nfit: move to nfit/ sub-directory

With the arrival of x86-machine-check support the nfit driver will add a
(conditionally-compiled) source file.  Prepare for this by moving all
nfit source to drivers/acpi/nfit/.  This is pure code movement, no
functional changes.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 2765 insertions, 0 deletions

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
new file mode 100644
index 000000000000..19d0dfdf9633
--- /dev/null
+++ b/drivers/acpi/nfit/core.c
@@ -0,0 +1,2765 @@
+/*
+ * 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/sysfs.h>
+#include <linux/delay.h>
+#include <linux/list.h>
+#include <linux/acpi.h>
+#include <linux/sort.h>
+#include <linux/pmem.h>
+#include <linux/io.h>
+#include <linux/nd.h>
+#include <asm/cacheflush.h>
+#include "nfit.h"
+
+/*
+ * For readq() and writeq() on 32-bit builds, the hi-lo, lo-hi order is
+ * irrelevant.
+ */
+#include <linux/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 unsigned int scrub_timeout = NFIT_ARS_TIMEOUT;
+module_param(scrub_timeout, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(scrub_timeout, "Initial scrub timeout in seconds");
+
+/* after three payloads of overflow, it's dead jim */
+static unsigned int scrub_overflow_abort = 3;
+module_param(scrub_overflow_abort, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(scrub_overflow_abort,
+		"Number of times we overflow ARS results before abort");
+
+static bool disable_vendor_specific;
+module_param(disable_vendor_specific, bool, S_IRUGO);
+MODULE_PARM_DESC(disable_vendor_specific,
+		"Limit commands to the publicly specified set\n");
+
+static struct workqueue_struct *nfit_wq;
+
+struct nfit_table_prev {
+	struct list_head spas;
+	struct list_head memdevs;
+	struct list_head dcrs;
+	struct list_head bdws;
+	struct list_head idts;
+	struct list_head flushes;
+};
+
+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 xlat_status(void *buf, unsigned int cmd)
+{
+	struct nd_cmd_clear_error *clear_err;
+	struct nd_cmd_ars_status *ars_status;
+	struct nd_cmd_ars_start *ars_start;
+	struct nd_cmd_ars_cap *ars_cap;
+	u16 flags;
+
+	switch (cmd) {
+	case ND_CMD_ARS_CAP:
+		ars_cap = buf;
+		if ((ars_cap->status & 0xffff) == NFIT_ARS_CAP_NONE)
+			return -ENOTTY;
+
+		/* Command failed */
+		if (ars_cap->status & 0xffff)
+			return -EIO;
+
+		/* No supported scan types for this range */
+		flags = ND_ARS_PERSISTENT | ND_ARS_VOLATILE;
+		if ((ars_cap->status >> 16 & flags) == 0)
+			return -ENOTTY;
+		break;
+	case ND_CMD_ARS_START:
+		ars_start = buf;
+		/* ARS is in progress */
+		if ((ars_start->status & 0xffff) == NFIT_ARS_START_BUSY)
+			return -EBUSY;
+
+		/* Command failed */
+		if (ars_start->status & 0xffff)
+			return -EIO;
+		break;
+	case ND_CMD_ARS_STATUS:
+		ars_status = buf;
+		/* Command failed */
+		if (ars_status->status & 0xffff)
+			return -EIO;
+		/* Check extended status (Upper two bytes) */
+		if (ars_status->status == NFIT_ARS_STATUS_DONE)
+			return 0;
+
+		/* ARS is in progress */
+		if (ars_status->status == NFIT_ARS_STATUS_BUSY)
+			return -EBUSY;
+
+		/* No ARS performed for the current boot */
+		if (ars_status->status == NFIT_ARS_STATUS_NONE)
+			return -EAGAIN;
+
+		/*
+		 * ARS interrupted, either we overflowed or some other
+		 * agent wants the scan to stop.  If we didn't overflow
+		 * then just continue with the returned results.
+		 */
+		if (ars_status->status == NFIT_ARS_STATUS_INTR) {
+			if (ars_status->flags & NFIT_ARS_F_OVERFLOW)
+				return -ENOSPC;
+			return 0;
+		}
+
+		/* Unknown status */
+		if (ars_status->status >> 16)
+			return -EIO;
+		break;
+	case ND_CMD_CLEAR_ERROR:
+		clear_err = buf;
+		if (clear_err->status & 0xffff)
+			return -EIO;
+		if (!clear_err->cleared)
+			return -EIO;
+		if (clear_err->length > clear_err->cleared)
+			return clear_err->cleared;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc,
+		struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+		unsigned int buf_len, int *cmd_rc)
+{
+	struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
+	union acpi_object in_obj, in_buf, *out_obj;
+	const struct nd_cmd_desc *desc = NULL;
+	struct device *dev = acpi_desc->dev;
+	struct nd_cmd_pkg *call_pkg = NULL;
+	const char *cmd_name, *dimm_name;
+	unsigned long cmd_mask, dsm_mask;
+	acpi_handle handle;
+	unsigned int func;
+	const u8 *uuid;
+	u32 offset;
+	int rc, i;
+
+	func = cmd;
+	if (cmd == ND_CMD_CALL) {
+		call_pkg = buf;
+		func = call_pkg->nd_command;
+	}
+
+	if (nvdimm) {
+		struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+		struct acpi_device *adev = nfit_mem->adev;
+
+		if (!adev)
+			return -ENOTTY;
+		if (call_pkg && nfit_mem->family != call_pkg->nd_family)
+			return -ENOTTY;
+
+		dimm_name = nvdimm_name(nvdimm);
+		cmd_name = nvdimm_cmd_name(cmd);
+		cmd_mask = nvdimm_cmd_mask(nvdimm);
+		dsm_mask = nfit_mem->dsm_mask;
+		desc = nd_cmd_dimm_desc(cmd);
+		uuid = to_nfit_uuid(nfit_mem->family);
+		handle = adev->handle;
+	} else {
+		struct acpi_device *adev = to_acpi_dev(acpi_desc);
+
+		cmd_name = nvdimm_bus_cmd_name(cmd);
+		cmd_mask = nd_desc->cmd_mask;
+		dsm_mask = cmd_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, &cmd_mask) || !test_bit(func, &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 (call_pkg) {
+		/* skip over package wrapper */
+		in_buf.buffer.pointer = (void *) &call_pkg->nd_payload;
+		in_buf.buffer.length = call_pkg->nd_size_in;
+	}
+
+	if (IS_ENABLED(CONFIG_ACPI_NFIT_DEBUG)) {
+		dev_dbg(dev, "%s:%s cmd: %d: func: %d input length: %d\n",
+				__func__, dimm_name, cmd, func,
+				in_buf.buffer.length);
+		print_hex_dump_debug("nvdimm in  ", DUMP_PREFIX_OFFSET, 4, 4,
+			in_buf.buffer.pointer,
+			min_t(u32, 256, in_buf.buffer.length), true);
+	}
+
+	out_obj = acpi_evaluate_dsm(handle, uuid, 1, func, &in_obj);
+	if (!out_obj) {
+		dev_dbg(dev, "%s:%s _DSM failed cmd: %s\n", __func__, dimm_name,
+				cmd_name);
+		return -EINVAL;
+	}
+
+	if (call_pkg) {
+		call_pkg->nd_fw_size = out_obj->buffer.length;
+		memcpy(call_pkg->nd_payload + call_pkg->nd_size_in,
+			out_obj->buffer.pointer,
+			min(call_pkg->nd_fw_size, call_pkg->nd_size_out));
+
+		ACPI_FREE(out_obj);
+		/*
+		 * Need to support FW function w/o known size in advance.
