Merge tag 'libnvdimm-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm

Pull libnvdimm subsystem from Dan Williams:
 "The libnvdimm sub-system introduces, in addition to the
  libnvdimm-core, 4 drivers / enabling modules:

  NFIT:
    Instantiates an "nvdimm bus" with the core and registers memory
    devices (NVDIMMs) enumerated by the ACPI 6.0 NFIT (NVDIMM Firmware
    Interface table).

    After registering NVDIMMs the NFIT driver then registers "region"
    devices.  A libnvdimm-region defines an access mode and the
    boundaries of persistent memory media.  A region may span multiple
    NVDIMMs that are interleaved by the hardware memory controller.  In
    turn, a libnvdimm-region can be carved into a "namespace" device and
    bound to the PMEM or BLK driver which will attach a Linux block
    device (disk) interface to the memory.

  PMEM:
    Initially merged in v4.1 this driver for contiguous spans of
    persistent memory address ranges is re-worked to drive
    PMEM-namespaces emitted by the libnvdimm-core.

    In this update the PMEM driver, on x86, gains the ability to assert
    that writes to persistent memory have been flushed all the way
    through the caches and buffers in the platform to persistent media.
    See memcpy_to_pmem() and wmb_pmem().

  BLK:
    This new driver enables access to persistent memory media through
    "Block Data Windows" as defined by the NFIT.  The primary difference
    of this driver to PMEM is that only a small window of persistent
    memory is mapped into system address space at any given point in
    time.

    Per-NVDIMM windows are reprogrammed at run time, per-I/O, to access
    different portions of the media.  BLK-mode, by definition, does not
    support DAX.

  BTT:
    This is a library, optionally consumed by either PMEM or BLK, that
    converts a byte-accessible namespace into a disk with atomic sector
    update semantics (prevents sector tearing on crash or power loss).

    The sinister aspect of sector tearing is that most applications do
    not know they have a atomic sector dependency.  At least today's
    disk's rarely ever tear sectors and if they do one almost certainly
    gets a CRC error on access.  NVDIMMs will always tear and always
    silently.  Until an application is audited to be robust in the
    presence of sector-tearing the usage of BTT is recommended.

  Thanks to: Ross Zwisler, Jeff Moyer, Vishal Verma, Christoph Hellwig,
  Ingo Molnar, Neil Brown, Boaz Harrosh, Robert Elliott, Matthew Wilcox,
  Andy Rudoff, Linda Knippers, Toshi Kani, Nicholas Moulin, Rafael
  Wysocki, and Bob Moore"

* tag 'libnvdimm-for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm: (33 commits)
  arch, x86: pmem api for ensuring durability of persistent memory updates
  libnvdimm: Add sysfs numa_node to NVDIMM devices
  libnvdimm: Set numa_node to NVDIMM devices
  acpi: Add acpi_map_pxm_to_online_node()
  libnvdimm, nfit: handle unarmed dimms, mark namespaces read-only
  pmem: flag pmem block devices as non-rotational
  libnvdimm: enable iostat
  pmem: make_request cleanups
  libnvdimm, pmem: fix up max_hw_sectors
  libnvdimm, blk: add support for blk integrity
  libnvdimm, btt: add support for blk integrity
  fs/block_dev.c: skip rw_page if bdev has integrity
  libnvdimm: Non-Volatile Devices
  tools/testing/nvdimm: libnvdimm unit test infrastructure
  libnvdimm, nfit, nd_blk: driver for BLK-mode access persistent memory
  nd_btt: atomic sector updates
  libnvdimm: infrastructure for btt devices
  libnvdimm: write blk label set
  libnvdimm: write pmem label set
  libnvdimm: blk labels and namespace instantiation
  ...

5 files changed, 1819 insertions, 3 deletions

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 35da507411a0..f15db002be8e 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -386,6 +386,32 @@ config ACPI_REDUCED_HARDWARE_ONLY
 
 	  If you are unsure what to do, do not enable this option.
 
+config ACPI_NFIT
+	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
+	depends on PHYS_ADDR_T_64BIT
+	depends on BLK_DEV
+	select LIBNVDIMM
+	help
+	  Infrastructure to probe ACPI 6 compliant platforms for
+	  NVDIMMs (NFIT) and register a libnvdimm device tree.  In
+	  addition to storage devices this also enables libnvdimm to pass
+	  ACPI._DSM messages for platform/dimm configuration.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called nfit.
+
+config ACPI_NFIT_DEBUG
+	bool "NFIT DSM debug"
+	depends on ACPI_NFIT
+	depends on DYNAMIC_DEBUG
+	default n
+	help
+	  Enabling this option causes the nfit driver to dump the
+	  input and output buffers of _DSM operations on the ACPI0012
+	  device and its children.  This can be very verbose, so leave
+	  it disabled unless you are debugging a hardware / firmware
+	  issue.
+
 source "drivers/acpi/apei/Kconfig"
 
