diff options
Diffstat (limited to 'arch/x86/kernel/io_delay.c')
-rw-r--r-- | arch/x86/kernel/io_delay.c | 106 |
1 files changed, 49 insertions, 57 deletions
diff --git a/arch/x86/kernel/io_delay.c b/arch/x86/kernel/io_delay.c index 4d955e74b97..f052e34dc94 100644 --- a/arch/x86/kernel/io_delay.c +++ b/arch/x86/kernel/io_delay.c @@ -1,5 +1,9 @@ /* * 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; } |