+		 * Caller can determine required size based upon nd_fw_size.
+		 * If we return an error (like elsewhere) then caller wouldn't
+		 * be able to rely upon data returned to make calculation.
+		 */
+		return 0;
+	}
+
+	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;
+			if (cmd_rc)
+				*cmd_rc = xlat_status(buf, cmd);
+		} 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;
+		if (cmd_rc)
+			*cmd_rc = xlat_status(buf, cmd);
+	}
+
+ 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 nfit_table_prev *prev,
+		struct acpi_nfit_system_address *spa)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (spa->header.length != sizeof(*spa))
+		return false;
+
+	list_for_each_entry(nfit_spa, &prev->spas, list) {
+		if (memcmp(nfit_spa->spa, spa, sizeof(*spa)) == 0) {
+			list_move_tail(&nfit_spa->list, &acpi_desc->spas);
+			return true;
+		}
+	}
+
+	nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa) + sizeof(*spa),
+			GFP_KERNEL);
+	if (!nfit_spa)
+		return false;
+	INIT_LIST_HEAD(&nfit_spa->list);
+	memcpy(nfit_spa->spa, spa, sizeof(*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 nfit_table_prev *prev,
+		struct acpi_nfit_memory_map *memdev)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_memdev *nfit_memdev;
+
+	if (memdev->header.length != sizeof(*memdev))
+		return false;
+
+	list_for_each_entry(nfit_memdev, &prev->memdevs, list)
+		if (memcmp(nfit_memdev->memdev, memdev, sizeof(*memdev)) == 0) {
+			list_move_tail(&nfit_memdev->list, &acpi_desc->memdevs);
+			return true;
+		}
+
+	nfit_memdev = devm_kzalloc(dev, sizeof(*nfit_memdev) + sizeof(*memdev),
+			GFP_KERNEL);
+	if (!nfit_memdev)
+		return false;
+	INIT_LIST_HEAD(&nfit_memdev->list);
+	memcpy(nfit_memdev->memdev, memdev, sizeof(*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;
+}
+
+/*
+ * An implementation may provide a truncated control region if no block windows
+ * are defined.
+ */
+static size_t sizeof_dcr(struct acpi_nfit_control_region *dcr)
+{
+	if (dcr->header.length < offsetof(struct acpi_nfit_control_region,
+				window_size))
+		return 0;
+	if (dcr->windows)
+		return sizeof(*dcr);
+	return offsetof(struct acpi_nfit_control_region, window_size);
+}
+
+static bool add_dcr(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_table_prev *prev,
+		struct acpi_nfit_control_region *dcr)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_dcr *nfit_dcr;
+
+	if (!sizeof_dcr(dcr))
+		return false;
+
+	list_for_each_entry(nfit_dcr, &prev->dcrs, list)
+		if (memcmp(nfit_dcr->dcr, dcr, sizeof_dcr(dcr)) == 0) {
+			list_move_tail(&nfit_dcr->list, &acpi_desc->dcrs);
+			return true;
+		}
+
+	nfit_dcr = devm_kzalloc(dev, sizeof(*nfit_dcr) + sizeof(*dcr),
+			GFP_KERNEL);
+	if (!nfit_dcr)
+		return false;
+	INIT_LIST_HEAD(&nfit_dcr->list);
+	memcpy(nfit_dcr->dcr, dcr, sizeof_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 nfit_table_prev *prev,
+		struct acpi_nfit_data_region *bdw)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_bdw *nfit_bdw;
+
+	if (bdw->header.length != sizeof(*bdw))
+		return false;
+	list_for_each_entry(nfit_bdw, &prev->bdws, list)
+		if (memcmp(nfit_bdw->bdw, bdw, sizeof(*bdw)) == 0) {
+			list_move_tail(&nfit_bdw->list, &acpi_desc->bdws);
+			return true;
+		}
+
+	nfit_bdw = devm_kzalloc(dev, sizeof(*nfit_bdw) + sizeof(*bdw),
+			GFP_KERNEL);
+	if (!nfit_bdw)
+		return false;
+	INIT_LIST_HEAD(&nfit_bdw->list);
+	memcpy(nfit_bdw->bdw, bdw, sizeof(*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 size_t sizeof_idt(struct acpi_nfit_interleave *idt)
+{
+	if (idt->header.length < sizeof(*idt))
+		return 0;
+	return sizeof(*idt) + sizeof(u32) * (idt->line_count - 1);
+}
+
+static bool add_idt(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_table_prev *prev,
+		struct acpi_nfit_interleave *idt)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_idt *nfit_idt;
+
+	if (!sizeof_idt(idt))
+		return false;
+
+	list_for_each_entry(nfit_idt, &prev->idts, list) {
+		if (sizeof_idt(nfit_idt->idt) != sizeof_idt(idt))
+			continue;
+
+		if (memcmp(nfit_idt->idt, idt, sizeof_idt(idt)) == 0) {
+			list_move_tail(&nfit_idt->list, &acpi_desc->idts);
+			return true;
+		}
+	}
+
+	nfit_idt = devm_kzalloc(dev, sizeof(*nfit_idt) + sizeof_idt(idt),
+			GFP_KERNEL);
+	if (!nfit_idt)
+		return false;
+	INIT_LIST_HEAD(&nfit_idt->list);
+	memcpy(nfit_idt->idt, idt, sizeof_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 size_t sizeof_flush(struct acpi_nfit_flush_address *flush)
+{
+	if (flush->header.length < sizeof(*flush))
+		return 0;
+	return sizeof(*flush) + sizeof(u64) * (flush->hint_count - 1);
+}
+
+static bool add_flush(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_table_prev *prev,
+		struct acpi_nfit_flush_address *flush)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_flush *nfit_flush;
+
+	if (!sizeof_flush(flush))
+		return false;
+
+	list_for_each_entry(nfit_flush, &prev->flushes, list) {
+		if (sizeof_flush(nfit_flush->flush) != sizeof_flush(flush))
+			continue;
+
+		if (memcmp(nfit_flush->flush, flush,
+					sizeof_flush(flush)) == 0) {
+			list_move_tail(&nfit_flush->list, &acpi_desc->flushes);
+			return true;
+		}
+	}
+
+	nfit_flush = devm_kzalloc(dev, sizeof(*nfit_flush)
+			+ sizeof_flush(flush), GFP_KERNEL);
+	if (!nfit_flush)
+		return false;
+	INIT_LIST_HEAD(&nfit_flush->list);
+	memcpy(nfit_flush->flush, flush, sizeof_flush(flush));
+	list_add_tail(&nfit_flush->list, &acpi_desc->flushes);
+	dev_dbg(dev, "%s: nfit_flush handle: %d hint_count: %d\n", __func__,
+			flush->device_handle, flush->hint_count);
+	return true;
+}
+
+static void *add_table(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_table_prev *prev, 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;
+	if (!hdr->length) {
+		dev_warn(dev, "found a zero length table '%d' parsing nfit\n",
+			hdr->type);
+		return NULL;
+	}
+
+	switch (hdr->type) {
+	case ACPI_NFIT_TYPE_SYSTEM_ADDRESS:
+		if (!add_spa(acpi_desc, prev, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_MEMORY_MAP:
+		if (!add_memdev(acpi_desc, prev, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_CONTROL_REGION:
+		if (!add_dcr(acpi_desc, prev, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_DATA_REGION:
+		if (!add_bdw(acpi_desc, prev, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_INTERLEAVE:
+		if (!add_idt(acpi_desc, prev, table))
+			return err;
+		break;
+	case ACPI_NFIT_TYPE_FLUSH_ADDRESS:
+		if (!add_flush(acpi_desc, prev, table))
+			return err;
+		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 void nfit_mem_init_bdw(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_bdw *nfit_bdw;
+	struct nfit_idt *nfit_idt;
+	u16 idt_idx, range_index;
+
+	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;
+
+	nfit_mem_find_spa_bdw(acpi_desc, nfit_mem);
+
+	if (!nfit_mem->spa_bdw)
+		return;
+
+	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;
+	}
+}
+
+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);
+
+	switch (type) {
+	case NFIT_SPA_DCR:
+	case NFIT_SPA_PM:
+		break;
+	default:
+		return 0;
+	}
+
+	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
+		struct nfit_flush *nfit_flush;
+		struct nfit_dcr *nfit_dcr;
+		u32 device_handle;
+		u16 dcr;
+
+		if (nfit_memdev->memdev->range_index != spa->range_index)
+			continue;
+		found = NULL;
+		dcr = nfit_memdev->memdev->region_index;
+		device_handle = nfit_memdev->memdev->device_handle;
+		list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
+			if (__to_nfit_memdev(nfit_mem)->device_handle
+					== device_handle) {
+				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);
+			nfit_mem->acpi_desc = acpi_desc;
+			list_add(&nfit_mem->list, &acpi_desc->dimms);
+		}
+
+		list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
+			if (nfit_dcr->dcr->region_index != dcr)
+				continue;
+			/*
+			 * Record the control region for the dimm.  For
+			 * the ACPI 6.1 case, where there are separate
+			 * control regions for the pmem vs blk
+			 * interfaces, be sure to record the extended
+			 * blk details.
