Kernel: Use unsigned instead of signed types in SerialDevice

Addresses are unsigned by definition, and the conversion from signed
to unsigned and back in SerialDevice looked a bit dubious.

Kernel/Devices/SerialDevice.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -9,7 +10,7 @@
 
 namespace Kernel {
 
-UNMAP_AFTER_INIT SerialDevice::SerialDevice(int base_addr, unsigned minor)
+UNMAP_AFTER_INIT SerialDevice::SerialDevice(u32 base_addr, unsigned minor)
     : CharacterDevice(4, minor)
     , m_base_addr(base_addr)
 {
@@ -67,14 +68,14 @@ String SerialDevice::device_name() const
 
 UNMAP_AFTER_INIT void SerialDevice::initialize()
 {
-    set_interrupts(0);
+    set_interrupts(false);
     set_baud(Baud38400);
     set_line_control(None, One, EightBits);
     set_fifo_control(EnableFIFO | ClearReceiveFIFO | ClearTransmitFIFO | TriggerLevel4);
     set_modem_control(RequestToSend | DataTerminalReady);
 }
 
-UNMAP_AFTER_INIT void SerialDevice::set_interrupts(char interrupt_enable)
+UNMAP_AFTER_INIT void SerialDevice::set_interrupts(bool interrupt_enable)
 {
     m_interrupt_enable = interrupt_enable;
 
@@ -86,12 +87,12 @@ void SerialDevice::set_baud(Baud baud)
     m_baud = baud;
 
     IO::out8(m_base_addr + 3, IO::in8(m_base_addr + 3) | 0x80); // turn on DLAB
-    IO::out8(m_base_addr + 0, ((char)(baud)) >> 2);             // lower half of divisor
-    IO::out8(m_base_addr + 1, ((char)(baud)) & 0xff);           // upper half of divisor
+    IO::out8(m_base_addr + 0, ((u8)(baud)) >> 2);               // lower half of divisor
+    IO::out8(m_base_addr + 1, ((u8)(baud)) & 0xff);             // upper half of divisor
     IO::out8(m_base_addr + 3, IO::in8(m_base_addr + 3) & 0x7f); // turn off DLAB
 }
 
-void SerialDevice::set_fifo_control(char fifo_control)
+void SerialDevice::set_fifo_control(u8 fifo_control)
 {
     m_fifo_control = fifo_control;
 
@@ -114,14 +115,14 @@ void SerialDevice::set_break_enable(bool break_enable)
     IO::out8(m_base_addr + 3, IO::in8(m_base_addr + 3) & (break_enable ? 0xff : 0xbf));
 }
 
-void SerialDevice::set_modem_control(char modem_control)
+void SerialDevice::set_modem_control(u8 modem_control)
 {
     m_modem_control = modem_control;
 
     IO::out8(m_base_addr + 4, modem_control);
 }
 
-char SerialDevice::get_line_status() const
+u8 SerialDevice::get_line_status() const
 {
     return IO::in8(m_base_addr + 5);
 }

Kernel/Devices/SerialDevice.h

@@ -18,7 +18,7 @@ namespace Kernel {
 class SerialDevice final : public CharacterDevice {
     AK_MAKE_ETERNAL
 public:
-    SerialDevice(int base_addr, unsigned minor);
+    SerialDevice(u32 base_addr, unsigned minor);
     virtual ~SerialDevice() override;
 
     // ^CharacterDevice
@@ -112,25 +112,23 @@ private:
     virtual const char* class_name() const override { return "SerialDevice"; }
 
     void initialize();
-    void set_interrupts(char interrupt_enable);
+    void set_interrupts(bool interrupt_enable);
     void set_baud(Baud);
-    void set_fifo_control(char fifo_control);
+    void set_fifo_control(u8 fifo_control);
     void set_line_control(ParitySelect, StopBits, WordLength);
     void set_break_enable(bool break_enable);
-    void set_modem_control(char modem_control);
-    char get_line_status() const;
-    bool rx_ready();
-    bool tx_ready();
-
-    int m_base_addr;
-    char m_interrupt_enable;
-    char m_fifo_control;
-    Baud m_baud;
-    ParitySelect m_parity_select;
-    StopBits m_stop_bits;
-    WordLength m_word_length;
-    bool m_break_enable;
-    char m_modem_control;
+    void set_modem_control(u8 modem_control);
+    u8 get_line_status() const;
+
+    u32 m_base_addr { 0 };
+    bool m_interrupt_enable { false };
+    u8 m_fifo_control { 0 };
+    Baud m_baud { Baud38400 };
+    ParitySelect m_parity_select { None };
+    StopBits m_stop_bits { One };
+    WordLength m_word_length { EightBits };
+    bool m_break_enable { false };
+    u8 m_modem_control { 0 };
 };
 
 }