diff mbox

[v5,02/21] libnvdimm, nfit: initial libnvdimm infrastructure and NFIT support

Message ID 20150602001419.4506.41953.stgit@dwillia2-desk3.amr.corp.intel.com
State Superseded
Headers show

Commit Message

Dan Williams June 2, 2015, 12:14 a.m. UTC
A libnvdimm bus is the anchor device for registering nvdimm resources and
interfaces, for example, a character control device, nvdimm devices,
and I/O region devices.  The ACPI NFIT (NVDIMM Firmware Interface Table)
is one possible platform description for such non-volatile memory
resources in a system.  The nfit.ko driver attaches to the "ACPI0012"
device that indicates the presence of the NFIT and parses the table to
register a libnvdimm bus instance.

Cc: <linux-acpi@vger.kernel.org>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/Kconfig             |    2 
 drivers/Makefile            |    1 
 drivers/acpi/Kconfig        |   15 +
 drivers/acpi/Makefile       |    1 
 drivers/acpi/nfit.c         |  444 +++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/nfit.h         |   89 +++++++++
 drivers/nvdimm/Kconfig      |   20 ++
 drivers/nvdimm/Makefile     |    3 
 drivers/nvdimm/core.c       |   67 ++++++
 drivers/nvdimm/nd-private.h |   23 ++
 include/linux/libnvdimm.h   |   34 +++
 11 files changed, 699 insertions(+)
 create mode 100644 drivers/acpi/nfit.c
 create mode 100644 drivers/acpi/nfit.h
 create mode 100644 drivers/nvdimm/Kconfig
 create mode 100644 drivers/nvdimm/Makefile
 create mode 100644 drivers/nvdimm/core.c
 create mode 100644 drivers/nvdimm/nd-private.h
 create mode 100644 include/linux/libnvdimm.h

Comments

Christoph Hellwig June 3, 2015, 2:57 p.m. UTC | #1
On Mon, Jun 01, 2015 at 08:14:19PM -0400, Dan Williams wrote:
> A libnvdimm bus is the anchor device for registering nvdimm resources and
> interfaces, for example, a character control device, nvdimm devices,
> and I/O region devices.  The ACPI NFIT (NVDIMM Firmware Interface Table)
> is one possible platform description for such non-volatile memory
> resources in a system.  The nfit.ko driver attaches to the "ACPI0012"
> device that indicates the presence of the NFIT and parses the table to
> register a libnvdimm bus instance.

Havin lib in a name of a bus seems odd.  Why not simply the nvdimm bus?

Also this seems to both have the generic nvdimm infrastructure as well
as the acpi wiring.  Might make sense to split this into two patches?

> +config ACPI_NFIT
> +	tristate "ACPI NVDIMM Firmware Interface Table (NFIT)"
> +	depends on PHYS_ADDR_T_64BIT
> +	depends on BLK_DEV
> +	select NVDIMM_DEVICES
> +	select LIBNVDIMM

Is this the right way for the user to chose it?  It seems like enabling
the NVMDIMM subsystem would be the obvious choice, and ACPI would
simply enable the table parsing in that case.

> +static u8 nfit_uuid[NFIT_UUID_MAX][16];

Should this use the uuid_le type?

> +static const char *spa_type_name(u16 type)
> +{
> +	switch (type) {
> +	case NFIT_SPA_VOLATILE: return "volatile";
> +	case NFIT_SPA_PM: return "pmem";
> +	case NFIT_SPA_DCR: return "dimm-control-region";
> +	case NFIT_SPA_BDW: return "block-data-window";
> +	default: return "unknown";

Please never put code on the same line as a switch (or goto) label.

> +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 = (struct acpi_nfit_header *) table;

No need to case from void * to another pointer type.

> +	switch (hdr->type) {
> +	case ACPI_NFIT_TYPE_SYSTEM_ADDRESS: {
> +		struct nfit_spa *nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa),
> +				GFP_KERNEL);
> +		struct acpi_nfit_system_address *spa = table;
> +
> +		if (!nfit_spa)
> +			return err;
> +		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)));

If you need local variables inside a switch statement you probably
want to split each case into a separate helper function.

> +static inline struct acpi_nfit_memory_map *__to_nfit_memdev(struct nfit_mem *nfit_mem)

This line is over 80 characters.

Also why the odd __-prefix?

> new file mode 100644
> index 000000000000..24b51dbc8215
> --- /dev/null
> +++ b/drivers/nvdimm/Kconfig
> @@ -0,0 +1,20 @@
> +menuconfig NVDIMM_DEVICES
> +	bool "NVDIMM (Non-Volatile Memory Device) Support"
> +	help
> +	  Generic support for non-volatile memory devices including
> +	  ACPI-6-NFIT defined resources.  On platforms that define an
> +	  NFIT, or otherwise can discover NVDIMM resources, a libnvdimm
> +	  bus is registered to advertise PMEM (persistent memory)
> +	  namespaces (/dev/pmemX) and BLK (sliding mmio window(s))
> +	  namespaces (/dev/ndX). A PMEM namespace refers to a memory
> +	  resource that may span multiple DIMMs and support DAX (see
> +	  CONFIG_DAX).  A BLK namespace refers to an NVDIMM control
> +	  region which exposes an mmio register set for windowed
> +	  access mode to non-volatile memory.
> +
> +if NVDIMM_DEVICES
> +
> +config LIBNVDIMM
> +	tristate
> +
> +endif

What different meanings will CONFIG_NVDIMM_DEVICES and CONFIG_LIBNVDIMM
have?

