xref: /openbmc/u-boot/drivers/serial/mcfuart.c (revision 63495ad7)
1 /*
2  * (C) Copyright 2004-2007 Freescale Semiconductor, Inc.
3  * TsiChung Liew, Tsi-Chung.Liew@freescale.com.
4  *
5  * See file CREDITS for list of people who contributed to this
6  * project.
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21  * MA 02111-1307 USA
22  *
23  */
24 
25 /*
26  * Minimal serial functions needed to use one of the uart ports
27  * as serial console interface.
28  */
29 
30 #include <common.h>
31 #include <serial.h>
32 #include <linux/compiler.h>
33 
34 #include <asm/immap.h>
35 #include <asm/uart.h>
36 
37 DECLARE_GLOBAL_DATA_PTR;
38 
39 extern void uart_port_conf(int port);
40 
41 static int mcf_serial_init(void)
42 {
43 	volatile uart_t *uart;
44 	u32 counter;
45 
46 	uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
47 
48 	uart_port_conf(CONFIG_SYS_UART_PORT);
49 
50 	/* write to SICR: SIM2 = uart mode,dcd does not affect rx */
51 	uart->ucr = UART_UCR_RESET_RX;
52 	uart->ucr = UART_UCR_RESET_TX;
53 	uart->ucr = UART_UCR_RESET_ERROR;
54 	uart->ucr = UART_UCR_RESET_MR;
55 	__asm__("nop");
56 
57 	uart->uimr = 0;
58 
59 	/* write to CSR: RX/TX baud rate from timers */
60 	uart->ucsr = (UART_UCSR_RCS_SYS_CLK | UART_UCSR_TCS_SYS_CLK);
61 
62 	uart->umr = (UART_UMR_BC_8 | UART_UMR_PM_NONE);
63 	uart->umr = UART_UMR_SB_STOP_BITS_1;
64 
65 	/* Setting up BaudRate */
66 	counter = (u32) ((gd->bus_clk / 32) + (gd->baudrate / 2));
67 	counter = counter / gd->baudrate;
68 
69 	/* write to CTUR: divide counter upper byte */
70 	uart->ubg1 = (u8) ((counter & 0xff00) >> 8);
71 	/* write to CTLR: divide counter lower byte */
72 	uart->ubg2 = (u8) (counter & 0x00ff);
73 
74 	uart->ucr = (UART_UCR_RX_ENABLED | UART_UCR_TX_ENABLED);
75 
76 	return (0);
77 }
78 
79 static void mcf_serial_putc(const char c)
80 {
81 	volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
82 
83 	if (c == '\n')
84 		serial_putc('\r');
85 
86 	/* Wait for last character to go. */
87 	while (!(uart->usr & UART_USR_TXRDY)) ;
88 
89 	uart->utb = c;
90 }
91 
92 static int mcf_serial_getc(void)
93 {
94 	volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
95 
96 	/* Wait for a character to arrive. */
97 	while (!(uart->usr & UART_USR_RXRDY)) ;
98 	return uart->urb;
99 }
100 
101 static int mcf_serial_tstc(void)
102 {
103 	volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
104 
105 	return (uart->usr & UART_USR_RXRDY);
106 }
107 
108 static void mcf_serial_setbrg(void)
109 {
110 	volatile uart_t *uart = (volatile uart_t *)(CONFIG_SYS_UART_BASE);
111 	u32 counter;
112 
113 	/* Setting up BaudRate */
114 	counter = (u32) ((gd->bus_clk / 32) + (gd->baudrate / 2));
115 	counter = counter / gd->baudrate;
116 
117 	/* write to CTUR: divide counter upper byte */
118 	uart->ubg1 = ((counter & 0xff00) >> 8);
119 	/* write to CTLR: divide counter lower byte */
120 	uart->ubg2 = (counter & 0x00ff);
121 
122 	uart->ucr = UART_UCR_RESET_RX;
123 	uart->ucr = UART_UCR_RESET_TX;
124 
125 	uart->ucr = UART_UCR_RX_ENABLED | UART_UCR_TX_ENABLED;
126 }
127 
128 static struct serial_device mcf_serial_drv = {
129 	.name	= "mcf_serial",
130 	.start	= mcf_serial_init,
131 	.stop	= NULL,
132 	.setbrg	= mcf_serial_setbrg,
133 	.putc	= mcf_serial_putc,
134 	.puts	= default_serial_puts,
135 	.getc	= mcf_serial_getc,
136 	.tstc	= mcf_serial_tstc,
137 };
138 
139 void mcf_serial_initialize(void)
140 {
141 	serial_register(&mcf_serial_drv);
142 }
143 
144 __weak struct serial_device *default_serial_console(void)
145 {
146 	return &mcf_serial_drv;
147 }
148