From 62c2c9df6918e843181aab57a9148c8b8b9d1b4f Mon Sep 17 00:00:00 2001
From: Liav A <liavalb@gmail.com>
Date: Sat, 5 Mar 2022 14:12:36 +0200
Subject: [PATCH] Kernel/HID: Add methods to attach and detach standalone
 devices

---
 Kernel/Devices/HID/Device.h       |  4 ++++
 Kernel/Devices/HID/Management.cpp | 14 ++++++++++++++
 Kernel/Devices/HID/Management.h   |  9 +++++++++
 3 files changed, 27 insertions(+)

diff --git a/Kernel/Devices/HID/Device.h b/Kernel/Devices/HID/Device.h
index ec99422548..0d0a57279b 100644
--- a/Kernel/Devices/HID/Device.h
+++ b/Kernel/Devices/HID/Device.h
@@ -11,7 +11,9 @@
 
 namespace Kernel {
 
+class HIDManagement;
 class HIDDevice : public CharacterDevice {
+    friend class HIDManagement;
 
 protected:
     HIDDevice(MajorNumber major, MinorNumber minor)
@@ -20,6 +22,8 @@ protected:
     }
 
     EntropySource m_entropy_source;
+
+    IntrusiveListNode<HIDDevice, NonnullRefPtr<HIDDevice>> m_list_node;
 };
 
 }
diff --git a/Kernel/Devices/HID/Management.cpp b/Kernel/Devices/HID/Management.cpp
index 030ee2439b..6badd34b8c 100644
--- a/Kernel/Devices/HID/Management.cpp
+++ b/Kernel/Devices/HID/Management.cpp
@@ -115,6 +115,20 @@ void HIDManagement::set_maps(NonnullOwnPtr<KString> character_map_name, Keyboard
     });
 }
 
+void HIDManagement::detach_standalone_hid_device(HIDDevice& device)
+{
+    m_standalone_hid_devices.with([&](auto& list) {
+        list.remove(device);
+    });
+}
+
+void HIDManagement::attach_standalone_hid_device(HIDDevice& device)
+{
+    m_standalone_hid_devices.with([&](auto& list) {
+        list.append(device);
+    });
+}
+
 UNMAP_AFTER_INIT ErrorOr<void> HIDManagement::enumerate()
 {
     // FIXME: When we have USB HID support, we should ensure that we disable
diff --git a/Kernel/Devices/HID/Management.h b/Kernel/Devices/HID/Management.h
index 39afe00f77..5dc07b416a 100644
--- a/Kernel/Devices/HID/Management.h
+++ b/Kernel/Devices/HID/Management.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/Atomic.h>
+#include <AK/Badge.h>
 #include <AK/CircularQueue.h>
 #include <AK/Error.h>
 #include <AK/IntrusiveList.h>
@@ -15,6 +16,7 @@
 #include <AK/Types.h>
 #include <Kernel/API/KeyCode.h>
 #include <Kernel/Bus/SerialIO/Controller.h>
+#include <Kernel/Devices/HID/Device.h>
 #include <Kernel/Locking/Spinlock.h>
 #include <Kernel/Locking/SpinlockProtected.h>
 #include <Kernel/UnixTypes.h>
@@ -51,6 +53,9 @@ public:
     void set_client(KeyboardClient* client);
     void set_maps(NonnullOwnPtr<KString> character_map_name, Keyboard::CharacterMapData const& character_map);
 
+    void attach_standalone_hid_device(HIDDevice&);
+    void detach_standalone_hid_device(HIDDevice&);
+
 private:
     size_t generate_minor_device_number_for_mouse();
     size_t generate_minor_device_number_for_keyboard();
@@ -61,6 +66,10 @@ private:
     KeyboardClient* m_client { nullptr };
 
     SpinlockProtected<IntrusiveList<&SerialIOController::m_list_node>, LockRank::None> m_hid_serial_io_controllers;
+    // NOTE: This list is used for standalone devices, like USB HID devices
+    // (which are not attached via a SerialIO controller in the sense that
+    // there's no specific serial IO controller to coordinate their usage).
+    SpinlockProtected<IntrusiveList<&HIDDevice::m_list_node>, LockRank::None> m_standalone_hid_devices;
     Spinlock<LockRank::None> m_client_lock;
 };