root/arch/x86/pci/mmconfig_64.c

DEFINITIONS

1. get_virt
2. pci_dev_base
3. pci_mmcfg_read
4. pci_mmcfg_write
5. mcfg_ioremap
6. pci_mmcfg_arch_init
7. pci_mmcfg_arch_free

/*
 * 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"

/* Static virtual mapping of the MMCONFIG aperture */
struct mmcfg_virt {
        struct acpi_mcfg_allocation *cfg;
        char __iomem *virt;
};
static struct mmcfg_virt *pci_mmcfg_virt;

static char __iomem *get_virt(unsigned int seg, unsigned bus)
{
        struct acpi_mcfg_allocation *cfg;
        int cfg_num;

        for (cfg_num = 0; cfg_num < pci_mmcfg_config_num; cfg_num++) {
                cfg = pci_mmcfg_virt[cfg_num].cfg;
                if (cfg->pci_segment == seg &&
                    (cfg->start_bus_number <= bus) &&
                    (cfg->end_bus_number >= bus))
                        return pci_mmcfg_virt[cfg_num].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;

        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))) {
err:            *value = -1;
                return -EINVAL;
        }

        addr = pci_dev_base(seg, bus, devfn);
        if (!addr)
                goto err;

        switch (len) {
        case 1:
                *value = mmio_config_readb(addr + reg);
                break;
        case 2:
                *value = mmio_config_readw(addr + reg);
                break;
        case 4:
                *value = mmio_config_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 -EINVAL;

        switch (len) {
        case 1:
                mmio_config_writeb(addr + reg, value);
                break;
        case 2:
                mmio_config_writew(addr + reg, value);
                break;
        case 4:
                mmio_config_writel(addr + reg, value);
                break;
        }

        return 0;
}

static struct pci_raw_ops pci_mmcfg = {
        .read =         pci_mmcfg_read,
        .write =        pci_mmcfg_write,
};

static void __iomem * __init mcfg_ioremap(struct acpi_mcfg_allocation *cfg)
{
        void __iomem *addr;
        u32 size;

        size = (cfg->end_bus_number + 1) << 20;
        addr = ioremap_nocache(cfg->address, size);
        if (addr) {
                printk(KERN_INFO "PCI: Using MMCONFIG at %Lx - %Lx\n",
                       cfg->address, cfg->address + size - 1);
        }
        return addr;
}

int __init pci_mmcfg_arch_init(void)
{
        int i;
        pci_mmcfg_virt = kzalloc(sizeof(*pci_mmcfg_virt) *
                                 pci_mmcfg_config_num, GFP_KERNEL);
        if (pci_mmcfg_virt == NULL) {
                printk(KERN_ERR "PCI: Can not allocate memory for mmconfig structures\n");
                return 0;
        }

        for (i = 0; i < pci_mmcfg_config_num; ++i) {
                pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i];
                pci_mmcfg_virt[i].virt = mcfg_ioremap(&pci_mmcfg_config[i]);
                if (!pci_mmcfg_virt[i].virt) {
                        printk(KERN_ERR "PCI: Cannot map mmconfig aperture for "
                                        "segment %d\n",
                                pci_mmcfg_config[i].pci_segment);
                        pci_mmcfg_arch_free();
                        return 0;
                }
        }
        raw_pci_ext_ops = &pci_mmcfg;
        return 1;
}

void __init pci_mmcfg_arch_free(void)
{
        int i;

        if (pci_mmcfg_virt == NULL)
                return;

        for (i = 0; i < pci_mmcfg_config_num; ++i) {
                if (pci_mmcfg_virt[i].virt) {
                        iounmap(pci_mmcfg_virt[i].virt);
                        pci_mmcfg_virt[i].virt = NULL;
                        pci_mmcfg_virt[i].cfg = NULL;
                }
        }

        kfree(pci_mmcfg_virt);
        pci_mmcfg_virt = NULL;
}