/*
   * mmconfig-shared.c - Low-level direct PCI config space access via
   *                     MMCONFIG - common code between i386 and x86-64.
   *
   * This code does:
   * - known chipset handling
   * - ACPI decoding and validation
   *
   * Per-architecture code takes care of the mappings and accesses
   * themselves.
   */
  
  #include <linux/pci.h>
  #include <linux/init.h>
  #include <linux/sfi_acpi.h>
  #include <linux/bitmap.h>
  #include <linux/dmi.h>
  #include <linux/slab.h>
  #include <linux/mutex.h>
  #include <linux/rculist.h>
  #include <asm/e820.h>
  #include <asm/pci_x86.h>
  #include <asm/acpi.h>
  
  #define PREFIX "PCI: "
  
  /* Indicate if the mmcfg resources have been placed into the resource table. */
  static bool pci_mmcfg_running_state;
  static bool pci_mmcfg_arch_init_failed;
  static DEFINE_MUTEX(pci_mmcfg_lock);
  
  LIST_HEAD(pci_mmcfg_list);
  
  static __init void pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
  {
  	if (cfg->res.parent)
  		release_resource(&cfg->res);
  	list_del(&cfg->list);
  	kfree(cfg);
  }
  
  static __init void free_all_mmcfg(void)
  {
  	struct pci_mmcfg_region *cfg, *tmp;
  
  	pci_mmcfg_arch_free();
  	list_for_each_entry_safe(cfg, tmp, &pci_mmcfg_list, list)
  		pci_mmconfig_remove(cfg);
  }
  
  static void list_add_sorted(struct pci_mmcfg_region *new)
  {
  	struct pci_mmcfg_region *cfg;
  
  	/* keep list sorted by segment and starting bus number */
  	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
  		if (cfg->segment > new->segment ||
  		    (cfg->segment == new->segment &&
  		     cfg->start_bus >= new->start_bus)) {
  			list_add_tail_rcu(&new->list, &cfg->list);
  			return;
  		}
  	}
  	list_add_tail_rcu(&new->list, &pci_mmcfg_list);
  }
  
  static struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
  						   int end, u64 addr)
  {
  	struct pci_mmcfg_region *new;
  	struct resource *res;
  
  	if (addr == 0)
  		return NULL;
  
  	new = kzalloc(sizeof(*new), GFP_KERNEL);
  	if (!new)
  		return NULL;
  
  	new->address = addr;
  	new->segment = segment;
  	new->start_bus = start;
  	new->end_bus = end;
  
  	res = &new->res;
  	res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
  	res->end = addr + PCI_MMCFG_BUS_OFFSET(end + 1) - 1;
  	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  	snprintf(new->name, PCI_MMCFG_RESOURCE_NAME_LEN,
  		 "PCI MMCONFIG %04x [bus %02x-%02x]", segment, start, end);
  	res->name = new->name;
  
  	return new;
  }
  
  static __init struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
  							int end, u64 addr)
  {
  	struct pci_mmcfg_region *new;
  
  	new = pci_mmconfig_alloc(segment, start, end, addr);
  	if (new) {
  		mutex_lock(&pci_mmcfg_lock);
  		list_add_sorted(new);
  		mutex_unlock(&pci_mmcfg_lock);
  
  		pr_info(PREFIX
  		       "MMCONFIG for domain %04x [bus %02x-%02x] at %pR "
  		       "(base %#lx)
  ",
  		       segment, start, end, &new->res, (unsigned long)addr);
  	}
  
  	return new;
  }
  
  struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
  {
  	struct pci_mmcfg_region *cfg;
  
