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