Viewing file:  ns87312.c (1.19 KB) -rw-r--r--
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/*
* linux/arch/alpha/kernel/ns87312.c
*/
#include <linux/init.h>
#include <asm/io.h>
#include "proto.h"
/*
* The SRM console *disables* the IDE interface, this code ensures it's
* enabled.
*
* This code bangs on a control register of the 87312 Super I/O chip
* that implements parallel port/serial ports/IDE/FDI. Depending on
* the motherboard, the Super I/O chip can be configured through a
* pair of registers that are located either at I/O ports 0x26e/0x26f
* or 0x398/0x399. Unfortunately, autodetecting which base address is
* in use works only once (right after a reset). The Super I/O chip
* has the additional quirk that configuration register data must be
* written twice (I believe this is a safety feature to prevent
* accidental modification---fun, isn't it?).
*/
void __init
ns87312_enable_ide(long ide_base)
{
int data;
unsigned long flags;
__save_and_cli(flags);
outb(0, ide_base); /* set the index register for reg #0 */
data = inb(ide_base+1); /* read the current contents */
outb(0, ide_base); /* set the index register for reg #0 */
outb(data | 0x40, ide_base+1); /* turn on IDE */
outb(data | 0x40, ide_base+1); /* turn on IDE, really! */
__restore_flags(flags);
}
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