aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/serial/serial_s3c44b0.c
blob: 95d0266c6c675cba1a31f98e8c007d9cae21fa37 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/*
 * (C) Copyright 2004
 * DAVE Srl
 * http://www.dave-tech.it
 * http://www.wawnet.biz
 * mailto:info@wawnet.biz
 *
 * (C) Copyright 2002-2004
 * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Marius Groeger <mgroeger@sysgo.de>
 *
 * (C) Copyright 2002
 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
 * Alex Zuepke <azu@sysgo.de>
 *
 * Copyright (C) 1999 2000 2001 Erik Mouw (J.A.K.Mouw@its.tudelft.nl)
 *
 * 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 <asm/hardware.h>

DECLARE_GLOBAL_DATA_PTR;

/* flush serial input queue. returns 0 on success or negative error
 * number otherwise
 */
static int serial_flush_input(void)
{
	volatile u32 tmp;

	/* keep on reading as long as the receiver is not empty */
	while(UTRSTAT0&0x01) {
		tmp = REGB(URXH0);
	}

	return 0;
}


/* flush output queue. returns 0 on success or negative error number
 * otherwise
 */
static int serial_flush_output(void)
{
	/* wait until the transmitter is no longer busy */
	while(!(UTRSTAT0 & 0x02)) {
	}

	return 0;
}


void serial_setbrg (void)
{
	u32 divisor = 0;

	/* get correct divisor */
	switch(gd->baudrate) {

	case 1200:
#if CONFIG_S3C44B0_CLOCK_SPEED==66
		divisor = 3124;
#elif CONFIG_S3C44B0_CLOCK_SPEED==75
		divisor = 3905;
#else
# error CONFIG_S3C44B0_CLOCK_SPEED undefined
#endif
		break;

	case 9600:
#if CONFIG_S3C44B0_CLOCK_SPEED==66
		divisor = 390;
#elif CONFIG_S3C44B0_CLOCK_SPEED==75
		divisor = 487;
#else
# error CONFIG_S3C44B0_CLOCK_SPEED undefined
#endif
		break;

	case 19200:
#if CONFIG_S3C44B0_CLOCK_SPEED==66
		divisor = 194;
#elif CONFIG_S3C44B0_CLOCK_SPEED==75
		divisor = 243;
#else
# error CONFIG_S3C44B0_CLOCK_SPEED undefined
#endif
		break;

	case 38400:
#if CONFIG_S3C44B0_CLOCK_SPEED==66
		divisor = 97;
#elif CONFIG_S3C44B0_CLOCK_SPEED==75
		divisor = 121;
#else
# error CONFIG_S3C44B0_CLOCK_SPEED undefined
#endif	/* break; */

	case 57600:
#if CONFIG_S3C44B0_CLOCK_SPEED==66
		divisor = 64;
#elif CONFIG_S3C44B0_CLOCK_SPEED==75
		divisor = 80;
#else
# error CONFIG_S3C44B0_CLOCK_SPEED undefined
#endif	/* break; */

	case 115200:
#if CONFIG_S3C44B0_CLOCK_SPEED==66
		divisor = 32;
#elif CONFIG_S3C44B0_CLOCK_SPEED==75
		divisor = 40;
#else
# error CONFIG_S3C44B0_CLOCK_SPEED undefined
#endif	/* break; */
	}

	serial_flush_output();
	serial_flush_input();
	UFCON0 = 0x0;
	ULCON0 = 0x03;
	UCON0 = 0x05;
	UBRDIV0 = divisor;

	UFCON1 = 0x0;
	ULCON1 = 0x03;
	UCON1 = 0x05;
	UBRDIV1 = divisor;

	for(divisor=0; divisor<100; divisor++) {
		/* NOP */
	}
}


/*
 * Initialise the serial port with the given baudrate. The settings
 * are always 8 data bits, no parity, 1 stop bit, no start bits.
 *
 */
int serial_init (void)
{
	serial_setbrg ();

	return (0);
}


/*
 * Output a single byte to the serial port.
 */
void serial_putc (const char c)
{
	/* wait for room in the transmit FIFO */
	while(!(UTRSTAT0 & 0x02));

	UTXH0 = (unsigned char)c;

	/*
		to be polite with serial console add a line feed
		to the carriage return character
	*/
	if (c=='\n')
		serial_putc('\r');
}

/*
 * Read a single byte from the serial port. Returns 1 on success, 0
 * otherwise. When the function is succesfull, the character read is
 * written into its argument c.
 */
int serial_tstc (void)
{
	return (UTRSTAT0 & 0x01);
}

/*
 * Read a single byte from the serial port. Returns 1 on success, 0
 * otherwise. When the function is succesfull, the character read is
 * written into its argument c.
 */
int serial_getc (void)
{
	int rv;

	for(;;) {
		rv = serial_tstc();

		if(rv > 0)
			return URXH0;
	}
}

void
serial_puts (const char *s)
{
	while (*s) {
		serial_putc (*s++);
	}
}