summaryrefslogtreecommitdiffstats
path: root/arch/ppc/boot/common/ns16550.c
blob: 4f00c93ac870240cac5807aadb8c29c15120198c (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
/*
 * COM1 NS16550 support
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <asm/serial.h>

#if defined(CONFIG_XILINX_VIRTEX)
#include <platforms/4xx/xparameters/xparameters.h>
#endif
#include "nonstdio.h"
#include "serial.h"

#define SERIAL_BAUD	9600

extern unsigned long ISA_io;

static struct serial_state rs_table[RS_TABLE_SIZE] = {
	SERIAL_PORT_DFNS	/* Defined in <asm/serial.h> */
};

static int shift;

unsigned long serial_init(int chan, void *ignored)
{
	unsigned long com_port, base_baud;
	unsigned char lcr, dlm;

	/* We need to find out which type io we're expecting.  If it's
	 * 'SERIAL_IO_PORT', we get an offset from the isa_io_base.
	 * If it's 'SERIAL_IO_MEM', we can the exact location.  -- Tom */
	switch (rs_table[chan].io_type) {
		case SERIAL_IO_PORT:
			com_port = rs_table[chan].port;
			break;
		case SERIAL_IO_MEM:
			com_port = (unsigned long)rs_table[chan].iomem_base;
			break;
		default:
			/* We can't deal with it. */
			return -1;
	}

	/* How far apart the registers are. */
	shift = rs_table[chan].iomem_reg_shift;
	/* Base baud.. */
	base_baud = rs_table[chan].baud_base;
	
	/* save the LCR */
	lcr = inb(com_port + (UART_LCR << shift));
	/* Access baud rate */
	outb(com_port + (UART_LCR << shift), 0x80);
	dlm = inb(com_port + (UART_DLM << shift));
	/*
	 * Test if serial port is unconfigured.
	 * We assume that no-one uses less than 110 baud or
	 * less than 7 bits per character these days.
	 *  -- paulus.
	 */

	if ((dlm <= 4) && (lcr & 2))
		/* port is configured, put the old LCR back */
		outb(com_port + (UART_LCR << shift), lcr);
	else {
		/* Input clock. */
		outb(com_port + (UART_DLL << shift),
		     (base_baud / SERIAL_BAUD) & 0xFF);
		outb(com_port + (UART_DLM << shift),
		     (base_baud / SERIAL_BAUD) >> 8);
		/* 8 data, 1 stop, no parity */
		outb(com_port + (UART_LCR << shift), 0x03);
		/* RTS/DTR */
		outb(com_port + (UART_MCR << shift), 0x03);
	}
	/* Clear & enable FIFOs */
	outb(com_port + (UART_FCR << shift), 0x07);

	return (com_port);
}

void
serial_putc(unsigned long com_port, unsigned char c)
{
	while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_THRE) == 0)
		;
	outb(com_port, c);
}

unsigned char
serial_getc(unsigned long com_port)
{
	while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) == 0)
		;
	return inb(com_port);
}

int
serial_tstc(unsigned long com_port)
{
	return ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) != 0);
}
OpenPOWER on IntegriCloud