mirror of
https://github.com/SerenityOS/serenity
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16244c490a
We used to allocate major numbers quite randomly, with no common place to look them up if needed. This commit is changing that by placing all major number allocations under a new C++ namespace, in the API/MajorNumberAllocation.h file. We also add the foundations of what is needed before we can publish this information (allocated numbers for block and char devices) to userspace.
136 lines
3.9 KiB
C++
136 lines
3.9 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/API/MajorNumberAllocation.h>
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#include <Kernel/Devices/DeviceManagement.h>
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#include <Kernel/Devices/SerialDevice.h>
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#include <Kernel/Library/IOWindow.h>
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#include <Kernel/Sections.h>
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namespace Kernel {
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SerialDevice::SerialDevice(NonnullOwnPtr<IOWindow> registers_io_window, unsigned minor)
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: CharacterDevice(MajorAllocation::CharacterDeviceFamily::Serial, minor)
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, m_registers_io_window(move(registers_io_window))
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{
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set_interrupts(false);
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set_baud(Baud38400);
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set_line_control(None, One, EightBits);
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set_fifo_control(EnableFIFO | ClearReceiveFIFO | ClearTransmitFIFO | TriggerLevel4);
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set_modem_control(RequestToSend | DataTerminalReady);
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}
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SerialDevice::~SerialDevice() = default;
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bool SerialDevice::can_read(OpenFileDescription const&, u64) const
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{
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return (get_line_status() & DataReady) != 0;
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}
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ErrorOr<size_t> SerialDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer& buffer, size_t size)
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{
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if (!size)
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return 0;
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SpinlockLocker lock(m_serial_lock);
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if (!(get_line_status() & DataReady))
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return 0;
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return buffer.write_buffered<128>(size, [&](Bytes bytes) {
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for (auto& byte : bytes)
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byte = m_registers_io_window->read8(0);
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return bytes.size();
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});
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}
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bool SerialDevice::can_write(OpenFileDescription const&, u64) const
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{
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return (get_line_status() & EmptyTransmitterHoldingRegister) != 0;
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}
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ErrorOr<size_t> SerialDevice::write(OpenFileDescription& description, u64, UserOrKernelBuffer const& buffer, size_t size)
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{
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if (!size)
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return 0;
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SpinlockLocker lock(m_serial_lock);
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if (!can_write(description, size))
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return EAGAIN;
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return buffer.read_buffered<128>(size, [&](ReadonlyBytes bytes) {
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for (auto const& byte : bytes)
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put_char(byte);
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return bytes.size();
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});
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}
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void SerialDevice::put_char(char ch)
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{
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while ((get_line_status() & EmptyTransmitterHoldingRegister) == 0)
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Processor::wait_check();
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if (ch == '\n' && !m_last_put_char_was_carriage_return)
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m_registers_io_window->write8(0, '\r');
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m_registers_io_window->write8(0, ch);
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m_last_put_char_was_carriage_return = (ch == '\r');
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}
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void SerialDevice::set_interrupts(bool interrupt_enable)
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{
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m_interrupt_enable = interrupt_enable;
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m_registers_io_window->write8(1, interrupt_enable);
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}
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void SerialDevice::set_baud(Baud baud)
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{
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m_baud = baud;
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m_registers_io_window->write8(3, m_registers_io_window->read8(3) | 0x80); // turn on DLAB
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m_registers_io_window->write8(0, ((u8)(baud)) & 0xff); // lower half of divisor
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m_registers_io_window->write8(1, ((u8)(baud)) >> 2); // lower half of divisor
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m_registers_io_window->write8(3, m_registers_io_window->read8(3) & 0x7f); // turn off DLAB
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}
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void SerialDevice::set_fifo_control(u8 fifo_control)
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{
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m_fifo_control = fifo_control;
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m_registers_io_window->write8(2, fifo_control);
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}
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void SerialDevice::set_line_control(ParitySelect parity_select, StopBits stop_bits, WordLength word_length)
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{
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m_parity_select = parity_select;
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m_stop_bits = stop_bits;
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m_word_length = word_length;
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m_registers_io_window->write8(3, (m_registers_io_window->read8(3) & ~0x3f) | parity_select | stop_bits | word_length);
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}
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void SerialDevice::set_break_enable(bool break_enable)
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{
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m_break_enable = break_enable;
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m_registers_io_window->write8(3, m_registers_io_window->read8(3) & (break_enable ? 0xff : 0xbf));
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}
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void SerialDevice::set_modem_control(u8 modem_control)
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{
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m_modem_control = modem_control;
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m_registers_io_window->write8(4, modem_control);
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}
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u8 SerialDevice::get_line_status() const
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{
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return m_registers_io_window->read8(5);
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}
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}
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