79 lines
1.7 KiB
C++
79 lines
1.7 KiB
C++
/*
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* \brief Console backend for PL011 UART on Codezero
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* \author Norman Feske
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* \date 2009-10-03
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*
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* This code assumes a PL011 UART as provided by 'qemu -M versatilepb'. Prior
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* executing this code, the kernel already initialized the UART to print some
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* startup message. So we can skip the UART initialization here. The kernel
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* maps the UART registers to the magic address PL011_BASE when starting mm0.
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* So we can just start using the device without any precautions.
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*/
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/*
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* Copyright (C) 2009-2012 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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/* Genode includes */
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#include <base/console.h>
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/* codezero includes */
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#include <codezero/syscalls.h>
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typedef unsigned char uint8_t;
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/**
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* Base address of default-mapped UART device
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*
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* defined in 'l4/arch/arm/io.h'
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*/
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enum { PL011_BASE = USERSPACE_CONSOLE_VBASE };
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/**
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* UART registers
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*/
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enum { PL011_REG_UARTDR = PL011_BASE + 0x00 };
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enum { PL011_REG_UARTFR = PL011_BASE + 0x18 };
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/**
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* Returns true if UART is ready to transmit a character
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*/
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static bool pl011_tx_ready()
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{
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enum { PL011_TX_FIFO_FULL = 1 << 5 };
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return !(*((volatile unsigned *)PL011_REG_UARTFR) & PL011_TX_FIFO_FULL);
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}
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/**
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* Output character to serial port
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*/
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static void pl011_out_char(uint8_t c)
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{
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/* wait until serial port is ready */
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while (!pl011_tx_ready());
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/* output character */
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*((volatile unsigned int *)PL011_REG_UARTDR) = c;
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}
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namespace Genode
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{
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class Core_console : public Console
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{
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protected:
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void _out_char(char c) {
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if(c == '\n')
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pl011_out_char('\r');
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pl011_out_char(c);
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}
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};
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}
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