aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/io_delay.c
blob: 720d2607aacbc2bee985b00289b8bc5c70cb4fb5 (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
/*
 * I/O delay strategies for inb_p/outb_p
 *
 * Allow for a DMI based override of port 0x80, needed for certain HP laptops
 * and possibly other systems. Also allow for the gradual elimination of
 * outb_p/inb_p API uses.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <asm/io.h>

int io_delay_type __read_mostly = CONFIG_DEFAULT_IO_DELAY_TYPE;

static int __initdata io_delay_override;

/*
 * Paravirt wants native_io_delay to be a constant.
 */
void native_io_delay(void)
{
	switch (io_delay_type) {
	default:
	case CONFIG_IO_DELAY_TYPE_0X80:
		asm volatile ("outb %al, $0x80");
		break;
	case CONFIG_IO_DELAY_TYPE_0XED:
		asm volatile ("outb %al, $0xed");
		break;
	case CONFIG_IO_DELAY_TYPE_UDELAY:
		/*
		 * 2 usecs is an upper-bound for the outb delay but
		 * note that udelay doesn't have the bus-level
		 * side-effects that outb does, nor does udelay() have
		 * precise timings during very early bootup (the delays
		 * are shorter until calibrated):
		 */
		udelay(2);
	case CONFIG_IO_DELAY_TYPE_NONE:
		break;
	}
}
EXPORT_SYMBOL(native_io_delay);

static int __init dmi_io_delay_0xed_port(const struct dmi_system_id *id)
{
	if (io_delay_type == CONFIG_IO_DELAY_TYPE_0X80) {
		printk(KERN_NOTICE "%s: using 0xed I/O delay port\n",
			id->ident);
		io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
	}

	return 0;
}

/*
 * Quirk table for systems that misbehave (lock up, etc.) if port
 * 0x80 is used:
 */
static struct dmi_system_id __initdata io_delay_0xed_port_dmi_table[] = {
	{
		.callback	= dmi_io_delay_0xed_port,
		.ident		= "Compaq Presario V6000",
		.matches	= {
			DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
			DMI_MATCH(DMI_BOARD_NAME, "30B7")
		}
	},
	{
		.callback	= dmi_io_delay_0xed_port,
		.ident		= "HP Pavilion dv9000z",
		.matches	= {
			DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
			DMI_MATCH(DMI_BOARD_NAME, "30B9")
		}
	},
	{
		.callback	= dmi_io_delay_0xed_port,
		.ident		= "HP Pavilion dv6000",
		.matches	= {
			DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
			DMI_MATCH(DMI_BOARD_NAME, "30B8")
		}
	},
	{
		.callback	= dmi_io_delay_0xed_port,
		.ident		= "HP Pavilion tx1000",
		.matches	= {
			DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
			DMI_MATCH(DMI_BOARD_NAME, "30BF")
		}
	},
	{
		.callback	= dmi_io_delay_0xed_port,
		.ident		= "Presario F700",
		.matches	= {
			DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
			DMI_MATCH(DMI_BOARD_NAME, "30D3")
		}
	},
	{ }
};

void __init io_delay_init(void)
{
	if (!io_delay_override)
		dmi_check_system(io_delay_0xed_port_dmi_table);
}

static int __init io_delay_param(char *s)
{
	if (!s)
		return -EINVAL;

	if (!strcmp(s, "0x80"))
		io_delay_type = CONFIG_IO_DELAY_TYPE_0X80;
	else if (!strcmp(s, "0xed"))
		io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
	else if (!strcmp(s, "udelay"))
		io_delay_type = CONFIG_IO_DELAY_TYPE_UDELAY;
	else if (!strcmp(s, "none"))
		io_delay_type = CONFIG_IO_DELAY_TYPE_NONE;
	else
		return -EINVAL;

	io_delay_override = 1;
	return 0;
}

early_param("io_delay", io_delay_param);