kernel: Add a PS/2 mouse driver

kernel/CMakeLists.txt

@@ -59,6 +59,7 @@ set(SOURCES
     src/fs/devices/ConsoleDevice.cpp
     src/fs/devices/FramebufferDevice.cpp
     src/fs/devices/UARTDevice.cpp
+    src/fs/devices/MouseDevice.cpp
     src/fs/InitRD.cpp
     src/binfmt/ELF.cpp
     src/binfmt/BinaryFormat.cpp
@@ -80,6 +81,7 @@ if("${LUNA_ARCH}" MATCHES "x86_64")
         src/arch/x86_64/init/GDT.cpp
         src/arch/x86_64/init/IDT.cpp
         src/arch/x86_64/init/PIC.cpp
+        src/arch/x86_64/PS2Mouse.cpp
     )
 endif()
 

kernel/src/api/Mouse.h

@@ -0,0 +1,22 @@
+#pragma once
+#include <luna/Types.h>
+
+namespace moon
+{
+    enum MouseButton
+    {
+        Left = (1 << 0),
+        Middle = (1 << 1),
+        Right = (1 << 2),
+    };
+
+    struct [[gnu::packed]] MousePacket
+    {
+        i16 xdelta;
+        i16 ydelta;
+        u8 buttons;
+        u8 _padding[3];
+    };
+
+    static_assert(sizeof(MousePacket) == 8);
+}

kernel/src/arch/x86_64/CPU.cpp

@@ -1,10 +1,12 @@
 #include "arch/CPU.h"
 #include "Log.h"
+#include "api/Mouse.h"
 #include "arch/Keyboard.h"
 #include "arch/Timer.h"
 #include "arch/x86_64/CPU.h"
 #include "arch/x86_64/IO.h"
 #include "fs/devices/ConsoleDevice.h"
+#include "fs/devices/MouseDevice.h"
 #include "memory/MemoryManager.h"
 #include "sys/Syscall.h"
 #include "thread/Scheduler.h"
@@ -27,8 +29,9 @@ extern void change_pic_masks(u8 pic1_mask, u8 pic2_mask);
 extern void pic_eoi(unsigned char irq);
 extern void pic_eoi(Registers* regs);
 extern void setup_idt();
+extern void init_mouse();
 
-static Thread* g_io_thread;
+Thread* g_io_thread;
 
 typedef void (*interrupt_handler_t)(Registers*, void*);
 
@@ -139,15 +142,19 @@ extern "C" void handle_x86_exception(Registers* regs)
 }
 
 CircularQueue<u8, 60> scancode_queue;
+CircularQueue<moon::MousePacket, 20> mouse_queue;
 
 void io_thread()
 {
     while (true)
     {
         u8 scancode;
-        while (!scancode_queue.try_pop(scancode)) kernel_wait_for_event();
+        moon::MousePacket packet;
 
-        ConsoleDevice::did_press_or_release_key(scancode);
+        if (scancode_queue.try_pop(scancode)) { ConsoleDevice::did_press_or_release_key(scancode); }
+        else if (mouse_queue.try_pop(packet)) { MouseDevice::add_mouse_event(packet); }
+        else
+            kernel_wait_for_event();
     }
 }
 
@@ -261,6 +268,8 @@ namespace CPU
 
         remap_pic();
 
+        init_mouse();
+
         sync_interrupts();
     }
 

kernel/src/arch/x86_64/PS2Mouse.cpp

@@ -0,0 +1,118 @@
+#include "Log.h"
+#include "api/Mouse.h"
+#include "arch/CPU.h"
+#include "arch/x86_64/IO.h"
+#include "fs/devices/MouseDevice.h"
+#include "thread/Thread.h"
+
+extern Thread* g_io_thread;
+
+static u8 g_mouse_packet[3];
+static int g_index = 0;
+
+#define PS2_MOUSE_Y_OVERFLOW 0x80
+#define PS2_MOUSE_X_OVERFLOW 0x40
+#define PS2_MOUSE_Y_SIGN 0x20
+#define PS2_MOUSE_X_SIGN 0x10
+#define PS2_MOUSE_ALWAYS_1 0x08
+#define PS2_MOUSE_MIDDLE_BTN 0x04
+#define PS2_MOUSE_RIGHT_BTN 0x02
+#define PS2_MOUSE_LEFT_BTN 0x01
+
+extern CircularQueue<moon::MousePacket, 20> mouse_queue;
+
+static void process_mouse_event(u8 data)
+{
+    if (g_index == 0)
+    {
+        // NOTE: https://wiki.osdev.org/Mouse_Input#PS2_Mouse says to discard the packet if X or Y overflow is 1, but
+        // https://wiki.osdev.org/PS2_Mouse uses it. Discard for now.
+        if (data & PS2_MOUSE_X_OVERFLOW) return;
+        if (data & PS2_MOUSE_Y_OVERFLOW) return;
+
+        if ((data & PS2_MOUSE_ALWAYS_1) == 0) return;
+    }
+
+    g_mouse_packet[g_index++] = data;
+    if (g_index < 3) return;
+    g_index = 0;
+
+    moon::MousePacket packet;
+    packet.xdelta = g_mouse_packet[1];
+    packet.ydelta = g_mouse_packet[2];
+    packet.buttons = 0;
+
+    u8 flags = g_mouse_packet[0];
+    if (flags & PS2_MOUSE_X_SIGN) packet.xdelta = -packet.xdelta;
+    if (flags & PS2_MOUSE_Y_SIGN) packet.ydelta = -packet.ydelta;
+
+    if (flags & PS2_MOUSE_MIDDLE_BTN) packet.buttons |= moon::MouseButton::Middle;
+    if (flags & PS2_MOUSE_RIGHT_BTN) packet.buttons |= moon::MouseButton::Right;
+    if (flags & PS2_MOUSE_LEFT_BTN) packet.buttons |= moon::MouseButton::Left;
+
+    MouseDevice::add_mouse_event(packet);
+}
+
+static void mouse_interrupt(Registers*, void*)
+{
+    const u8 data = IO::inb(0x60);
+    process_mouse_event(data);
+}
+
+#define PS2_MOUSE_TIMEOUT 100000
+
+static void mouse_wait()
+{
+    int timeout = PS2_MOUSE_TIMEOUT;
+    while (--timeout)
+    {
+        if ((IO::inb(0x64) & 0b10) == 0) return;
+        CPU::pause();
+    }
+}
+
+static void mouse_wait_for_input()
+{
+    int timeout = PS2_MOUSE_TIMEOUT;
+    while (--timeout)
+    {
+        if (IO::inb(0x64) & 0b1) return;
+        CPU::pause();
+    }
+}
+
+static void mouse_write_data(u8 byte)
+{
+    mouse_wait();
+    IO::outb(0x64, 0xD4);
+    mouse_wait();
+    IO::outb(0x60, byte);
+}
+
+void init_mouse()
+{
+    CPU::register_interrupt(12, mouse_interrupt, nullptr);
+
+    IO::outb(0x64, 0xA8); // Enable PS/2 auxiliary port
+
+    mouse_wait();
+    IO::outb(0x64, 0x20); // Get Compaq status byte
+    mouse_wait_for_input();
+    u8 status = IO::inb(0x60);
+    status |= 0x02;  // Enable IRQ12
+    status &= ~0x20; // Disable Mouse Clock
+    mouse_wait();
+    IO::outb(0x64, 0x60); // Set Compaq status byte
+    mouse_wait();
+    IO::outb(0x60, status);
+
+    mouse_write_data(0xF6); // Reset defaults
+    mouse_wait();
+    IO::inb(0x60);
+
+    mouse_write_data(0xF4); // Send automatic packets when the mouse moves or is clicked
+    mouse_wait();
+    IO::inb(0x60);
+
+    g_index = 0;
+}