  	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
  		if (cfg->segment == segment &&
  		    cfg->start_bus <= bus && bus <= cfg->end_bus)
  			return cfg;
  
  	return NULL;
  }
  
  static const char __init *pci_mmcfg_e7520(void)
  {
  	u32 win;
  	raw_pci_ops->read(0, 0, PCI_DEVFN(0, 0), 0xce, 2, &win);
  
  	win = win & 0xf000;
  	if (win == 0x0000 || win == 0xf000)
  		return NULL;
  
  	if (pci_mmconfig_add(0, 0, 255, win << 16) == NULL)
  		return NULL;
  
  	return "Intel Corporation E7520 Memory Controller Hub";
  }
  
  static const char __init *pci_mmcfg_intel_945(void)
  {
  	u32 pciexbar, mask = 0, len = 0;
  
  	raw_pci_ops->read(0, 0, PCI_DEVFN(0, 0), 0x48, 4, &pciexbar);
  
  	/* Enable bit */
  	if (!(pciexbar & 1))
  		return NULL;
  
  	/* Size bits */
  	switch ((pciexbar >> 1) & 3) {
  	case 0:
  		mask = 0xf0000000U;
  		len  = 0x10000000U;
  		break;
  	case 1:
  		mask = 0xf8000000U;
  		len  = 0x08000000U;
  		break;
  	case 2:
  		mask = 0xfc000000U;
  		len  = 0x04000000U;
  		break;
  	default:
  		return NULL;
  	}
  
  	/* Errata #2, things break when not aligned on a 256Mb boundary */
  	/* Can only happen in 64M/128M mode */
  
  	if ((pciexbar & mask) & 0x0fffffffU)
  		return NULL;
  
  	/* Don't hit the APIC registers and their friends */
  	if ((pciexbar & mask) >= 0xf0000000U)
  		return NULL;
  
  	if (pci_mmconfig_add(0, 0, (len >> 20) - 1, pciexbar & mask) == NULL)
  		return NULL;
  
  	return "Intel Corporation 945G/GZ/P/PL Express Memory Controller Hub";
  }
  
  static const char __init *pci_mmcfg_amd_fam10h(void)
  {
  	u32 low, high, address;
  	u64 base, msr;
  	int i;
  	unsigned segnbits = 0, busnbits, end_bus;
  
  	if (!(pci_probe & PCI_CHECK_ENABLE_AMD_MMCONF))
  		return NULL;
  
  	address = MSR_FAM10H_MMIO_CONF_BASE;
  	if (rdmsr_safe(address, &low, &high))
  		return NULL;
  
  	msr = high;
  	msr <<= 32;
  	msr |= low;
  
  	/* mmconfig is not enable */
  	if (!(msr & FAM10H_MMIO_CONF_ENABLE))
  		return NULL;
  
  	base = msr & (FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT);
  
  	busnbits = (msr >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
  			 FAM10H_MMIO_CONF_BUSRANGE_MASK;
  
  	/*
  	 * only handle bus 0 ?
  	 * need to skip it
  	 */
  	if (!busnbits)
  		return NULL;
  
  	if (busnbits > 8) {
  		segnbits = busnbits - 8;
  		busnbits = 8;
  	}
  
  	end_bus = (1 << busnbits) - 1;
  	for (i = 0; i < (1 << segnbits); i++)
  		if (pci_mmconfig_add(i, 0, end_bus,
  				     base + (1<<28) * i) == NULL) {
  			free_all_mmcfg();
  			return NULL;
  		}
  
  	return "AMD Family 10h NB";
  }
  
  static bool __initdata mcp55_checked;
  static const char __init *pci_mmcfg_nvidia_mcp55(void)
  {
  	int bus;
  	int mcp55_mmconf_found = 0;
  
  	static const u32 extcfg_regnum		= 0x90;
  	static const u32 extcfg_regsize		= 4;
  	static const u32 extcfg_enable_mask	= 1<<31;
  	static const u32 extcfg_start_mask	= 0xff<<16;
  	static const int extcfg_start_shift	= 16;
  	static const u32 extcfg_size_mask	= 0x3<<28;
  	static const int extcfg_size_shift	= 28;
  	static const int extcfg_sizebus[]	= {0x100, 0x80, 0x40, 0x20};
  	static const u32 extcfg_base_mask[]	= {0x7ff8, 0x7ffc, 0x7ffe, 0x7fff};
  	static const int extcfg_base_lshift	= 25;
  