+			 */
+			if (!nfit_mem->dcr)
+				nfit_mem->dcr = nfit_dcr->dcr;
+			else if (nfit_mem->dcr->windows == 0
+					&& nfit_dcr->dcr->windows)
+				nfit_mem->dcr = nfit_dcr->dcr;
+			break;
+		}
+
+		list_for_each_entry(nfit_flush, &acpi_desc->flushes, list) {
+			struct acpi_nfit_flush_address *flush;
+			u16 i;
+
+			if (nfit_flush->flush->device_handle != device_handle)
+				continue;
+			nfit_mem->nfit_flush = nfit_flush;
+			flush = nfit_flush->flush;
+			nfit_mem->flush_wpq = devm_kzalloc(acpi_desc->dev,
+					flush->hint_count
+					* sizeof(struct resource), GFP_KERNEL);
+			if (!nfit_mem->flush_wpq)
+				return -ENOMEM;
+			for (i = 0; i < flush->hint_count; i++) {
+				struct resource *res = &nfit_mem->flush_wpq[i];
+
+				res->start = flush->hint_address[i];
+				res->end = res->start + 8 - 1;
+			}
+			break;
+		}
+
+		if (dcr && !nfit_mem->dcr) {
+			dev_err(acpi_desc->dev, "SPA %d missing DCR %d\n",
+					spa->range_index, dcr);
+			return -ENODEV;
+		}
+
+		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;
+			}
+			nfit_mem_init_bdw(acpi_desc, nfit_mem, spa);
+		} 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;
+		}
+	}
+
+	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->acpi_header.revision);
+}
+static DEVICE_ATTR_RO(revision);
+
+/*
+ * This shows the number of full Address Range Scrubs that have been
+ * completed since driver load time. Userspace can wait on this using
+ * select/poll etc. A '+' at the end indicates an ARS is in progress
+ */
+static ssize_t scrub_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc = -ENXIO;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
+				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+	}
+	device_unlock(dev);
+	return rc;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
+
+static ssize_t scrub_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+	ssize_t rc;
+	long val;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+	if (val != 1)
+		return -EINVAL;
+
+	device_lock(dev);
+	nd_desc = dev_get_drvdata(dev);
+	if (nd_desc) {
+		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+
+		rc = acpi_nfit_ars_rescan(acpi_desc);
+	}
+	device_unlock(dev);
+	if (rc)
+		return rc;
+	return size;
+}
+static DEVICE_ATTR_RW(scrub);
+
+static bool ars_supported(struct nvdimm_bus *nvdimm_bus)
+{
+	struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
+	const unsigned long mask = 1 << ND_CMD_ARS_CAP | 1 << ND_CMD_ARS_START
+		| 1 << ND_CMD_ARS_STATUS;
+
+	return (nd_desc->cmd_mask & mask) == mask;
+}
+
+static umode_t nfit_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
+
+	if (a == &dev_attr_scrub.attr && !ars_supported(nvdimm_bus))
+		return 0;
+	return a->mode;
+}
+
+static struct attribute *acpi_nfit_attributes[] = {
+	&dev_attr_revision.attr,
+	&dev_attr_scrub.attr,
+	NULL,
+};
+
+static struct attribute_group acpi_nfit_attribute_group = {
+	.name = "nfit",
+	.attrs = acpi_nfit_attributes,
+	.is_visible = nfit_visible,
+};
+
+static const struct attribute_group *acpi_nfit_attribute_groups[] = {
+	&nvdimm_bus_attribute_group,
+	&acpi_nfit_attribute_group,
+	NULL,
+};
+
+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, "0x%04x\n", be16_to_cpu(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, "0x%04x\n", be16_to_cpu(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, "0x%04x\n", be16_to_cpu(dcr->device_id));
+}
+static DEVICE_ATTR_RO(device);
+
+static ssize_t subsystem_vendor_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	return sprintf(buf, "0x%04x\n", be16_to_cpu(dcr->subsystem_vendor_id));
+}
+static DEVICE_ATTR_RO(subsystem_vendor);
+
+static ssize_t subsystem_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, "0x%04x\n",
+			be16_to_cpu(dcr->subsystem_revision_id));
+}
+static DEVICE_ATTR_RO(subsystem_rev_id);
+
+static ssize_t subsystem_device_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	return sprintf(buf, "0x%04x\n", be16_to_cpu(dcr->subsystem_device_id));
+}
+static DEVICE_ATTR_RO(subsystem_device);
+
+static int num_nvdimm_formats(struct nvdimm *nvdimm)
+{
+	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+	int formats = 0;
+
+	if (nfit_mem->memdev_pmem)
+		formats++;
+	if (nfit_mem->memdev_bdw)
+		formats++;
+	return formats;
+}
+
+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, "0x%04x\n", be16_to_cpu(dcr->code));
+}
+static DEVICE_ATTR_RO(format);
+
+static ssize_t format1_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	u32 handle;
+	ssize_t rc = -ENXIO;
+	struct nfit_mem *nfit_mem;
+	struct nfit_memdev *nfit_memdev;
+	struct acpi_nfit_desc *acpi_desc;
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	nfit_mem = nvdimm_provider_data(nvdimm);
+	acpi_desc = nfit_mem->acpi_desc;
+	handle = to_nfit_memdev(dev)->device_handle;
+
+	/* assumes DIMMs have at most 2 published interface codes */
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
+		struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev;
