Added a new COM Port driver.
Any detected COM ports available as /dev/comN. It currently utilizes AGAIN to do polling in user-space. This prevents it from locking up the whole system and makes it respond to the SIGINT hack. There is also a more reliable and faster polling-blocking mode, but it locks up the entire system. The main interrupt mode is broken, perhaps by a bug in VirtualBox.
This commit is contained in:
Jonas 'Sortie' Termansen
parent
f54cb6ab94
commit
0364ce6f55
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@ -111,6 +111,7 @@ scheduler.o \
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syscall.o \
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sound.o \
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pci.o \
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com.o \
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uart.o \
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terminal.o \
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linebuffer.o \
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@ -0,0 +1,455 @@
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/*******************************************************************************
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011, 2012.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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com.cpp
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Handles communication to COM serial ports.
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*******************************************************************************/
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#include "platform.h"
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#include <libmaxsi/error.h>
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#include "interrupt.h"
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#include "event.h"
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#include "stream.h"
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#include "syscall.h"
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#include "thread.h"
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#include "fs/devfs.h"
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#include "com.h"
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using namespace Maxsi;
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namespace Sortix {
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namespace COM {
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// It appears this code is unable to get interrupts working correctly. Somehow
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// we don't get interrupts upon receiving data, at least under VirtualBox. This
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// hack changes the code such that it polls occasionally instead. Hopefully this
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// won't cause data loss, but I suspect that it will.
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// TODO: It appears that this code causes kernel instability, possibly due to
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// the broken way blocking system calls are implemented in Sortix.
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#define POLL_HACK 1
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// Another alternative is to use the polling code in a completely blocking
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// manner. While this may give nicer transfer speeds and less data loss, it
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// locks up the whole system.
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#define POLL_BLOCKING 0
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// Yet another alternative is to use POLL_HACK, but return EGAIN and let user-
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// space call retry, rather than relying on the broken syscall interstructure.
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#define POLL_EAGAIN 1
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const uint16_t TXR = 0; // Transmit register
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const uint16_t RXR = 0; // Receive register
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const uint16_t IER = 1; // Interrupt Enable
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const uint16_t IIR = 2; // Interrupt ID
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const uint16_t FCR = 2; // FIFO control
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const uint16_t LCR = 3; // Line control
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const uint16_t MCR = 4; // Modem control
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const uint16_t LSR = 5; // Line Status
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const uint16_t MSR = 6; // Modem Status
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const uint16_t SCR = 7; // Scratch Register
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const uint16_t DLL = 0; // Divisor Latch Low
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const uint16_t DLM = 1; // Divisor latch High
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const uint8_t LCR_DLAB = 0x80; // Divisor latch access bit
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const uint8_t LCR_SBC = 0x40; // Set break control
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const uint8_t LCR_SPAR = 0x20; // Stick parity (?)
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const uint8_t LCR_EPAR = 0x10; // Even parity select
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const uint8_t LCR_PARITY = 0x08; // Parity Enable
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const uint8_t LCR_STOP = 0x04; // Stop bits: 0=1 bit, 1=2 bits
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const uint8_t LCR_WLEN5 = 0x00; // Wordlength: 5 bits
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const uint8_t LCR_WLEN6 = 0x01; // Wordlength: 6 bits
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const uint8_t LCR_WLEN7 = 0x02; // Wordlength: 7 bits
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const uint8_t LCR_WLEN8 = 0x03; // Wordlength: 8 bits
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const uint8_t LSR_TEMT = 0x40; // Transmitter empty
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const uint8_t LSR_THRE = 0x20; // Transmit-hold-register empty
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const uint8_t LSR_READY = 0x1; // Data received
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const uint8_t LSR_BOTH_EMPTY = LSR_TEMT | LSR_THRE;
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const uint8_t IIR_NO_INTERRUPT = (1U<<0U);
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const uint8_t IIR_INTERRUPT_TYPE = ((1U<<1U) | (1U<<2U) | (1U<<3U));
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const uint8_t IIR_TIMEOUT = ((1U<<2U) | (1U<<3U));
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const uint8_t IIR_RECV_LINE_STATUS = ((1U<<1U) | (1U<<2U));
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const uint8_t IIR_RECV_DATA = (1U<<2U);
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const uint8_t IIR_SENT_DATA = (1U<<1U);
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const uint8_t IIR_MODEM_STATUS = 0;
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const uint8_t IER_DATA = (1U<<0U);
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const uint8_t IER_SENT = (1U<<1U);
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const uint8_t IER_LINE_STATUS = (1U<<2U);
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const uint8_t IER_MODEM_STATUS = (1U<<3U);
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const uint8_t IER_SLEEP_MODE = (1U<<4U);
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const uint8_t IER_LOW_POWER = (1U<<5U);
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const unsigned BASE_BAUD = 1843200/16;
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const unsigned UART8250 = 1;
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const unsigned UART16450 = 2;
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const unsigned UART16550 = 3;
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const unsigned UART16550A = 4;
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const unsigned UART16750 = 5;
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const size_t NUMCOMPORTS = 4;
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// The IO base ports of each COM port.
