1 /*
2  * Copyright (C) 2011 Vladimir Zapolskiy <vz@mleia.com>
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public License
6  * as published by the Free Software Foundation; either version 2
7  * of the License, or (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., 51 Franklin Street, Fifth Floor, Boston,
17  * MA 02110-1301, USA.
18  */
19 
20 #include <common.h>
21 #include <asm/arch/cpu.h>
22 #include <asm/arch/clk.h>
23 #include <asm/arch/uart.h>
24 #include <asm/io.h>
25 #include <serial.h>
26 #include <linux/compiler.h>
27 
28 DECLARE_GLOBAL_DATA_PTR;
29 
30 static struct hsuart_regs *hsuart = (struct hsuart_regs *)HS_UART_BASE;
31 
32 static void lpc32xx_serial_setbrg(void)
33 {
34 	u32 div;
35 
36 	/* UART rate = PERIPH_CLK / ((HSU_RATE + 1) x 14) */
37 	div = (get_serial_clock() / 14 + gd->baudrate / 2) / gd->baudrate - 1;
38 	if (div > 255)
39 		div = 255;
40 
41 	writel(div, &hsuart->rate);
42 }
43 
44 static int lpc32xx_serial_getc(void)
45 {
46 	while (!(readl(&hsuart->level) & HSUART_LEVEL_RX))
47 		/* NOP */;
48 
49 	return readl(&hsuart->rx) & HSUART_RX_DATA;
50 }
51 
52 static void lpc32xx_serial_putc(const char c)
53 {
54 	writel(c, &hsuart->tx);
55 
56 	/* Wait for character to be sent */
57 	while (readl(&hsuart->level) & HSUART_LEVEL_TX)
58 		/* NOP */;
59 }
60 
61 static int lpc32xx_serial_tstc(void)
62 {
63 	if (readl(&hsuart->level) & HSUART_LEVEL_RX)
64 		return 1;
65 
66 	return 0;
67 }
68 
69 static int lpc32xx_serial_init(void)
70 {
71 	lpc32xx_serial_setbrg();
72 
73 	/* Disable hardware RTS and CTS flow control, set up RX and TX FIFO */
74 	writel(HSUART_CTRL_TMO_16 | HSUART_CTRL_HSU_OFFSET(20) |
75 	       HSUART_CTRL_HSU_RX_TRIG_32 | HSUART_CTRL_HSU_TX_TRIG_0,
76 	       &hsuart->ctrl);
77 	return 0;
78 }
79 
80 static void lpc32xx_serial_puts(const char *s)
81 {
82 	while (*s)
83 		serial_putc(*s++);
84 }
85 
86 static struct serial_device lpc32xx_serial_drv = {
87 	.name	= "lpc32xx_serial",
88 	.start	= lpc32xx_serial_init,
89 	.stop	= NULL,
90 	.setbrg	= lpc32xx_serial_setbrg,
91 	.putc	= lpc32xx_serial_putc,
92 	.puts	= lpc32xx_serial_puts,
93 	.getc	= lpc32xx_serial_getc,
94 	.tstc	= lpc32xx_serial_tstc,
95 };
96 
97 void lpc32xx_serial_initialize(void)
98 {
99 	serial_register(&lpc32xx_serial_drv);
100 }
101 
102 __weak struct serial_device *default_serial_console(void)
103 {
104 	return &lpc32xx_serial_drv;
105 }
106