x86: various changes and cleanups to in_p/out_p delay details
various changes to the in_p/out_p delay details: - add the io_delay=none method - make each method selectable from the kernel config - simplify the delay code a bit by getting rid of an indirect function call - add the /proc/sys/kernel/io_delay_type sysctl - change 'io_delay=standard|alternate' to io_delay=0x80 and io_delay=0xed - make the io delay config not depend on CONFIG_DEBUG_KERNEL Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: "David P. Reed" <dpreed@reed.com>
This commit is contained in:
Ingo Molnar
parent
b02aae9cf5
commit
6e7c402590
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@ -795,12 +795,14 @@ and is between 256 and 4096 characters. It is defined in the file
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then look in the higher range.
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io_delay= [X86-32,X86-64] I/O delay method
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standard
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Standard port 0x80 delay
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alternate
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Alternate port 0xed delay
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0x80
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Standard port 0x80 based delay
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0xed
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Alternate port 0xed based delay (needed on some systems)
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udelay
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Simple two microsecond delay
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Simple two microseconds delay
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none
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No delay
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io7= [HW] IO7 for Marvel based alpha systems
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See comment before marvel_specify_io7 in
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@ -112,13 +112,78 @@ config IOMMU_LEAK
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Add a simple leak tracer to the IOMMU code. This is useful when you
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are debugging a buggy device driver that leaks IOMMU mappings.
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config UDELAY_IO_DELAY
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bool "Delay I/O through udelay instead of outb"
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depends on DEBUG_KERNEL
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#
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# IO delay types:
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#
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config IO_DELAY_TYPE_0X80
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int
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default "0"
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config IO_DELAY_TYPE_0XED
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int
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default "1"
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config IO_DELAY_TYPE_UDELAY
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int
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default "2"
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config IO_DELAY_TYPE_NONE
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int
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default "3"
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choice
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prompt "IO delay type"
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default IO_DELAY_0X80
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config IO_DELAY_0X80
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bool "port 0x80 based port-IO delay [recommended]"
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help
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Make inb_p/outb_p use udelay() based delays by default. Please note
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that udelay() does not have the same bus-level side-effects that
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the normal outb based delay does meaning this could cause drivers
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to change behaviour and/or bugs to surface.
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This is the traditional Linux IO delay used for in/out_p.
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It is the most tested hence safest selection here.
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config IO_DELAY_0XED
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bool "port 0xed based port-IO delay"
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help
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Use port 0xed as the IO delay. This frees up port 0x80 which is
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often used as a hardware-debug port.
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config IO_DELAY_UDELAY
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bool "udelay based port-IO delay"
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help
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Use udelay(2) as the IO delay method. This provides the delay
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while not having any side-effect on the IO port space.
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config IO_DELAY_NONE
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bool "no port-IO delay"
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help
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No port-IO delay. Will break on old boxes that require port-IO
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delay for certain operations. Should work on most new machines.