  	/*
  	 * do check if amd fam10h already took over
  	 */
  	if (!acpi_disabled || !list_empty(&pci_mmcfg_list) || mcp55_checked)
  		return NULL;
  
  	mcp55_checked = true;
  	for (bus = 0; bus < 256; bus++) {
  		u64 base;
  		u32 l, extcfg;
  		u16 vendor, device;
  		int start, size_index, end;
  
  		raw_pci_ops->read(0, bus, PCI_DEVFN(0, 0), 0, 4, &l);
  		vendor = l & 0xffff;
  		device = (l >> 16) & 0xffff;
  
  		if (PCI_VENDOR_ID_NVIDIA != vendor || 0x0369 != device)
  			continue;
  
  		raw_pci_ops->read(0, bus, PCI_DEVFN(0, 0), extcfg_regnum,
  				  extcfg_regsize, &extcfg);
  
  		if (!(extcfg & extcfg_enable_mask))
  			continue;
  
  		size_index = (extcfg & extcfg_size_mask) >> extcfg_size_shift;
  		base = extcfg & extcfg_base_mask[size_index];
  		/* base could > 4G */
  		base <<= extcfg_base_lshift;
  		start = (extcfg & extcfg_start_mask) >> extcfg_start_shift;
  		end = start + extcfg_sizebus[size_index] - 1;
  		if (pci_mmconfig_add(0, start, end, base) == NULL)
  			continue;
  		mcp55_mmconf_found++;
  	}
  
  	if (!mcp55_mmconf_found)
  		return NULL;
  
  	return "nVidia MCP55";
  }
  
  struct pci_mmcfg_hostbridge_probe {
  	u32 bus;
  	u32 devfn;
  	u32 vendor;
  	u32 device;
  	const char *(*probe)(void);
  };
  
  static struct pci_mmcfg_hostbridge_probe pci_mmcfg_probes[] __initdata = {
  	{ 0, PCI_DEVFN(0, 0), PCI_VENDOR_ID_INTEL,
  	  PCI_DEVICE_ID_INTEL_E7520_MCH, pci_mmcfg_e7520 },
  	{ 0, PCI_DEVFN(0, 0), PCI_VENDOR_ID_INTEL,
  	  PCI_DEVICE_ID_INTEL_82945G_HB, pci_mmcfg_intel_945 },
  	{ 0, PCI_DEVFN(0x18, 0), PCI_VENDOR_ID_AMD,
  	  0x1200, pci_mmcfg_amd_fam10h },
  	{ 0xff, PCI_DEVFN(0, 0), PCI_VENDOR_ID_AMD,
  	  0x1200, pci_mmcfg_amd_fam10h },
  	{ 0, PCI_DEVFN(0, 0), PCI_VENDOR_ID_NVIDIA,
  	  0x0369, pci_mmcfg_nvidia_mcp55 },
  };
  
  static void __init pci_mmcfg_check_end_bus_number(void)
  {
  	struct pci_mmcfg_region *cfg, *cfgx;
  
  	/* Fixup overlaps */
  	list_for_each_entry(cfg, &pci_mmcfg_list, list) {
  		if (cfg->end_bus < cfg->start_bus)
  			cfg->end_bus = 255;
  