+		struct nfit_dcr *nfit_dcr;
+
+		if (memdev->device_handle != handle)
+			continue;
+
+		list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
+			if (nfit_dcr->dcr->region_index != memdev->region_index)
+				continue;
+			if (nfit_dcr->dcr->code == dcr->code)
+				continue;
+			rc = sprintf(buf, "%#x\n",
+					be16_to_cpu(nfit_dcr->dcr->code));
+			break;
+		}
+		if (rc != ENXIO)
+			break;
+	}
+	mutex_unlock(&acpi_desc->init_mutex);
+	return rc;
+}
+static DEVICE_ATTR_RO(format1);
+
+static ssize_t formats_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	return sprintf(buf, "%d\n", num_nvdimm_formats(nvdimm));
+}
+static DEVICE_ATTR_RO(formats);
+
+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, "0x%08x\n", be32_to_cpu(dcr->serial_number));
+}
+static DEVICE_ATTR_RO(serial);
+
+static ssize_t family_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+
+	if (nfit_mem->family < 0)
+		return -ENXIO;
+	return sprintf(buf, "%d\n", nfit_mem->family);
+}
+static DEVICE_ATTR_RO(family);
+
+static ssize_t dsm_mask_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct nfit_mem *nfit_mem = nvdimm_provider_data(nvdimm);
+
+	if (nfit_mem->family < 0)
+		return -ENXIO;
+	return sprintf(buf, "%#lx\n", nfit_mem->dsm_mask);
+}
+static DEVICE_ATTR_RO(dsm_mask);
+
+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_fail " : "",
+		flags & ACPI_NFIT_MEM_RESTORE_FAILED ? "restore_fail " : "",
+		flags & ACPI_NFIT_MEM_FLUSH_FAILED ? "flush_fail " : "",
+		flags & ACPI_NFIT_MEM_NOT_ARMED ? "not_armed " : "",
+		flags & ACPI_NFIT_MEM_HEALTH_OBSERVED ? "smart_event " : "");
+}
+static DEVICE_ATTR_RO(flags);
+
+static ssize_t id_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct acpi_nfit_control_region *dcr = to_nfit_dcr(dev);
+
+	if (dcr->valid_fields & ACPI_NFIT_CONTROL_MFG_INFO_VALID)
+		return sprintf(buf, "%04x-%02x-%04x-%08x\n",
+				be16_to_cpu(dcr->vendor_id),
+				dcr->manufacturing_location,
+				be16_to_cpu(dcr->manufacturing_date),
+				be32_to_cpu(dcr->serial_number));
+	else
+		return sprintf(buf, "%04x-%08x\n",
+				be16_to_cpu(dcr->vendor_id),
+				be32_to_cpu(dcr->serial_number));
+}
+static DEVICE_ATTR_RO(id);
+
+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_rev_id.attr,
+	&dev_attr_subsystem_vendor.attr,
+	&dev_attr_subsystem_device.attr,
+	&dev_attr_subsystem_rev_id.attr,
+	&dev_attr_format.attr,
+	&dev_attr_formats.attr,
+	&dev_attr_format1.attr,
+	&dev_attr_serial.attr,
+	&dev_attr_flags.attr,
+	&dev_attr_id.attr,
+	&dev_attr_family.attr,
+	&dev_attr_dsm_mask.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);
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	if (!to_nfit_dcr(dev))
+		return 0;
+	if (a == &dev_attr_format1.attr && num_nvdimm_formats(nvdimm) <= 1)
+		return 0;
+	return a->mode;
+}
+
+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;
+	unsigned long dsm_mask;
+	const u8 *uuid;
+	int i;
+
+	/* nfit test assumes 1:1 relationship between commands and dsms */
+	nfit_mem->dsm_mask = acpi_desc->dimm_cmd_force_en;
+	nfit_mem->family = NVDIMM_FAMILY_INTEL;
+	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;
+	}
+
+	/*
+	 * Until standardization materializes we need to consider 4
+	 * different command sets.  Note, that checking for function0 (bit0)
+	 * tells us if any commands are reachable through this uuid.
+	 */
+	for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_MSFT; i++)
+		if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1))
+			break;
+
+	/* limit the supported commands to those that are publicly documented */
+	nfit_mem->family = i;
+	if (nfit_mem->family == NVDIMM_FAMILY_INTEL) {
+		dsm_mask = 0x3fe;
+		if (disable_vendor_specific)
+			dsm_mask &= ~(1 << ND_CMD_VENDOR);
+	} else if (nfit_mem->family == NVDIMM_FAMILY_HPE1) {
+		dsm_mask = 0x1c3c76;
+	} else if (nfit_mem->family == NVDIMM_FAMILY_HPE2) {
+		dsm_mask = 0x1fe;
+		if (disable_vendor_specific)
+			dsm_mask &= ~(1 << 8);
+	} else if (nfit_mem->family == NVDIMM_FAMILY_MSFT) {
+		dsm_mask = 0xffffffff;
+	} else {
+		dev_err(dev, "unknown dimm command family\n");
+		nfit_mem->family = -1;
+		return force_enable_dimms ? 0 : -ENODEV;
+	}
+
+	uuid = to_nfit_uuid(nfit_mem->family);
+	for_each_set_bit(i, &dsm_mask, BITS_PER_LONG)
+		if (acpi_check_dsm(adev_dimm->handle, uuid, 1, 1ULL << i))
+			set_bit(i, &nfit_mem->dsm_mask);
+
+	return 0;
+}
+
+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 acpi_nfit_flush_address *flush;
+		unsigned long flags = 0, cmd_mask;
+		struct nvdimm *nvdimm;
+		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) {
+			dimm_count++;
+			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_NOT_ARMED)
+			flags |= NDD_UNARMED;
+
+		rc = acpi_nfit_add_dimm(acpi_desc, nfit_mem, device_handle);
+		if (rc)
+			continue;
+
+		/*
+		 * TODO: provide translation for non-NVDIMM_FAMILY_INTEL
+		 * devices (i.e. from nd_cmd to acpi_dsm) to standardize the
+		 * userspace interface.