> diff --git a/drivers/nvdimm/nd-private.h b/drivers/nvdimm/nd-private.h
> new file mode 100644
> index 000000000000..e7c4e99a22a4
> --- /dev/null
> +++ b/drivers/nvdimm/nd-private.h

No need for -private if you're already under drivers/nvdimm..

> +#ifndef __ND_PRIVATE_H__
> +#define __ND_PRIVATE_H__
> +#include <linux/libnvdimm.h>
> +#include <linux/device.h>
> +
> +struct nvdimm_bus {
> +	struct nvdimm_bus_descriptor *nd_desc;
> +	struct device dev;
> +	int id;
> +};
> +#endif /* __ND_PRIVATE_H__ */

At least so far this header doesn't need libnvdimm.h

> +#ifndef __LIBNVDIMM_H__
> +#define __LIBNVDIMM_H__
> +struct nvdimm;
> +struct nvdimm_bus_descriptor;
> +typedef int (*ndctl_fn)(struct nvdimm_bus_descriptor *nd_desc,
> +		struct nvdimm *nvdimm, unsigned int cmd, void *buf,
> +		unsigned int buf_len);
> +
> +struct nvdimm_bus_descriptor {
> +	unsigned long dsm_mask;
> +	char *provider_name;
> +	ndctl_fn ndctl;
> +};

Please provide proper methods that do one thing properly instead of
ioctl-like multiplexers.
diff mbox

Patch

diff --git a/drivers/Kconfig b/drivers/Kconfig
index c0cc96bab9e7..6e973b8e3a3b 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -182,4 +182,6 @@  source "drivers/thunderbolt/Kconfig"
 
 source "drivers/android/Kconfig"
 
+source "drivers/nvdimm/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 46d2554be404..80025088115e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -64,6 +64,7 @@  obj-$(CONFIG_FB_INTEL)          += video/fbdev/intelfb/
 
 obj-$(CONFIG_PARPORT)		+= parport/
 obj-y				+= base/ block/ misc/ mfd/ nfc/
+obj-$(CONFIG_NVDIMM_DEVICES)	+= nvdimm/
 obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf/
 obj-$(CONFIG_NUBUS)		+= nubus/
 obj-y				+= macintosh/
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ab2cbb51c6aa..3989660ceb8f 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -383,6 +383,21 @@  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 NVDIMM_DEVICES
+	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.
+
 source "drivers/acpi/apei/Kconfig"
 