 config ACPI_EXTLOG
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 73d840bef455..8321430d7f24 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_ACPI_PCI_SLOT)	+= pci_slot.o
 obj-$(CONFIG_ACPI_PROCESSOR)	+= processor.o
 obj-y				+= container.o
 obj-$(CONFIG_ACPI_THERMAL)	+= thermal.o
+obj-$(CONFIG_ACPI_NFIT)		+= nfit.o
 obj-y				+= acpi_memhotplug.o
 obj-$(CONFIG_ACPI_HOTPLUG_IOAPIC) += ioapic.o
 obj-$(CONFIG_ACPI_BATTERY)	+= battery.o
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
new file mode 100644
index 000000000000..2161fa178c8d
--- /dev/null
+++ b/drivers/acpi/nfit.c
@@ -0,0 +1,1587 @@
+/*
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#include <linux/list_sort.h>
+#include <linux/libnvdimm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/ndctl.h>
+#include <linux/list.h>
+#include <linux/acpi.h>
+#include <linux/sort.h>
+#include <linux/io.h>
+#include "nfit.h"
+
+/*
+ * For readq() and writeq() on 32-bit builds, the hi-lo, lo-hi order is
+ * irrelevant.
+ */
+#include <asm-generic/io-64-nonatomic-hi-lo.h>
+
+static bool force_enable_dimms;
+module_param(force_enable_dimms, bool, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(force_enable_dimms, "Ignore _STA (ACPI DIMM device) status");
+
+static u8 nfit_uuid[NFIT_UUID_MAX][16];
+
+const u8 *to_nfit_uuid(enum nfit_uuids id)
+{
+	return nfit_uuid[id];
+}
+EXPORT_SYMBOL(to_nfit_uuid);
+
+static struct acpi_nfit_desc *to_acpi_nfit_desc(
+		struct nvdimm_bus_descriptor *nd_desc)
+{
+	return container_of(nd_desc, struct acpi_nfit_desc, nd_desc);
+}
+
+static struct acpi_device *to_acpi_dev(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+
+	/*
+	 * If provider == 'ACPI.NFIT' we can assume 'dev' is a struct
+	 * acpi_device.
+	 */
+	if (!nd_desc->provider_name
+			|| strcmp(nd_desc->provider_name, "ACPI.NFIT") != 0)
+		return NULL;
+
+	return to_acpi_device(acpi_desc->dev);
+}
+
+static int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc,
+		struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+		unsigned int buf_len)
+{
+	struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
+	const struct nd_cmd_desc *desc = NULL;
+	union acpi_object in_obj, in_buf, *out_obj;
+	struct device *dev = acpi_desc->dev;
+	const char *cmd_name, *dimm_name;
+	unsigned long dsm_mask;
+	acpi_handle handle;
+	const u8 *uuid;
+	u32 offset;
+	int rc, i;
+
+	if (nvdimm) {
+		struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+		struct acpi_device *adev = nfit_mem->adev;
+
+		if (!adev)
+			return -ENOTTY;
+		dimm_name = nvdimm_name(nvdimm);
+		cmd_name = nvdimm_cmd_name(cmd);
+		dsm_mask = nfit_mem->dsm_mask;
+		desc = nd_cmd_dimm_desc(cmd);
+		uuid = to_nfit_uuid(NFIT_DEV_DIMM);
+		handle = adev->handle;
+	} else {
+		struct acpi_device *adev = to_acpi_dev(acpi_desc);
+
+		cmd_name = nvdimm_bus_cmd_name(cmd);
+		dsm_mask = nd_desc->dsm_mask;
+		desc = nd_cmd_bus_desc(cmd);
+		uuid = to_nfit_uuid(NFIT_DEV_BUS);
+		handle = adev->handle;
+		dimm_name = "bus";
+	}
+
+	if (!desc || (cmd && (desc->out_num + desc->in_num == 0)))
+		return -ENOTTY;
+
+	if (!test_bit(cmd, &dsm_mask))
+		return -ENOTTY;
+
+	in_obj.type = ACPI_TYPE_PACKAGE;
+	in_obj.package.count = 1;
+	in_obj.package.elements = &in_buf;
+	in_buf.type = ACPI_TYPE_BUFFER;
+	in_buf.buffer.pointer = buf;
+	in_buf.buffer.length = 0;
+
+	/* libnvdimm has already validated the input envelope */
+	for (i = 0; i < desc->in_num; i++)
+		in_buf.buffer.length += nd_cmd_in_size(nvdimm, cmd, desc,
+				i, buf);
+
+	if (IS_ENABLED(CONFIG_ACPI_NFIT_DEBUG)) {
+		dev_dbg(dev, "%s:%s cmd: %s input length: %d\n", __func__,
+				dimm_name, cmd_name, in_buf.buffer.length);
+		print_hex_dump_debug(cmd_name, DUMP_PREFIX_OFFSET, 4,
+				4, in_buf.buffer.pointer, min_t(u32, 128,
+					in_buf.buffer.length), true);
+	}
+
+	out_obj = acpi_evaluate_dsm(handle, uuid, 1, cmd, &in_obj);
+	if (!out_obj) {
+		dev_dbg(dev, "%s:%s _DSM failed cmd: %s\n", __func__, dimm_name,
+				cmd_name);
+		return -EINVAL;
+	}
+
+	if (out_obj->package.type != ACPI_TYPE_BUFFER) {
+		dev_dbg(dev, "%s:%s unexpected output object type cmd: %s type: %d\n",
+				__func__, dimm_name, cmd_name, out_obj->type);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	if (IS_ENABLED(CONFIG_ACPI_NFIT_DEBUG)) {
+		dev_dbg(dev, "%s:%s cmd: %s output length: %d\n", __func__,
+				dimm_name, cmd_name, out_obj->buffer.length);
+		print_hex_dump_debug(cmd_name, DUMP_PREFIX_OFFSET, 4,
+				4, out_obj->buffer.pointer, min_t(u32, 128,
+					out_obj->buffer.length), true);
+	}
+
+	for (i = 0, offset = 0; i < desc->out_num; i++) {
+		u32 out_size = nd_cmd_out_size(nvdimm, cmd, desc, i, buf,
+				(u32 *) out_obj->buffer.pointer);
+
+		if (offset + out_size > out_obj->buffer.length) {
+			dev_dbg(dev, "%s:%s output object underflow cmd: %s field: %d\n",
+					__func__, dimm_name, cmd_name, i);
+			break;
+		}
+
+		if (in_buf.buffer.length + offset + out_size > buf_len) {
+			dev_dbg(dev, "%s:%s output overrun cmd: %s field: %d\n",
+					__func__, dimm_name, cmd_name, i);
+			rc = -ENXIO;
+			goto out;
+		}
+		memcpy(buf + in_buf.buffer.length + offset,
+				out_obj->buffer.pointer + offset, out_size);
+		offset += out_size;
+	}
+	if (offset + in_buf.buffer.length < buf_len) {
+		if (i >= 1) {
+			/*
+			 * status valid, return the number of bytes left
+			 * unfilled in the output buffer
+			 */
+			rc = buf_len - offset - in_buf.buffer.length;
+		} else {
+			dev_err(dev, "%s:%s underrun cmd: %s buf_len: %d out_len: %d\n",
+					__func__, dimm_name, cmd_name, buf_len,
+					offset);
+			rc = -ENXIO;
+		}
+	} else
+		rc = 0;
+
+ out:
+	ACPI_FREE(out_obj);
+
+	return rc;
+}
+
+static const char *spa_type_name(u16 type)
+{
+	static const char *to_name[] = {
+		[NFIT_SPA_VOLATILE] = "volatile",
+		[NFIT_SPA_PM] = "pmem",
+		[NFIT_SPA_DCR] = "dimm-control-region",
+		[NFIT_SPA_BDW] = "block-data-window",
+		[NFIT_SPA_VDISK] = "volatile-disk",
+		[NFIT_SPA_VCD] = "volatile-cd",
+		[NFIT_SPA_PDISK] = "persistent-disk",
+		[NFIT_SPA_PCD] = "persistent-cd",
+
+	};
+
+	if (type > NFIT_SPA_PCD)
+		return "unknown";
+
+	return to_name[type];
+}
+
+static int nfit_spa_type(struct acpi_nfit_system_address *spa)
+{
+	int i;
+
+	for (i = 0; i < NFIT_UUID_MAX; i++)
+		if (memcmp(to_nfit_uuid(i), spa->range_guid, 16) == 0)
+			return i;
+	return -1;
+}
+
+static bool add_spa(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_system_address *spa)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa),
+			GFP_KERNEL);
+
+	if (!nfit_spa)
+		return false;
+	INIT_LIST_HEAD(&nfit_spa->list);
+	nfit_spa->spa = spa;
+	list_add_tail(&nfit_spa->list, &acpi_desc->spas);
+	dev_dbg(dev, "%s: spa index: %d type: %s\n", __func__,
+			spa->range_index,
+			spa_type_name(nfit_spa_type(spa)));
+	return true;
+}
+
+static bool add_memdev(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_memory_map *memdev)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_memdev *nfit_memdev = devm_kzalloc(dev,
+			sizeof(*nfit_memdev), GFP_KERNEL);
+
+	if (!nfit_memdev)
+		return false;
+	INIT_LIST_HEAD(&nfit_memdev->list);
+	nfit_memdev->memdev = memdev;
+	list_add_tail(&nfit_memdev->list, &acpi_desc->memdevs);
+	dev_dbg(dev, "%s: memdev handle: %#x spa: %d dcr: %d\n",
+			__func__, memdev->device_handle, memdev->range_index,
+			memdev->region_index);
+	return true;
+}
+
+static bool add_dcr(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_control_region *dcr)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_dcr *nfit_dcr = devm_kzalloc(dev, sizeof(*nfit_dcr),
+			GFP_KERNEL);
+
+	if (!nfit_dcr)
+		return false;
+	INIT_LIST_HEAD(&nfit_dcr->list);
+	nfit_dcr->dcr = dcr;
+	list_add_tail(&nfit_dcr->list, &acpi_desc->dcrs);
+	dev_dbg(dev, "%s: dcr index: %d windows: %d\n", __func__,
+			dcr->region_index, dcr->windows);
+	return true;
+}
+