+		 */
+		cmd_mask = 1UL << ND_CMD_CALL;
+		if (nfit_mem->family == NVDIMM_FAMILY_INTEL)
+			cmd_mask |= nfit_mem->dsm_mask;
+
+		flush = nfit_mem->nfit_flush ? nfit_mem->nfit_flush->flush
+			: NULL;
+		nvdimm = nvdimm_create(acpi_desc->nvdimm_bus, nfit_mem,
+				acpi_nfit_dimm_attribute_groups,
+				flags, cmd_mask, flush ? flush->hint_count : 0,
+				nfit_mem->flush_wpq);
+		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 flags:%s%s%s%s\n",
+				nvdimm_name(nvdimm),
+		  mem_flags & ACPI_NFIT_MEM_SAVE_FAILED ? " save_fail" : "",
+		  mem_flags & ACPI_NFIT_MEM_RESTORE_FAILED ? " restore_fail":"",
+		  mem_flags & ACPI_NFIT_MEM_FLUSH_FAILED ? " flush_fail" : "",
+		  mem_flags & ACPI_NFIT_MEM_NOT_ARMED ? " not_armed" : "");
+
+	}
+
+	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;
+
+	nd_desc->cmd_mask = acpi_desc->bus_cmd_force_en;
+	adev = to_acpi_dev(acpi_desc);
+	if (!adev)
+		return;
+
+	for (i = ND_CMD_ARS_CAP; i <= ND_CMD_CLEAR_ERROR; i++)
+		if (acpi_check_dsm(adev->handle, uuid, 1, 1ULL << i))
+			set_bit(i, &nd_desc->cmd_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 u32 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 readl(mmio->addr.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->addr.base + offset);
+	nvdimm_flush(nfit_blk->nd_region);
+
+	if (nfit_blk->dimm_flags & NFIT_BLK_DCR_LATCH)
+		readq(mmio->addr.base + offset);
+}
+
+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;
+	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_to_pmem(mmio->addr.aperture + offset,
+					iobuf + copied, c);
+		else {
+			if (nfit_blk->dimm_flags & NFIT_BLK_READ_FLUSH)
+				mmio_flush_range((void __force *)
+					mmio->addr.aperture + offset, c);
+
+			memcpy_from_pmem(iobuf + copied,
+					mmio->addr.aperture + offset, c);
+		}
+
+		copied += c;
+		len -= c;
+	}
+
+	if (rw)
+		nvdimm_flush(nfit_blk->nd_region);
+
+	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 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_get_flags(struct nvdimm_bus_descriptor *nd_desc,
+		struct nvdimm *nvdimm, struct nfit_blk *nfit_blk)
+{
+	struct nd_cmd_dimm_flags flags;
+	int rc;
+
+	memset(&flags, 0, sizeof(flags));
+	rc = nd_desc->ndctl(nd_desc, nvdimm, ND_CMD_DIMM_FLAGS, &flags,
+			sizeof(flags), NULL);
+
+	if (rc >= 0 && flags.status == 0)
+		nfit_blk->dimm_flags = flags.flags;
+	else if (rc == -ENOTTY) {
+		/* fall back to a conservative default */
+		nfit_blk->dimm_flags = NFIT_BLK_DCR_LATCH | NFIT_BLK_READ_FLUSH;
+		rc = 0;
+	} else
+		rc = -ENXIO;
+
+	return rc;
+}
+
+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 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 && nfit_mem->dcr) ? "" : " dcr",
+				(nfit_mem && 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->addr.base = devm_nvdimm_memremap(dev, nfit_mem->spa_bdw->address,
+                        nfit_mem->spa_bdw->length, ARCH_MEMREMAP_PMEM);
+	if (!mmio->addr.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->addr.base = devm_nvdimm_ioremap(dev, nfit_mem->spa_dcr->address,
+			nfit_mem->spa_dcr->length);
+	if (!mmio->addr.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;
+	}
+
+	rc = acpi_nfit_blk_get_flags(nd_desc, nvdimm, nfit_blk);
+	if (rc < 0) {
+		dev_dbg(dev, "%s: %s failed get DIMM flags\n",
+				__func__, nvdimm_name(nvdimm));
+		return rc;
+	}
+
+	if (nvdimm_has_flush(nfit_blk->nd_region) < 0)
+		dev_warn(dev, "unable to guarantee persistence of writes\n");
+
+	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 int ars_get_cap(struct acpi_nfit_desc *acpi_desc,
+		struct nd_cmd_ars_cap *cmd, struct nfit_spa *nfit_spa)
+{
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	int cmd_rc, rc;
+
+	cmd->address = spa->address;
+	cmd->length = spa->length;
+	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_CAP, cmd,
+			sizeof(*cmd), &cmd_rc);
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
+}
+
+static int ars_start(struct acpi_nfit_desc *acpi_desc, struct nfit_spa *nfit_spa)
+{
+	int rc;
+	int cmd_rc;
+	struct nd_cmd_ars_start ars_start;
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+
+	memset(&ars_start, 0, sizeof(ars_start));
+	ars_start.address = spa->address;
+	ars_start.length = spa->length;
+	if (nfit_spa_type(spa) == NFIT_SPA_PM)
+		ars_start.type = ND_ARS_PERSISTENT;
+	else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE)
+		ars_start.type = ND_ARS_VOLATILE;
+	else
+		return -ENOTTY;
+
+	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_START, &ars_start,
+			sizeof(ars_start), &cmd_rc);
+
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
+}
+
+static int ars_continue(struct acpi_nfit_desc *acpi_desc)
+{
+	int rc, cmd_rc;
+	struct nd_cmd_ars_start ars_start;
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+	struct nd_cmd_ars_status *ars_status = acpi_desc->ars_status;
+
+	memset(&ars_start, 0, sizeof(ars_start));
+	ars_start.address = ars_status->restart_address;
+	ars_start.length = ars_status->restart_length;
+	ars_start.type = ars_status->type;
+	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_START, &ars_start,
+			sizeof(ars_start), &cmd_rc);
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
+}
+
+static int ars_get_status(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+	struct nd_cmd_ars_status *ars_status = acpi_desc->ars_status;
+	int rc, cmd_rc;
+
+	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_STATUS, ars_status,
+			acpi_desc->ars_status_size, &cmd_rc);
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
+}
+
+static int ars_status_process_records(struct nvdimm_bus *nvdimm_bus,
+		struct nd_cmd_ars_status *ars_status)
+{
+	int rc;
+	u32 i;
+
+	for (i = 0; i < ars_status->num_records; i++) {
+		rc = nvdimm_bus_add_poison(nvdimm_bus,
+				ars_status->records[i].err_address,
+				ars_status->records[i].length);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+static void acpi_nfit_remove_resource(void *data)
+{
+	struct resource *res = data;
+
+	remove_resource(res);
+}
+
+static int acpi_nfit_insert_resource(struct acpi_nfit_desc *acpi_desc,
+		struct nd_region_desc *ndr_desc)
+{
+	struct resource *res, *nd_res = ndr_desc->res;
+	int is_pmem, ret;
+
+	/* No operation if the region is already registered as PMEM */
+	is_pmem = region_intersects(nd_res->start, resource_size(nd_res),
+				IORESOURCE_MEM, IORES_DESC_PERSISTENT_MEMORY);
+	if (is_pmem == REGION_INTERSECTS)
+		return 0;
+
+	res = devm_kzalloc(acpi_desc->dev, sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return -ENOMEM;
+
+	res->name = "Persistent Memory";
+	res->start = nd_res->start;
+	res->end = nd_res->end;
+	res->flags = IORESOURCE_MEM;
+	res->desc = IORES_DESC_PERSISTENT_MEMORY;
+
+	ret = insert_resource(&iomem_resource, res);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(acpi_desc->dev,