  		/* Don't access the list head ! */
  		if (cfg->list.next == &pci_mmcfg_list)
  			break;
  
  		cfgx = list_entry(cfg->list.next, typeof(*cfg), list);
  		if (cfg->end_bus >= cfgx->start_bus)
  			cfg->end_bus = cfgx->start_bus - 1;
  	}
  }
  
  static int __init pci_mmcfg_check_hostbridge(void)
  {
  	u32 l;
  	u32 bus, devfn;
  	u16 vendor, device;
  	int i;
  	const char *name;
  
  	if (!raw_pci_ops)
  		return 0;
  
  	free_all_mmcfg();
  
  	for (i = 0; i < ARRAY_SIZE(pci_mmcfg_probes); i++) {
  		bus =  pci_mmcfg_probes[i].bus;
  		devfn = pci_mmcfg_probes[i].devfn;
  		raw_pci_ops->read(0, bus, devfn, 0, 4, &l);
  		vendor = l & 0xffff;
  		device = (l >> 16) & 0xffff;
  
  		name = NULL;
  		if (pci_mmcfg_probes[i].vendor == vendor &&
  		    pci_mmcfg_probes[i].device == device)
  			name = pci_mmcfg_probes[i].probe();
  
  		if (name)
  			pr_info(PREFIX "%s with MMCONFIG support
  ", name);
  	}
  
  	/* some end_bus_number is crazy, fix it */
  	pci_mmcfg_check_end_bus_number();
  
  	return !list_empty(&pci_mmcfg_list);
  }
  
  static acpi_status check_mcfg_resource(struct acpi_resource *res, void *data)
  {
  	struct resource *mcfg_res = data;
  	struct acpi_resource_address64 address;
  	acpi_status status;
  
  	if (res->type == ACPI_RESOURCE_TYPE_FIXED_MEMORY32) {
  		struct acpi_resource_fixed_memory32 *fixmem32 =
  			&res->data.fixed_memory32;
  		if (!fixmem32)
  			return AE_OK;
  		if ((mcfg_res->start >= fixmem32->address) &&
  		    (mcfg_res->end < (fixmem32->address +
  				      fixmem32->address_length))) {
  			mcfg_res->flags = 1;
  			return AE_CTRL_TERMINATE;
  		}
  	}
  	if ((res->type != ACPI_RESOURCE_TYPE_ADDRESS32) &&
  	    (res->type != ACPI_RESOURCE_TYPE_ADDRESS64))
  		return AE_OK;
  
  	status = acpi_resource_to_address64(res, &address);
  	if (ACPI_FAILURE(status) ||
  	   (address.address_length <= 0) ||
  	   (address.resource_type != ACPI_MEMORY_RANGE))
  		return AE_OK;
  
  	if ((mcfg_res->start >= address.minimum) &&
  	    (mcfg_res->end < (address.minimum + address.address_length))) {
  		mcfg_res->flags = 1;
  		return AE_CTRL_TERMINATE;
  	}
  	return AE_OK;
  }
  
  static acpi_status find_mboard_resource(acpi_handle handle, u32 lvl,
  					void *context, void **rv)
  {
  	struct resource *mcfg_res = context;
  
  	acpi_walk_resources(handle, METHOD_NAME__CRS,
  			    check_mcfg_resource, context);
  
  	if (mcfg_res->flags)
  		return AE_CTRL_TERMINATE;
  
  	return AE_OK;
  }
  
  static int is_acpi_reserved(u64 start, u64 end, unsigned not_used)
  {
  	struct resource mcfg_res;
  
  	mcfg_res.start = start;
  	mcfg_res.end = end - 1;
  	mcfg_res.flags = 0;
  
  	acpi_get_devices("PNP0C01", find_mboard_resource, &mcfg_res, NULL);
  
  	if (!mcfg_res.flags)
  		acpi_get_devices("PNP0C02", find_mboard_resource, &mcfg_res,
  				 NULL);
  
  	return mcfg_res.flags;
  }
  
  typedef int (*check_reserved_t)(u64 start, u64 end, unsigned type);
  