+static bool add_bdw(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_data_region *bdw)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_bdw *nfit_bdw = devm_kzalloc(dev, sizeof(*nfit_bdw),
+			GFP_KERNEL);
+
+	if (!nfit_bdw)
+		return false;
+	INIT_LIST_HEAD(&nfit_bdw->list);
+	nfit_bdw->bdw = bdw;
+	list_add_tail(&nfit_bdw->list, &acpi_desc->bdws);
+	dev_dbg(dev, "%s: bdw dcr: %d windows: %d\n", __func__,
+			bdw->region_index, bdw->windows);
+	return true;
+}
+
+static bool add_idt(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_interleave *idt)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_idt *nfit_idt = devm_kzalloc(dev, sizeof(*nfit_idt),
+			GFP_KERNEL);
+
+	if (!nfit_idt)
+		return false;
+	INIT_LIST_HEAD(&nfit_idt->list);
+	nfit_idt->idt = idt;
+	list_add_tail(&nfit_idt->list, &acpi_desc->idts);
+	dev_dbg(dev, "%s: idt index: %d num_lines: %d\n", __func__,
+			idt->interleave_index, idt->line_count);
+	return true;
+}
+
+static void *add_table(struct acpi_nfit_desc *acpi_desc, void *table,
+		const void *end)
+{
+	struct device *dev = acpi_desc->dev;
+	struct acpi_nfit_header *hdr;
+	void *err = ERR_PTR(-ENOMEM);
+
+	if (table >= end)
+		return NULL;
+
+	hdr = table;
+	switch (hdr->type) {
+	case ACPI_NFIT_TYPE_SYSTEM_ADDRESS:
+		if (!add_spa(acpi_desc, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_MEMORY_MAP:
+		if (!add_memdev(acpi_desc, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_CONTROL_REGION:
+		if (!add_dcr(acpi_desc, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_DATA_REGION:
+		if (!add_bdw(acpi_desc, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_INTERLEAVE:
+		if (!add_idt(acpi_desc, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_FLUSH_ADDRESS:
+		dev_dbg(dev, "%s: flush\n", __func__);
+		break;
+	case ACPI_NFIT_TYPE_SMBIOS:
+		dev_dbg(dev, "%s: smbios\n", __func__);
+		break;
+	default:
+		dev_err(dev, "unknown table '%d' parsing nfit\n", hdr->type);
+		break;
+	}
+
+	return table + hdr->length;
+}
+
+static void nfit_mem_find_spa_bdw(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_mem *nfit_mem)
+{
+	u32 device_handle = __to_nfit_memdev(nfit_mem)->device_handle;
+	u16 dcr = nfit_mem->dcr->region_index;
+	struct nfit_spa *nfit_spa;
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		u16 range_index = nfit_spa->spa->range_index;
+		int type = nfit_spa_type(nfit_spa->spa);
+		struct nfit_memdev *nfit_memdev;
+
+		if (type != NFIT_SPA_BDW)
+			continue;
+
+		list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
+			if (nfit_memdev->memdev->range_index != range_index)
+				continue;
+			if (nfit_memdev->memdev->device_handle != device_handle)
+				continue;
+			if (nfit_memdev->memdev->region_index != dcr)
+				continue;
+
+			nfit_mem->spa_bdw = nfit_spa->spa;
+			return;
+		}
+	}
+
+	dev_dbg(acpi_desc->dev, "SPA-BDW not found for SPA-DCR %d\n",
+			nfit_mem->spa_dcr->range_index);
+	nfit_mem->bdw = NULL;
+}
+
+static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_mem *nfit_mem, struct acpi_nfit_system_address *spa)
+{
+	u16 dcr = __to_nfit_memdev(nfit_mem)->region_index;
+	struct nfit_memdev *nfit_memdev;
+	struct nfit_dcr *nfit_dcr;
+	struct nfit_bdw *nfit_bdw;
+	struct nfit_idt *nfit_idt;
+	u16 idt_idx, range_index;
+
+	list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
+		if (nfit_dcr->dcr->region_index != dcr)
+			continue;
+		nfit_mem->dcr = nfit_dcr->dcr;
+		break;
+	}
+
+	if (!nfit_mem->dcr) {
+		dev_dbg(acpi_desc->dev, "SPA %d missing:%s%s\n",
+				spa->range_index, __to_nfit_memdev(nfit_mem)
+				? "" : " MEMDEV", nfit_mem->dcr ? "" : " DCR");
+		return -ENODEV;
+	}
+
+	/*
+	 * We've found enough to create an nvdimm, optionally
+	 * find an associated BDW
+	 */
+	list_add(&nfit_mem->list, &acpi_desc->dimms);
+
+	list_for_each_entry(nfit_bdw, &acpi_desc->bdws, list) {
+		if (nfit_bdw->bdw->region_index != dcr)
+			continue;
+		nfit_mem->bdw = nfit_bdw->bdw;
+		break;
+	}
+
+	if (!nfit_mem->bdw)
+		return 0;
+
+	nfit_mem_find_spa_bdw(acpi_desc, nfit_mem);
+
+	if (!nfit_mem->spa_bdw)
+		return 0;
+
+	range_index = nfit_mem->spa_bdw->range_index;
+	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
+		if (nfit_memdev->memdev->range_index != range_index ||
+				nfit_memdev->memdev->region_index != dcr)
+			continue;
+		nfit_mem->memdev_bdw = nfit_memdev->memdev;
+		idt_idx = nfit_memdev->memdev->interleave_index;
+		list_for_each_entry(nfit_idt, &acpi_desc->idts, list) {
+			if (nfit_idt->idt->interleave_index != idt_idx)
+				continue;
+			nfit_mem->idt_bdw = nfit_idt->idt;
+			break;
+		}
+		break;
+	}
+
+	return 0;
+}
+
+static int nfit_mem_dcr_init(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_system_address *spa)
+{
+	struct nfit_mem *nfit_mem, *found;
+	struct nfit_memdev *nfit_memdev;
+	int type = nfit_spa_type(spa);
+	u16 dcr;
+
+	switch (type) {
+	case NFIT_SPA_DCR:
+	case NFIT_SPA_PM:
+		break;
+	default:
+		return 0;
+	}
+
+	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
+		int rc;
+
+		if (nfit_memdev->memdev->range_index != spa->range_index)
+			continue;
+		found = NULL;
+		dcr = nfit_memdev->memdev->region_index;
+		list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
+			if (__to_nfit_memdev(nfit_mem)->region_index == dcr) {
+				found = nfit_mem;
+				break;
+			}
+
+		if (found)
+			nfit_mem = found;
+		else {
+			nfit_mem = devm_kzalloc(acpi_desc->dev,
+					sizeof(*nfit_mem), GFP_KERNEL);
+			if (!nfit_mem)
+				return -ENOMEM;
+			INIT_LIST_HEAD(&nfit_mem->list);
+		}
+
+		if (type == NFIT_SPA_DCR) {
+			struct nfit_idt *nfit_idt;
+			u16 idt_idx;
+
+			/* multiple dimms may share a SPA when interleaved */
+			nfit_mem->spa_dcr = spa;
+			nfit_mem->memdev_dcr = nfit_memdev->memdev;
+			idt_idx = nfit_memdev->memdev->interleave_index;
+			list_for_each_entry(nfit_idt, &acpi_desc->idts, list) {
+				if (nfit_idt->idt->interleave_index != idt_idx)
+					continue;
+				nfit_mem->idt_dcr = nfit_idt->idt;
+				break;
+			}
+		} else {
+			/*
+			 * A single dimm may belong to multiple SPA-PM
+			 * ranges, record at least one in addition to
+			 * any SPA-DCR range.
+			 */
+			nfit_mem->memdev_pmem = nfit_memdev->memdev;
+		}
+
+		if (found)
+			continue;
+
+		rc = nfit_mem_add(acpi_desc, nfit_mem, spa);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+static int nfit_mem_cmp(void *priv, struct list_head *_a, struct list_head *_b)
+{
+	struct nfit_mem *a = container_of(_a, typeof(*a), list);
+	struct nfit_mem *b = container_of(_b, typeof(*b), list);
+	u32 handleA, handleB;
+
+	handleA = __to_nfit_memdev(a)->device_handle;
+	handleB = __to_nfit_memdev(b)->device_handle;
+	if (handleA < handleB)
+		return -1;
+	else if (handleA > handleB)
+		return 1;
+	return 0;
+}
+
+static int nfit_mem_init(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nfit_spa *nfit_spa;
+
+	/*
+	 * For each SPA-DCR or SPA-PMEM address range find its
+	 * corresponding MEMDEV(s).  From each MEMDEV find the
+	 * corresponding DCR.  Then, if we're operating on a SPA-DCR,
+	 * try to find a SPA-BDW and a corresponding BDW that references
+	 * the DCR.  Throw it all into an nfit_mem object.  Note, that
+	 * BDWs are optional.
+	 */
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		int rc;
+
+		rc = nfit_mem_dcr_init(acpi_desc, nfit_spa->spa);
+		if (rc)
+			return rc;
+	}
+
+	list_sort(NULL, &acpi_desc->dimms, nfit_mem_cmp);
+
+	return 0;
+}
+
+static ssize_t revision_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+	return sprintf(buf, "%d\n", acpi_desc->nfit->header.revision);
+}
+static DEVICE_ATTR_RO(revision);
+
+static struct attribute *acpi_nfit_attributes[] = {
+	&dev_attr_revision.attr,
+	NULL,
+};
+
+static struct attribute_group acpi_nfit_attribute_group = {
+	.name = "nfit",
+	.attrs = acpi_nfit_attributes,
+};
+
+const struct attribute_group *acpi_nfit_attribute_groups[] = {
+	&nvdimm_bus_attribute_group,
+	&acpi_nfit_attribute_group,
+	NULL,
+};
+EXPORT_SYMBOL_GPL(acpi_nfit_attribute_groups);
+
