Root/Examples/hello_nand/build/jz_serial.c

1/*
2 * Jz47xx UART support
3 *
4 * Options hardcoded to 8N1
5 *
6 * Copyright (c) 2009, yajin <yajin@vm-kernel.org>
7 * Copyright (c) 2005 - 2008, Ingenic Semiconductor Inc.
8 * Ingenic Semiconductor, <jlwei@ingenic.cn>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of
13 * the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
23 * MA 02111-1307 USA
24 */
25
26
27#include <jz4740.h>
28#include <board.h>
29
30#undef UART_BASE
31#ifndef CFG_UART_BASE
32#define UART_BASE UART0_BASE
33#else
34#define UART_BASE CFG_UART_BASE
35#endif
36
37/******************************************************************************
38*
39* serial_init - initialize a channel
40*
41* This routine initializes the number of data bits, parity
42* and set the selected baud rate. Interrupts are disabled.
43* Set the modem control signals if the option is selected.
44*
45* RETURNS: N/A
46*/
47
48static void serial_setbrg(void)
49{
50    volatile u8 *uart_lcr = (volatile u8 *) (UART_BASE + OFF_LCR);
51    volatile u8 *uart_dlhr = (volatile u8 *) (UART_BASE + OFF_DLHR);
52    volatile u8 *uart_dllr = (volatile u8 *) (UART_BASE + OFF_DLLR);
53    u32 baud_div, tmp;
54
55    baud_div = CFG_EXTAL / 16 / CONFIG_BAUDRATE;
56    tmp = *uart_lcr;
57    tmp |= UART_LCR_DLAB;
58    *uart_lcr = tmp;
59
60    *uart_dlhr = (baud_div >> 8) & 0xff;
61    *uart_dllr = baud_div & 0xff;
62
63    tmp &= ~UART_LCR_DLAB;
64    *uart_lcr = tmp;
65}
66
67int serial_init(void)
68{
69    volatile u8 *uart_fcr = (volatile u8 *) (UART_BASE + OFF_FCR);
70    volatile u8 *uart_lcr = (volatile u8 *) (UART_BASE + OFF_LCR);
71    volatile u8 *uart_ier = (volatile u8 *) (UART_BASE + OFF_IER);
72    volatile u8 *uart_sircr = (volatile u8 *) (UART_BASE + OFF_SIRCR);
73
74    /* Disable port interrupts while changing hardware */
75    *uart_ier = 0;
76
77    /* Disable UART unit function */
78    *uart_fcr = ~UART_FCR_UUE;
79
80    /* Set both receiver and transmitter in UART mode (not SIR) */
81    *uart_sircr = ~(SIRCR_RSIRE | SIRCR_TSIRE);
82
83    /* Set databits, stopbits and parity. (8-bit data, 1 stopbit, no parity) */
84    *uart_lcr = UART_LCR_WLEN_8 | UART_LCR_STOP_1;
85
86    /* Set baud rate */
87    serial_setbrg();
88
89    /* Enable UART unit, enable and clear FIFO */
90    *uart_fcr = UART_FCR_UUE | UART_FCR_FE | UART_FCR_TFLS | UART_FCR_RFLS;
91
92    return 0;
93}
94
95void serial_putc(const char c)
96{
97    volatile u8 *uart_lsr = (volatile u8 *) (UART_BASE + OFF_LSR);
98    volatile u8 *uart_tdr = (volatile u8 *) (UART_BASE + OFF_TDR);
99
100    if (c == '\n')
101        serial_putc('\r');
102
103    /* Wait for fifo to shift out some bytes */
104    while (!((*uart_lsr & (UART_LSR_TDRQ | UART_LSR_TEMT)) == 0x60));
105
106    *uart_tdr = (u8) c;
107}
108
109void serial_puts(const char *s)
110{
111    while (*s)
112    {
113        serial_putc(*s++);
114    }
115}
116

Archive Download this file

Branches:
master



interactive