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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/Devices/SerialDevice.h>
#include <Kernel/IO.h>
namespace Kernel {
UNMAP_AFTER_INIT SerialDevice::SerialDevice(u32 base_addr, unsigned minor)
: CharacterDevice(4, minor)
, m_base_addr(base_addr)
{
initialize();
}
UNMAP_AFTER_INIT SerialDevice::~SerialDevice()
{
}
bool SerialDevice::can_read(const FileDescription&, size_t) const
{
return (get_line_status() & DataReady) != 0;
}
KResultOr<size_t> SerialDevice::read(FileDescription&, u64, UserOrKernelBuffer& buffer, size_t size)
{
if (!size)
return 0;
if (!(get_line_status() & DataReady))
return 0;
return buffer.write_buffered<128>(size, [&](u8* data, size_t data_size) {
for (size_t i = 0; i < data_size; i++)
data[i] = IO::in8(m_base_addr);
return data_size;
});
}
bool SerialDevice::can_write(const FileDescription&, size_t) const
{
return (get_line_status() & EmptyTransmitterHoldingRegister) != 0;
}
KResultOr<size_t> SerialDevice::write(FileDescription&, u64, const UserOrKernelBuffer& buffer, size_t size)
{
if (!size)
return 0;
if (!(get_line_status() & EmptyTransmitterHoldingRegister))
return 0;
return buffer.read_buffered<128>(size, [&](u8 const* data, size_t data_size) {
for (size_t i = 0; i < data_size; i++)
IO::out8(m_base_addr, data[i]);
return data_size;
});
}
String SerialDevice::device_name() const
{
return String::formatted("ttyS{}", minor() - 64);
}
UNMAP_AFTER_INIT void SerialDevice::initialize()
{
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(bool 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, ((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(u8 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(u8 modem_control)
{
m_modem_control = modem_control;
IO::out8(m_base_addr + 4, modem_control);
}
u8 SerialDevice::get_line_status() const
{
return IO::in8(m_base_addr + 5);
}
}
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