78 lines
1.6 KiB
C
78 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* legacy.c - traditional, old school PCI bus probing
|
|
*/
|
|
#include <linux/init.h>
|
|
#include <linux/export.h>
|
|
#include <linux/pci.h>
|
|
#include <asm/jailhouse_para.h>
|
|
#include <asm/pci_x86.h>
|
|
|
|
/*
|
|
* Discover remaining PCI buses in case there are peer host bridges.
|
|
* We use the number of last PCI bus provided by the PCI BIOS.
|
|
*/
|
|
static void pcibios_fixup_peer_bridges(void)
|
|
{
|
|
int n;
|
|
|
|
if (pcibios_last_bus <= 0 || pcibios_last_bus > 0xff)
|
|
return;
|
|
DBG("PCI: Peer bridge fixup\n");
|
|
|
|
for (n=0; n <= pcibios_last_bus; n++)
|
|
pcibios_scan_specific_bus(n);
|
|
}
|
|
|
|
int __init pci_legacy_init(void)
|
|
{
|
|
if (!raw_pci_ops)
|
|
return 1;
|
|
|
|
pr_info("PCI: Probing PCI hardware\n");
|
|
pcibios_scan_root(0);
|
|
return 0;
|
|
}
|
|
|
|
void pcibios_scan_specific_bus(int busn)
|
|
{
|
|
int stride = jailhouse_paravirt() ? 1 : 8;
|
|
int devfn;
|
|
u32 l;
|
|
|
|
if (pci_find_bus(0, busn))
|
|
return;
|
|
|
|
for (devfn = 0; devfn < 256; devfn += stride) {
|
|
if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) &&
|
|
l != 0x0000 && l != 0xffff) {
|
|
DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l);
|
|
pr_info("PCI: Discovered peer bus %02x\n", busn);
|
|
pcibios_scan_root(busn);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(pcibios_scan_specific_bus);
|
|
|
|
static int __init pci_subsys_init(void)
|
|
{
|
|
/*
|
|
* The init function returns an non zero value when
|
|
* pci_legacy_init should be invoked.
|
|
*/
|
|
if (x86_init.pci.init()) {
|
|
if (pci_legacy_init()) {
|
|
pr_info("PCI: System does not support PCI\n");
|
|
return -ENODEV;
|
|
}
|
|
}
|
|
|
|
pcibios_fixup_peer_bridges();
|
|
x86_init.pci.init_irq();
|
|
pcibios_init();
|
|
|
|
return 0;
|
|
}
|
|
subsys_initcall(pci_subsys_init);
|