149 lines
3.4 KiB
C
149 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* I/O delay strategies for inb_p/outb_p
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*
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* Allow for a DMI based override of port 0x80, needed for certain HP laptops
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* and possibly other systems. Also allow for the gradual elimination of
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* outb_p/inb_p API uses.
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*/
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/dmi.h>
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#include <linux/io.h>
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#define IO_DELAY_TYPE_0X80 0
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#define IO_DELAY_TYPE_0XED 1
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#define IO_DELAY_TYPE_UDELAY 2
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#define IO_DELAY_TYPE_NONE 3
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#if defined(CONFIG_IO_DELAY_0X80)
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#define DEFAULT_IO_DELAY_TYPE IO_DELAY_TYPE_0X80
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#elif defined(CONFIG_IO_DELAY_0XED)
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#define DEFAULT_IO_DELAY_TYPE IO_DELAY_TYPE_0XED
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#elif defined(CONFIG_IO_DELAY_UDELAY)
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#define DEFAULT_IO_DELAY_TYPE IO_DELAY_TYPE_UDELAY
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#elif defined(CONFIG_IO_DELAY_NONE)
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#define DEFAULT_IO_DELAY_TYPE IO_DELAY_TYPE_NONE
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#endif
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int io_delay_type __read_mostly = DEFAULT_IO_DELAY_TYPE;
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static int __initdata io_delay_override;
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/*
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* Paravirt wants native_io_delay to be a constant.
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*/
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void native_io_delay(void)
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{
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switch (io_delay_type) {
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default:
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case IO_DELAY_TYPE_0X80:
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asm volatile ("outb %al, $0x80");
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break;
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case IO_DELAY_TYPE_0XED:
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asm volatile ("outb %al, $0xed");
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break;
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case IO_DELAY_TYPE_UDELAY:
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/*
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* 2 usecs is an upper-bound for the outb delay but
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* note that udelay doesn't have the bus-level
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* side-effects that outb does, nor does udelay() have
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* precise timings during very early bootup (the delays
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* are shorter until calibrated):
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*/
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udelay(2);
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break;
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case IO_DELAY_TYPE_NONE:
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break;
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}
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}
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EXPORT_SYMBOL(native_io_delay);
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static int __init dmi_io_delay_0xed_port(const struct dmi_system_id *id)
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{
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if (io_delay_type == IO_DELAY_TYPE_0X80) {
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pr_notice("%s: using 0xed I/O delay port\n", id->ident);
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io_delay_type = IO_DELAY_TYPE_0XED;
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}
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return 0;
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}
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/*
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* Quirk table for systems that misbehave (lock up, etc.) if port
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* 0x80 is used:
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*/
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static const struct dmi_system_id io_delay_0xed_port_dmi_table[] __initconst = {
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{
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.callback = dmi_io_delay_0xed_port,
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.ident = "Compaq Presario V6000",
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.matches = {
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DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
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DMI_MATCH(DMI_BOARD_NAME, "30B7")
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}
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},
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{
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.callback = dmi_io_delay_0xed_port,
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.ident = "HP Pavilion dv9000z",
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.matches = {
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DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
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DMI_MATCH(DMI_BOARD_NAME, "30B9")
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}
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},
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{
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.callback = dmi_io_delay_0xed_port,
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.ident = "HP Pavilion dv6000",
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.matches = {
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DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
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DMI_MATCH(DMI_BOARD_NAME, "30B8")
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}
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},
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{
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.callback = dmi_io_delay_0xed_port,
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.ident = "HP Pavilion tx1000",
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.matches = {
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DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
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DMI_MATCH(DMI_BOARD_NAME, "30BF")
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}
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},
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{
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.callback = dmi_io_delay_0xed_port,
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.ident = "Presario F700",
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.matches = {
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DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
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DMI_MATCH(DMI_BOARD_NAME, "30D3")
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}
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},
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{ }
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};
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void __init io_delay_init(void)
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{
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if (!io_delay_override)
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dmi_check_system(io_delay_0xed_port_dmi_table);
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}
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static int __init io_delay_param(char *s)
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{
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if (!s)
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return -EINVAL;
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if (!strcmp(s, "0x80"))
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io_delay_type = IO_DELAY_TYPE_0X80;
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else if (!strcmp(s, "0xed"))
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io_delay_type = IO_DELAY_TYPE_0XED;
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else if (!strcmp(s, "udelay"))
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io_delay_type = IO_DELAY_TYPE_UDELAY;
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else if (!strcmp(s, "none"))
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io_delay_type = IO_DELAY_TYPE_NONE;
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else
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return -EINVAL;
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io_delay_override = 1;
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return 0;
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}
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early_param("io_delay", io_delay_param);
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