1 /***********************************************************************
3 * Copyright (C) 2004 by FS Forth-Systeme GmbH.
6 * $Id: ns9750_serial.c,v 1.1 2004/02/16 10:37:20 mpietrek Exp $
7 * @Author: Markus Pietrek
8 * @Descr: Serial driver for the NS9750. Only one UART is supported yet.
9 * @References: [1] NS9750 Hardware Reference/December 2003
10 * @TODO: Implement Character GAP Timer when chip is fixed for PLL bypass
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of
15 * the License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 ***********************************************************************/
31 #include "ns9750_bbus.h" /* for GPIOs */
32 #include "ns9750_ser.h" /* for serial configuration */
34 DECLARE_GLOBAL_DATA_PTR
;
36 #if !defined(CONFIG_CONS_INDEX)
37 #error "No console index specified."
40 #define CONSOLE CONFIG_CONS_INDEX
42 static unsigned int calcBitrateRegister( void );
43 static unsigned int calcRxCharGapRegister( void );
45 static char cCharsAvailable
; /* Numbers of chars in unCharCache */
46 static unsigned int unCharCache
; /* unCharCache is only valid if
47 * cCharsAvailable > 0 */
49 /***********************************************************************
50 * @Function: serial_init
52 * @Descr: configures GPIOs and UART. Requires BBUS Master Reset turned off
53 ***********************************************************************/
55 int serial_init( void )
57 unsigned int aunGPIOTxD
[] = { 0, 8, 40, 44 };
58 unsigned int aunGPIORxD
[] = { 1, 9, 41, 45 };
62 /* configure TxD and RxD pins for their special function */
63 set_gpio_cfg_reg_val( aunGPIOTxD
[ CONSOLE
],
64 NS9750_GPIO_CFG_FUNC_0
| NS9750_GPIO_CFG_OUTPUT
);
65 set_gpio_cfg_reg_val( aunGPIORxD
[ CONSOLE
],
66 NS9750_GPIO_CFG_FUNC_0
| NS9750_GPIO_CFG_INPUT
);
68 /* configure serial engine */
69 *get_ser_reg_addr_channel( NS9750_SER_CTRL_A
, CONSOLE
) =
70 NS9750_SER_CTRL_A_CE
|
71 NS9750_SER_CTRL_A_STOP
|
72 NS9750_SER_CTRL_A_WLS_8
;
76 *get_ser_reg_addr_channel( NS9750_SER_CTRL_B
, CONSOLE
) =
77 NS9750_SER_CTRL_B_RCGT
;
82 /***********************************************************************
83 * @Function: serial_putc
85 * @Descr: writes one character to the FIFO. Blocks until FIFO is not full
86 ***********************************************************************/
88 void serial_putc( const char c
)
93 while (!(*get_ser_reg_addr_channel( NS9750_SER_STAT_A
, CONSOLE
) &
94 NS9750_SER_STAT_A_TRDY
) ) {
95 /* do nothing, wait for characters in FIFO sent */
98 *(volatile char*) get_ser_reg_addr_channel( NS9750_SER_FIFO
,
102 /***********************************************************************
103 * @Function: serial_puts
105 * @Descr: writes non-zero string to the FIFO.
106 ***********************************************************************/
108 void serial_puts( const char *s
)
115 /***********************************************************************
116 * @Function: serial_getc
117 * @Return: the character read
118 * @Descr: performs only 8bit accesses to the FIFO. No error handling
119 ***********************************************************************/
121 int serial_getc( void )
125 while (!serial_tstc() ) {
126 /* do nothing, wait for incoming characters */
129 /* at least one character in unCharCache */
130 i
= (int) (unCharCache
& 0xff);
138 /***********************************************************************
139 * @Function: serial_tstc
140 * @Return: 0 if no input available, otherwise != 0
141 * @Descr: checks for incoming FIFO not empty. Stores the incoming chars in
142 * unCharCache and the numbers of characters in cCharsAvailable
143 ***********************************************************************/
145 int serial_tstc( void )
147 unsigned int unRegCache
;
149 if ( cCharsAvailable
)
152 unRegCache
= *get_ser_reg_addr_channel( NS9750_SER_STAT_A
,CONSOLE
);
153 if( unRegCache
& NS9750_SER_STAT_A_RBC
) {
154 *get_ser_reg_addr_channel( NS9750_SER_STAT_A
, CONSOLE
) =
155 NS9750_SER_STAT_A_RBC
;
156 unRegCache
= *get_ser_reg_addr_channel( NS9750_SER_STAT_A
,
160 if ( unRegCache
& NS9750_SER_STAT_A_RRDY
) {
161 cCharsAvailable
= (unRegCache
& NS9750_SER_STAT_A_RXFDB_MA
)>>20;
162 if ( !cCharsAvailable
)
165 unCharCache
= *get_ser_reg_addr_channel( NS9750_SER_FIFO
,
170 /* no chars available */
174 void serial_setbrg( void )
176 *get_ser_reg_addr_channel( NS9750_SER_BITRATE
, CONSOLE
) =
177 calcBitrateRegister();
178 *get_ser_reg_addr_channel( NS9750_SER_RX_CHAR_TIMER
, CONSOLE
) =
179 calcRxCharGapRegister();
182 /***********************************************************************
183 * @Function: calcBitrateRegister
184 * @Return: value for the serial bitrate register
185 * @Descr: register value depends on clock frequency and baudrate
186 ***********************************************************************/
188 static unsigned int calcBitrateRegister( void )
190 return ( NS9750_SER_BITRATE_EBIT
|
191 NS9750_SER_BITRATE_CLKMUX_BCLK
|
192 NS9750_SER_BITRATE_TMODE
|
193 NS9750_SER_BITRATE_TCDR_16
|
194 NS9750_SER_BITRATE_RCDR_16
|
195 ( ( ( ( CONFIG_SYS_CLK_FREQ
/ 8 ) / /* BBUS clock,[1] Fig. 38 */
196 ( gd
->baudrate
* 16 ) ) - 1 ) &
197 NS9750_SER_BITRATE_N_MA
) );
200 /***********************************************************************
201 * @Function: calcRxCharGapRegister
202 * @Return: value for the character gap timer register
203 * @Descr: register value depends on clock frequency and baudrate. Currently 0
204 * is used as there is a bug with the gap timer in PLL bypass mode.
205 ***********************************************************************/
207 static unsigned int calcRxCharGapRegister( void )
209 return NS9750_SER_RX_CHAR_TIMER_TRUN
;