linux/arch/i386/pci/early.c
Andi Kleen 0637a70a5d [PATCH] x86: Allow disabling early pci scans with pci=noearly or disallowing conf1
Some buggy systems can machine check when config space accesses
happen for some non existent devices.  i386/x86-64 do some early
device scans that might trigger this. Allow pci=noearly to disable
this. Also when type 1 is disabling also don't do any early
accesses which are always type1.

This moves the pci= configuration parsing to be a early parameter.
I don't think this can break anything because it only changes
a single global that is only used by PCI.

Cc: gregkh@suse.de
Cc: Trammell Hudson <hudson@osresearch.net>

Signed-off-by: Andi Kleen <ak@suse.de>
2006-09-26 10:52:41 +02:00

53 lines
1.3 KiB
C

#include <linux/kernel.h>
#include <linux/pci.h>
#include <asm/pci-direct.h>
#include <asm/io.h>
#include "pci.h"
/* Direct PCI access. This is used for PCI accesses in early boot before
the PCI subsystem works. */
#define PDprintk(x...)
u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
{
u32 v;
outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
v = inl(0xcfc);
if (v != 0xffffffff)
PDprintk("%x reading 4 from %x: %x\n", slot, offset, v);
return v;
}
u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset)
{
u8 v;
outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
v = inb(0xcfc + (offset&3));
PDprintk("%x reading 1 from %x: %x\n", slot, offset, v);
return v;
}
u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset)
{
u16 v;
outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
v = inw(0xcfc + (offset&2));
PDprintk("%x reading 2 from %x: %x\n", slot, offset, v);
return v;
}
void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
u32 val)
{
PDprintk("%x writing to %x: %x\n", slot, offset, val);
outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
outl(val, 0xcfc);
}
int early_pci_allowed(void)
{
return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
PCI_PROBE_CONF1;
}