+static struct acpi_nfit_memory_map *to_nfit_memdev(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+
+	return __to_nfit_memdev(nfit_mem);
+}
+
+static struct acpi_nfit_control_region *to_nfit_dcr(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+
+	return nfit_mem->dcr;
+}
+
+static ssize_t handle_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_memory_map *memdev = to_nfit_memdev(dev);
+
+	return sprintf(buf, "%#x\n", memdev->device_handle);
+}
+static DEVICE_ATTR_RO(handle);
+
+static ssize_t phys_id_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_memory_map *memdev = to_nfit_memdev(dev);
+
+	return sprintf(buf, "%#x\n", memdev->physical_id);
+}
+static DEVICE_ATTR_RO(phys_id);
+
+static ssize_t vendor_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	return sprintf(buf, "%#x\n", dcr->vendor_id);
+}
+static DEVICE_ATTR_RO(vendor);
+
+static ssize_t rev_id_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	return sprintf(buf, "%#x\n", dcr->revision_id);
+}
+static DEVICE_ATTR_RO(rev_id);
+
+static ssize_t device_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	return sprintf(buf, "%#x\n", dcr->device_id);
+}
+static DEVICE_ATTR_RO(device);
+
+static ssize_t format_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	return sprintf(buf, "%#x\n", dcr->code);
+}
+static DEVICE_ATTR_RO(format);
+
+static ssize_t serial_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	return sprintf(buf, "%#x\n", dcr->serial_number);
+}
+static DEVICE_ATTR_RO(serial);
+
+static ssize_t flags_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	u16 flags = to_nfit_memdev(dev)->flags;
+
+	return sprintf(buf, "%s%s%s%s%s\n",
+			flags & ACPI_NFIT_MEM_SAVE_FAILED ? "save " : "",
+			flags & ACPI_NFIT_MEM_RESTORE_FAILED ? "restore " : "",
+			flags & ACPI_NFIT_MEM_FLUSH_FAILED ? "flush " : "",
+			flags & ACPI_NFIT_MEM_ARMED ? "arm " : "",
+			flags & ACPI_NFIT_MEM_HEALTH_OBSERVED ? "smart " : "");
+}
+static DEVICE_ATTR_RO(flags);
+
+static struct attribute *acpi_nfit_dimm_attributes[] = {
+	&dev_attr_handle.attr,
+	&dev_attr_phys_id.attr,
+	&dev_attr_vendor.attr,
+	&dev_attr_device.attr,
+	&dev_attr_format.attr,
+	&dev_attr_serial.attr,
+	&dev_attr_rev_id.attr,
+	&dev_attr_flags.attr,
+	NULL,
+};
+
+static umode_t acpi_nfit_dimm_attr_visible(struct kobject *kobj,
+		struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+
+	if (to_nfit_dcr(dev))
+		return a->mode;
+	else
+		return 0;
+}
+
+static struct attribute_group acpi_nfit_dimm_attribute_group = {
+	.name = "nfit",
+	.attrs = acpi_nfit_dimm_attributes,
+	.is_visible = acpi_nfit_dimm_attr_visible,
+};
+
+static const struct attribute_group *acpi_nfit_dimm_attribute_groups[] = {
+	&nvdimm_attribute_group,
+	&nd_device_attribute_group,
+	&acpi_nfit_dimm_attribute_group,
+	NULL,
+};
+
+static struct nvdimm *acpi_nfit_dimm_by_handle(struct acpi_nfit_desc *acpi_desc,
+		u32 device_handle)
+{
+	struct nfit_mem *nfit_mem;
+
+	list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
+		if (__to_nfit_memdev(nfit_mem)->device_handle == device_handle)
+			return nfit_mem->nvdimm;
+
+	return NULL;
+}
+
+static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_mem *nfit_mem, u32 device_handle)
+{
+	struct acpi_device *adev, *adev_dimm;
+	struct device *dev = acpi_desc->dev;
+	const u8 *uuid = to_nfit_uuid(NFIT_DEV_DIMM);
+	unsigned long long sta;
+	int i, rc = -ENODEV;
+	acpi_status status;
+
+	nfit_mem->dsm_mask = acpi_desc->dimm_dsm_force_en;
+	adev = to_acpi_dev(acpi_desc);
+	if (!adev)
+		return 0;
+
+	adev_dimm = acpi_find_child_device(adev, device_handle, false);
+	nfit_mem->adev = adev_dimm;
+	if (!adev_dimm) {
+		dev_err(dev, "no ACPI.NFIT device with _ADR %#x, disabling...\n",
+				device_handle);
+		return force_enable_dimms ? 0 : -ENODEV;
+	}
+
+	status = acpi_evaluate_integer(adev_dimm->handle, "_STA", NULL, &sta);
+	if (status == AE_NOT_FOUND) {
+		dev_dbg(dev, "%s missing _STA, assuming enabled...\n",
+				dev_name(&adev_dimm->dev));
+		rc = 0;
+	} else if (ACPI_FAILURE(status))
+		dev_err(dev, "%s failed to retrieve_STA, disabling...\n",
+				dev_name(&adev_dimm->dev));
+	else if ((sta & ACPI_STA_DEVICE_ENABLED) == 0)
+		dev_info(dev, "%s disabled by firmware\n",
+				dev_name(&adev_dimm->dev));
+	else
+		rc = 0;
+
+	for (i = ND_CMD_SMART; i <= ND_CMD_VENDOR; i++)
+		if (acpi_check_dsm(adev_dimm->handle, uuid, 1, 1ULL << i))
+			set_bit(i, &nfit_mem->dsm_mask);
+
+	return force_enable_dimms ? 0 : rc;
+}
+
+static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nfit_mem *nfit_mem;
+	int dimm_count = 0;
+
+	list_for_each_entry(nfit_mem, &acpi_desc->dimms, list) {
+		struct nvdimm *nvdimm;
+		unsigned long flags = 0;
+		u32 device_handle;
+		u16 mem_flags;
+		int rc;
+
+		device_handle = __to_nfit_memdev(nfit_mem)->device_handle;
+		nvdimm = acpi_nfit_dimm_by_handle(acpi_desc, device_handle);
+		if (nvdimm) {
+			/*
+			 * If for some reason we find multiple DCRs the
+			 * first one wins
+			 */
+			dev_err(acpi_desc->dev, "duplicate DCR detected: %s\n",
+					nvdimm_name(nvdimm));
+			continue;
+		}
+
+		if (nfit_mem->bdw && nfit_mem->memdev_pmem)
+			flags |= NDD_ALIASING;
+
+		mem_flags = __to_nfit_memdev(nfit_mem)->flags;
+		if (mem_flags & ACPI_NFIT_MEM_ARMED)
+			flags |= NDD_UNARMED;
+
+		rc = acpi_nfit_add_dimm(acpi_desc, nfit_mem, device_handle);
+		if (rc)
+			continue;
+
+		nvdimm = nvdimm_create(acpi_desc->nvdimm_bus, nfit_mem,
+				acpi_nfit_dimm_attribute_groups,
+				flags, &nfit_mem->dsm_mask);
+		if (!nvdimm)
+			return -ENOMEM;
+
+		nfit_mem->nvdimm = nvdimm;
+		dimm_count++;
+
+		if ((mem_flags & ACPI_NFIT_MEM_FAILED_MASK) == 0)
+			continue;
+
+		dev_info(acpi_desc->dev, "%s: failed: %s%s%s%s\n",
+				nvdimm_name(nvdimm),
+			mem_flags & ACPI_NFIT_MEM_SAVE_FAILED ? "save " : "",
+			mem_flags & ACPI_NFIT_MEM_RESTORE_FAILED ? "restore " : "",
+			mem_flags & ACPI_NFIT_MEM_FLUSH_FAILED ? "flush " : "",
+			mem_flags & ACPI_NFIT_MEM_ARMED ? "arm " : "");
+
+	}
+
+	return nvdimm_bus_check_dimm_count(acpi_desc->nvdimm_bus, dimm_count);
+}
+
+static void acpi_nfit_init_dsms(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+	const u8 *uuid = to_nfit_uuid(NFIT_DEV_BUS);
+	struct acpi_device *adev;
+	int i;
+
+	adev = to_acpi_dev(acpi_desc);
+	if (!adev)
+		return;
+
+	for (i = ND_CMD_ARS_CAP; i <= ND_CMD_ARS_STATUS; i++)
+		if (acpi_check_dsm(adev->handle, uuid, 1, 1ULL << i))
+			set_bit(i, &nd_desc->dsm_mask);
+}
+
+static ssize_t range_index_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nd_region *nd_region = to_nd_region(dev);
+	struct nfit_spa *nfit_spa = nd_region_provider_data(nd_region);
+
+	return sprintf(buf, "%d\n", nfit_spa->spa->range_index);
+}
+static DEVICE_ATTR_RO(range_index);
+
+static struct attribute *acpi_nfit_region_attributes[] = {
+	&dev_attr_range_index.attr,
+	NULL,
+};
+
+static struct attribute_group acpi_nfit_region_attribute_group = {
+	.name = "nfit",
+	.attrs = acpi_nfit_region_attributes,
+};
+
+static const struct attribute_group *acpi_nfit_region_attribute_groups[] = {
+	&nd_region_attribute_group,
+	&nd_mapping_attribute_group,
+	&nd_device_attribute_group,
+	&nd_numa_attribute_group,
+	&acpi_nfit_region_attribute_group,
+	NULL,
+};
+
+/* enough info to uniquely specify an interleave set */
+struct nfit_set_info {
+	struct nfit_set_info_map {
+		u64 region_offset;
+		u32 serial_number;
+		u32 pad;
+	} mapping[0];
+};
+
+static size_t sizeof_nfit_set_info(int num_mappings)
+{
+	return sizeof(struct nfit_set_info)
+		+ num_mappings * sizeof(struct nfit_set_info_map);
+}
+
+static int cmp_map(const void *m0, const void *m1)
+{
+	const struct nfit_set_info_map *map0 = m0;
+	const struct nfit_set_info_map *map1 = m1;
+
+	return memcmp(&map0->region_offset, &map1->region_offset,
+			sizeof(u64));
+}
+
+/* Retrieve the nth entry referencing this spa */
+static struct acpi_nfit_memory_map *memdev_from_spa(
+		struct acpi_nfit_desc *acpi_desc, u16 range_index, int n)
