diff options
Diffstat (limited to 'src/arch/x86/core/x86_uart.c')
-rw-r--r-- | src/arch/x86/core/x86_uart.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/src/arch/x86/core/x86_uart.c b/src/arch/x86/core/x86_uart.c new file mode 100644 index 00000000..7c3a01d6 --- /dev/null +++ b/src/arch/x86/core/x86_uart.c @@ -0,0 +1,62 @@ +/* + * Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>. + * + * This program 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 2 of the + * License, or any later version. + * + * This program 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 this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + * + * You can also choose to distribute this program under the terms of + * the Unmodified Binary Distribution Licence (as given in the file + * COPYING.UBDL), provided that you have satisfied its requirements. + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); + +/** @file + * + * 16550-compatible UART + * + */ + +#include <errno.h> +#include <ipxe/uart.h> + +/** UART port bases */ +static uint16_t uart_base[] = { + [COM1] = 0x3f8, + [COM2] = 0x2f8, + [COM3] = 0x3e8, + [COM4] = 0x2e8, +}; + +/** + * Select UART port + * + * @v uart UART + * @v port Port number, or 0 to disable + * @ret rc Return status code + */ +int uart_select ( struct uart *uart, unsigned int port ) { + + /* Clear UART base */ + uart->base = NULL; + + /* Set new UART base */ + if ( port < ( sizeof ( uart_base ) / sizeof ( uart_base[0] ) ) ) { + uart->base = ( ( void * ) ( intptr_t ) uart_base[port] ); + return 0; + } else { + return -ENODEV; + } +} |