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static uint16_t comports[1+NUMCOMPORTS];
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// The results of running HardwareProbe on each COM port.
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unsigned hwversion[1+NUMCOMPORTS];
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// Uses various characteristics of the UART chips to determine the hardware.
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static unsigned HardwareProbe(uint16_t port)
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{
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// Set the value "0xE7" to the FCR to test the status of the FIFO flags.
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CPU::OutPortB(port + FCR, 0xE7);
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uint8_t iir = CPU::InPortB(port + IIR);
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if ( iir & (1U<<6U) )
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{
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if ( iir & (1<<7U) )
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{
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return (iir & (1U<<5U)) ? UART16750 : UART16550A;
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}
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return UART16550;
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}
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// See if the scratch register returns what we write into it. The 8520
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// doesn't do it. This is technically undefined behavior, but it is useful
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// to detect hardware versions.
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uint16_t anyvalue = 0x2A;
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CPU::OutPortB(port + SCR, anyvalue);
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return CPU::InPortB(port + SCR) == anyvalue ? UART16450 : UART8250;
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}
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static inline void WaitForEmptyBuffers(uint16_t port)
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{
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while ( (CPU::InPortB(port + LSR) & LSR_BOTH_EMPTY) != LSR_BOTH_EMPTY ) { }
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}
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static inline bool IsLineReady(uint16_t port)
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{
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return CPU::InPortB(port + LSR) & LSR_READY;
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}
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static inline bool CanWriteByte(uint16_t port)
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{
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return CPU::InPortB(port + LSR) & LSR_THRE;
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}
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ssize_t ReadBlocking(uint16_t port, void* buf, size_t size)
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{
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if ( SSIZE_MAX < size ) { size = SSIZE_MAX; }
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uint8_t* buffer = (uint8_t*) buf;
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uint8_t interruptsenabled = CPU::InPortB(port + IER);
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CPU::OutPortB(port + IER, 0);
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for ( size_t i = 0; i < size; i++ )
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{
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while ( !IsLineReady(port) ) { }
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buffer[i] = CPU::InPortB(port + RXR);
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}
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WaitForEmptyBuffers(port);
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CPU::OutPortB(port + IER, interruptsenabled);
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return size;
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}
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ssize_t WriteBlocking(uint16_t port, const void* buf, size_t size)
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{
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if ( SSIZE_MAX < size ) { size = SSIZE_MAX; }
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const uint8_t* buffer = (const uint8_t*) buf;
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uint8_t interruptsenabled = CPU::InPortB(port + IER);
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CPU::OutPortB(port + IER, 0);
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for ( size_t i = 0; i < size; i++ )
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{
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while ( !CanWriteByte(port) ) { }
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CPU::OutPortB(port + TXR, buffer[i]);
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}
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WaitForEmptyBuffers(port);
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CPU::OutPortB(port + IER, interruptsenabled);
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return size;
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}
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void EarlyInit()
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{
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// We can fetch COM port information from the BIOS Data Area.
