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mmconfig_64.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 <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;
      if (seg == 0 && bus < PCI_MMCFG_MAX_CHECK_BUS &&
            test_bit(32*bus + PCI_SLOT(devfn), pci_mmcfg_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 = 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 pci_conf1_write(seg,bus,devfn,reg,len,value);

      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_reachable(unsigned int seg, unsigned int bus,
                            unsigned int devfn)
{
      return pci_dev_base(seg, bus, devfn) != NULL;
}

int __init pci_mmcfg_arch_init(void)
{
      int i;
      pci_mmcfg_virt = kmalloc(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);
                  return 0;
            }
      }
      raw_pci_ops = &pci_mmcfg;
      return 1;
}

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