  static int __ref is_mmconf_reserved(check_reserved_t is_reserved,
  				    struct pci_mmcfg_region *cfg,
  				    struct device *dev, int with_e820)
  {
  	u64 addr = cfg->res.start;
  	u64 size = resource_size(&cfg->res);
  	u64 old_size = size;
  	int num_buses;
  	char *method = with_e820 ? "E820" : "ACPI motherboard resources";
  
  	while (!is_reserved(addr, addr + size, E820_RESERVED)) {
  		size >>= 1;
  		if (size < (16UL<<20))
  			break;
  	}
  
  	if (size < (16UL<<20) && size != old_size)
  		return 0;
  
  	if (dev)
  		dev_info(dev, "MMCONFIG at %pR reserved in %s
  ",
  			 &cfg->res, method);
  	else
  		pr_info(PREFIX "MMCONFIG at %pR reserved in %s
  ",
  		       &cfg->res, method);
  
  	if (old_size != size) {
  		/* update end_bus */
  		cfg->end_bus = cfg->start_bus + ((size>>20) - 1);
  		num_buses = cfg->end_bus - cfg->start_bus + 1;
  		cfg->res.end = cfg->res.start +
  		    PCI_MMCFG_BUS_OFFSET(num_buses) - 1;
  		snprintf(cfg->name, PCI_MMCFG_RESOURCE_NAME_LEN,
  			 "PCI MMCONFIG %04x [bus %02x-%02x]",
  			 cfg->segment, cfg->start_bus, cfg->end_bus);
  
  		if (dev)
  			dev_info(dev,
  				"MMCONFIG "
  				"at %pR (base %#lx) (size reduced!)
  ",
  				&cfg->res, (unsigned long) cfg->address);
  		else
  			pr_info(PREFIX
  				"MMCONFIG for %04x [bus%02x-%02x] "
  				"at %pR (base %#lx) (size reduced!)
  ",
  				cfg->segment, cfg->start_bus, cfg->end_bus,
  				&cfg->res, (unsigned long) cfg->address);
  	}
  
  	return 1;
  }
  
  static int __ref pci_mmcfg_check_reserved(struct device *dev,
  		  struct pci_mmcfg_region *cfg, int early)
  {
  	if (!early && !acpi_disabled) {
  		if (is_mmconf_reserved(is_acpi_reserved, cfg, dev, 0))
  			return 1;
  
  		if (dev)
  			dev_info(dev, FW_INFO
  				 "MMCONFIG at %pR not reserved in "
  				 "ACPI motherboard resources
  ",
  				 &cfg->res);
  		else
  			pr_info(FW_INFO PREFIX
  			       "MMCONFIG at %pR not reserved in "
  			       "ACPI motherboard resources
  ",
  			       &cfg->res);
  	}
  
  	/*
  	 * e820_all_mapped() is marked as __init.
  	 * All entries from ACPI MCFG table have been checked at boot time.
  	 * For MCFG information constructed from hotpluggable host bridge's
  	 * _CBA method, just assume it's reserved.
  	 */
  	if (pci_mmcfg_running_state)
  		return 1;
  
  	/* Don't try to do this check unless configuration
  	   type 1 is available. how about type 2 ?*/
  	if (raw_pci_ops)
  		return is_mmconf_reserved(e820_all_mapped, cfg, dev, 1);
  
  	return 0;
  }
  
  static void __init pci_mmcfg_reject_broken(int early)
  {
  	struct pci_mmcfg_region *cfg;
  
  	list_for_each_entry(cfg, &pci_mmcfg_list, list) {
  		if (pci_mmcfg_check_reserved(NULL, cfg, early) == 0) {
  			pr_info(PREFIX "not using MMCONFIG
  ");
  			free_all_mmcfg();
  			return;
  		}
  	}
  }
  
  static int __init acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
  					struct acpi_mcfg_allocation *cfg)
  {
  	int year;
  
  	if (cfg->address < 0xFFFFFFFF)
  		return 0;
  
  	if (!strncmp(mcfg->header.oem_id, "SGI", 3))
  		return 0;
  