+{
+	struct nfit_memdev *nfit_memdev;
+
+	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list)
+		if (nfit_memdev->memdev->range_index == range_index)
+			if (n-- == 0)
+				return nfit_memdev->memdev;
+	return NULL;
+}
+
+static int acpi_nfit_init_interleave_set(struct acpi_nfit_desc *acpi_desc,
+		struct nd_region_desc *ndr_desc,
+		struct acpi_nfit_system_address *spa)
+{
+	int i, spa_type = nfit_spa_type(spa);
+	struct device *dev = acpi_desc->dev;
+	struct nd_interleave_set *nd_set;
+	u16 nr = ndr_desc->num_mappings;
+	struct nfit_set_info *info;
+
+	if (spa_type == NFIT_SPA_PM || spa_type == NFIT_SPA_VOLATILE)
+		/* pass */;
+	else
+		return 0;
+
+	nd_set = devm_kzalloc(dev, sizeof(*nd_set), GFP_KERNEL);
+	if (!nd_set)
+		return -ENOMEM;
+
+	info = devm_kzalloc(dev, sizeof_nfit_set_info(nr), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	for (i = 0; i < nr; i++) {
+		struct nd_mapping *nd_mapping = &ndr_desc->nd_mapping[i];
+		struct nfit_set_info_map *map = &info->mapping[i];
+		struct nvdimm *nvdimm = nd_mapping->nvdimm;
+		struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+		struct acpi_nfit_memory_map *memdev = memdev_from_spa(acpi_desc,
+				spa->range_index, i);
+
+		if (!memdev || !nfit_mem->dcr) {
+			dev_err(dev, "%s: failed to find DCR\n", __func__);
+			return -ENODEV;
+		}
+
+		map->region_offset = memdev->region_offset;
+		map->serial_number = nfit_mem->dcr->serial_number;
+	}
+
+	sort(&info->mapping[0], nr, sizeof(struct nfit_set_info_map),
+			cmp_map, NULL);
+	nd_set->cookie = nd_fletcher64(info, sizeof_nfit_set_info(nr), 0);
+	ndr_desc->nd_set = nd_set;
+	devm_kfree(dev, info);
+
+	return 0;
+}
+
+static u64 to_interleave_offset(u64 offset, struct nfit_blk_mmio *mmio)
+{
+	struct acpi_nfit_interleave *idt = mmio->idt;
+	u32 sub_line_offset, line_index, line_offset;
+	u64 line_no, table_skip_count, table_offset;
+
+	line_no = div_u64_rem(offset, mmio->line_size, &sub_line_offset);
+	table_skip_count = div_u64_rem(line_no, mmio->num_lines, &line_index);
+	line_offset = idt->line_offset[line_index]
+		* mmio->line_size;
+	table_offset = table_skip_count * mmio->table_size;
+
+	return mmio->base_offset + line_offset + table_offset + sub_line_offset;
+}
+
+static u64 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
+{
+	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
+	u64 offset = nfit_blk->stat_offset + mmio->size * bw;
+
+	if (mmio->num_lines)
+		offset = to_interleave_offset(offset, mmio);
+
+	return readq(mmio->base + offset);
+}
+
+static void write_blk_ctl(struct nfit_blk *nfit_blk, unsigned int bw,
+		resource_size_t dpa, unsigned int len, unsigned int write)
+{
+	u64 cmd, offset;
+	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
+
+	enum {
+		BCW_OFFSET_MASK = (1ULL << 48)-1,
+		BCW_LEN_SHIFT = 48,
+		BCW_LEN_MASK = (1ULL << 8) - 1,
+		BCW_CMD_SHIFT = 56,
+	};
+
+	cmd = (dpa >> L1_CACHE_SHIFT) & BCW_OFFSET_MASK;
+	len = len >> L1_CACHE_SHIFT;
+	cmd |= ((u64) len & BCW_LEN_MASK) << BCW_LEN_SHIFT;
+	cmd |= ((u64) write) << BCW_CMD_SHIFT;
+
+	offset = nfit_blk->cmd_offset + mmio->size * bw;
+	if (mmio->num_lines)
+		offset = to_interleave_offset(offset, mmio);
+
+	writeq(cmd, mmio->base + offset);
+	/* FIXME: conditionally perform read-back if mandated by firmware */
+}
+
+static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk,
+		resource_size_t dpa, void *iobuf, size_t len, int rw,
+		unsigned int lane)
+{
+	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[BDW];
+	unsigned int copied = 0;
+	u64 base_offset;
+	int rc;
+
+	base_offset = nfit_blk->bdw_offset + dpa % L1_CACHE_BYTES
+		+ lane * mmio->size;
+	/* TODO: non-temporal access, flush hints, cache management etc... */
+	write_blk_ctl(nfit_blk, lane, dpa, len, rw);
+	while (len) {
+		unsigned int c;
+		u64 offset;
+
+		if (mmio->num_lines) {
+			u32 line_offset;
+
+			offset = to_interleave_offset(base_offset + copied,
+					mmio);
+			div_u64_rem(offset, mmio->line_size, &line_offset);
+			c = min_t(size_t, len, mmio->line_size - line_offset);
+		} else {
+			offset = base_offset + nfit_blk->bdw_offset;
+			c = len;
+		}
+
+		if (rw)
+			memcpy(mmio->aperture + offset, iobuf + copied, c);
+		else
+			memcpy(iobuf + copied, mmio->aperture + offset, c);
+
+		copied += c;
+		len -= c;
+	}
+	rc = read_blk_stat(nfit_blk, lane) ? -EIO : 0;
+	return rc;
+}
+
+static int acpi_nfit_blk_region_do_io(struct nd_blk_region *ndbr,
+		resource_size_t dpa, void *iobuf, u64 len, int rw)
+{
+	struct nfit_blk *nfit_blk = nd_blk_region_provider_data(ndbr);
+	struct nfit_blk_mmio *mmio = &nfit_blk->mmio[BDW];
+	struct nd_region *nd_region = nfit_blk->nd_region;
+	unsigned int lane, copied = 0;
+	int rc = 0;
+
+	lane = nd_region_acquire_lane(nd_region);
+	while (len) {
+		u64 c = min(len, mmio->size);
+
+		rc = acpi_nfit_blk_single_io(nfit_blk, dpa + copied,
+				iobuf + copied, c, rw, lane);
+		if (rc)
+			break;
+
+		copied += c;
+		len -= c;
+	}
+	nd_region_release_lane(nd_region, lane);
+
+	return rc;
+}
+
+static void nfit_spa_mapping_release(struct kref *kref)
+{
+	struct nfit_spa_mapping *spa_map = to_spa_map(kref);
+	struct acpi_nfit_system_address *spa = spa_map->spa;
+	struct acpi_nfit_desc *acpi_desc = spa_map->acpi_desc;
+
+	WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
+	dev_dbg(acpi_desc->dev, "%s: SPA%d\n", __func__, spa->range_index);
+	iounmap(spa_map->iomem);
+	release_mem_region(spa->address, spa->length);
+	list_del(&spa_map->list);
+	kfree(spa_map);
+}
+
+static struct nfit_spa_mapping *find_spa_mapping(
+		struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_system_address *spa)
+{
+	struct nfit_spa_mapping *spa_map;
+
+	WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
+	list_for_each_entry(spa_map, &acpi_desc->spa_maps, list)
+		if (spa_map->spa == spa)
+			return spa_map;
+
+	return NULL;
+}
+
+static void nfit_spa_unmap(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_system_address *spa)
+{
+	struct nfit_spa_mapping *spa_map;
+
+	mutex_lock(&acpi_desc->spa_map_mutex);
+	spa_map = find_spa_mapping(acpi_desc, spa);
+
+	if (spa_map)
+		kref_put(&spa_map->kref, nfit_spa_mapping_release);
+	mutex_unlock(&acpi_desc->spa_map_mutex);
+}
+
+static void __iomem *__nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_system_address *spa)
+{
+	resource_size_t start = spa->address;
+	resource_size_t n = spa->length;
+	struct nfit_spa_mapping *spa_map;
+	struct resource *res;
+
+	WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
+
+	spa_map = find_spa_mapping(acpi_desc, spa);
+	if (spa_map) {
+		kref_get(&spa_map->kref);
+		return spa_map->iomem;
+	}
+
+	spa_map = kzalloc(sizeof(*spa_map), GFP_KERNEL);
+	if (!spa_map)
+		return NULL;
+
+	INIT_LIST_HEAD(&spa_map->list);
+	spa_map->spa = spa;
+	kref_init(&spa_map->kref);
+	spa_map->acpi_desc = acpi_desc;
+
+	res = request_mem_region(start, n, dev_name(acpi_desc->dev));
+	if (!res)
+		goto err_mem;
+
+	/* TODO: cacheability based on the spa type */
+	spa_map->iomem = ioremap_nocache(start, n);
+	if (!spa_map->iomem)
+		goto err_map;
+
+	list_add_tail(&spa_map->list, &acpi_desc->spa_maps);
+	return spa_map->iomem;
+
+ err_map:
+	release_mem_region(start, n);
+ err_mem:
+	kfree(spa_map);
+	return NULL;
+}
+
+/**
+ * nfit_spa_map - interleave-aware managed-mappings of acpi_nfit_system_address ranges
+ * @nvdimm_bus: NFIT-bus that provided the spa table entry
+ * @nfit_spa: spa table to map
+ *
+ * In the case where block-data-window apertures and
+ * dimm-control-regions are interleaved they will end up sharing a
+ * single request_mem_region() + ioremap() for the address range.  In
+ * the style of devm nfit_spa_map() mappings are automatically dropped
+ * when all region devices referencing the same mapping are disabled /
+ * unbound.
+ */
+static void __iomem *nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
+		struct acpi_nfit_system_address *spa)
+{
