From 66ffd2ad8c793c4eea1527848fe4772e42595718 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Thu, 2 Apr 2026 14:24:52 +0200
Subject: kapi: extract common bus code

---
 kapi/include/kapi/devices/bus.hpp | 61 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 57 insertions(+), 4 deletions(-)

(limited to 'kapi')

diff --git a/kapi/include/kapi/devices/bus.hpp b/kapi/include/kapi/devices/bus.hpp
index a8d7df8..ccaf0f2 100644
--- a/kapi/include/kapi/devices/bus.hpp
+++ b/kapi/include/kapi/devices/bus.hpp
@@ -2,12 +2,17 @@
 #define TEACHOS_KAPI_DEVICES_BUS_HPP
 
 #include "kapi/devices/device.hpp"
+#include "kapi/system.hpp"
 
 #include <kstd/memory>
+#include <kstd/print>
 #include <kstd/string>
 #include <kstd/vector>
 
+#include <algorithm>
+#include <atomic>
 #include <cstddef>
+#include <utility>
 
 namespace kapi::devices
 {
@@ -23,17 +28,65 @@ namespace kapi::devices
         : device(major, minor, name)
     {}
 
+    //! Initialize the bus and all of its children.
+    //!
+    //! @return true iff. the bus and all of its children are healthy, false otherwise.
+    auto init() -> bool final
+    {
+      if (m_initialized.test_and_set())
+      {
+        return true;
+      }
+
+      if (!probe())
+      {
+        return false;
+      }
+
+      return std::ranges::fold_left(m_devices, true, [&](bool acc, auto & child) -> bool {
+        kstd::println("[kAPI:BUS] Initializing child device {}@{}", child->name(), name());
+        return acc && child->init();
+      });
+    }
+
     //! Attach a child device to this bus.
     //!
     //! Whenever a device is attached to a bus, the bus takes sole ownership of the device.
     //!
     //! @param child The child device to attach.
-    virtual auto add_child(kstd::unique_ptr<device> child) -> void = 0;
+    auto add_child(kstd::unique_ptr<device> child) -> void
+    {
+      auto observer = m_observers.emplace_back(child.get());
+      m_devices.push_back(std::move(child));
 
-    //! Get a list of all child devices attached to this bus.
+      if (m_initialized.test())
+      {
+        kstd::println("[kAPI:BUS] Initializing child device {}@{}", observer->name(), name());
+        if (!observer->init())
+        {
+          kapi::system::panic("[kAPI:BUS] Failed to initialize child device");
+        }
+      }
+    }
+
+    [[nodiscard]] auto children() const -> kstd::vector<kstd::observer_ptr<device>> const &
+    {
+      return m_observers;
+    }
+
+  protected:
+    //! Probe the bus hardware state.
     //!
-    //! @return A reference to list of child devices of this bus.
-    [[nodiscard]] virtual auto children() const -> kstd::vector<kstd::observer_ptr<device>> const & = 0;
+    //! @return true iff. the bus hardware is healthy, false otherwise.
+    auto virtual probe() -> bool
+    {
+      return true;
+    }
+
+  private:
+    kstd::vector<kstd::unique_ptr<device>> m_devices;
+    kstd::vector<kstd::observer_ptr<device>> m_observers;
+    std::atomic_flag m_initialized{};
   };
 }  // namespace kapi::devices
 
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