+					acpi_nfit_remove_resource,
+					res);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+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 nfit_spa *nfit_spa)
+{
+	struct nvdimm *nvdimm = acpi_nfit_dimm_by_handle(acpi_desc,
+			memdev->device_handle);
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	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->do_io = acpi_desc->blk_do_io;
+		nfit_spa->nd_region = nvdimm_blk_region_create(acpi_desc->nvdimm_bus,
+				ndr_desc);
+		if (!nfit_spa->nd_region)
+			return -ENOMEM;
+		break;
+	}
+
+	return 0;
+}
+
+static bool nfit_spa_is_virtual(struct acpi_nfit_system_address *spa)
+{
+	return (nfit_spa_type(spa) == NFIT_SPA_VDISK ||
+		nfit_spa_type(spa) == NFIT_SPA_VCD   ||
+		nfit_spa_type(spa) == NFIT_SPA_PDISK ||
+		nfit_spa_type(spa) == NFIT_SPA_PCD);
+}
+
+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 (nfit_spa->nd_region)
+		return 0;
+
+	if (spa->range_index == 0 && !nfit_spa_is_virtual(spa)) {
+		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, nfit_spa);
+		if (rc)
+			goto out;
+	}
+
+	ndr_desc->nd_mapping = nd_mappings;
+	ndr_desc->num_mappings = count;
+	rc = acpi_nfit_init_interleave_set(acpi_desc, ndr_desc, spa);
+	if (rc)
+		goto out;
+
+	nvdimm_bus = acpi_desc->nvdimm_bus;
+	if (nfit_spa_type(spa) == NFIT_SPA_PM) {
+		rc = acpi_nfit_insert_resource(acpi_desc, ndr_desc);
+		if (rc) {
+			dev_warn(acpi_desc->dev,
+				"failed to insert pmem resource to iomem: %d\n",
+				rc);
+			goto out;
+		}
+
+		nfit_spa->nd_region = nvdimm_pmem_region_create(nvdimm_bus,
+				ndr_desc);
+		if (!nfit_spa->nd_region)
+			rc = -ENOMEM;
+	} else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE) {
+		nfit_spa->nd_region = nvdimm_volatile_region_create(nvdimm_bus,
+				ndr_desc);
+		if (!nfit_spa->nd_region)
+			rc = -ENOMEM;
+	} else if (nfit_spa_is_virtual(spa)) {
+		nfit_spa->nd_region = nvdimm_pmem_region_create(nvdimm_bus,
+				ndr_desc);
+		if (!nfit_spa->nd_region)
+			rc = -ENOMEM;
+	}
+
+ out:
+	if (rc)
+		dev_err(acpi_desc->dev, "failed to register spa range %d\n",
+				nfit_spa->spa->range_index);
+	return rc;
+}
+
+static int ars_status_alloc(struct acpi_nfit_desc *acpi_desc,
+		u32 max_ars)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nd_cmd_ars_status *ars_status;
+
+	if (acpi_desc->ars_status && acpi_desc->ars_status_size >= max_ars) {
+		memset(acpi_desc->ars_status, 0, acpi_desc->ars_status_size);
+		return 0;
+	}
+
+	if (acpi_desc->ars_status)
+		devm_kfree(dev, acpi_desc->ars_status);
+	acpi_desc->ars_status = NULL;
+	ars_status = devm_kzalloc(dev, max_ars, GFP_KERNEL);
+	if (!ars_status)
+		return -ENOMEM;
+	acpi_desc->ars_status = ars_status;
+	acpi_desc->ars_status_size = max_ars;
+	return 0;
+}
+
+static int acpi_nfit_query_poison(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_spa *nfit_spa)
+{
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	int rc;
+
+	if (!nfit_spa->max_ars) {
+		struct nd_cmd_ars_cap ars_cap;
+
+		memset(&ars_cap, 0, sizeof(ars_cap));
+		rc = ars_get_cap(acpi_desc, &ars_cap, nfit_spa);
+		if (rc < 0)
+			return rc;
+		nfit_spa->max_ars = ars_cap.max_ars_out;
+		nfit_spa->clear_err_unit = ars_cap.clear_err_unit;
+		/* check that the supported scrub types match the spa type */
+		if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE &&
+				((ars_cap.status >> 16) & ND_ARS_VOLATILE) == 0)
+			return -ENOTTY;
+		else if (nfit_spa_type(spa) == NFIT_SPA_PM &&
+				((ars_cap.status >> 16) & ND_ARS_PERSISTENT) == 0)
+			return -ENOTTY;
+	}
+
+	if (ars_status_alloc(acpi_desc, nfit_spa->max_ars))
+		return -ENOMEM;
+
+	rc = ars_get_status(acpi_desc);
+	if (rc < 0 && rc != -ENOSPC)
+		return rc;
+
+	if (ars_status_process_records(acpi_desc->nvdimm_bus,
+				acpi_desc->ars_status))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_spa *nfit_spa)
+{
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	unsigned int overflow_retry = scrub_overflow_abort;
+	u64 init_ars_start = 0, init_ars_len = 0;
+	struct device *dev = acpi_desc->dev;
+	unsigned int tmo = scrub_timeout;
+	int rc;
+
+	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
+		return;
+
+	rc = ars_start(acpi_desc, nfit_spa);
+	/*
+	 * If we timed out the initial scan we'll still be busy here,
+	 * and will wait another timeout before giving up permanently.
+	 */
+	if (rc < 0 && rc != -EBUSY)
+		return;
+
+	do {
+		u64 ars_start, ars_len;
+
+		if (acpi_desc->cancel)
+			break;
+		rc = acpi_nfit_query_poison(acpi_desc, nfit_spa);
+		if (rc == -ENOTTY)
+			break;
+		if (rc == -EBUSY && !tmo) {
+			dev_warn(dev, "range %d ars timeout, aborting\n",
+					spa->range_index);
+			break;
+		}
+
+		if (rc == -EBUSY) {
+			/*
+			 * Note, entries may be appended to the list
+			 * while the lock is dropped, but the workqueue
+			 * being active prevents entries being deleted /
+			 * freed.
+			 */
+			mutex_unlock(&acpi_desc->init_mutex);
+			ssleep(1);
+			tmo--;
+			mutex_lock(&acpi_desc->init_mutex);
+			continue;
+		}
+
+		/* we got some results, but there are more pending... */
+		if (rc == -ENOSPC && overflow_retry--) {
+			if (!init_ars_len) {
+				init_ars_len = acpi_desc->ars_status->length;
+				init_ars_start = acpi_desc->ars_status->address;
+			}
+			rc = ars_continue(acpi_desc);
+		}
+
+		if (rc < 0) {
+			dev_warn(dev, "range %d ars continuation failed\n",
+					spa->range_index);
+			break;
+		}
+
+		if (init_ars_len) {
+			ars_start = init_ars_start;
+			ars_len = init_ars_len;
+		} else {
+			ars_start = acpi_desc->ars_status->address;
+			ars_len = acpi_desc->ars_status->length;
+		}
+		dev_dbg(dev, "spa range: %d ars from %#llx + %#llx complete\n",
+				spa->range_index, ars_start, ars_len);
+		/* notify the region about new poison entries */
+		nvdimm_region_notify(nfit_spa->nd_region,
+				NVDIMM_REVALIDATE_POISON);
+		break;
+	} while (1);
+}
+
+static void acpi_nfit_scrub(struct work_struct *work)
+{
+	struct device *dev;
+	u64 init_scrub_length = 0;
+	struct nfit_spa *nfit_spa;
+	u64 init_scrub_address = 0;
+	bool init_ars_done = false;
+	struct acpi_nfit_desc *acpi_desc;
+	unsigned int tmo = scrub_timeout;
+	unsigned int overflow_retry = scrub_overflow_abort;
+
+	acpi_desc = container_of(work, typeof(*acpi_desc), work);
+	dev = acpi_desc->dev;
+
+	/*
+	 * We scrub in 2 phases.  The first phase waits for any platform
+	 * firmware initiated scrubs to complete and then we go search for the
+	 * affected spa regions to mark them scanned.  In the second phase we
+	 * initiate a directed scrub for every range that was not scrubbed in
+	 * phase 1. If we're called for a 'rescan', we harmlessly pass through
+	 * the first phase, but really only care about running phase 2, where
+	 * regions can be notified of new poison.
