diff options
Diffstat (limited to 'src/drivers/uart/util.c')
| -rw-r--r-- | src/drivers/uart/util.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/drivers/uart/util.c b/src/drivers/uart/util.c new file mode 100644 index 0000000000..c577048fb5 --- /dev/null +++ b/src/drivers/uart/util.c @@ -0,0 +1,48 @@ +/* + * This file is part of the coreboot project. + * + * 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; version 2 of the License. + * + * 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 St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <console/console.h> +#include <uart.h> +#if CONFIG_USE_OPTION_TABLE +#include <pc80/mc146818rtc.h> +#include "option_table.h" +#endif + +unsigned int default_baudrate(void) +{ +#if !defined(__SMM__) && CONFIG_USE_OPTION_TABLE + static const unsigned baud[8] = + { 115200, 57600, 38400, 19200, 9600, 4800, 2400, 1200 }; + unsigned b_index = 0; +#if defined(__PRE_RAM__) + b_index = read_option(baud_rate, 0xff); +#else + if (get_option(&b_index, "baud_rate") != CB_SUCCESS) + b_index = 0xff; +#endif + if (b_index < 8) + return baud[b_index]; +#endif + return CONFIG_TTYS0_BAUD; +} + +/* Calculate divisor. Do not floor but round to nearest integer. */ +unsigned int uart_baudrate_divisor(unsigned int baudrate, + unsigned int refclk, unsigned int oversample) +{ + return (1 + (2 * refclk) / (baudrate * oversample)) / 2; +} |