x86: various changes and cleanups to in_p/out_p delay details (6e7c4025) · Commits · 戴 / test

Documentation/kernel-parameters.txt

+7 −5

Original line number	Diff line number	Diff line
		@@ -795,12 +795,14 @@ and is between 256 and 4096 characters. It is defined in the file
		then look in the higher range.

		io_delay= [X86-32,X86-64] I/O delay method
		standard
		Standard port 0x80 delay
		alternate
		Alternate port 0xed delay
		0x80
		Standard port 0x80 based delay
		0xed
		Alternate port 0xed based delay (needed on some systems)
		udelay
		Simple two microsecond delay
		Simple two microseconds delay
		none
		No delay

		io7= [HW] IO7 for Marvel based alpha systems
		See comment before marvel_specify_io7 in

arch/x86/Kconfig.debug

+72 −7

Original line number	Diff line number	Diff line
		@@ -112,13 +112,78 @@ config IOMMU_LEAK
		Add a simple leak tracer to the IOMMU code. This is useful when you
		are debugging a buggy device driver that leaks IOMMU mappings.

		config UDELAY_IO_DELAY
		bool "Delay I/O through udelay instead of outb"
		depends on DEBUG_KERNEL
		#
		# IO delay types:
		#

		config IO_DELAY_TYPE_0X80
		int
		default "0"

		config IO_DELAY_TYPE_0XED
		int
		default "1"

		config IO_DELAY_TYPE_UDELAY
		int
		default "2"

		config IO_DELAY_TYPE_NONE
		int
		default "3"

		choice
		prompt "IO delay type"
		default IO_DELAY_0X80

		config IO_DELAY_0X80
		bool "port 0x80 based port-IO delay [recommended]"
		help
		This is the traditional Linux IO delay used for in/out_p.
		It is the most tested hence safest selection here.

		config IO_DELAY_0XED
		bool "port 0xed based port-IO delay"
		help
		Use port 0xed as the IO delay. This frees up port 0x80 which is
		often used as a hardware-debug port.

		config IO_DELAY_UDELAY
		bool "udelay based port-IO delay"
		help
		Use udelay(2) as the IO delay method. This provides the delay
		while not having any side-effect on the IO port space.

		config IO_DELAY_NONE
		bool "no port-IO delay"
		help
		Make inb_p/outb_p use udelay() based delays by default. Please note
		that udelay() does not have the same bus-level side-effects that
		the normal outb based delay does meaning this could cause drivers
		to change behaviour and/or bugs to surface.
		No port-IO delay. Will break on old boxes that require port-IO
		delay for certain operations. Should work on most new machines.

		endchoice

		if IO_DELAY_0X80
		config DEFAULT_IO_DELAY_TYPE
		int
		default IO_DELAY_TYPE_0X80
		endif

		if IO_DELAY_0XED
		config DEFAULT_IO_DELAY_TYPE
		int
		default IO_DELAY_TYPE_0XED
		endif

		if IO_DELAY_UDELAY
		config DEFAULT_IO_DELAY_TYPE
		int
		default IO_DELAY_TYPE_UDELAY
		endif

		if IO_DELAY_NONE
		config DEFAULT_IO_DELAY_TYPE
		int
		default IO_DELAY_TYPE_NONE
		endif

		endmenu

arch/x86/kernel/io_delay.c

+49 −57

Original line number	Diff line number	Diff line
		/*
		* 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>
		@@ -8,98 +12,86 @@
		#include <linux/dmi.h>
		#include <asm/io.h>

		/*
		* Allow for a DMI based override of port 0x80 needed for certain HP laptops
		*/
		#define IO_DELAY_PORT_STD 0x80
		#define IO_DELAY_PORT_ALT 0xed

		static void standard_io_delay(void)
		{
		asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_STD));
		}

		static void alternate_io_delay(void)
		{
		asm volatile ("outb %%al, %0" : : "N" (IO_DELAY_PORT_ALT));
		}

		/*
		* 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
		*/
		#define IO_DELAY_USECS 2

		/*
		* High on a hill was a lonely goatherd
		*/
		static void udelay_io_delay(void)
		{
		udelay(IO_DELAY_USECS);
		}
		int io_delay_type __read_mostly = CONFIG_DEFAULT_IO_DELAY_TYPE;
		EXPORT_SYMBOL_GPL(io_delay_type);

		#ifndef CONFIG_UDELAY_IO_DELAY
		static void (*io_delay)(void) = standard_io_delay;
		#else
		static void (*io_delay)(void) = udelay_io_delay;
		#endif
		static int __initdata io_delay_override;

		/*
		* Paravirt wants native_io_delay to be a constant.
		*/
		void native_io_delay(void)
		{
		io_delay();
		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);

		#ifndef CONFIG_UDELAY_IO_DELAY
		static int __init dmi_alternate_io_delay_port(const struct dmi_system_id *id)
		static int __init dmi_io_delay_0xed_port(const struct dmi_system_id *id)
		{
		printk(KERN_NOTICE "%s: using alternate I/O delay port\n", id->ident);
		io_delay = alternate_io_delay;
		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;
		}

		static struct dmi_system_id __initdata alternate_io_delay_port_dmi_table[] = {
		/*
		* 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_alternate_io_delay_port,
		.callback = dmi_io_delay_0xed_port,
		.ident = "HP Pavilion dv9000z",
		.matches = {
		DMI_MATCH(DMI_BOARD_VENDOR, "Quanta"),
		DMI_MATCH(DMI_BOARD_NAME, "30B9")
		}
		},
		{
		}
		{ }
		};

		static int __initdata io_delay_override;

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

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

		if (!strcmp(s, "standard"))
		io_delay = standard_io_delay;
		else if (!strcmp(s, "alternate"))
		io_delay = alternate_io_delay;
		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 = udelay_io_delay;
		io_delay_type = CONFIG_IO_DELAY_TYPE_UDELAY;
		else if (!strcmp(s, "none"))
		io_delay_type = CONFIG_IO_DELAY_TYPE_NONE;
		else
		return -EINVAL;

		#ifndef CONFIG_UDELAY_IO_DELAY
		io_delay_override = 1;
		#endif
		return 0;
		}

include/asm-x86/io_32.h

+3 −7

Original line number	Diff line number	Diff line
		@@ -250,15 +250,11 @@ static inline void flush_write_buffers(void)

		#endif /* __KERNEL__ */

		#ifndef CONFIG_UDELAY_IO_DELAY
		extern void io_delay_init(void);
		#else
		static inline void io_delay_init(void)
		{
		}
		#endif
		extern void native_io_delay(void);

		extern int io_delay_type;
		extern void io_delay_init(void);

		#if defined(CONFIG_PARAVIRT)
		#include <asm/paravirt.h>
		#else

include/asm-x86/io_64.h

+3 −7

Original line number	Diff line number	Diff line
		@@ -35,15 +35,11 @@
		* - Arnaldo Carvalho de Melo <acme@conectiva.com.br>
		*/

		#ifndef CONFIG_UDELAY_IO_DELAY
		extern void io_delay_init(void);
		#else
		static inline void io_delay_init(void)
		{
		}
		#endif
		extern void native_io_delay(void);

		extern int io_delay_type;
		extern void io_delay_init(void);

		static inline void slow_down_io(void)
		{
		native_io_delay();

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