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Sourcecode: linux-2.6 version File versions

ns87312.c

/*
 *    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;

      local_irq_save(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! */
      local_irq_restore(flags);
}

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