summaryrefslogtreecommitdiff
path: root/src/lib/uart8250mem.c
blob: e79cb633467c40444d1e03ad627e6afe72f7f505 (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
/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2003 Eric Biederman
 * Copyright (C) 2006-2010 coresystems GmbH
 *
 * 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; version 2 of the License.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <arch/io.h>
#include <uart8250.h>
#include <pc80/mc146818rtc.h>
#if CONFIG_USE_OPTION_TABLE
#include "option_table.h"
#endif
#if !defined(__SMM__) && !defined(__PRE_RAM__)
#include <device/device.h>
#endif

/* Should support 8250, 16450, 16550, 16550A type UARTs */

static inline int uart8250_mem_can_tx_byte(unsigned base_port)
{
	return read8(base_port + UART_LSR) & UART_MSR_DSR;
}

static inline void uart8250_mem_wait_to_tx_byte(unsigned base_port)
{
	while(!uart8250_mem_can_tx_byte(base_port))
		;
}

static inline void uart8250_mem_wait_until_sent(unsigned base_port)
{
	while(!(read8(base_port + UART_LSR) & UART_LSR_TEMT))
		;
}

void uart8250_mem_tx_byte(unsigned base_port, unsigned char data)
{
	uart8250_mem_wait_to_tx_byte(base_port);
	write8(base_port + UART_TBR, data);
}

void uart8250_mem_tx_flush(unsigned base_port)
{
	uart8250_mem_wait_until_sent(base_port);
}

int uart8250_mem_can_rx_byte(unsigned base_port)
{
	return read8(base_port + UART_LSR) & UART_LSR_DR;
}

unsigned char uart8250_mem_rx_byte(unsigned base_port)
{
	while(!uart8250_mem_can_rx_byte(base_port))
		;
	return read8(base_port + UART_RBR);
}

void uart8250_mem_init(unsigned base_port, unsigned divisor)
{
	/* Disable interrupts */
	write8(base_port + UART_IER, 0x0);
	/* Enable FIFOs */
	write8(base_port + UART_FCR, UART_FCR_FIFO_EN);

	/* Assert DTR and RTS so the other end is happy */
	write8(base_port + UART_MCR, UART_MCR_DTR | UART_MCR_RTS);

	/* DLAB on */
	write8(base_port + UART_LCR, UART_LCR_DLAB | CONFIG_TTYS0_LCS);

	/* Set Baud Rate Divisor. 12 ==> 115200 Baud */
	write8(base_port + UART_DLL, divisor & 0xFF);
	write8(base_port + UART_DLM, (divisor >> 8) & 0xFF);

	/* Set to 3 for 8N1 */
	write8(base_port + UART_LCR, CONFIG_TTYS0_LCS);
}

u32 uart_mem_init(void)
{
	unsigned uart_baud = CONFIG_TTYS0_BAUD;
	u32 uart_bar = 0;
	unsigned div;

	/* find out the correct baud rate */
#if !defined(__SMM__) && CONFIG_USE_OPTION_TABLE
	static const unsigned baud[8] = { 115200, 57600, 38400, 19200, 9600, 4800, 2400, 1200 };
	unsigned b_index = 0;
#if defined(__PRE_RAM__)
	b_index = read_option(CMOS_VSTART_baud_rate, CMOS_VLEN_baud_rate, 0);
	b_index &= 7;
	uart_baud = baud[b_index];
#else
	if (get_option(&b_index, "baud_rate") == 0) {
		uart_baud = baud[b_index];
	}
#endif
#endif

	/* Now find the UART base address and calculate the divisor */
#if CONFIG_DRIVERS_OXFORD_OXPCIE

#if defined(MORE_TESTING) && !defined(__SMM__) && !defined(__PRE_RAM__)
	device_t dev = dev_find_device(0x1415, 0xc158, NULL);

	if (dev) {
		struct resource *res = find_resource(dev, 0x10);
	
		if (res) {
			uart_bar = res->base + 0x1000; // for 1st UART
			// uart_bar = res->base + 0x2000; // for 2nd UART
		}
	}

	if (!uart_bar)
#endif
	uart_bar = CONFIG_OXFORD_OXPCIE_BASE_ADDRESS + 0x1000; // 1st UART
	// uart_bar = CONFIG_OXFORD_OXPCIE_BASE_ADDRESS + 0x2000; // 2nd UART
	
	div = 4000000 / uart_baud;
#endif

	if (uart_bar)
		uart8250_mem_init(uart_bar, div);

	return uart_bar;
}