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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 "pci.h"
#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;
/*
* Functions for accessing PCI configuration space with MMCONFIG accesses
*/
static u32 get_base_addr(unsigned int seg, int bus)
{
int cfg_num = -1;
struct acpi_table_mcfg_config *cfg;
while (1) {
++cfg_num;
if (cfg_num >= pci_mmcfg_config_num) {
/* something bad is going on, no cfg table is found. */
/* so we fall back to the old way we used to do this */
/* and just rely on the first entry to be correct. */
return pci_mmcfg_config[0].base_address;
}
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;
}
}
static inline void pci_exp_set_dev_base(unsigned int seg, int bus, int devfn)
{
u32 dev_base = get_base_addr(seg, bus) | (bus << 20) | (devfn << 12);
if (dev_base != mmcfg_last_accessed_device) {
mmcfg_last_accessed_device = dev_base;
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;
if (!value || (bus > 255) || (devfn > 255) || (reg > 4095))
return -EINVAL;
spin_lock_irqsave(&pci_config_lock, flags);
pci_exp_set_dev_base(seg, 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;
if ((bus > 255) || (devfn > 255) || (reg > 4095))
return -EINVAL;
spin_lock_irqsave(&pci_config_lock, flags);
pci_exp_set_dev_base(seg, 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,
};
static int __init pci_mmcfg_init(void)
{
if ((pci_probe & PCI_PROBE_MMCONF) == 0)
goto out;
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))
goto out;
printk(KERN_INFO "PCI: Using MMCONFIG\n");
raw_pci_ops = &pci_mmcfg;
pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
out:
return 0;
}
arch_initcall(pci_mmcfg_init);
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