72dccce0c9
Do not directly check the return value of get_option, but instead compare the returned value against a CB_CMOS_ error code, or against CB_SUCCESS. Change-Id: I2fa7761d13ebb5e9b4606076991a43f18ae370ad Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com> Reviewed-on: http://review.coreboot.org/4266 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
132 lines
3.7 KiB
C
132 lines
3.7 KiB
C
/*
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* This file is part of the coreboot project.
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*
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* Copyright (C) 2003 Eric Biederman
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* Copyright (C) 2006-2010 coresystems GmbH
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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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* 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 St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <arch/io.h>
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#include <uart8250.h>
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#include <pc80/mc146818rtc.h>
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#include <trace.h>
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#if CONFIG_USE_OPTION_TABLE
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#include "option_table.h"
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#endif
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/* Should support 8250, 16450, 16550, 16550A type UARTs */
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/* Expected character delay at 1200bps is 9ms for a working UART
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* and no flow-control. Assume UART as stuck if shift register
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* or FIFO takes more than 50ms per character to appear empty.
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*
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* Estimated that inb() from UART takes 1 microsecond.
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*/
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#define SINGLE_CHAR_TIMEOUT (50 * 1000)
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#define FIFO_TIMEOUT (16 * SINGLE_CHAR_TIMEOUT)
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static inline int uart8250_can_tx_byte(unsigned base_port)
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{
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return inb(base_port + UART_LSR) & UART_LSR_THRE;
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}
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static inline void uart8250_wait_to_tx_byte(unsigned base_port)
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{
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unsigned long int i = SINGLE_CHAR_TIMEOUT;
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while (i-- && !uart8250_can_tx_byte(base_port));
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}
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static inline void uart8250_wait_until_sent(unsigned base_port)
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{
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unsigned long int i = FIFO_TIMEOUT;
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while (i-- && !(inb(base_port + UART_LSR) & UART_LSR_TEMT));
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}
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void uart8250_tx_byte(unsigned base_port, unsigned char data)
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{
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uart8250_wait_to_tx_byte(base_port);
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outb(data, base_port + UART_TBR);
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}
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void uart8250_tx_flush(unsigned base_port)
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{
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uart8250_wait_until_sent(base_port);
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}
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int uart8250_can_rx_byte(unsigned base_port)
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{
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return inb(base_port + UART_LSR) & UART_LSR_DR;
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}
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unsigned char uart8250_rx_byte(unsigned base_port)
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{
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unsigned long int i = SINGLE_CHAR_TIMEOUT;
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while (i-- && !uart8250_can_rx_byte(base_port));
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if (i)
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return inb(base_port + UART_RBR);
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else
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return 0x0;
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}
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void uart8250_init(unsigned base_port, unsigned divisor)
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{
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DISABLE_TRACE;
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/* Disable interrupts */
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outb(0x0, base_port + UART_IER);
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/* Enable FIFOs */
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outb(UART_FCR_FIFO_EN, base_port + UART_FCR);
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/* assert DTR and RTS so the other end is happy */
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outb(UART_MCR_DTR | UART_MCR_RTS, base_port + UART_MCR);
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/* DLAB on */
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outb(UART_LCR_DLAB | CONFIG_TTYS0_LCS, base_port + UART_LCR);
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/* Set Baud Rate Divisor. 12 ==> 9600 Baud */
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outb(divisor & 0xFF, base_port + UART_DLL);
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outb((divisor >> 8) & 0xFF, base_port + UART_DLM);
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/* Set to 3 for 8N1 */
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outb(CONFIG_TTYS0_LCS, base_port + UART_LCR);
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ENABLE_TRACE;
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}
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void uart_init(void)
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{
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/* TODO the divisor calculation is hard coded to standard UARTs. Some
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* UARTs won't work with these values. This should be a property of the
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* UART used, worst case a Kconfig variable. For now live with hard
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* codes as the only devices that might be different are the iWave
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* iRainbowG6 and the OXPCIe952 card (and the latter is memory mapped)
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*/
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unsigned int div = (115200 / CONFIG_TTYS0_BAUD);
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#if !defined(__SMM__) && CONFIG_USE_OPTION_TABLE
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static const unsigned char divisor[8] = { 1, 2, 3, 6, 12, 24, 48, 96 };
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unsigned b_index = 0;
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#if defined(__PRE_RAM__)
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b_index = read_option(baud_rate, 0);
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b_index &= 7;
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div = divisor[b_index];
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#else
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if (get_option(&b_index, "baud_rate") == CB_SUCCESS)
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div = divisor[b_index];
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#endif
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#endif
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uart8250_init(CONFIG_TTYS0_BASE, div);
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}
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