+	 */
+
+	/* process platform firmware initiated scrubs */
+ retry:
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct nd_cmd_ars_status *ars_status;
+		struct acpi_nfit_system_address *spa;
+		u64 ars_start, ars_len;
+		int rc;
+
+		if (acpi_desc->cancel)
+			break;
+
+		if (nfit_spa->nd_region)
+			continue;
+
+		if (init_ars_done) {
+			/*
+			 * No need to re-query, we're now just
+			 * reconciling all the ranges covered by the
+			 * initial scrub
+			 */
+			rc = 0;
+		} else
+			rc = acpi_nfit_query_poison(acpi_desc, nfit_spa);
+
+		if (rc == -ENOTTY) {
+			/* no ars capability, just register spa and move on */
+			acpi_nfit_register_region(acpi_desc, nfit_spa);
+			continue;
+		}
+
+		if (rc == -EBUSY && !tmo) {
+			/* fallthrough to directed scrub in phase 2 */
+			dev_warn(dev, "timeout awaiting ars results, continuing...\n");
+			break;
+		} else if (rc == -EBUSY) {
+			mutex_unlock(&acpi_desc->init_mutex);
+			ssleep(1);
+			tmo--;
+			goto retry;
+		}
+
+		/* we got some results, but there are more pending... */
+		if (rc == -ENOSPC && overflow_retry--) {
+			ars_status = acpi_desc->ars_status;
+			/*
+			 * Record the original scrub range, so that we
+			 * can recall all the ranges impacted by the
+			 * initial scrub.
+			 */
+			if (!init_scrub_length) {
+				init_scrub_length = ars_status->length;
+				init_scrub_address = ars_status->address;
+			}
+			rc = ars_continue(acpi_desc);
+			if (rc == 0) {
+				mutex_unlock(&acpi_desc->init_mutex);
+				goto retry;
+			}
+		}
+
+		if (rc < 0) {
+			/*
+			 * Initial scrub failed, we'll give it one more
+			 * try below...
+			 */
+			break;
+		}
+
+		/* We got some final results, record completed ranges */
+		ars_status = acpi_desc->ars_status;
+		if (init_scrub_length) {
+			ars_start = init_scrub_address;
+			ars_len = ars_start + init_scrub_length;
+		} else {
+			ars_start = ars_status->address;
+			ars_len = ars_status->length;
+		}
+		spa = nfit_spa->spa;
+
+		if (!init_ars_done) {
+			init_ars_done = true;
+			dev_dbg(dev, "init scrub %#llx + %#llx complete\n",
+					ars_start, ars_len);
+		}
+		if (ars_start <= spa->address && ars_start + ars_len
+				>= spa->address + spa->length)
+			acpi_nfit_register_region(acpi_desc, nfit_spa);
+	}
+
+	/*
+	 * For all the ranges not covered by an initial scrub we still
+	 * want to see if there are errors, but it's ok to discover them
+	 * asynchronously.
+	 */
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		/*
+		 * Flag all the ranges that still need scrubbing, but
+		 * register them now to make data available.
+		 */
+		if (!nfit_spa->nd_region) {
+			nfit_spa->ars_required = 1;
+			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		}
+	}
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
+		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	acpi_desc->scrub_count++;
+	if (acpi_desc->scrub_count_state)
+		sysfs_notify_dirent(acpi_desc->scrub_count_state);
+	mutex_unlock(&acpi_desc->init_mutex);
+}
+
+static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nfit_spa *nfit_spa;
+	int rc;
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
+		if (nfit_spa_type(nfit_spa->spa) == NFIT_SPA_DCR) {
+			/* BLK regions don't need to wait for ars results */
+			rc = acpi_nfit_register_region(acpi_desc, nfit_spa);
+			if (rc)
+				return rc;
+		}
+
+	queue_work(nfit_wq, &acpi_desc->work);
+	return 0;
+}
+
+static int acpi_nfit_check_deletions(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_table_prev *prev)
+{
+	struct device *dev = acpi_desc->dev;
+
+	if (!list_empty(&prev->spas) ||
+			!list_empty(&prev->memdevs) ||
+			!list_empty(&prev->dcrs) ||
+			!list_empty(&prev->bdws) ||
+			!list_empty(&prev->idts) ||
+			!list_empty(&prev->flushes)) {
+		dev_err(dev, "new nfit deletes entries (unsupported)\n");
+		return -ENXIO;
+	}
+	return 0;
+}
+
+static int acpi_nfit_desc_init_scrub_attr(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct kernfs_node *nfit;
+	struct device *bus_dev;
+
+	if (!ars_supported(acpi_desc->nvdimm_bus))
+		return 0;
+
+	bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+	nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
+	if (!nfit) {
+		dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
+		return -ENODEV;
+	}
+	acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
+	sysfs_put(nfit);
+	if (!acpi_desc->scrub_count_state) {
+		dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static void acpi_nfit_destruct(void *data)
+{
+	struct acpi_nfit_desc *acpi_desc = data;
+	struct device *bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
+
+	acpi_desc->cancel = 1;
+	/*
+	 * Bounce the nvdimm bus lock to make sure any in-flight
+	 * acpi_nfit_ars_rescan() submissions have had a chance to
+	 * either submit or see ->cancel set.
+	 */
+	device_lock(bus_dev);
+	device_unlock(bus_dev);
+
+	flush_workqueue(nfit_wq);
+	if (acpi_desc->scrub_count_state)
+		sysfs_put(acpi_desc->scrub_count_state);
+	nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
+	acpi_desc->nvdimm_bus = NULL;
+}
+
+int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_table_prev prev;
+	const void *end;
+	int rc;
+
+	if (!acpi_desc->nvdimm_bus) {
+		acpi_nfit_init_dsms(acpi_desc);
+
+		acpi_desc->nvdimm_bus = nvdimm_bus_register(dev,
+				&acpi_desc->nd_desc);
+		if (!acpi_desc->nvdimm_bus)
+			return -ENOMEM;
+
+		rc = devm_add_action_or_reset(dev, acpi_nfit_destruct,
+				acpi_desc);
+		if (rc)
+			return rc;
+
+		rc = acpi_nfit_desc_init_scrub_attr(acpi_desc);
+		if (rc)
+			return rc;
+	}
+
+	mutex_lock(&acpi_desc->init_mutex);
+
+	INIT_LIST_HEAD(&prev.spas);
+	INIT_LIST_HEAD(&prev.memdevs);
+	INIT_LIST_HEAD(&prev.dcrs);
+	INIT_LIST_HEAD(&prev.bdws);
+	INIT_LIST_HEAD(&prev.idts);
+	INIT_LIST_HEAD(&prev.flushes);
+
+	list_cut_position(&prev.spas, &acpi_desc->spas,
+				acpi_desc->spas.prev);
+	list_cut_position(&prev.memdevs, &acpi_desc->memdevs,
+				acpi_desc->memdevs.prev);
+	list_cut_position(&prev.dcrs, &acpi_desc->dcrs,
+				acpi_desc->dcrs.prev);
+	list_cut_position(&prev.bdws, &acpi_desc->bdws,
+				acpi_desc->bdws.prev);
+	list_cut_position(&prev.idts, &acpi_desc->idts,
+				acpi_desc->idts.prev);
+	list_cut_position(&prev.flushes, &acpi_desc->flushes,
+				acpi_desc->flushes.prev);
+
+	end = data + sz;
+	while (!IS_ERR_OR_NULL(data))
+		data = add_table(acpi_desc, &prev, data, end);
+
+	if (IS_ERR(data)) {
+		dev_dbg(dev, "%s: nfit table parsing error: %ld\n", __func__,
+				PTR_ERR(data));
+		rc = PTR_ERR(data);
+		goto out_unlock;
+	}
+
+	rc = acpi_nfit_check_deletions(acpi_desc, &prev);
+	if (rc)
+		goto out_unlock;
+
+	rc = nfit_mem_init(acpi_desc);
+	if (rc)
+		goto out_unlock;
+
+	rc = acpi_nfit_register_dimms(acpi_desc);
+	if (rc)
+		goto out_unlock;
+
+	rc = acpi_nfit_register_regions(acpi_desc);
+
+ out_unlock:
+	mutex_unlock(&acpi_desc->init_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(acpi_nfit_init);
+
+struct acpi_nfit_flush_work {
+	struct work_struct work;
+	struct completion cmp;
+};
+
+static void flush_probe(struct work_struct *work)
+{
+	struct acpi_nfit_flush_work *flush;
+
+	flush = container_of(work, typeof(*flush), work);
+	complete(&flush->cmp);
+}
+
+static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc)
+{
+	struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
+	struct device *dev = acpi_desc->dev;
+	struct acpi_nfit_flush_work flush;
+
+	/* bounce the device lock to flush acpi_nfit_add / acpi_nfit_notify */
+	device_lock(dev);
+	device_unlock(dev);
+
+	/*
+	 * Scrub work could take 10s of seconds, userspace may give up so we
+	 * need to be interruptible while waiting.