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endchoice
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if IO_DELAY_0X80
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_0X80
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endif
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if IO_DELAY_0XED
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_0XED
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endif
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if IO_DELAY_UDELAY
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_UDELAY
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endif
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if IO_DELAY_NONE
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config DEFAULT_IO_DELAY_TYPE
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int
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default IO_DELAY_TYPE_NONE
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endif
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endmenu
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@ -1,5 +1,9 @@
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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/module.h>
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@ -8,98 +12,86 @@
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#include <linux/dmi.h>
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#include <asm/io.h>
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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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*/
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#define IO_DELAY_PORT_STD 0x80
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#define IO_DELAY_PORT_ALT 0xed
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int io_delay_type __read_mostly = CONFIG_DEFAULT_IO_DELAY_TYPE;
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EXPORT_SYMBOL_GPL(io_delay_type);
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static void standard_io_delay(void)
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{
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asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_STD));
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}
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static void alternate_io_delay(void)
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{
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asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_ALT));
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}
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/*
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* 2 usecs is an upper-bound for the outb delay but note that udelay doesn't
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* have the bus-level side-effects that outb does
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*/
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#define IO_DELAY_USECS 2
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/*
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* High on a hill was a lonely goatherd
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*/
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static void udelay_io_delay(void)
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{
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udelay(IO_DELAY_USECS);
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}
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#ifndef CONFIG_UDELAY_IO_DELAY
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static void (*io_delay)(void) = standard_io_delay;
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#else
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static void (*io_delay)(void) = udelay_io_delay;
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#endif
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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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io_delay();
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switch (io_delay_type) {
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default:
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case CONFIG_IO_DELAY_TYPE_0X80:
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asm volatile ("outb %al, $0x80");
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break;
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case CONFIG_IO_DELAY_TYPE_0XED:
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asm volatile ("outb %al, $0xed");
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break;
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case CONFIG_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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case CONFIG_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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#ifndef CONFIG_UDELAY_IO_DELAY
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static int __init dmi_alternate_io_delay_port(const struct dmi_system_id *id)
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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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printk(KERN_NOTICE "%s: using alternate I/O delay port\n", id->ident);
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io_delay = alternate_io_delay;
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if (io_delay_type == CONFIG_IO_DELAY_TYPE_0X80) {
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printk(KERN_NOTICE "%s: using 0xed I/O delay port\n",
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id->ident);
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io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
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}
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return 0;
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}
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static struct dmi_system_id __initdata alternate_io_delay_port_dmi_table[] = {
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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 struct dmi_system_id __initdata io_delay_0xed_port_dmi_table[] = {
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{
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.callback = dmi_alternate_io_delay_port,
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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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}
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{ }
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};
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static int __initdata io_delay_override;
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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(alternate_io_delay_port_dmi_table);
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dmi_check_system(io_delay_0xed_port_dmi_table);
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}
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#endif
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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, "standard"))
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io_delay = standard_io_delay;
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else if (!strcmp(s, "alternate"))
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io_delay = alternate_io_delay;
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if (!strcmp(s, "0x80"))
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io_delay_type = CONFIG_IO_DELAY_TYPE_0X80;
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else if (!strcmp(s, "0xed"))
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io_delay_type = CONFIG_IO_DELAY_TYPE_0XED;
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else if (!strcmp(s, "udelay"))
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io_delay = udelay_io_delay;
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io_delay_type = CONFIG_IO_DELAY_TYPE_UDELAY;
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else if (!strcmp(s, "none"))
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io_delay_type = CONFIG_IO_DELAY_TYPE_NONE;
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else
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return -EINVAL;
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#ifndef CONFIG_UDELAY_IO_DELAY
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io_delay_override = 1;
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#endif
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return 0;
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}
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@ -250,15 +250,11 @@ static inline void flush_write_buffers(void)
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#endif /* __KERNEL__ */
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#ifndef CONFIG_UDELAY_IO_DELAY
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extern void io_delay_init(void);
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#else
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static inline void io_delay_init(void)
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{
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}
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#endif
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extern void native_io_delay(void);
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extern int io_delay_type;
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extern void io_delay_init(void);
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#if defined(CONFIG_PARAVIRT)
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#include <asm/paravirt.h>
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#else
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@ -35,15 +35,11 @@
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* - Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*/
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#ifndef CONFIG_UDELAY_IO_DELAY
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extern void io_delay_init(void);
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#else
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static inline void io_delay_init(void)
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{
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}
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#endif
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extern void native_io_delay(void);
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extern int io_delay_type;
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extern void io_delay_init(void);
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static inline void slow_down_io(void)
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{
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native_io_delay();
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@ -53,6 +53,7 @@
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#ifdef CONFIG_X86
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#include <asm/nmi.h>
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#include <asm/stacktrace.h>
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#include <asm/io.h>
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#endif
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static int deprecated_sysctl_warning(struct __sysctl_args *args);
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@ -727,6 +728,14 @@ static struct ctl_table kern_table[] = {
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.mode = 0644,
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.proc_handler = &proc_dointvec,
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},
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{
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.ctl_name = CTL_UNNUMBERED,
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.procname = "io_delay_type",
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.data = &io_delay_type,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = &proc_dointvec,
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},
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#endif
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#if defined(CONFIG_MMU)
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{
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