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volatile uint16_t* const bioscomports = (uint16_t* const) 0x0400UL;
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for ( size_t i = 1; i <= NUMCOMPORTS; i++ )
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{
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comports[i] = bioscomports[i-1];
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if ( !comports[i] ) { continue; }
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hwversion[i] = HardwareProbe(comports[i]);
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CPU::OutPortB(comports[i] + IER, 0x0);
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}
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}
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class DevCOMPort : public DevStream
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{
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public:
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typedef DevStream BaseClass;
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public:
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DevCOMPort(uint16_t port);
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virtual ~DevCOMPort();
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public:
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virtual ssize_t Read(byte* dest, size_t count);
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virtual ssize_t Write(const byte* src, size_t count);
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virtual bool IsReadable();
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virtual bool IsWritable();
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public:
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void OnInterrupt();
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private:
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uint16_t port;
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Event dataevent;
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Event sentevent;
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};
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DevCOMPort::DevCOMPort(uint16_t port)
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{
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this->port = port;
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}
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DevCOMPort::~DevCOMPort()
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{
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}
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bool DevCOMPort::IsReadable() { return true; }
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bool DevCOMPort::IsWritable() { return true; }
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#if POLL_HACK
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const unsigned TRIES = 1000;
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ssize_t DevCOMPort::Read(byte* dest, size_t count)
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{
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if ( !count ) { return 0; }
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if ( SSIZE_MAX < count ) { count = SSIZE_MAX; }
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uint8_t lsr;
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for ( unsigned i = 0; i < TRIES; i++ )
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{
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lsr = CPU::InPortB(port + LSR);
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if ( lsr & LSR_READY ) { break; }
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}
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if ( !(lsr & LSR_READY) )
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{
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#if POLL_EAGAIN
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Error::Set(EAGAIN);
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#else
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Error::Set(EBLOCKING);
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Syscall::Yield();
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#endif
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return -1;
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}
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size_t sofar = 0;
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do
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{
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if ( count <= sofar ) { break; }
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dest[sofar++] = CPU::InPortB(port + RXR);
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} while ( CPU::InPortB(port + LSR) & LSR_READY);
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return sofar;
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}
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ssize_t DevCOMPort::Write(const byte* src, size_t count)
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{
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if ( !count ) { return 0; }
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if ( SSIZE_MAX < count ) { count = SSIZE_MAX; };
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uint8_t lsr;
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for ( unsigned i = 0; i < TRIES; i++ )
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{
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lsr = CPU::InPortB(port + LSR);
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if ( lsr & LSR_THRE ) { break; }
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}
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if ( !(lsr & LSR_THRE) )
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{
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#if POLL_EAGAIN
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Error::Set(EAGAIN);
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#else
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Error::Set(EBLOCKING);
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Syscall::Yield();
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#endif
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return -1;
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}
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size_t sofar = 0;
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do
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{
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if ( count <= sofar ) { break; }
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CPU::OutPortB(port + TXR, src[sofar++]);
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} while ( CPU::InPortB(port + LSR) & LSR_THRE );
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return sofar;
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}
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#else
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ssize_t DevCOMPort::Read(byte* dest, size_t count)
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{
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if ( !count ) { return 0; }
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if ( SSIZE_MAX < count ) { count = SSIZE_MAX; }
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#if POLL_BLOCKING
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return ReadBlocking(port, dest, 1);
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#endif
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uint8_t lsr = CPU::InPortB(port + LSR);
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if ( !(lsr & LSR_READY) )
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{
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dataevent.Register();
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Error::Set(EBLOCKING);
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return -1;
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}
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size_t sofar = 0;
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do
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{
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if ( count <= sofar ) { break; }
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dest[sofar++] = CPU::InPortB(port + RXR);
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} while ( CPU::InPortB(port + LSR) & LSR_READY);
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return sofar;
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}
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ssize_t DevCOMPort::Write(const byte* src, size_t count)
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{
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if ( !count ) { return 0; }
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if ( SSIZE_MAX < count ) { count = SSIZE_MAX; };
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#if POLL_BLOCKING
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return WriteBlocking(port, src, 1);
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#endif
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uint8_t lsr = CPU::InPortB(port + LSR);
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if ( !(lsr & LSR_THRE) )
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{
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sentevent.Register();
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Error::Set(EBLOCKING);
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return -1;
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}
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size_t sofar = 0;
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do
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{
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if ( count <= sofar ) { break; }
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CPU::OutPortB(port + TXR, src[sofar++]);
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} while ( CPU::InPortB(port + LSR) & LSR_THRE );
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return sofar;
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}
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#endif
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void DevCOMPort::OnInterrupt()
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{
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#if POLL_HACK || POLL_BLOCKING
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return;
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#endif
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uint8_t iir = CPU::InPortB(port + IIR);
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if ( iir & IIR_NO_INTERRUPT ) { return; }
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uint8_t intrtype = iir & IIR_INTERRUPT_TYPE;
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switch ( intrtype )
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{
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case IIR_TIMEOUT:
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CPU::InPortB(port + RXR);
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break;
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case IIR_RECV_LINE_STATUS:
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// TODO: Proper error handling!