+	 */
+	INIT_WORK_ONSTACK(&flush.work, flush_probe);
+	COMPLETION_INITIALIZER_ONSTACK(flush.cmp);
+	queue_work(nfit_wq, &flush.work);
+	return wait_for_completion_interruptible(&flush.cmp);
+}
+
+static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
+		struct nvdimm *nvdimm, unsigned int cmd)
+{
+	struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
+
+	if (nvdimm)
+		return 0;
+	if (cmd != ND_CMD_ARS_START)
+		return 0;
+
+	/*
+	 * The kernel and userspace may race to initiate a scrub, but
+	 * the scrub thread is prepared to lose that initial race.  It
+	 * just needs guarantees that any ars it initiates are not
+	 * interrupted by any intervening start reqeusts from userspace.
+	 */
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	return 0;
+}
+
+static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
+
+	if (work_busy(&acpi_desc->work))
+		return -EBUSY;
+
+	if (acpi_desc->cancel)
+		return 0;
+
+	mutex_lock(&acpi_desc->init_mutex);
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+
+		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+			continue;
+
+		nfit_spa->ars_required = 1;
+	}
+	queue_work(nfit_wq, &acpi_desc->work);
+	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
+	mutex_unlock(&acpi_desc->init_mutex);
+
+	return 0;
+}
+
+void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
+{
+	struct nvdimm_bus_descriptor *nd_desc;
+
+	dev_set_drvdata(dev, acpi_desc);
+	acpi_desc->dev = dev;
+	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->module = THIS_MODULE;
+	nd_desc->ndctl = acpi_nfit_ctl;
+	nd_desc->flush_probe = acpi_nfit_flush_probe;
+	nd_desc->clear_to_send = acpi_nfit_clear_to_send;
+	nd_desc->attr_groups = acpi_nfit_attribute_groups;
+
+	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->flushes);
+	INIT_LIST_HEAD(&acpi_desc->memdevs);
+	INIT_LIST_HEAD(&acpi_desc->dimms);
+	mutex_init(&acpi_desc->init_mutex);
+	INIT_WORK(&acpi_desc->work, acpi_nfit_scrub);
+}
+EXPORT_SYMBOL_GPL(acpi_nfit_desc_init);
+
+static int acpi_nfit_add(struct acpi_device *adev)
+{
+	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
+	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 = 0;
+
+	status = acpi_get_table_with_size(ACPI_SIG_NFIT, 0, &tbl, &sz);
+	if (ACPI_FAILURE(status)) {
+		/* This is ok, we could have an nvdimm hotplugged later */
+		dev_dbg(dev, "failed to find NFIT at startup\n");
+		return 0;
+	}
+
+	acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL);
+	if (!acpi_desc)
+		return -ENOMEM;
+	acpi_nfit_desc_init(acpi_desc, &adev->dev);
+
+	/* Save the acpi header for exporting the revision via sysfs */
+	acpi_desc->acpi_header = *tbl;
+
+	/* Evaluate _FIT and override with that if present */
+	status = acpi_evaluate_object(adev->handle, "_FIT", NULL, &buf);
+	if (ACPI_SUCCESS(status) && buf.length > 0) {
+		union acpi_object *obj = buf.pointer;
+
+		if (obj->type == ACPI_TYPE_BUFFER)
+			rc = acpi_nfit_init(acpi_desc, obj->buffer.pointer,
+					obj->buffer.length);
+		else
+			dev_dbg(dev, "%s invalid type %d, ignoring _FIT\n",
+				 __func__, (int) obj->type);
+		kfree(buf.pointer);
+	} else
+		/* skip over the lead-in header table */
+		rc = acpi_nfit_init(acpi_desc, (void *) tbl
+				+ sizeof(struct acpi_table_nfit),
+				sz - sizeof(struct acpi_table_nfit));
+	return rc;
+}
+
+static int acpi_nfit_remove(struct acpi_device *adev)
+{
+	/* see acpi_nfit_destruct */
+	return 0;
+}
+
+static void acpi_nfit_notify(struct acpi_device *adev, u32 event)
+{
+	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
+	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
+	struct device *dev = &adev->dev;
+	union acpi_object *obj;
+	acpi_status status;
+	int ret;
+
+	dev_dbg(dev, "%s: event: %d\n", __func__, event);
+
+	device_lock(dev);
+	if (!dev->driver) {
+		/* dev->driver may be null if we're being removed */
+		dev_dbg(dev, "%s: no driver found for dev\n", __func__);
+		goto out_unlock;
+	}
+
+	if (!acpi_desc) {
+		acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL);
+		if (!acpi_desc)
+			goto out_unlock;
+		acpi_nfit_desc_init(acpi_desc, &adev->dev);
+	} else {
+		/*
+		 * Finish previous registration before considering new
+		 * regions.
+		 */
+		flush_workqueue(nfit_wq);
+	}
+
+	/* Evaluate _FIT */
+	status = acpi_evaluate_object(adev->handle, "_FIT", NULL, &buf);
+	if (ACPI_FAILURE(status)) {
+		dev_err(dev, "failed to evaluate _FIT\n");
+		goto out_unlock;
+	}
+
+	obj = buf.pointer;
+	if (obj->type == ACPI_TYPE_BUFFER) {
+		ret = acpi_nfit_init(acpi_desc, obj->buffer.pointer,
+				obj->buffer.length);
+		if (ret)
+			dev_err(dev, "failed to merge updated NFIT\n");
+	} else
+		dev_err(dev, "Invalid _FIT\n");
+	kfree(buf.pointer);
+
+ out_unlock:
+	device_unlock(dev);
+}
+
+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,
+		.notify = acpi_nfit_notify,
+	},
+};
+
+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]);
+	acpi_str_to_uuid(UUID_NFIT_DIMM_N_HPE1, nfit_uuid[NFIT_DEV_DIMM_N_HPE1]);
+	acpi_str_to_uuid(UUID_NFIT_DIMM_N_HPE2, nfit_uuid[NFIT_DEV_DIMM_N_HPE2]);
+	acpi_str_to_uuid(UUID_NFIT_DIMM_N_MSFT, nfit_uuid[NFIT_DEV_DIMM_N_MSFT]);
+
+	nfit_wq = create_singlethread_workqueue("nfit");
+	if (!nfit_wq)
+		return -ENOMEM;
+
+	return acpi_bus_register_driver(&acpi_nfit_driver);
+}
+
+static __exit void nfit_exit(void)
+{
+	acpi_bus_unregister_driver(&acpi_nfit_driver);
+	destroy_workqueue(nfit_wq);
+}
+
+module_init(nfit_init);
+module_exit(nfit_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Intel Corporation");