kernel-hacking-2024-linux-s.../arch/x86_64/pci/mmconfig.c
Greg Kroah-Hartman 545493917d [PATCH] PCI: add proper MCFG table parsing to ACPI core.
This patch is the first step in properly handling the MCFG PCI table.
It defines the structures properly, and saves off the table so that the
pci mmconfig code can access it.  It moves the parsing of the table a
little later in the boot process, but still before the information is
needed.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-06-27 21:52:47 -07:00

106 lines
2.5 KiB
C

/*
* mmconfig.c - Low-level direct PCI config space access via MMCONFIG
*
* This is an 64bit optimized version that always keeps the full mmconfig
* space mapped. This allows lockless config space operation.
*/
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include "pci.h"
#define MMCONFIG_APER_SIZE (256*1024*1024)
/* Static virtual mapping of the MMCONFIG aperture */
static char *pci_mmcfg_virt;
static inline char *pci_dev_base(unsigned int bus, unsigned int devfn)
{
return pci_mmcfg_virt + ((bus << 20) | (devfn << 12));
}
static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 *value)
{
char *addr = pci_dev_base(bus, devfn);
if (unlikely(!value || (bus > 255) || (devfn > 255) || (reg > 4095)))
return -EINVAL;
switch (len) {
case 1:
*value = readb(addr + reg);
break;
case 2:
*value = readw(addr + reg);
break;
case 4:
*value = readl(addr + reg);
break;
}
return 0;
}
static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 value)
{
char *addr = pci_dev_base(bus,devfn);
if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
return -EINVAL;
switch (len) {
case 1:
writeb(value, addr + reg);
break;
case 2:
writew(value, addr + reg);
break;
case 4:
writel(value, addr + reg);
break;
}
return 0;
}
static struct pci_raw_ops pci_mmcfg = {
.read = pci_mmcfg_read,
.write = pci_mmcfg_write,
};
static int __init pci_mmcfg_init(void)
{
if ((pci_probe & PCI_PROBE_MMCONF) == 0)
return 0;
acpi_table_parse(ACPI_MCFG, acpi_parse_mcfg);
if ((pci_mmcfg_config_num == 0) ||
(pci_mmcfg_config == NULL) ||
(pci_mmcfg_config[0].base_address == 0))
return 0;
/* Kludge for now. Don't use mmconfig on AMD systems because
those have some busses where mmconfig doesn't work,
and we don't parse ACPI MCFG well enough to handle that.
Remove when proper handling is added. */
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
return 0;
/* RED-PEN i386 doesn't do _nocache right now */
pci_mmcfg_virt = ioremap_nocache(pci_mmcfg_config[0].base_address, MMCONFIG_APER_SIZE);
if (!pci_mmcfg_virt) {
printk("PCI: Cannot map mmconfig aperture\n");
return 0;
}
printk(KERN_INFO "PCI: Using MMCONFIG at %x\n", pci_mmcfg_config[0].base_address);
raw_pci_ops = &pci_mmcfg;
pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
return 0;
}
arch_initcall(pci_mmcfg_init);