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Diffstat (limited to 'drivers/ns9750_serial.c')
| -rw-r--r-- | drivers/ns9750_serial.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/ns9750_serial.c b/drivers/ns9750_serial.c new file mode 100644 index 0000000..aced3da --- /dev/null +++ b/drivers/ns9750_serial.c @@ -0,0 +1,212 @@ +/*********************************************************************** + * + * 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> + +#ifdef CFG_NS9750_UART + +#include "ns9750_bbus.h" /* for GPIOs */ +#include "ns9750_ser.h" /* for serial configuration */ + +#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 ) +{ + DECLARE_GLOBAL_DATA_PTR; + + 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 ) +{ + DECLARE_GLOBAL_DATA_PTR; + + return NS9750_SER_RX_CHAR_TIMER_TRUN; +} + +#endif /* CFG_NS9750_UART */ |