Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/alpha/kernel/ns87312.c |
| 3 | */ |
| 4 | |
| 5 | #include <linux/init.h> |
| 6 | #include <asm/io.h> |
| 7 | #include "proto.h" |
| 8 | |
| 9 | |
| 10 | /* |
| 11 | * The SRM console *disables* the IDE interface, this code ensures it's |
| 12 | * enabled. |
| 13 | * |
| 14 | * This code bangs on a control register of the 87312 Super I/O chip |
| 15 | * that implements parallel port/serial ports/IDE/FDI. Depending on |
| 16 | * the motherboard, the Super I/O chip can be configured through a |
| 17 | * pair of registers that are located either at I/O ports 0x26e/0x26f |
| 18 | * or 0x398/0x399. Unfortunately, autodetecting which base address is |
| 19 | * in use works only once (right after a reset). The Super I/O chip |
| 20 | * has the additional quirk that configuration register data must be |
| 21 | * written twice (I believe this is a safety feature to prevent |
| 22 | * accidental modification---fun, isn't it?). |
| 23 | */ |
| 24 | |
| 25 | void __init |
| 26 | ns87312_enable_ide(long ide_base) |
| 27 | { |
| 28 | int data; |
| 29 | unsigned long flags; |
| 30 | |
| 31 | local_irq_save(flags); |
| 32 | outb(0, ide_base); /* set the index register for reg #0 */ |
| 33 | data = inb(ide_base+1); /* read the current contents */ |
| 34 | outb(0, ide_base); /* set the index register for reg #0 */ |
| 35 | outb(data | 0x40, ide_base+1); /* turn on IDE */ |
| 36 | outb(data | 0x40, ide_base+1); /* turn on IDE, really! */ |
| 37 | local_irq_restore(flags); |
| 38 | } |