70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
/*
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* Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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/** @file
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*
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* 16550-compatible UART
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*
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*/
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#include <errno.h>
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#include <ipxe/uart.h>
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/** UART port bases */
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static uint16_t uart_base[] = {
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[COM1] = 0x3f8,
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[COM2] = 0x2f8,
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[COM3] = 0x3e8,
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[COM4] = 0x2e8,
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};
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/**
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* Select UART port
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*
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* @v uart UART
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* @v port Port number, or 0 to disable
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* @ret rc Return status code
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*/
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int uart_select ( struct uart *uart, unsigned int port ) {
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int rc;
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/* Set new UART base */
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if ( port >= ( sizeof ( uart_base ) / sizeof ( uart_base[0] ) ) ) {
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rc = -ENODEV;
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goto err;
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}
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uart->base = ( ( void * ) ( intptr_t ) uart_base[port] );
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/* Check that UART exists */
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if ( ( rc = uart_exists ( uart ) ) != 0 )
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goto err;
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return 0;
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err:
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uart->base = NULL;
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return rc;
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}
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