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CPU::InPortB(port + LSR);
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break;
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case IIR_RECV_DATA:
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dataevent.Signal();
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break;
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case IIR_SENT_DATA:
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sentevent.Signal();
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CPU::InPortB(port + IIR);
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break;
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case IIR_MODEM_STATUS:
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CPU::InPortB(port + MSR);
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break;
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}
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}
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DevCOMPort* comdevices[1+NUMCOMPORTS];
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static void UARTIRQHandler(CPU::InterruptRegisters* /*regs*/, void* /*user*/)
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{
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for ( size_t i = 1; i <= NUMCOMPORTS; i++ )
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{
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if ( !comdevices[i] ) { continue; }
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comdevices[i]->OnInterrupt();
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}
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}
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void Init()
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{
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for ( size_t i = 1; i <= NUMCOMPORTS; i++ )
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{
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if ( !comports[i] ) { comdevices[i] = NULL; continue; }
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comdevices[i] = new DevCOMPort(comports[i]);
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if ( !comdevices[i] )
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{
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PanicF("Unable to allocate device for COM port %zu at 0x%x", i,
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comports[i]);
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}
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char name[5] = "comN";
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name[3] = '0' + i;
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if ( !DeviceFS::RegisterDevice(name, comdevices[i]) )
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{
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PanicF("Unable to register device /dev/%s", name);
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}
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}
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Interrupt::RegisterHandler(Interrupt::IRQ3, UARTIRQHandler, NULL);
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Interrupt::RegisterHandler(Interrupt::IRQ4, UARTIRQHandler, NULL);
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// Initialize the ports so we can transfer data.
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for ( size_t i = 1; i <= NUMCOMPORTS; i++ )
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{
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uint16_t port = comports[i];
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if ( !port ) { continue; }
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#if POLL_HACK || POLL_BLOCKING
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uint8_t interrupts = 0;
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#else
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uint8_t interrupts = IER_DATA
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| IER_SENT
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| IER_LINE_STATUS
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| IER_MODEM_STATUS;
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#endif
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CPU::OutPortB(port + FCR, 0);
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CPU::OutPortB(port + LCR, 0x80);
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CPU::OutPortB(port + DLL, 0xC);
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CPU::OutPortB(port + DLM, 0x0);
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CPU::OutPortB(port + LCR, 0x3); // 8n1
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CPU::OutPortB(port + MCR, 0x3); // DTR + RTS
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CPU::OutPortB(port + IER, interrupts);
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}
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}
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} // namespace COM
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} // namespace Sortix
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|
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@ -0,0 +1,37 @@
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/*******************************************************************************
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|
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011, 2012.
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|
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This file is part of Sortix.
|
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|
||||
Sortix is free software: you can redistribute it and/or modify it under the
|
||||
terms of the GNU General Public License as published by the Free Software
|
||||
Foundation, either version 3 of the License, or (at your option) any later
|
||||
version.
|
||||
|
||||
Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
|
||||
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
||||
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
|
||||
details.
|
||||
|
||||
You should have received a copy of the GNU General Public License along with
|
||||
Sortix. If not, see <http://www.gnu.org/licenses/>.
|
||||
|
||||
com.cpp
|
||||
Handles communication to COM serial ports.
|
||||
|
||||
*******************************************************************************/
|
||||
|
||||
#ifndef SORTIX_COM_H
|
||||
#define SORTIX_COM_H
|
||||
|
||||
namespace Sortix {
|
||||
namespace COM {
|
||||
|
||||
void EarlyInit();
|
||||
void Init();
|
||||
|
||||
} // namespace COM
|
||||
} // namespace Sortix
|
||||
|
||||
#endif
|
||||
|
|
@ -40,6 +40,7 @@
|
|||
#include "scheduler.h"
|
||||
#include "syscall.h"
|
||||
#include "pci.h"
|
||||
#include "com.h"
|
||||
#include "uart.h"
|
||||
#include "terminal.h"
|
||||
#include "serialterminal.h"
|
||||
|
|
@ -184,6 +185,8 @@ namespace Sortix
|
|||
|
||||
if ( BootInfo == NULL ) { Panic("kernel.cpp: The bootinfo structure was NULL. Are your bootloader multiboot compliant?"); }
|
||||
|
||||
COM::EarlyInit();
|
||||
|
||||
addr_t initrd = NULL;
|
||||
size_t initrdsize = 0;
|
||||
|
||||
|
|
@ -221,6 +224,9 @@ namespace Sortix
|
|||
// Initialize the list of kernel devices.
|
||||
DeviceFS::Init();
|
||||
|
||||
// Initialize the COM ports.
|
||||
COM::Init();
|
||||
|
||||
// Initialize the keyboard.
|
||||
Keyboard::Init();
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue