xref: /openbmc/u-boot/drivers/serial/atmel_usart.c (revision 15855700)
1 /*
2  * Copyright (C) 2004-2006 Atmel Corporation
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17  */
18 #include <common.h>
19 #ifndef CONFIG_AT91_LEGACY
20 #define CONFIG_AT91_LEGACY
21 #warning Please update to use C structur SoC access !
22 #endif
23 #include <watchdog.h>
24 
25 #include <asm/io.h>
26 #include <asm/arch/clk.h>
27 #include <asm/arch/memory-map.h>
28 
29 #if defined(CONFIG_USART0)
30 # define USART_ID	0
31 # define USART_BASE	USART0_BASE
32 #elif defined(CONFIG_USART1)
33 # define USART_ID	1
34 # define USART_BASE	USART1_BASE
35 #elif defined(CONFIG_USART2)
36 # define USART_ID	2
37 # define USART_BASE	USART2_BASE
38 #elif defined(CONFIG_USART3)
39 # define USART_ID	3
40 # define USART_BASE	USART3_BASE
41 #endif
42 
43 #include "atmel_usart.h"
44 
45 DECLARE_GLOBAL_DATA_PTR;
46 
47 void serial_setbrg(void)
48 {
49 	unsigned long divisor;
50 	unsigned long usart_hz;
51 
52 	/*
53 	 *              Master Clock
54 	 * Baud Rate = --------------
55 	 *                16 * CD
56 	 */
57 	usart_hz = get_usart_clk_rate(USART_ID);
58 	divisor = (usart_hz / 16 + gd->baudrate / 2) / gd->baudrate;
59 	usart3_writel(BRGR, USART3_BF(CD, divisor));
60 }
61 
62 int serial_init(void)
63 {
64 	usart3_writel(CR, USART3_BIT(RSTRX) | USART3_BIT(RSTTX));
65 
66 	serial_setbrg();
67 
68 	usart3_writel(CR, USART3_BIT(RXEN) | USART3_BIT(TXEN));
69 	usart3_writel(MR, (USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
70 			   | USART3_BF(USCLKS, USART3_USCLKS_MCK)
71 			   | USART3_BF(CHRL, USART3_CHRL_8)
72 			   | USART3_BF(PAR, USART3_PAR_NONE)
73 			   | USART3_BF(NBSTOP, USART3_NBSTOP_1)));
74 
75 	return 0;
76 }
77 
78 void serial_putc(char c)
79 {
80 	if (c == '\n')
81 		serial_putc('\r');
82 
83 	while (!(usart3_readl(CSR) & USART3_BIT(TXRDY))) ;
84 	usart3_writel(THR, c);
85 }
86 
87 void serial_puts(const char *s)
88 {
89 	while (*s)
90 		serial_putc(*s++);
91 }
92 
93 int serial_getc(void)
94 {
95 	while (!(usart3_readl(CSR) & USART3_BIT(RXRDY)))
96 		 WATCHDOG_RESET();
97 	return usart3_readl(RHR);
98 }
99 
100 int serial_tstc(void)
101 {
102 	return (usart3_readl(CSR) & USART3_BIT(RXRDY)) != 0;
103 }
104