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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Kernel/Devices/SerialDevice.h>
#include <LibBareMetal/IO.h>
namespace Kernel {
SerialDevice::SerialDevice(int base_addr, unsigned minor)
: CharacterDevice(4, minor)
, m_base_addr(base_addr)
{
initialize();
}
SerialDevice::~SerialDevice()
{
}
bool SerialDevice::can_read(const 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(const 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);
}
}
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