LXR linux/arch/x86/kernel/io

   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/init.h>
  11#include <linux/delay.h>
  12#include <linux/dmi.h>
  13#include <asm/io.h>
  14
  15int io_delay_type __read_mostly = CONFIG_DEFAULT_IO_DELAY_TYPE;
  16
  17static int __initdata io_delay_override;
  18
  19/*
  20 * Paravirt wants native_io_delay to be a constant.
  21 */
  22void 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}
  45EXPORT_SYMBOL(native_io_delay);
  46
  47static 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                printk(KERN_NOTICE "%s: using 0xed I/O delay port\n",
  51                        id->ident);
  52                io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
  53        }
  54
  55        return 0;
  56}
  57
  58/*
  59 * Quirk table for systems that misbehave (lock up, etc.) if port
  60 * 0x80 is used:
  61 */
  62static struct dmi_system_id __initdata io_delay_0xed_port_dmi_table[] = {
  63        {
  64                .callback       = dmi_io_delay_0xed_port,
  65                .ident          = "Compaq Presario V6000",
  66                .matches        = {
  67                        DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
  68                        DMI_MATCH(DMI_BOARD_NAME, "30B7")
  69                }
  70        },
  71        {
  72                .callback       = dmi_io_delay_0xed_port,
  73                .ident          = "HP Pavilion dv9000z",
  74                .matches        = {
  75                        DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
  76                        DMI_MATCH(DMI_BOARD_NAME, "30B9")
  77                }
  78        },
  79        {
  80                .callback       = dmi_io_delay_0xed_port,
  81                .ident          = "HP Pavilion dv6000",
  82                .matches        = {
  83                        DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
  84                        DMI_MATCH(DMI_BOARD_NAME, "30B8")
  85                }
  86        },
  87        {
  88                .callback       = dmi_io_delay_0xed_port,
  89                .ident          = "HP Pavilion tx1000",
  90                .matches        = {
  91                        DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
  92                        DMI_MATCH(DMI_BOARD_NAME, "30BF")
  93                }
  94        },
  95        {
  96                .callback       = dmi_io_delay_0xed_port,
  97                .ident          = "Presario F700",
  98                .matches        = {
  99                        DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
 100                        DMI_MATCH(DMI_BOARD_NAME, "30D3")
 101                }
 102        },
 103        { }
 104};
 105
 106void __init io_delay_init(void)
 107{
 108        if (!io_delay_override)
 109                dmi_check_system(io_delay_0xed_port_dmi_table);
 110}
 111
 112static int __init io_delay_param(char *s)
 113{
 114        if (!s)
 115                return -EINVAL;
 116
 117        if (!strcmp(s, "0x80"))
 118                io_delay_type = CONFIG_IO_DELAY_TYPE_0X80;
 119        else if (!strcmp(s, "0xed"))
 120                io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
 121        else if (!strcmp(s, "udelay"))
 122                io_delay_type = CONFIG_IO_DELAY_TYPE_UDELAY;
 123        else if (!strcmp(s, "none"))
 124                io_delay_type = CONFIG_IO_DELAY_TYPE_NONE;
 125        else
 126                return -EINVAL;
 127
 128        io_delay_override = 1;
 129        return 0;
 130}
 131
 132early_param("io_delay", io_delay_param);
 133