summaryrefslogtreecommitdiff
path: root/drivers/serial_pl011.c
blob: 60fcc9132abe737c75b078028f863905db01d1dc (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
/*
 * (C) Copyright 2000
 * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
 *
 * (C) Copyright 2004
 * ARM Ltd.
 * Philippe Robin, <philippe.robin@arm.com>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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
 */

/* Simple U-Boot driver for the PrimeCell PL011 UARTs on the IntegratorCP */
/* Should be fairly simple to make it work with the PL010 as well */

#include <common.h>

#ifdef CFG_PL011_SERIAL

#include "serial_pl011.h"

#define IO_WRITE(addr, val) (*(volatile unsigned int *)(addr) = (val))
#define IO_READ(addr) (*(volatile unsigned int *)(addr))

/*
 * IntegratorCP has two UARTs, use the first one, at 38400-8-N-1 
 * Versatile PB has four UARTs.
 */
#define NUM_PORTS 2
#define CONSOLE_PORT CONFIG_CONS_INDEX
#define baudRate CONFIG_BAUDRATE
static volatile unsigned char * const port[NUM_PORTS] = {(void*)(CFG_SERIAL0),
                                                         (void*)(CFG_SERIAL1)};


static void pl011_putc(int portnum, char c);
static int pl011_getc(int portnum);
static int pl011_tstc(int portnum);


int serial_init (void)
{
    unsigned int temp;
    unsigned int divider;
    unsigned int remainder;
    unsigned int fraction;

    /*
    ** First, disable everything.
    */
    IO_WRITE(port[CONSOLE_PORT] + UART_PL011_CR, 0x0);

    /*
    ** Set baud rate
    **
    ** IBRD = UART_CLK / (16 * BAUD_RATE)
    ** FBRD = ROUND((64 * MOD(UART_CLK,(16 * BAUD_RATE))) / (16 * BAUD_RATE))
    */
#ifdef CONFIG_VERSATILE
    temp      = 16 * baudRate;
    divider   = 24000000 / temp;
    remainder = 24000000 % temp;
    temp      = (8 * remainder) / baudRate;
    fraction  = (temp >> 1) + (temp & 1);
#endif
#ifdef CONFIG_INTEGRATOR
    temp      = 16 * baudRate;
    divider   = 14745600 / temp;
    remainder = 14745600 % temp;
    temp      = (8 * remainder) / baudRate;
    fraction  = (temp >> 1) + (temp & 1);
#endif
 
    IO_WRITE(port[CONSOLE_PORT] + UART_PL011_IBRD, divider);
    IO_WRITE(port[CONSOLE_PORT] + UART_PL011_FBRD, fraction);

    /*
    ** Set the UART to be 8 bits, 1 stop bit, no parity, fifo enabled.
    */
    IO_WRITE(port[CONSOLE_PORT] + UART_PL011_LCRH,
        (UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN));

    /*
    ** Finally, enable the UART
    */
    IO_WRITE(port[CONSOLE_PORT] + UART_PL011_CR,
        (UART_PL011_CR_UARTEN | UART_PL011_CR_TXE | UART_PL011_CR_RXE));

    return (0);
}

void
serial_putc(const char c)
{
	if (c == '\n')
		pl011_putc(CONSOLE_PORT, '\r');

	pl011_putc(CONSOLE_PORT, c);
}

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

int
serial_getc(void)
{
	return pl011_getc(CONSOLE_PORT);
}

int
serial_tstc(void)
{
	return pl011_tstc(CONSOLE_PORT);
}

void
serial_setbrg (void)
{
}

static void pl011_putc(int portnum, char c)
{
    /* Wait until there is space in the FIFO */
    while (IO_READ(port[portnum] + UART_PL01x_FR) & UART_PL01x_FR_TXFF);
    
    /* Send the character */
    IO_WRITE(port[portnum] + UART_PL01x_DR, c);
}

static int pl011_getc(int portnum)
{
    unsigned int data;

    /* Wait until there is data in the FIFO */
    while (IO_READ(port[portnum] + UART_PL01x_FR) & UART_PL01x_FR_RXFE);
    
    data = IO_READ(port[portnum] + UART_PL01x_DR);
    
    /* Check for an error flag */
    if (data & 0xFFFFFF00)
    {
        /* Clear the error */
        IO_WRITE(port[portnum] + UART_PL01x_ECR, 0xFFFFFFFF);
        return -1;
    }
    
    return (int)data;
}

static int pl011_tstc(int portnum)
{
    return !(IO_READ(port[portnum] + UART_PL01x_FR) & UART_PL01x_FR_RXFE);
}

#endif