+	void __iomem *iomem;
+
+	mutex_lock(&acpi_desc->spa_map_mutex);
+	iomem = __nfit_spa_map(acpi_desc, spa);
+	mutex_unlock(&acpi_desc->spa_map_mutex);
+
+	return iomem;
+}
+
+static int nfit_blk_init_interleave(struct nfit_blk_mmio *mmio,
+		struct acpi_nfit_interleave *idt, u16 interleave_ways)
+{
+	if (idt) {
+		mmio->num_lines = idt->line_count;
+		mmio->line_size = idt->line_size;
+		if (interleave_ways == 0)
+			return -ENXIO;
+		mmio->table_size = mmio->num_lines * interleave_ways
+			* mmio->line_size;
+	}
+
+	return 0;
+}
+
+static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
+		struct device *dev)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+	struct nd_blk_region *ndbr = to_nd_blk_region(dev);
+	struct nfit_blk_mmio *mmio;
+	struct nfit_blk *nfit_blk;
+	struct nfit_mem *nfit_mem;
+	struct nvdimm *nvdimm;
+	int rc;
+
+	nvdimm = nd_blk_region_to_dimm(ndbr);
+	nfit_mem = nvdimm_provider_data(nvdimm);
+	if (!nfit_mem || !nfit_mem->dcr || !nfit_mem->bdw) {
+		dev_dbg(dev, "%s: missing%s%s%s\n", __func__,
+				nfit_mem ? "" : " nfit_mem",
+				nfit_mem->dcr ? "" : " dcr",
+				nfit_mem->bdw ? "" : " bdw");
+		return -ENXIO;
+	}
+
+	nfit_blk = devm_kzalloc(dev, sizeof(*nfit_blk), GFP_KERNEL);
+	if (!nfit_blk)
+		return -ENOMEM;
+	nd_blk_region_set_provider_data(ndbr, nfit_blk);
+	nfit_blk->nd_region = to_nd_region(dev);
+
+	/* map block aperture memory */
+	nfit_blk->bdw_offset = nfit_mem->bdw->offset;
+	mmio = &nfit_blk->mmio[BDW];
+	mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_bdw);
+	if (!mmio->base) {
+		dev_dbg(dev, "%s: %s failed to map bdw\n", __func__,
+				nvdimm_name(nvdimm));
+		return -ENOMEM;
+	}
+	mmio->size = nfit_mem->bdw->size;
+	mmio->base_offset = nfit_mem->memdev_bdw->region_offset;
+	mmio->idt = nfit_mem->idt_bdw;
+	mmio->spa = nfit_mem->spa_bdw;
+	rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_bdw,
+			nfit_mem->memdev_bdw->interleave_ways);
+	if (rc) {
+		dev_dbg(dev, "%s: %s failed to init bdw interleave\n",
+				__func__, nvdimm_name(nvdimm));
+		return rc;
+	}
+
+	/* map block control memory */
+	nfit_blk->cmd_offset = nfit_mem->dcr->command_offset;
+	nfit_blk->stat_offset = nfit_mem->dcr->status_offset;
+	mmio = &nfit_blk->mmio[DCR];
+	mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_dcr);
+	if (!mmio->base) {
+		dev_dbg(dev, "%s: %s failed to map dcr\n", __func__,
+				nvdimm_name(nvdimm));
+		return -ENOMEM;
+	}
+	mmio->size = nfit_mem->dcr->window_size;
+	mmio->base_offset = nfit_mem->memdev_dcr->region_offset;
+	mmio->idt = nfit_mem->idt_dcr;
+	mmio->spa = nfit_mem->spa_dcr;
+	rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_dcr,
+			nfit_mem->memdev_dcr->interleave_ways);
+	if (rc) {
+		dev_dbg(dev, "%s: %s failed to init dcr interleave\n",
+				__func__, nvdimm_name(nvdimm));
+		return rc;
+	}
+
+	if (mmio->line_size == 0)
+		return 0;
+
+	if ((u32) nfit_blk->cmd_offset % mmio->line_size
+			+ 8 > mmio->line_size) {
+		dev_dbg(dev, "cmd_offset crosses interleave boundary\n");
+		return -ENXIO;
+	} else if ((u32) nfit_blk->stat_offset % mmio->line_size
+			+ 8 > mmio->line_size) {
+		dev_dbg(dev, "stat_offset crosses interleave boundary\n");
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static void acpi_nfit_blk_region_disable(struct nvdimm_bus *nvdimm_bus,
+		struct device *dev)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+	struct nd_blk_region *ndbr = to_nd_blk_region(dev);
+	struct nfit_blk *nfit_blk = nd_blk_region_provider_data(ndbr);
+	int i;
+
+	if (!nfit_blk)
+		return; /* never enabled */
+
+	/* auto-free BLK spa mappings */
+	for (i = 0; i < 2; i++) {
+		struct nfit_blk_mmio *mmio = &nfit_blk->mmio[i];
+
+		if (mmio->base)
+			nfit_spa_unmap(acpi_desc, mmio->spa);
+	}
+	nd_blk_region_set_provider_data(ndbr, NULL);
+	/* devm will free nfit_blk */
+}
+
+static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
+		struct nd_mapping *nd_mapping, struct nd_region_desc *ndr_desc,
+		struct acpi_nfit_memory_map *memdev,
+		struct acpi_nfit_system_address *spa)
+{
+	struct nvdimm *nvdimm = acpi_nfit_dimm_by_handle(acpi_desc,
+			memdev->device_handle);
+	struct nd_blk_region_desc *ndbr_desc;
+	struct nfit_mem *nfit_mem;
+	int blk_valid = 0;
+
+	if (!nvdimm) {
+		dev_err(acpi_desc->dev, "spa%d dimm: %#x not found\n",
+				spa->range_index, memdev->device_handle);
+		return -ENODEV;
+	}
+
+	nd_mapping->nvdimm = nvdimm;
+	switch (nfit_spa_type(spa)) {
+	case NFIT_SPA_PM:
+	case NFIT_SPA_VOLATILE:
+		nd_mapping->start = memdev->address;
+		nd_mapping->size = memdev->region_size;
+		break;
+	case NFIT_SPA_DCR:
+		nfit_mem = nvdimm_provider_data(nvdimm);
+		if (!nfit_mem || !nfit_mem->bdw) {
+			dev_dbg(acpi_desc->dev, "spa%d %s missing bdw\n",
+					spa->range_index, nvdimm_name(nvdimm));
+		} else {
+			nd_mapping->size = nfit_mem->bdw->capacity;
+			nd_mapping->start = nfit_mem->bdw->start_address;
+			ndr_desc->num_lanes = nfit_mem->bdw->windows;
+			blk_valid = 1;
+		}
+
+		ndr_desc->nd_mapping = nd_mapping;
+		ndr_desc->num_mappings = blk_valid;
+		ndbr_desc = to_blk_region_desc(ndr_desc);
+		ndbr_desc->enable = acpi_nfit_blk_region_enable;
+		ndbr_desc->disable = acpi_nfit_blk_region_disable;
+		ndbr_desc->do_io = acpi_desc->blk_do_io;
+		if (!nvdimm_blk_region_create(acpi_desc->nvdimm_bus, ndr_desc))
+			return -ENOMEM;
+		break;
+	}
+
+	return 0;
+}
+
+static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_spa *nfit_spa)
+{
+	static struct nd_mapping nd_mappings[ND_MAX_MAPPINGS];
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	struct nd_blk_region_desc ndbr_desc;
+	struct nd_region_desc *ndr_desc;
+	struct nfit_memdev *nfit_memdev;
+	struct nvdimm_bus *nvdimm_bus;
+	struct resource res;
+	int count = 0, rc;
+
+	if (spa->range_index == 0) {
+		dev_dbg(acpi_desc->dev, "%s: detected invalid spa index\n",
+				__func__);
+		return 0;
+	}
+
+	memset(&res, 0, sizeof(res));
+	memset(&nd_mappings, 0, sizeof(nd_mappings));
+	memset(&ndbr_desc, 0, sizeof(ndbr_desc));
+	res.start = spa->address;
+	res.end = res.start + spa->length - 1;
+	ndr_desc = &ndbr_desc.ndr_desc;
+	ndr_desc->res = &res;
+	ndr_desc->provider_data = nfit_spa;
+	ndr_desc->attr_groups = acpi_nfit_region_attribute_groups;
+	if (spa->flags & ACPI_NFIT_PROXIMITY_VALID)
+		ndr_desc->numa_node = acpi_map_pxm_to_online_node(
+						spa->proximity_domain);
+	else
+		ndr_desc->numa_node = NUMA_NO_NODE;
+
+	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
+		struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev;
+		struct nd_mapping *nd_mapping;
+
+		if (memdev->range_index != spa->range_index)
+			continue;
+		if (count >= ND_MAX_MAPPINGS) {
+			dev_err(acpi_desc->dev, "spa%d exceeds max mappings %d\n",
+					spa->range_index, ND_MAX_MAPPINGS);
+			return -ENXIO;
+		}
+		nd_mapping = &nd_mappings[count++];
+		rc = acpi_nfit_init_mapping(acpi_desc, nd_mapping, ndr_desc,
+				memdev, spa);
+		if (rc)
+			return rc;
+	}
+
+	ndr_desc->nd_mapping = nd_mappings;
+	ndr_desc->num_mappings = count;
+	rc = acpi_nfit_init_interleave_set(acpi_desc, ndr_desc, spa);
+	if (rc)
+		return rc;
+
+	nvdimm_bus = acpi_desc->nvdimm_bus;
+	if (nfit_spa_type(spa) == NFIT_SPA_PM) {
+		if (!nvdimm_pmem_region_create(nvdimm_bus, ndr_desc))
+			return -ENOMEM;
+	} else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE) {
+		if (!nvdimm_volatile_region_create(nvdimm_bus, ndr_desc))
+			return -ENOMEM;
+	}
+	return 0;
+}
+
+static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nfit_spa *nfit_spa;
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		int rc = acpi_nfit_register_region(acpi_desc, nfit_spa);
+
+		if (rc)
+			return rc;
+	}
+	return 0;
+}
+
+int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, acpi_size sz)
+{
+	struct device *dev = acpi_desc->dev;
+	const void *end;
+	u8 *data;
+	int rc;
+
+	INIT_LIST_HEAD(&acpi_desc->spa_maps);
+	INIT_LIST_HEAD(&acpi_desc->spas);
+	INIT_LIST_HEAD(&acpi_desc->dcrs);
