Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394...
[linux-2.6] / arch / x86 / kernel / io_delay.c
1 /*
2  * I/O delay strategies for inb_p/outb_p
3  *
4  * Allow for a DMI based override of port 0x80, needed for certain HP laptops
5  * and possibly other systems. Also allow for the gradual elimination of
6  * outb_p/inb_p API uses.
7  */
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/delay.h>
11 #include <linux/init.h>
12 #include <linux/dmi.h>
13 #include <linux/io.h>
14
15 int io_delay_type __read_mostly = CONFIG_DEFAULT_IO_DELAY_TYPE;
16
17 static int __initdata io_delay_override;
18
19 /*
20  * Paravirt wants native_io_delay to be a constant.
21  */
22 void native_io_delay(void)
23 {
24         switch (io_delay_type) {
25         default:
26         case CONFIG_IO_DELAY_TYPE_0X80:
27                 asm volatile ("outb %al, $0x80");
28                 break;
29         case CONFIG_IO_DELAY_TYPE_0XED:
30                 asm volatile ("outb %al, $0xed");
31                 break;
32         case CONFIG_IO_DELAY_TYPE_UDELAY:
33                 /*
34                  * 2 usecs is an upper-bound for the outb delay but
35                  * note that udelay doesn't have the bus-level
36                  * side-effects that outb does, nor does udelay() have
37                  * precise timings during very early bootup (the delays
38                  * are shorter until calibrated):
39                  */
40                 udelay(2);
41         case CONFIG_IO_DELAY_TYPE_NONE:
42                 break;
43         }
44 }
45 EXPORT_SYMBOL(native_io_delay);
46
47 static int __init dmi_io_delay_0xed_port(const struct dmi_system_id *id)
48 {
49         if (io_delay_type == CONFIG_IO_DELAY_TYPE_0X80) {
50                 pr_notice("%s: using 0xed I/O delay port\n", id->ident);
51                 io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
52         }
53
54         return 0;
55 }
56
57 /*
58  * Quirk table for systems that misbehave (lock up, etc.) if port
59  * 0x80 is used:
60  */
61 static struct dmi_system_id __initdata io_delay_0xed_port_dmi_table[] = {
62         {
63                 .callback       = dmi_io_delay_0xed_port,
64                 .ident          = "Compaq Presario V6000",
65                 .matches        = {
66                         DMI_MATCH(DMI_BOARD_VENDOR,     "Quanta"),
67                         DMI_MATCH(DMI_BOARD_NAME,       "30B7")
68                 }
69         },
70         {
71                 .callback       = dmi_io_delay_0xed_port,
72                 .ident          = "HP Pavilion dv9000z",
73                 .matches        = {
74                         DMI_MATCH(DMI_BOARD_VENDOR,     "Quanta"),
75                         DMI_MATCH(DMI_BOARD_NAME,       "30B9")
76                 }
77         },
78         {
79                 .callback       = dmi_io_delay_0xed_port,
80                 .ident          = "HP Pavilion dv6000",
81                 .matches        = {
82                         DMI_MATCH(DMI_BOARD_VENDOR,     "Quanta"),
83                         DMI_MATCH(DMI_BOARD_NAME,       "30B8")
84                 }
85         },
86         {
87                 .callback       = dmi_io_delay_0xed_port,
88                 .ident          = "HP Pavilion tx1000",
89                 .matches        = {
90                         DMI_MATCH(DMI_BOARD_VENDOR,     "Quanta"),
91                         DMI_MATCH(DMI_BOARD_NAME,       "30BF")
92                 }
93         },
94         {
95                 .callback       = dmi_io_delay_0xed_port,
96                 .ident          = "Presario F700",
97                 .matches        = {
98                         DMI_MATCH(DMI_BOARD_VENDOR,     "Quanta"),
99                         DMI_MATCH(DMI_BOARD_NAME,       "30D3")
100                 }
101         },
102         { }
103 };
104
105 void __init io_delay_init(void)
106 {
107         if (!io_delay_override)
108                 dmi_check_system(io_delay_0xed_port_dmi_table);
109 }
110
111 static int __init io_delay_param(char *s)
112 {
113         if (!s)
114                 return -EINVAL;
115
116         if (!strcmp(s, "0x80"))
117                 io_delay_type = CONFIG_IO_DELAY_TYPE_0X80;
118         else if (!strcmp(s, "0xed"))
119                 io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
120         else if (!strcmp(s, "udelay"))
121                 io_delay_type = CONFIG_IO_DELAY_TYPE_UDELAY;
122         else if (!strcmp(s, "none"))
123                 io_delay_type = CONFIG_IO_DELAY_TYPE_NONE;
124         else
125                 return -EINVAL;
126
127         io_delay_override = 1;
128         return 0;
129 }
130
131 early_param("io_delay", io_delay_param);