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wdenk80885a92004-02-26 23:46:20 +00001/***********************************************************************
2 *
3 * Copyright (C) 2004 by FS Forth-Systeme GmbH.
4 * All rights reserved.
5 *
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
11 *
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.
16 *
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.
21 *
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,
25 * MA 02111-1307 USA
26 *
27 ***********************************************************************/
28
29#include <common.h>
30
31#ifdef CFG_NS9750_UART
32
33#include "ns9750_bbus.h" /* for GPIOs */
34#include "ns9750_ser.h" /* for serial configuration */
35
36#define CONSOLE CONFIG_CONS_INDEX
37
38static unsigned int calcBitrateRegister( void );
39static unsigned int calcRxCharGapRegister( void );
40
41static char cCharsAvailable; /* Numbers of chars in unCharCache */
42static unsigned int unCharCache; /* unCharCache is only valid if
43 * cCharsAvailable > 0 */
44
45/***********************************************************************
46 * @Function: serial_init
47 * @Return: 0
48 * @Descr: configures GPIOs and UART. Requires BBUS Master Reset turned off
49 ***********************************************************************/
50
51int serial_init( void )
52{
53 unsigned int aunGPIOTxD[] = { 0, 8, 40, 44 };
54 unsigned int aunGPIORxD[] = { 1, 9, 41, 45 };
55
56 cCharsAvailable = 0;
57
58 /* configure TxD and RxD pins for their special function */
59 set_gpio_cfg_reg_val( aunGPIOTxD[ CONSOLE ],
60 NS9750_GPIO_CFG_FUNC_0 | NS9750_GPIO_CFG_OUTPUT );
61 set_gpio_cfg_reg_val( aunGPIORxD[ CONSOLE ],
62 NS9750_GPIO_CFG_FUNC_0 | NS9750_GPIO_CFG_INPUT );
63
64 /* configure serial engine */
65 *get_ser_reg_addr_channel( NS9750_SER_CTRL_A, CONSOLE ) =
66 NS9750_SER_CTRL_A_CE |
67 NS9750_SER_CTRL_A_STOP |
68 NS9750_SER_CTRL_A_WLS_8;
69
70 serial_setbrg();
71
72 *get_ser_reg_addr_channel( NS9750_SER_CTRL_B, CONSOLE ) =
73 NS9750_SER_CTRL_B_RCGT;
74
75 return 0;
76}
77
78/***********************************************************************
79 * @Function: serial_putc
80 * @Return: n/a
81 * @Descr: writes one character to the FIFO. Blocks until FIFO is not full
82 ***********************************************************************/
83
84void serial_putc( const char c )
85{
86 if (c == '\n')
87 serial_putc( '\r' );
88
89 while (!(*get_ser_reg_addr_channel( NS9750_SER_STAT_A, CONSOLE) &
90 NS9750_SER_STAT_A_TRDY ) ) {
91 /* do nothing, wait for characters in FIFO sent */
92 }
93
94 *(volatile char*) get_ser_reg_addr_channel( NS9750_SER_FIFO,
95 CONSOLE) = c;
96}
97
98/***********************************************************************
99 * @Function: serial_puts
100 * @Return: n/a
101 * @Descr: writes non-zero string to the FIFO.
102 ***********************************************************************/
103
104void serial_puts( const char *s )
105{
106 while (*s) {
107 serial_putc( *s++ );
108 }
109}
110
111/***********************************************************************
112 * @Function: serial_getc
113 * @Return: the character read
114 * @Descr: performs only 8bit accesses to the FIFO. No error handling
115 ***********************************************************************/
116
117int serial_getc( void )
118{
119 int i;
120
121 while (!serial_tstc() ) {
122 /* do nothing, wait for incoming characters */
123 }
124
125 /* at least one character in unCharCache */
126 i = (int) (unCharCache & 0xff);
127
128 unCharCache >>= 8;
129 cCharsAvailable--;
130
131 return i;
132}
133
134/***********************************************************************
135 * @Function: serial_tstc
136 * @Return: 0 if no input available, otherwise != 0
137 * @Descr: checks for incoming FIFO not empty. Stores the incoming chars in
138 * unCharCache and the numbers of characters in cCharsAvailable
139 ***********************************************************************/
140
141int serial_tstc( void )
142{
143 unsigned int unRegCache;
144
145 if ( cCharsAvailable )
146 return 1;
147
148 unRegCache = *get_ser_reg_addr_channel( NS9750_SER_STAT_A,CONSOLE );
149 if( unRegCache & NS9750_SER_STAT_A_RBC ) {
150 *get_ser_reg_addr_channel( NS9750_SER_STAT_A, CONSOLE ) =
151 NS9750_SER_STAT_A_RBC;
152 unRegCache = *get_ser_reg_addr_channel( NS9750_SER_STAT_A,
153 CONSOLE );
154 }
155
156 if ( unRegCache & NS9750_SER_STAT_A_RRDY ) {
157 cCharsAvailable = (unRegCache & NS9750_SER_STAT_A_RXFDB_MA)>>20;
158 if ( !cCharsAvailable )
159 cCharsAvailable = 4;
160
161 unCharCache = *get_ser_reg_addr_channel( NS9750_SER_FIFO,
162 CONSOLE );
163 return 1;
164 }
165
166 /* no chars available */
167 return 0;
168}
169
170void serial_setbrg( void )
171{
172 *get_ser_reg_addr_channel( NS9750_SER_BITRATE, CONSOLE ) =
173 calcBitrateRegister();
174 *get_ser_reg_addr_channel( NS9750_SER_RX_CHAR_TIMER, CONSOLE ) =
175 calcRxCharGapRegister();
176}
177
178/***********************************************************************
179 * @Function: calcBitrateRegister
180 * @Return: value for the serial bitrate register
181 * @Descr: register value depends on clock frequency and baudrate
182 ***********************************************************************/
183
184static unsigned int calcBitrateRegister( void )
185{
186 DECLARE_GLOBAL_DATA_PTR;
187
188 return ( NS9750_SER_BITRATE_EBIT |
189 NS9750_SER_BITRATE_CLKMUX_BCLK |
190 NS9750_SER_BITRATE_TMODE |
191 NS9750_SER_BITRATE_TCDR_16 |
192 NS9750_SER_BITRATE_RCDR_16 |
193 ( ( ( ( CONFIG_SYS_CLK_FREQ / 8 ) / /* BBUS clock,[1] Fig. 38 */
194 ( gd->baudrate * 16 ) ) - 1 ) &
195 NS9750_SER_BITRATE_N_MA ) );
196}
197
198/***********************************************************************
199 * @Function: calcRxCharGapRegister
200 * @Return: value for the character gap timer register
201 * @Descr: register value depends on clock frequency and baudrate. Currently 0
202 * is used as there is a bug with the gap timer in PLL bypass mode.
203 ***********************************************************************/
204
205static unsigned int calcRxCharGapRegister( void )
206{
207 DECLARE_GLOBAL_DATA_PTR;
208
209 return NS9750_SER_RX_CHAR_TIMER_TRUN;
210}
211
212#endif /* CFG_NS9750_UART */