ladybird/Kernel/Devices/SerialDevice.cpp
Andreas Kling 27f699ef0c AK: Rename the common integer typedefs to make it obvious what they are.
These types can be picked up by including <AK/Types.h>:

* u8, u16, u32, u64 (unsigned)
* i8, i16, i32, i64 (signed)
2019-07-03 21:20:13 +02:00

111 lines
2.6 KiB
C++

#include <Kernel/Devices/SerialDevice.h>
#include <Kernel/IO.h>
SerialDevice::SerialDevice(int base_addr, unsigned minor)
: CharacterDevice(4, minor)
, m_base_addr(base_addr)
{
initialize();
}
SerialDevice::~SerialDevice()
{
}
bool SerialDevice::can_read(FileDescription&) const
{
return (get_line_status() & DataReady) != 0;
}
ssize_t SerialDevice::read(FileDescription&, u8* buffer, ssize_t size)
{
if (!size)
return 0;
if (!(get_line_status() & DataReady))
return 0;
buffer[0] = IO::in8(m_base_addr);
return 1;
}
bool SerialDevice::can_write(FileDescription&) const
{
return (get_line_status() & EmptyTransmitterHoldingRegister) != 0;
}
ssize_t SerialDevice::write(FileDescription&, const u8* buffer, ssize_t size)
{
if (!size)
return 0;
if (!(get_line_status() & EmptyTransmitterHoldingRegister))
return 0;
IO::out8(m_base_addr, buffer[0]);
return 1;
}
void SerialDevice::initialize()
{
set_interrupts(0);
set_baud(Baud38400);
set_line_control(None, One, EightBits);
set_fifo_control(EnableFIFO | ClearReceiveFIFO | ClearTransmitFIFO | TriggerLevel4);
set_modem_control(RequestToSend | DataTerminalReady);
}
void SerialDevice::set_interrupts(char interrupt_enable)
{
m_interrupt_enable = interrupt_enable;
IO::out8(m_base_addr + 1, interrupt_enable);
}
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 + 3, IO::in8(m_base_addr + 3) & 0x7f); // turn off DLAB
}
void SerialDevice::set_fifo_control(char fifo_control)
{
m_fifo_control = fifo_control;
IO::out8(m_base_addr + 2, fifo_control);
}
void SerialDevice::set_line_control(ParitySelect parity_select, StopBits stop_bits, WordLength word_length)
{
m_parity_select = parity_select;
m_stop_bits = stop_bits;
m_word_length = word_length;
IO::out8(m_base_addr + 3, IO::in8(m_base_addr + 3) & (0xc0 | parity_select | stop_bits | word_length));
}
void SerialDevice::set_break_enable(bool break_enable)
{
m_break_enable = 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)
{
m_modem_control = modem_control;
IO::out8(m_base_addr + 4, modem_control);
}
char SerialDevice::get_line_status() const
{
return IO::in8(m_base_addr + 5);
}