5b4edeb031
The new 'Uart::Session' interface is an extension of the 'Terminal::Session' interface that allows for configuring UART-specific parameters, i.e., the baud rate.
143 lines
2.8 KiB
C++
143 lines
2.8 KiB
C++
/*
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* \brief i8250 UART driver
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* \author Norman Feske
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* \date 2011-09-12
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*/
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/*
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* Copyright (C) 2011-2012 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _I8250_H_
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#define _I8250_H_
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/* Genode includes */
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#include <base/env.h>
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#include <base/lock.h>
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#include <base/printf.h>
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#include <os/irq_activation.h>
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#include <io_port_session/connection.h>
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/* local includes */
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#include "uart_driver.h"
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class I8250 : public Uart::Driver, public Genode::Irq_handler
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{
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private:
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unsigned _port_base;
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Genode::Io_port_connection _io_port;
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/**
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* Register offsets relative to '_port_base'
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*/
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enum Reg {
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TRB = 0, /* transmit/receive buffer */
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IER = 1,
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EIR = 2,
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LCR = 3,
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MCR = 4,
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LSR = 5, /* line status register */
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MSR = 6,
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DLLO = 0,
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DLHI = 1,
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};
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/**
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* Read byte from i8250 register
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*/
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template <Reg REG>
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char _inb() { return _io_port.inb(_port_base + REG); }
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/**
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* Write byte to i8250 register
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*/
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template <Reg REG>
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void _outb(char value) { _io_port.outb(_port_base + REG, value); }
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/**
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* Initialize UART
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*
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* Based on 'init_serial' of L4ka::Pistachio's 'kdb/platform/pc99/io.cc'
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*/
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void _init_comport(unsigned baud)
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{
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_outb<LCR>(0x80); /* select bank 1 */
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for (volatile int i = 10000000; i--; );
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_outb<DLLO>((115200/baud) >> 0);
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_outb<DLHI>((115200/baud) >> 8);
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_outb<LCR>(0x03); /* set 8,N,1 */
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_outb<IER>(0x00); /* disable interrupts */
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_outb<EIR>(0x07); /* enable FIFOs */
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_outb<MCR>(0x0b); /* force data terminal ready */
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_outb<IER>(0x01); /* enable RX interrupts */
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_inb<IER>();
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_inb<EIR>();
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_inb<LCR>();
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_inb<MCR>();
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_inb<LSR>();
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_inb<MSR>();
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}
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Uart::Char_avail_callback &_char_avail_callback;
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enum { IRQ_STACK_SIZE = 4096 };
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Genode::Irq_activation _irq_activation;
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public:
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/**
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* Constructor
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*/
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I8250(unsigned port_base, int irq_number, unsigned baud,
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Uart::Char_avail_callback &callback)
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:
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_port_base(port_base),
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_io_port(port_base, 0xf),
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_char_avail_callback(callback),
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_irq_activation(irq_number, *this, IRQ_STACK_SIZE)
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{
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_init_comport(baud);
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}
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/***************************
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** IRQ handler interface **
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***************************/
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void handle_irq(int irq_number)
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{
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/* inform client about the availability of data */
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_char_avail_callback();
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}
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/***************************
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** UART driver interface **
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***************************/
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void put_char(char c)
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{
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/* wait until serial port is ready */
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while (!(_inb<LSR>() & 0x60));
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/* output character */
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_outb<TRB>(c);
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}
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bool char_avail()
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{
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return _inb<LSR>() & 1;
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}
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char get_char()
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{
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return _inb<TRB>();
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}
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};
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#endif /* _I8250_H_ */
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