summaryrefslogtreecommitdiff
path: root/arch/ppc64/kernel/udbg_scc.c
blob: c47fd6c635313d7ac66855b2d48d9cd8bfe1b958 (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
/*
 * udbg for for zilog scc ports as found on Apple PowerMacs
 *
 * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp
 *
 *      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; either version
 *      2 of the License, or (at your option) any later version.
 */
#include <linux/config.h>
#include <linux/types.h>
#include <asm/udbg.h>
#include <asm/processor.h>
#include <asm/naca.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/pmac_feature.h>

extern u8 real_readb(volatile u8 __iomem  *addr);
extern void real_writeb(u8 data, volatile u8 __iomem *addr);

#define	SCC_TXRDY	4
#define SCC_RXRDY	1

static volatile u8 __iomem *sccc;
static volatile u8 __iomem *sccd;

static void udbg_scc_putc(unsigned char c)
{
	if (sccc) {
		while ((in_8(sccc) & SCC_TXRDY) == 0)
			;
		out_8(sccd,  c);
		if (c == '\n')
			udbg_scc_putc('\r');
	}
}

static int udbg_scc_getc_poll(void)
{
	if (sccc) {
		if ((in_8(sccc) & SCC_RXRDY) != 0)
			return in_8(sccd);
		else
			return -1;
	}
	return -1;
}

static unsigned char udbg_scc_getc(void)
{
	if (sccc) {
		while ((in_8(sccc) & SCC_RXRDY) == 0)
			;
		return in_8(sccd);
	}
	return 0;
}

static unsigned char scc_inittab[] = {
    13, 0,		/* set baud rate divisor */
    12, 0,
    14, 1,		/* baud rate gen enable, src=rtxc */
    11, 0x50,		/* clocks = br gen */
    5,  0xea,		/* tx 8 bits, assert DTR & RTS */
    4,  0x46,		/* x16 clock, 1 stop */
    3,  0xc1,		/* rx enable, 8 bits */
};

void udbg_init_scc(struct device_node *np)
{
	u32 *reg;
	unsigned long addr;
	int i, x;

	if (np == NULL)
		np = of_find_node_by_name(NULL, "escc");
	if (np == NULL || np->parent == NULL)
		return;

	udbg_printf("found SCC...\n");
	/* Get address within mac-io ASIC */
	reg = (u32 *)get_property(np, "reg", NULL);
	if (reg == NULL)
		return;
	addr = reg[0];
	udbg_printf("local addr: %lx\n", addr);
	/* Get address of mac-io PCI itself */
	reg = (u32 *)get_property(np->parent, "assigned-addresses", NULL);
	if (reg == NULL)
		return;
	addr += reg[2];
	udbg_printf("final addr: %lx\n", addr);

	/* Setup for 57600 8N1 */
	addr += 0x20;
	sccc = (volatile u8 * __iomem) ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
	sccc += addr & ~PAGE_MASK;
	sccd = sccc + 0x10;

	udbg_printf("ioremap result sccc: %p\n", sccc);
	mb();

	for (i = 20000; i != 0; --i)
		x = in_8(sccc);
	out_8(sccc, 0x09);		/* reset A or B side */
	out_8(sccc, 0xc0);
	for (i = 0; i < sizeof(scc_inittab); ++i)
		out_8(sccc, scc_inittab[i]);

	udbg_putc = udbg_scc_putc;
	udbg_getc = udbg_scc_getc;
	udbg_getc_poll = udbg_scc_getc_poll;

	udbg_puts("Hello World !\n");
}

static void udbg_real_scc_putc(unsigned char c)
{
	while ((real_readb(sccc) & SCC_TXRDY) == 0)
		;
	real_writeb(c, sccd);
	if (c == '\n')
		udbg_real_scc_putc('\r');
}

void udbg_init_pmac_realmode(void)
{
	sccc = (volatile u8 __iomem *)0x80013020ul;
	sccd = (volatile u8 __iomem *)0x80013030ul;

	udbg_putc = udbg_real_scc_putc;
	udbg_getc = NULL;
	udbg_getc_poll = NULL;
}