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/*
* mmconfig-shared.c - Low-level direct PCI config space access via
* MMCONFIG - common code between i386 and x86-64.
*
* This code does:
* - ACPI decoding and validation
*
* Per-architecture code takes care of the mappings and accesses
* themselves.
*/
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/bitmap.h>
#include <asm/e820.h>
#include "pci.h"
/* aperture is up to 256MB but BIOS may reserve less */
#define MMCONFIG_APER_MIN (2 * 1024*1024)
#define MMCONFIG_APER_MAX (256 * 1024*1024)
/* Verify the first 16 busses. We assume that systems with more busses
get MCFG right. */
#define PCI_MMCFG_MAX_CHECK_BUS 16
DECLARE_BITMAP(pci_mmcfg_fallback_slots, 32*PCI_MMCFG_MAX_CHECK_BUS);
/* K8 systems have some devices (typically in the builtin northbridge)
that are only accessible using type1
Normally this can be expressed in the MCFG by not listing them
and assigning suitable _SEGs, but this isn't implemented in some BIOS.
Instead try to discover all devices on bus 0 that are unreachable using MM
and fallback for them. */
static __init void unreachable_devices(void)
{
int i, k;
/* Use the max bus number from ACPI here? */
for (k = 0; k < PCI_MMCFG_MAX_CHECK_BUS; k++) {
for (i = 0; i < 32; i++) {
u32 val1, val2;
pci_conf1_read(0, k, PCI_DEVFN(i,0), 0, 4, &val1);
if (val1 == 0xffffffff)
continue;
raw_pci_ops->read(0, k, PCI_DEVFN(i, 0), 0, 4, &val2);
if (val1 != val2) {
set_bit(i + 32*k, pci_mmcfg_fallback_slots);
printk(KERN_NOTICE "PCI: No mmconfig possible"
" on device %02x:%02x\n", k, i);
}
}
}
}
void __init pci_mmcfg_init(int type)
{
if ((pci_probe & PCI_PROBE_MMCONF) == 0)
return;
acpi_table_parse(ACPI_SIG_MCFG, acpi_parse_mcfg);
if ((pci_mmcfg_config_num == 0) ||
(pci_mmcfg_config == NULL) ||
(pci_mmcfg_config[0].address == 0))
return;
/* Only do this check when type 1 works. If it doesn't work
assume we run on a Mac and always use MCFG */
if (type == 1 &&
!e820_all_mapped(pci_mmcfg_config[0].address,
pci_mmcfg_config[0].address + MMCONFIG_APER_MIN,
E820_RESERVED)) {
printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %Lx is not E820-reserved\n",
pci_mmcfg_config[0].address);
printk(KERN_ERR "PCI: Not using MMCONFIG.\n");
return;
}
if (pci_mmcfg_arch_init()) {
unreachable_devices();
pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
}
}
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