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/*
* 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 <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 MAX_CHECK_BUS 16
static DECLARE_BITMAP(fallback_slots, 32*MAX_CHECK_BUS);
/* Static virtual mapping of the MMCONFIG aperture */
struct mmcfg_virt {
struct acpi_table_mcfg_config *cfg;
char __iomem *virt;
};
static struct mmcfg_virt *pci_mmcfg_virt;
static char __iomem *get_virt(unsigned int seg, unsigned bus)
{
int cfg_num = -1;
struct acpi_table_mcfg_config *cfg;
while (1) {
++cfg_num;
if (cfg_num >= pci_mmcfg_config_num)
break;
cfg = pci_mmcfg_virt[cfg_num].cfg;
if (cfg->pci_segment_group_number != seg)
continue;
if ((cfg->start_bus_number <= bus) &&
(cfg->end_bus_number >= bus))
return pci_mmcfg_virt[cfg_num].virt;
}
/* Handle more broken MCFG tables on Asus etc.
They only contain a single entry for bus 0-0. Assume
this applies to all busses. */
cfg = &pci_mmcfg_config[0];
if (pci_mmcfg_config_num == 1 &&
cfg->pci_segment_group_number == 0 &&
(cfg->start_bus_number | cfg->end_bus_number) == 0)
return pci_mmcfg_virt[0].virt;
/* Fall back to type 0 */
return NULL;
}
static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
{
char __iomem *addr;
if (seg == 0 && bus < MAX_CHECK_BUS &&
test_bit(32*bus + PCI_SLOT(devfn), fallback_slots))
return NULL;
addr = get_virt(seg, bus);
if (!addr)
return NULL;
return addr + ((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 __iomem *addr;
/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
*value = -1;
return -EINVAL;
}
addr = pci_dev_base(seg, bus, devfn);
if (!addr)
return pci_conf1_read(seg,bus,devfn,reg,len,value);
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 __iomem *addr;
/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
return -EINVAL;
addr = pci_dev_base(seg, bus, devfn);
if (!addr)
return pci_conf1_write(seg,bus,devfn,reg,len,value);
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,
};
/* 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 < MAX_CHECK_BUS; k++) {
for (i = 0; i < 32; i++) {
u32 val1;
char __iomem *addr;
pci_conf1_read(0, k, PCI_DEVFN(i,0), 0, 4, &val1);
if (val1 == 0xffffffff)
continue;
addr = pci_dev_base(0, k, PCI_DEVFN(i, 0));
if (addr == NULL|| readl(addr) != val1) {
set_bit(i + 32*k, fallback_slots);
printk(KERN_NOTICE
"PCI: No mmconfig possible on device %x:%x\n",
k, i);
}
}
}
}
void __init pci_mmcfg_init(void)
{
int i;
if ((pci_probe & PCI_PROBE_MMCONF) == 0)
return;
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;
if (!e820_all_mapped(pci_mmcfg_config[0].base_address,
pci_mmcfg_config[0].base_address + MMCONFIG_APER_MIN,
E820_RESERVED)) {
printk(KERN_ERR "PCI: BIOS Bug: MCFG area at %x is not E820-reserved\n",
pci_mmcfg_config[0].base_address);
printk(KERN_ERR "PCI: Not using MMCONFIG.\n");
return;
}
/* RED-PEN i386 doesn't do _nocache right now */
pci_mmcfg_virt = kmalloc(sizeof(*pci_mmcfg_virt) * pci_mmcfg_config_num, GFP_KERNEL);
if (pci_mmcfg_virt == NULL) {
printk("PCI: Can not allocate memory for mmconfig structures\n");
return;
}
for (i = 0; i < pci_mmcfg_config_num; ++i) {
pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i];
pci_mmcfg_virt[i].virt = ioremap_nocache(pci_mmcfg_config[i].base_address,
MMCONFIG_APER_MAX);
if (!pci_mmcfg_virt[i].virt) {
printk("PCI: Cannot map mmconfig aperture for segment %d\n",
pci_mmcfg_config[i].pci_segment_group_number);
return;
}
printk(KERN_INFO "PCI: Using MMCONFIG at %x\n", pci_mmcfg_config[i].base_address);
}
unreachable_devices();
raw_pci_ops = &pci_mmcfg;
pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
}
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