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/*
* Copyright (C) 2004 Matthew Wilcox <matthew@wil.cx>
* Copyright (C) 2004 Intel Corp.
*
* This code is released under the GNU General Public License version 2.
*/
/*
* mmconfig.c - Low-level direct PCI config space access via MMCONFIG
*/
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/acpi.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)
/* Assume systems with more busses have correct MCFG */
#define MAX_CHECK_BUS 16
#define mmcfg_virt_addr ((void __iomem *) fix_to_virt(FIX_PCIE_MCFG))
/* The base address of the last MMCONFIG device accessed */
static u32 mmcfg_last_accessed_device;
static int mmcfg_last_accessed_cpu;
static DECLARE_BITMAP(fallback_slots, MAX_CHECK_BUS*32);
/*
* Functions for accessing PCI configuration space with MMCONFIG accesses
*/
static u32 get_base_addr(unsigned int seg, int bus, unsigned devfn)
{
int cfg_num = -1;
struct acpi_table_mcfg_config *cfg;
if (seg == 0 && bus < MAX_CHECK_BUS &&
test_bit(PCI_SLOT(devfn) + 32*bus, fallback_slots))
return 0;
while (1) {
++cfg_num;
if (cfg_num >= pci_mmcfg_config_num) {
break;
}
cfg = &pci_mmcfg_config[cfg_num];
if (cfg->pci_segment_group_number != seg)
continue;
if ((cfg->start_bus_number <= bus) &&
(cfg->end_bus_number >= bus))
return cfg->base_address;
}
/* 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 cfg->base_address;
/* Fall back to type 0 */
return 0;
}
/*
* This is always called under pci_config_lock
*/
static void pci_exp_set_dev_base(unsigned int base, int bus, int devfn)
{
u32 dev_base = base | (bus << 20) | (devfn << 12);
int cpu = smp_processor_id();
if (dev_base != mmcfg_last_accessed_device ||
cpu != mmcfg_last_accessed_cpu) {
mmcfg_last_accessed_device = dev_base;
mmcfg_last_accessed_cpu = cpu;
set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
}
}
static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 *value)
{
unsigned long flags;
u32 base;
if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
*value = -1;
return -EINVAL;
}
base = get_base_addr(seg, bus, devfn);
if (!base)
return pci_conf1_read(seg,bus,devfn,reg,len,value);
spin_lock_irqsave(&pci_config_lock, flags);
pci_exp_set_dev_base(base, bus, devfn);
switch (len) {
case 1:
*value = readb(mmcfg_virt_addr + reg);
break;
case 2:
*value = readw(mmcfg_virt_addr + reg);
break;
case 4:
*value = readl(mmcfg_virt_addr + reg);
break;
}
spin_unlock_irqrestore(&pci_config_lock, flags);
return 0;
}
static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
unsigned int devfn, int reg, int len, u32 value)
{
unsigned long flags;
u32 base;
if ((bus > 255) || (devfn > 255) || (reg > 4095))
return -EINVAL;
base = get_base_addr(seg, bus, devfn);
if (!base)
return pci_conf1_write(seg,bus,devfn,reg,len,value);
spin_lock_irqsave(&pci_config_lock, flags);
pci_exp_set_dev_base(base, bus, devfn);
switch (len) {
case 1:
writeb(value, mmcfg_virt_addr + reg);
break;
case 2:
writew(value, mmcfg_virt_addr + reg);
break;
case 4:
writel(value, mmcfg_virt_addr + reg);
break;
}
spin_unlock_irqrestore(&pci_config_lock, flags);
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;
unsigned long flags;
for (k = 0; k < MAX_CHECK_BUS; k++) {
for (i = 0; i < 32; i++) {
u32 val1;
u32 addr;
pci_conf1_read(0, k, PCI_DEVFN(i, 0), 0, 4, &val1);
if (val1 == 0xffffffff)
continue;
/* Locking probably not needed, but safer */
spin_lock_irqsave(&pci_config_lock, flags);
addr = get_base_addr(0, k, PCI_DEVFN(i, 0));
if (addr != 0)
pci_exp_set_dev_base(addr, k, PCI_DEVFN(i, 0));
if (addr == 0 ||
readl((u32 __iomem *)mmcfg_virt_addr) != val1) {
set_bit(i + 32*k, fallback_slots);
printk(KERN_NOTICE
"PCI: No mmconfig possible on %x:%x\n", k, i);
}
spin_unlock_irqrestore(&pci_config_lock, flags);
}
}
}
void __init pci_mmcfg_init(int type)
{
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;
/* 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].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;
}
printk(KERN_INFO "PCI: Using MMCONFIG\n");
raw_pci_ops = &pci_mmcfg;
pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
unreachable_devices();
}
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