+	INIT_LIST_HEAD(&acpi_desc->bdws);
+	INIT_LIST_HEAD(&acpi_desc->idts);
+	INIT_LIST_HEAD(&acpi_desc->memdevs);
+	INIT_LIST_HEAD(&acpi_desc->dimms);
+	mutex_init(&acpi_desc->spa_map_mutex);
+
+	data = (u8 *) acpi_desc->nfit;
+	end = data + sz;
+	data += sizeof(struct acpi_table_nfit);
+	while (!IS_ERR_OR_NULL(data))
+		data = add_table(acpi_desc, data, end);
+
+	if (IS_ERR(data)) {
+		dev_dbg(dev, "%s: nfit table parsing error: %ld\n", __func__,
+				PTR_ERR(data));
+		return PTR_ERR(data);
+	}
+
+	if (nfit_mem_init(acpi_desc) != 0)
+		return -ENOMEM;
+
+	acpi_nfit_init_dsms(acpi_desc);
+
+	rc = acpi_nfit_register_dimms(acpi_desc);
+	if (rc)
+		return rc;
+
+	return acpi_nfit_register_regions(acpi_desc);
+}
+EXPORT_SYMBOL_GPL(acpi_nfit_init);
+
+static int acpi_nfit_add(struct acpi_device *adev)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	struct acpi_nfit_desc *acpi_desc;
+	struct device *dev = &adev->dev;
+	struct acpi_table_header *tbl;
+	acpi_status status = AE_OK;
+	acpi_size sz;
+	int rc;
+
+	status = acpi_get_table_with_size("NFIT", 0, &tbl, &sz);
+	if (ACPI_FAILURE(status)) {
+		dev_err(dev, "failed to find NFIT\n");
+		return -ENXIO;
+	}
+
+	acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL);
+	if (!acpi_desc)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, acpi_desc);
+	acpi_desc->dev = dev;
+	acpi_desc->nfit = (struct acpi_table_nfit *) tbl;
+	acpi_desc->blk_do_io = acpi_nfit_blk_region_do_io;
+	nd_desc = &acpi_desc->nd_desc;
+	nd_desc->provider_name = "ACPI.NFIT";
+	nd_desc->ndctl = acpi_nfit_ctl;
+	nd_desc->attr_groups = acpi_nfit_attribute_groups;
+
+	acpi_desc->nvdimm_bus = nvdimm_bus_register(dev, nd_desc);
+	if (!acpi_desc->nvdimm_bus)
+		return -ENXIO;
+
+	rc = acpi_nfit_init(acpi_desc, sz);
+	if (rc) {
+		nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
+		return rc;
+	}
+	return 0;
+}
+
+static int acpi_nfit_remove(struct acpi_device *adev)
+{
+	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
+
+	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
+	return 0;
+}
+
+static const struct acpi_device_id acpi_nfit_ids[] = {
+	{ "ACPI0012", 0 },
+	{ "", 0 },
+};
+MODULE_DEVICE_TABLE(acpi, acpi_nfit_ids);
+
+static struct acpi_driver acpi_nfit_driver = {
+	.name = KBUILD_MODNAME,
+	.ids = acpi_nfit_ids,
+	.ops = {
+		.add = acpi_nfit_add,
+		.remove = acpi_nfit_remove,
+	},
+};
+
+static __init int nfit_init(void)
+{
+	BUILD_BUG_ON(sizeof(struct acpi_table_nfit) != 40);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_system_address) != 56);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_memory_map) != 48);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_interleave) != 20);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 9);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_control_region) != 80);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_data_region) != 40);
+
+	acpi_str_to_uuid(UUID_VOLATILE_MEMORY, nfit_uuid[NFIT_SPA_VOLATILE]);
+	acpi_str_to_uuid(UUID_PERSISTENT_MEMORY, nfit_uuid[NFIT_SPA_PM]);
+	acpi_str_to_uuid(UUID_CONTROL_REGION, nfit_uuid[NFIT_SPA_DCR]);
+	acpi_str_to_uuid(UUID_DATA_REGION, nfit_uuid[NFIT_SPA_BDW]);
+	acpi_str_to_uuid(UUID_VOLATILE_VIRTUAL_DISK, nfit_uuid[NFIT_SPA_VDISK]);
+	acpi_str_to_uuid(UUID_VOLATILE_VIRTUAL_CD, nfit_uuid[NFIT_SPA_VCD]);
+	acpi_str_to_uuid(UUID_PERSISTENT_VIRTUAL_DISK, nfit_uuid[NFIT_SPA_PDISK]);
+	acpi_str_to_uuid(UUID_PERSISTENT_VIRTUAL_CD, nfit_uuid[NFIT_SPA_PCD]);
+	acpi_str_to_uuid(UUID_NFIT_BUS, nfit_uuid[NFIT_DEV_BUS]);
+	acpi_str_to_uuid(UUID_NFIT_DIMM, nfit_uuid[NFIT_DEV_DIMM]);
+
+	return acpi_bus_register_driver(&acpi_nfit_driver);
+}
+
+static __exit void nfit_exit(void)
+{
+	acpi_bus_unregister_driver(&acpi_nfit_driver);
+}
+
+module_init(nfit_init);
+module_exit(nfit_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Intel Corporation");
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
new file mode 100644
index 000000000000..81f2e8c5a79c
--- /dev/null
+++ b/drivers/acpi/nfit.h
@@ -0,0 +1,158 @@
+/*
+ * NVDIMM Firmware Interface Table - NFIT
+ *
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#ifndef __NFIT_H__
+#define __NFIT_H__
+#include <linux/libnvdimm.h>
+#include <linux/types.h>
+#include <linux/uuid.h>
+#include <linux/acpi.h>
+#include <acpi/acuuid.h>
+
+#define UUID_NFIT_BUS "2f10e7a4-9e91-11e4-89d3-123b93f75cba"
+#define UUID_NFIT_DIMM "4309ac30-0d11-11e4-9191-0800200c9a66"
+#define ACPI_NFIT_MEM_FAILED_MASK (ACPI_NFIT_MEM_SAVE_FAILED \
+		| ACPI_NFIT_MEM_RESTORE_FAILED | ACPI_NFIT_MEM_FLUSH_FAILED \
+		| ACPI_NFIT_MEM_ARMED)
+
+enum nfit_uuids {
+	NFIT_SPA_VOLATILE,
+	NFIT_SPA_PM,
+	NFIT_SPA_DCR,
+	NFIT_SPA_BDW,
+	NFIT_SPA_VDISK,
+	NFIT_SPA_VCD,
+	NFIT_SPA_PDISK,
+	NFIT_SPA_PCD,
+	NFIT_DEV_BUS,
+	NFIT_DEV_DIMM,
+	NFIT_UUID_MAX,
+};
+
+struct nfit_spa {
+	struct acpi_nfit_system_address *spa;
+	struct list_head list;
+};
+
+struct nfit_dcr {
+	struct acpi_nfit_control_region *dcr;
+	struct list_head list;
+};
+
+struct nfit_bdw {
+	struct acpi_nfit_data_region *bdw;
+	struct list_head list;
+};
+
+struct nfit_idt {
+	struct acpi_nfit_interleave *idt;
+	struct list_head list;
+};
+
+struct nfit_memdev {
+	struct acpi_nfit_memory_map *memdev;
+	struct list_head list;
+};
+
+/* assembled tables for a given dimm/memory-device */
+struct nfit_mem {
+	struct nvdimm *nvdimm;
+	struct acpi_nfit_memory_map *memdev_dcr;
+	struct acpi_nfit_memory_map *memdev_pmem;
+	struct acpi_nfit_memory_map *memdev_bdw;
+	struct acpi_nfit_control_region *dcr;
+	struct acpi_nfit_data_region *bdw;
+	struct acpi_nfit_system_address *spa_dcr;
+	struct acpi_nfit_system_address *spa_bdw;
+	struct acpi_nfit_interleave *idt_dcr;
+	struct acpi_nfit_interleave *idt_bdw;
+	struct list_head list;
+	struct acpi_device *adev;
+	unsigned long dsm_mask;
+};
+
+struct acpi_nfit_desc {
+	struct nvdimm_bus_descriptor nd_desc;
+	struct acpi_table_nfit *nfit;
+	struct mutex spa_map_mutex;
+	struct list_head spa_maps;
+	struct list_head memdevs;
+	struct list_head dimms;
+	struct list_head spas;
+	struct list_head dcrs;
+	struct list_head bdws;
+	struct list_head idts;
+	struct nvdimm_bus *nvdimm_bus;
+	struct device *dev;
+	unsigned long dimm_dsm_force_en;
+	int (*blk_do_io)(struct nd_blk_region *ndbr, resource_size_t dpa,
+			void *iobuf, u64 len, int rw);
+};
+
+enum nd_blk_mmio_selector {
+	BDW,
+	DCR,
+};
+
+struct nfit_blk {
+	struct nfit_blk_mmio {
+		union {
+			void __iomem *base;
+			void *aperture;
+		};
+		u64 size;
+		u64 base_offset;
+		u32 line_size;
+		u32 num_lines;
+		u32 table_size;
+		struct acpi_nfit_interleave *idt;
+		struct acpi_nfit_system_address *spa;
+	} mmio[2];
+	struct nd_region *nd_region;
+	u64 bdw_offset; /* post interleave offset */
+	u64 stat_offset;
+	u64 cmd_offset;
+};
+
+struct nfit_spa_mapping {
+	struct acpi_nfit_desc *acpi_desc;
+	struct acpi_nfit_system_address *spa;
+	struct list_head list;
+	struct kref kref;
+	void __iomem *iomem;
+};
+
+static inline struct nfit_spa_mapping *to_spa_map(struct kref *kref)
+{
+	return container_of(kref, struct nfit_spa_mapping, kref);
+}
+
+static inline struct acpi_nfit_memory_map *__to_nfit_memdev(
+		struct nfit_mem *nfit_mem)
+{
+	if (nfit_mem->memdev_dcr)
+		return nfit_mem->memdev_dcr;
+	return nfit_mem->memdev_pmem;
+}
+
+static inline struct acpi_nfit_desc *to_acpi_desc(
+		struct nvdimm_bus_descriptor *nd_desc)
+{
+	return container_of(nd_desc, struct acpi_nfit_desc, nd_desc);
+}
+
+const u8 *to_nfit_uuid(enum nfit_uuids id);
+int acpi_nfit_init(struct acpi_nfit_desc *nfit, acpi_size sz);
+extern const struct attribute_group *acpi_nfit_attribute_groups[];
+#endif /* __NFIT_H__ */
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 1333cbdc3ea2..acaa3b4ea504 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -29,6 +29,8 @@
 #include <linux/errno.h>
 #include <linux/acpi.h>
 #include <linux/numa.h>
+#include <linux/nodemask.h>
+#include <linux/topology.h>
 
