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