  	if (mcfg->header.revision >= 1) {
  		if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) &&
  		    year >= 2010)
  			return 0;
  	}
  
  	pr_err(PREFIX "MCFG region for %04x [bus %02x-%02x] at %#llx "
  	       "is above 4GB, ignored
  ", cfg->pci_segment,
  	       cfg->start_bus_number, cfg->end_bus_number, cfg->address);
  	return -EINVAL;
  }
  
  static int __init pci_parse_mcfg(struct acpi_table_header *header)
  {
  	struct acpi_table_mcfg *mcfg;
  	struct acpi_mcfg_allocation *cfg_table, *cfg;
  	unsigned long i;
  	int entries;
  
  	if (!header)
  		return -EINVAL;
  
  	mcfg = (struct acpi_table_mcfg *)header;
  
  	/* how many config structures do we have */
  	free_all_mmcfg();
  	entries = 0;
  	i = header->length - sizeof(struct acpi_table_mcfg);
  	while (i >= sizeof(struct acpi_mcfg_allocation)) {
  		entries++;
  		i -= sizeof(struct acpi_mcfg_allocation);
  	}
  	if (entries == 0) {
  		pr_err(PREFIX "MMCONFIG has no entries
  ");
  		return -ENODEV;
  	}
  
  	cfg_table = (struct acpi_mcfg_allocation *) &mcfg[1];
  	for (i = 0; i < entries; i++) {
  		cfg = &cfg_table[i];
  		if (acpi_mcfg_check_entry(mcfg, cfg)) {
  			free_all_mmcfg();
  			return -ENODEV;
  		}
  
  		if (pci_mmconfig_add(cfg->pci_segment, cfg->start_bus_number,
  				   cfg->end_bus_number, cfg->address) == NULL) {
  			pr_warn(PREFIX "no memory for MCFG entries
  ");
  			free_all_mmcfg();
  			return -ENOMEM;
  		}
  	}
  
  	return 0;
  }
  
  static void __init __pci_mmcfg_init(int early)
  {
  	pci_mmcfg_reject_broken(early);
  	if (list_empty(&pci_mmcfg_list))
  		return;
  
  	if (pcibios_last_bus < 0) {
  		const struct pci_mmcfg_region *cfg;
  
  		list_for_each_entry(cfg, &pci_mmcfg_list, list) {
  			if (cfg->segment)
  				break;
  			pcibios_last_bus = cfg->end_bus;
  		}
  	}
  
  	if (pci_mmcfg_arch_init())
  		pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
  	else {
  		free_all_mmcfg();
  		pci_mmcfg_arch_init_failed = true;
  	}
  }
  
  static int __initdata known_bridge;
  
  void __init pci_mmcfg_early_init(void)
  {
  	if (pci_probe & PCI_PROBE_MMCONF) {
  		if (pci_mmcfg_check_hostbridge())
  			known_bridge = 1;
  		else
  			acpi_sfi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
  		__pci_mmcfg_init(1);
  	}
  }
  
  void __init pci_mmcfg_late_init(void)
  {
  	/* MMCONFIG disabled */
  	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
  		return;
  
  	if (known_bridge)
  		return;
  
  	/* MMCONFIG hasn't been enabled yet, try again */
  	if (pci_probe & PCI_PROBE_MASK & ~PCI_PROBE_MMCONF) {
  		acpi_sfi_table_parse(ACPI_SIG_MCFG, pci_parse_mcfg);
  		__pci_mmcfg_init(0);
  	}
  }
  
  static int __init pci_mmcfg_late_insert_resources(void)
  {
  	struct pci_mmcfg_region *cfg;
  
  	pci_mmcfg_running_state = true;
  
  	/* If we are not using MMCONFIG, don't insert the resources. */
  	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
  		return 1;
  