 #define PREFIX "ACPI: "
 
@@ -70,7 +72,12 @@ static void __acpi_map_pxm_to_node(int pxm, int node)
 
 int acpi_map_pxm_to_node(int pxm)
 {
-	int node = pxm_to_node_map[pxm];
+	int node;
+
+	if (pxm < 0 || pxm >= MAX_PXM_DOMAINS)
+		return NUMA_NO_NODE;
+
+	node = pxm_to_node_map[pxm];
 
 	if (node == NUMA_NO_NODE) {
 		if (nodes_weight(nodes_found_map) >= MAX_NUMNODES)
@@ -83,6 +90,45 @@ int acpi_map_pxm_to_node(int pxm)
 	return node;
 }
 
+/**
+ * acpi_map_pxm_to_online_node - Map proximity ID to online node
+ * @pxm: ACPI proximity ID
+ *
+ * This is similar to acpi_map_pxm_to_node(), but always returns an online
+ * node.  When the mapped node from a given proximity ID is offline, it
+ * looks up the node distance table and returns the nearest online node.
+ *
+ * ACPI device drivers, which are called after the NUMA initialization has
+ * completed in the kernel, can call this interface to obtain their device
+ * NUMA topology from ACPI tables.  Such drivers do not have to deal with
+ * offline nodes.  A node may be offline when a device proximity ID is
+ * unique, SRAT memory entry does not exist, or NUMA is disabled, ex.
+ * "numa=off" on x86.
+ */
+int acpi_map_pxm_to_online_node(int pxm)
+{
+	int node, n, dist, min_dist;
+
+	node = acpi_map_pxm_to_node(pxm);
+
+	if (node == NUMA_NO_NODE)
+		node = 0;
+
+	if (!node_online(node)) {
+		min_dist = INT_MAX;
+		for_each_online_node(n) {
+			dist = node_distance(node, n);
+			if (dist < min_dist) {
+				min_dist = dist;
+				node = n;
+			}
+		}
+	}
+
+	return node;
+}
+EXPORT_SYMBOL(acpi_map_pxm_to_online_node);
+
 static void __init
 acpi_table_print_srat_entry(struct acpi_subtable_header *header)
 {
@@ -328,8 +374,6 @@ int acpi_get_node(acpi_handle handle)
 	int pxm;
 
 	pxm = acpi_get_pxm(handle);
-	if (pxm < 0 || pxm >= MAX_PXM_DOMAINS)
-		return NUMA_NO_NODE;
 
 	return acpi_map_pxm_to_node(pxm);
 }