parent;
+    return m_state;
+  }
+
+  auto device::set_state(enum state state) -> void
+  {
+    m_state = state;
+  }
+
+  auto device::bind_driver(kstd::weak_ptr<struct driver> driver) -> void
+  {
+    m_driver = driver;
+  }
+
+  auto device::driver_data() const -> kstd::shared_ptr<void> const &
+  {
+    return m_driver_data;
+  }
+
+  auto device::set_driver_data(kstd::shared_ptr<void> data) -> void
+  {
+    m_driver_data = data;
   }
 
   auto device::query_interface(interface) -> void *
@@ -32,4 +52,9 @@ namespace kapi::devices
     return nullptr;
   }
 
+  auto device::set_parent(kstd::weak_ptr<bus> parent) -> void
+  {
+    m_parent = parent;
+  }
+
 }  // namespace kapi::devices
\ No newline at end of file
diff --git a/kernel/kapi/devices/driver_registry.cpp b/kernel/kapi/devices/driver_registry.cpp
new file mode 100644
index 00000000..67da9877
--- /dev/null
+++ b/kernel/kapi/devices/driver_registry.cpp
@@ -0,0 +1,135 @@
+#include <kapi/devices/driver_registry.hpp>
+
+#include <kapi/devices/bus.hpp>
+#include <kapi/devices/bus_protocol.hpp>
+#include <kapi/devices/device.hpp>
+#include <kapi/devices/driver.hpp>
+#include <kapi/devices/manager.hpp>
+#include <kapi/system.hpp>
+#include <kapi/test_support/devices.hpp>
+
+#include <kstd/memory.hpp>
+#include <kstd/print.hpp>
+#include <kstd/system_error.hpp>
+#include <kstd/vector.hpp>
+
+#include <algorithm>
+#include <cstdint>
+#include <functional>
+#include <optional>
+#include <utility>
+
+namespace kapi::devices
+{
+
+  namespace
+  {
+    constinit auto static registry = std::optional<driver_registry>{};
+
+    struct candidate
+    {
+      std::uint32_t priority;
+      kstd::shared_ptr<driver> driver_handle;
+    };
+  }  // namespace
+
+  auto driver_registry::init() -> void
+  {
+    if (registry.has_value())
+    {
+      system::panic("[kernel] Device driver registry has already been initialized.");
+    }
+
+    registry.emplace();
+  }
+
+  auto driver_registry::get() -> driver_registry &
+  {
+    if (!registry)
+    {
+      system::panic("[kernel] Device driver registry has not been initialized.");
+    }
+
+    return *registry;
+  }
+
+  auto driver_registry::add(kstd::shared_ptr<driver> driver) -> void
+  {
+    m_drivers.emplace_back(std::move(driver));
+
+    for (auto const & device : kapi::devices::all())
+    {
+      if (device->state() != state::bound)
+      {
+        try_bind(device);
+      }
+    }
+  }
+
+  auto driver_registry::device_attached(kstd::shared_ptr<device> const & device) -> void
+  {
+    try_bind(device);
+  }
+
+  auto driver_registry::try_bind(kstd::shared_ptr<device> const & device) -> void
+  {
+    if (!device || device->state() == state::bound)
+    {
+      return;
+    }
+
+    auto parent = device->parent();
+    auto protocol = parent ? parent->protocol() : nullptr;
+    if (!protocol)
+    {
+      return;
+    }
+
+    auto candidates = kstd::vector<candidate>{};
+
+    for (auto const & driver : m_drivers)
+    {
+      auto match = protocol->match(*device, *driver);
+      if (match)
+      {
+        candidates.push_back({.priority = *match, .driver_handle = driver});
+      }
+      else if (match.error() != kstd::errc::not_supported)
+      {
+        kstd::println(kstd::print_sink::stderr, "[OS:DRV] match() failed for device {}: {}", device->name(),
+                      match.error().message());
+      }
+    }
+
+    std::ranges::stable_sort(candidates, std::ranges::greater{}, &candidate::priority);
+
+    for (auto const & candidate : candidates)
+    {
+      auto probed = candidate.driver_handle->probe(*device);
+      if (probed)
+      {
+        device->bind_driver(candidate.driver_handle);
+        device->set_state(state::bound);
+        kstd::println("[OS:DRV] Bound device {} (priority {})", device->name(), candidate.priority);
+        return;
+      }
+
+      kstd::println(kstd::print_sink::stderr, "[OS:DRV] probe() failed for device {} (priority {}): {}", device->name(),
+                    candidate.priority, probed.error().message());
+    }
+
+    if (!candidates.empty())
+    {
+      device->set_state(state::failed);
+    }
+  }
+
+}  // namespace kapi::devices
+
+namespace kapi::test_support::devices
+{
+  auto deinit_driver_registry() -> void
+  {
+    kapi::devices::registry.reset();
+  }
+}  // namespace kapi::test_support::devices
\ No newline at end of file