mirror of
https://github.com/fail0verflow/switch-coreboot.git
synced 2025-05-04 01:39:18 -04:00
2872f34f89
And don't link it. It's for ROMCC.
To make code happy that uses the ROMCC interface read_option(),
read_option_lowlevel() is ported to mc146818rtc.c along with
a message to use get_option() instead.
BUG=none
BRANCH=none
TEST=none
Change-Id: I9e6b1aeca2824199bbdec7dcb2bee9306d0e46cb
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Original-Commit-Id: c3da3fe1d3
Original-Change-Id: I54ea08de034766c8140b320075d36d5e811582fa
Original-Signed-off-by: Nico Huber <nico.huber@secunet.com>
Original-Reviewed-on: https://review.coreboot.org/19663
Original-Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Original-Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-by: Philippe Mathieu-Daud <philippe.mathieu.daude@gmail.com>
Original-Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: https://chromium-review.googlesource.com/506221
Commit-Ready: Patrick Georgi <pgeorgi@chromium.org>
Tested-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-by: Patrick Georgi <pgeorgi@chromium.org>
77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <console/console.h>
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#include <console/uart.h>
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#if CONFIG_USE_OPTION_TABLE
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#include <option.h>
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#include "option_table.h"
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#endif
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unsigned int default_baudrate(void)
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{
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#if !defined(__SMM__) && CONFIG_USE_OPTION_TABLE
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static const unsigned baud[8] =
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{ 115200, 57600, 38400, 19200, 9600, 4800, 2400, 1200 };
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unsigned b_index = 0;
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#if defined(__ROMCC__)
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b_index = read_option(baud_rate, 0xff);
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#else
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if (get_option(&b_index, "baud_rate") != CB_SUCCESS)
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b_index = 0xff;
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#endif
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if (b_index < 8)
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return baud[b_index];
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#endif
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return CONFIG_TTYS0_BAUD;
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}
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/* Calculate divisor. Do not floor but round to nearest integer. */
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unsigned int uart_baudrate_divisor(unsigned int baudrate,
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unsigned int refclk, unsigned int oversample)
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{
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return (1 + (2 * refclk) / (baudrate * oversample)) / 2;
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}
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#if !IS_ENABLED(CONFIG_UART_OVERRIDE_INPUT_CLOCK_DIVIDER)
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unsigned int uart_input_clock_divider(void)
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{
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/* Specify the default oversample rate for the UART.
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*
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* UARTs oversample the receive data. The UART's input clock first
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* enters the baud-rate divider to generate the oversample clock. Then
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* the UART typically divides the result by 16. The asynchronous
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* receive data is synchronized with the oversample clock and when a
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* start bit is detected the UART delays half a bit time using the
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* oversample clock. Samples are then taken to verify the start bit and
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* if present, samples are taken for the rest of the frame.
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*/
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return 16;
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}
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#endif
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#if !IS_ENABLED(CONFIG_UART_OVERRIDE_REFCLK)
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unsigned int uart_platform_refclk(void)
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{
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/* Specify the default input clock frequency for the UART.
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*
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* The older UART's used an input clock frequency of 1.8432 MHz which
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* with the 16x oversampling provided the maximum baud-rate of 115200.
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* Specify this as maximum baud-rate multiplied by oversample so that
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* it is obvious that the maximum baud rate is 115200 when divided by
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* oversample clock. Also note that crystal on the board does not
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* change when software selects another input clock divider.
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*/
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return 115200 * 16;
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}
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#endif
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