kernel/src/fs/devices/DeviceRegistry.cpp

@@ -4,6 +4,7 @@
 #include "fs/devices/ConsoleDevice.h"
 #include "fs/devices/FramebufferDevice.h"
 #include "fs/devices/FullDevice.h"
+#include "fs/devices/MouseDevice.h"
 #include "fs/devices/NullDevice.h"
 #include "fs/devices/UARTDevice.h"
 #include "fs/devices/ZeroDevice.h"
@@ -70,6 +71,7 @@ namespace DeviceRegistry
         ConsoleDevice::create();
         FramebufferDevice::create();
         UARTDevice::create();
+        MouseDevice::create();
 
         return {};
     }

kernel/src/fs/devices/DeviceRegistry.h

@@ -16,6 +16,7 @@ namespace DeviceRegistry
         Disk = 4,
         DiskPartition = 5,
         Serial = 6,
+        Input = 7,
     };
 
     Result<SharedPtr<Device>> fetch_special_device(u32 major, u32 minor);

kernel/src/fs/devices/MouseDevice.cpp

@@ -0,0 +1,50 @@
+#include "fs/devices/MouseDevice.h"
+
+SharedPtr<MouseDevice> MouseDevice::s_mouse_device = {};
+
+Result<void> MouseDevice::create()
+{
+    auto device = TRY(make_shared<MouseDevice>());
+    s_mouse_device = device;
+    return DeviceRegistry::register_special_device(DeviceRegistry::Input, 0, device);
+}
+
+Result<usize> MouseDevice::read(u8* buf, usize, usize length) const
+{
+    usize nread = 0;
+    while (length >= sizeof(moon::MousePacket))
+    {
+        if (!m_packet_queue.try_pop(*(moon::MousePacket*)buf)) break;
+
+        buf += sizeof(moon::MousePacket);
+        length -= sizeof(moon::MousePacket);
+        nread += sizeof(moon::MousePacket);
+    }
+
+    return nread;
+}
+
+Result<usize> MouseDevice::write(const u8* buf, usize, usize length)
+{
+    usize nwritten = 0;
+    while (length >= sizeof(moon::MousePacket))
+    {
+        if (!m_packet_queue.try_push(*(const moon::MousePacket*)buf)) break;
+
+        buf += sizeof(moon::MousePacket);
+        length -= sizeof(moon::MousePacket);
+        nwritten += sizeof(moon::MousePacket);
+    }
+
+    return nwritten;
+}
+
+void MouseDevice::add_mouse_event(const moon::MousePacket& packet)
+{
+    if (s_mouse_device) s_mouse_device->m_packet_queue.try_push(packet);
+}
+
+bool MouseDevice::will_block_if_read() const
+{
+    return m_packet_queue.is_empty();
+}

kernel/src/fs/devices/MouseDevice.h

@@ -0,0 +1,31 @@
+#pragma once
+#include "api/Mouse.h"
+#include "fs/devices/DeviceRegistry.h"
+#include <luna/CircularQueue.h>
+
+class MouseDevice : public Device
+{
+  public:
+    // Initializer for DeviceRegistry.
+    static Result<void> create();
+
+    Result<usize> read(u8*, usize, usize) const override;
+
+    Result<usize> write(const u8*, usize, usize) override;
+
+    static void add_mouse_event(const moon::MousePacket& packet);
+
+    bool will_block_if_read() const override;
+
+    StringView device_path() const override
+    {
+        return "mouse";
+    }
+
+    virtual ~MouseDevice() = default;
+
+  private:
+    mutable CircularQueue<moon::MousePacket, 200> m_packet_queue;
+
+    static SharedPtr<MouseDevice> s_mouse_device;
+};