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215 lines
6.5 KiB
C
215 lines
6.5 KiB
C
/***********************************************************************
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*
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* Copyright (C) 2004 by FS Forth-Systeme GmbH.
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* All rights reserved.
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*
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* $Id: ns9750_serial.c,v 1.1 2004/02/16 10:37:20 mpietrek Exp $
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* @Author: Markus Pietrek
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* @Descr: Serial driver for the NS9750. Only one UART is supported yet.
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* @References: [1] NS9750 Hardware Reference/December 2003
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* @TODO: Implement Character GAP Timer when chip is fixed for PLL bypass
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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
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* the License, or (at your option) any later version.
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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., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*
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***********************************************************************/
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#include <common.h>
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#ifdef CFG_NS9750_UART
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#include "ns9750_bbus.h" /* for GPIOs */
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#include "ns9750_ser.h" /* for serial configuration */
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DECLARE_GLOBAL_DATA_PTR;
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#if !defined(CONFIG_CONS_INDEX)
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#error "No console index specified."
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#endif
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#define CONSOLE CONFIG_CONS_INDEX
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static unsigned int calcBitrateRegister( void );
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static unsigned int calcRxCharGapRegister( void );
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static char cCharsAvailable; /* Numbers of chars in unCharCache */
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static unsigned int unCharCache; /* unCharCache is only valid if
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* cCharsAvailable > 0 */
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/***********************************************************************
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* @Function: serial_init
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* @Return: 0
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* @Descr: configures GPIOs and UART. Requires BBUS Master Reset turned off
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***********************************************************************/
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int serial_init( void )
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{
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unsigned int aunGPIOTxD[] = { 0, 8, 40, 44 };
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unsigned int aunGPIORxD[] = { 1, 9, 41, 45 };
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cCharsAvailable = 0;
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/* configure TxD and RxD pins for their special function */
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set_gpio_cfg_reg_val( aunGPIOTxD[ CONSOLE ],
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NS9750_GPIO_CFG_FUNC_0 | NS9750_GPIO_CFG_OUTPUT );
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set_gpio_cfg_reg_val( aunGPIORxD[ CONSOLE ],
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NS9750_GPIO_CFG_FUNC_0 | NS9750_GPIO_CFG_INPUT );
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/* configure serial engine */
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*get_ser_reg_addr_channel( NS9750_SER_CTRL_A, CONSOLE ) =
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NS9750_SER_CTRL_A_CE |
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NS9750_SER_CTRL_A_STOP |
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NS9750_SER_CTRL_A_WLS_8;
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serial_setbrg();
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*get_ser_reg_addr_channel( NS9750_SER_CTRL_B, CONSOLE ) =
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NS9750_SER_CTRL_B_RCGT;
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return 0;
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}
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/***********************************************************************
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* @Function: serial_putc
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* @Return: n/a
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* @Descr: writes one character to the FIFO. Blocks until FIFO is not full
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***********************************************************************/
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void serial_putc( const char c )
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{
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if (c == '\n')
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serial_putc( '\r' );
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while (!(*get_ser_reg_addr_channel( NS9750_SER_STAT_A, CONSOLE) &
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NS9750_SER_STAT_A_TRDY ) ) {
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/* do nothing, wait for characters in FIFO sent */
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}
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*(volatile char*) get_ser_reg_addr_channel( NS9750_SER_FIFO,
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CONSOLE) = c;
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}
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/***********************************************************************
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* @Function: serial_puts
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* @Return: n/a
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* @Descr: writes non-zero string to the FIFO.
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***********************************************************************/
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void serial_puts( const char *s )
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{
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while (*s) {
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serial_putc( *s++ );
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}
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}
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/***********************************************************************
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* @Function: serial_getc
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* @Return: the character read
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* @Descr: performs only 8bit accesses to the FIFO. No error handling
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***********************************************************************/
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int serial_getc( void )
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{
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int i;
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while (!serial_tstc() ) {
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/* do nothing, wait for incoming characters */
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}
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/* at least one character in unCharCache */
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i = (int) (unCharCache & 0xff);
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unCharCache >>= 8;
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cCharsAvailable--;
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return i;
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}
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/***********************************************************************
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* @Function: serial_tstc
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* @Return: 0 if no input available, otherwise != 0
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* @Descr: checks for incoming FIFO not empty. Stores the incoming chars in
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* unCharCache and the numbers of characters in cCharsAvailable
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***********************************************************************/
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int serial_tstc( void )
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{
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unsigned int unRegCache;
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if ( cCharsAvailable )
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return 1;
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unRegCache = *get_ser_reg_addr_channel( NS9750_SER_STAT_A,CONSOLE );
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if( unRegCache & NS9750_SER_STAT_A_RBC ) {
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*get_ser_reg_addr_channel( NS9750_SER_STAT_A, CONSOLE ) =
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NS9750_SER_STAT_A_RBC;
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unRegCache = *get_ser_reg_addr_channel( NS9750_SER_STAT_A,
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CONSOLE );
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}
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if ( unRegCache & NS9750_SER_STAT_A_RRDY ) {
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cCharsAvailable = (unRegCache & NS9750_SER_STAT_A_RXFDB_MA)>>20;
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if ( !cCharsAvailable )
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cCharsAvailable = 4;
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unCharCache = *get_ser_reg_addr_channel( NS9750_SER_FIFO,
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CONSOLE );
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return 1;
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}
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/* no chars available */
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return 0;
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}
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void serial_setbrg( void )
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{
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*get_ser_reg_addr_channel( NS9750_SER_BITRATE, CONSOLE ) =
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calcBitrateRegister();
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*get_ser_reg_addr_channel( NS9750_SER_RX_CHAR_TIMER, CONSOLE ) =
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calcRxCharGapRegister();
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}
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/***********************************************************************
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* @Function: calcBitrateRegister
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* @Return: value for the serial bitrate register
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* @Descr: register value depends on clock frequency and baudrate
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***********************************************************************/
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static unsigned int calcBitrateRegister( void )
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{
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return ( NS9750_SER_BITRATE_EBIT |
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NS9750_SER_BITRATE_CLKMUX_BCLK |
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NS9750_SER_BITRATE_TMODE |
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NS9750_SER_BITRATE_TCDR_16 |
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NS9750_SER_BITRATE_RCDR_16 |
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( ( ( ( CONFIG_SYS_CLK_FREQ / 8 ) / /* BBUS clock,[1] Fig. 38 */
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( gd->baudrate * 16 ) ) - 1 ) &
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NS9750_SER_BITRATE_N_MA ) );
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}
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/***********************************************************************
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* @Function: calcRxCharGapRegister
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* @Return: value for the character gap timer register
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* @Descr: register value depends on clock frequency and baudrate. Currently 0
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* is used as there is a bug with the gap timer in PLL bypass mode.
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***********************************************************************/
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static unsigned int calcRxCharGapRegister( void )
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{
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return NS9750_SER_RX_CHAR_TIMER_TRUN;
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}
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#endif /* CFG_NS9750_UART */
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