  	/*
  	 * Attempt to insert the mmcfg resources but not with the busy flag
  	 * marked so it won't cause request errors when __request_region is
  	 * called.
  	 */
  	list_for_each_entry(cfg, &pci_mmcfg_list, list)
  		if (!cfg->res.parent)
  			insert_resource(&iomem_resource, &cfg->res);
  
  	return 0;
  }
  
  /*
   * Perform MMCONFIG resource insertion after PCI initialization to allow for
   * misprogrammed MCFG tables that state larger sizes but actually conflict
   * with other system resources.
   */
  late_initcall(pci_mmcfg_late_insert_resources);
  
  /* Add MMCFG information for host bridges */
  int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
  			phys_addr_t addr)
  {
  	int rc;
  	struct resource *tmp = NULL;
  	struct pci_mmcfg_region *cfg;
  
  	if (!(pci_probe & PCI_PROBE_MMCONF) || pci_mmcfg_arch_init_failed)
  		return -ENODEV;
  
  	if (start > end)
  		return -EINVAL;
  
  	mutex_lock(&pci_mmcfg_lock);
  	cfg = pci_mmconfig_lookup(seg, start);
  	if (cfg) {
  		if (cfg->end_bus < end)
  			dev_info(dev, FW_INFO
  				 "MMCONFIG for "
  				 "domain %04x [bus %02x-%02x] "
  				 "only partially covers this bridge
  ",
  				  cfg->segment, cfg->start_bus, cfg->end_bus);
  		mutex_unlock(&pci_mmcfg_lock);
  		return -EEXIST;
  	}
  
  	if (!addr) {
  		mutex_unlock(&pci_mmcfg_lock);
  		return -EINVAL;
  	}
  
  	rc = -EBUSY;
  	cfg = pci_mmconfig_alloc(seg, start, end, addr);
  	if (cfg == NULL) {
  		dev_warn(dev, "fail to add MMCONFIG (out of memory)
  ");
  		rc = -ENOMEM;
  	} else if (!pci_mmcfg_check_reserved(dev, cfg, 0)) {
  		dev_warn(dev, FW_BUG "MMCONFIG %pR isn't reserved
  ",
  			 &cfg->res);
  	} else {
  		/* Insert resource if it's not in boot stage */
  		if (pci_mmcfg_running_state)
  			tmp = insert_resource_conflict(&iomem_resource,
  						       &cfg->res);
  
  		if (tmp) {
  			dev_warn(dev,
  				 "MMCONFIG %pR conflicts with "
  				 "%s %pR
  ",
  				 &cfg->res, tmp->name, tmp);
  		} else if (pci_mmcfg_arch_map(cfg)) {
  			dev_warn(dev, "fail to map MMCONFIG %pR.
  ",
  				 &cfg->res);
  		} else {
  			list_add_sorted(cfg);
  			dev_info(dev, "MMCONFIG at %pR (base %#lx)
  ",
  				 &cfg->res, (unsigned long)addr);
  			cfg = NULL;
  			rc = 0;
  		}
  	}
  
  	if (cfg) {
  		if (cfg->res.parent)
  			release_resource(&cfg->res);
  		kfree(cfg);
  	}
  
  	mutex_unlock(&pci_mmcfg_lock);
  
  	return rc;
  }
  
  /* Delete MMCFG information for host bridges */
  int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
  {
  	struct pci_mmcfg_region *cfg;
  
  	mutex_lock(&pci_mmcfg_lock);
  	list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
  		if (cfg->segment == seg && cfg->start_bus == start &&
  		    cfg->end_bus == end) {
  			list_del_rcu(&cfg->list);
  			synchronize_rcu();
  			pci_mmcfg_arch_unmap(cfg);
  			if (cfg->res.parent)
  				release_resource(&cfg->res);
  			mutex_unlock(&pci_mmcfg_lock);
  			kfree(cfg);
  			return 0;
  		}
  	mutex_unlock(&pci_mmcfg_lock);
  
  	return -ENOENT;
  }