 config ACPI_EXTLOG
diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 8a063e276530..f7e9c92ccdcb 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -71,6 +71,7 @@  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..314cf9d2522b
--- /dev/null
+++ b/drivers/acpi/nfit.c
@@ -0,0 +1,444 @@ 
+/*
+ * 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/list.h>
+#include <linux/acpi.h>
+#include "nfit.h"
+
+static u8 nfit_uuid[NFIT_UUID_MAX][16];
+
+static const u8 *to_nfit_uuid(enum nfit_uuids id)
+{
+	return nfit_uuid[id];
+}
+
+static int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc,
+		struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+		unsigned int buf_len)
+{
+	return -ENOTTY;
+}
+
+static const char *spa_type_name(u16 type)
+{
+	switch (type) {
+	case NFIT_SPA_VOLATILE: return "volatile";
+	case NFIT_SPA_PM: return "pmem";
+	case NFIT_SPA_DCR: return "dimm-control-region";
+	case NFIT_SPA_BDW: return "block-data-window";
+	default: return "unknown";
+	}
+}
+
+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 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 = (struct acpi_nfit_header *) table;
+	switch (hdr->type) {
+	case ACPI_NFIT_TYPE_SYSTEM_ADDRESS: {
+		struct nfit_spa *nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa),
+				GFP_KERNEL);
+		struct acpi_nfit_system_address *spa = table;
+
+		if (!nfit_spa)
+			return err;
+		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)));
+		break;
+	}
+	case ACPI_NFIT_TYPE_MEMORY_MAP: {
+		struct nfit_memdev *nfit_memdev = devm_kzalloc(dev,
+				sizeof(*nfit_memdev), GFP_KERNEL);
+		struct acpi_nfit_memory_map *memdev = table;
+
+		if (!nfit_memdev)
+			return err;
+		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);
+		break;
+	}
+	case ACPI_NFIT_TYPE_CONTROL_REGION: {
+		struct nfit_dcr *nfit_dcr = devm_kzalloc(dev, sizeof(*nfit_dcr),
+				GFP_KERNEL);
+		struct acpi_nfit_control_region *dcr = table;
+
+		if (!nfit_dcr)
+			return err;
+		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);
+		break;
+	}
+	case ACPI_NFIT_TYPE_DATA_REGION: {
+		struct nfit_bdw *nfit_bdw = devm_kzalloc(dev, sizeof(*nfit_bdw),
+				GFP_KERNEL);
+		struct acpi_nfit_data_region *bdw = table;
+
+		if (!nfit_bdw)
+			return err;
+		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);
+		break;
+	}
+	/* TODO */
+	case ACPI_NFIT_TYPE_INTERLEAVE:
+		dev_dbg(dev, "%s: idt\n", __func__);
+		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_index = 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_index)
+				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_index = __to_nfit_memdev(nfit_mem)->region_index;
+	struct nfit_dcr *nfit_dcr;
+	struct nfit_bdw *nfit_bdw;
+
+	list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
+		if (nfit_dcr->dcr->region_index != dcr_index)
+			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_index)
+			continue;
+		nfit_mem->bdw = nfit_bdw->bdw;
+		break;
+	}
+
+	if (!nfit_mem->bdw)
+		return 0;
+
+	nfit_mem_find_spa_bdw(acpi_desc, nfit_mem);
+	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_index;
+
+	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_index = nfit_memdev->memdev->region_index;
+		list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
+			if (__to_nfit_memdev(nfit_mem)->region_index == dcr_index) {
+				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) {
+			/* multiple dimms may share a SPA when interleaved */
+			nfit_mem->spa_dcr = spa;
+			nfit_mem->memdev_dcr = nfit_memdev->memdev;
+		} 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 int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, acpi_size sz)
+{
+	struct device *dev = acpi_desc->dev;
+	const void *end;
+	u8 *data;
+
+	INIT_LIST_HEAD(&acpi_desc->spas);
+	INIT_LIST_HEAD(&acpi_desc->dcrs);
+	INIT_LIST_HEAD(&acpi_desc->bdws);
+	INIT_LIST_HEAD(&acpi_desc->memdevs);
+	INIT_LIST_HEAD(&acpi_desc->dimms);
+
+	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;
+
+	return 0;
+}
+
+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;
+	nd_desc = &acpi_desc->nd_desc;
+	nd_desc->provider_name = "ACPI.NFIT";
+	nd_desc->ndctl = acpi_nfit_ctl;
+
+	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,
+	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
+	.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..2d98cc1b7b6c
--- /dev/null
+++ b/drivers/acpi/nfit.h
@@ -0,0 +1,89 @@ 
+/*
+ * 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"
+
+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_memdev {
+	struct acpi_nfit_memory_map *memdev;
+	struct list_head list;
+};
+
+/* assembled tables for a given dimm/memory-device */
+struct nfit_mem {
+	struct acpi_nfit_memory_map *memdev_dcr;
+	struct acpi_nfit_memory_map *memdev_pmem;
+	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 list_head list;
+};
+
+struct acpi_nfit_desc {
+	struct nvdimm_bus_descriptor nd_desc;
+	struct acpi_table_nfit *nfit;
+	struct list_head memdevs;
+	struct list_head dimms;
+	struct list_head spas;
+	struct list_head dcrs;
+	struct list_head bdws;
+	struct nvdimm_bus *nvdimm_bus;
+	struct device *dev;
+};
+
+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;
+}
+#endif /* __NFIT_H__ */
diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
new file mode 100644
index 000000000000..24b51dbc8215
--- /dev/null
+++ b/drivers/nvdimm/Kconfig
@@ -0,0 +1,20 @@ 
+menuconfig NVDIMM_DEVICES
+	bool "NVDIMM (Non-Volatile Memory Device) Support"
+	help
+	  Generic support for non-volatile memory devices including
+	  ACPI-6-NFIT defined resources.  On platforms that define an
+	  NFIT, or otherwise can discover NVDIMM resources, a libnvdimm
+	  bus is registered to advertise PMEM (persistent memory)
+	  namespaces (/dev/pmemX) and BLK (sliding mmio window(s))
+	  namespaces (/dev/ndX). A PMEM namespace refers to a memory
+	  resource that may span multiple DIMMs and support DAX (see
+	  CONFIG_DAX).  A BLK namespace refers to an NVDIMM control
+	  region which exposes an mmio register set for windowed
+	  access mode to non-volatile memory.
+
+if NVDIMM_DEVICES
+
+config LIBNVDIMM
+	tristate
+
+endif
diff --git a/drivers/nvdimm/Makefile b/drivers/nvdimm/Makefile
new file mode 100644
index 000000000000..10bc7af47992
--- /dev/null
+++ b/drivers/nvdimm/Makefile
@@ -0,0 +1,3 @@ 
+obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o
+
+libnvdimm-y := core.o
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
new file mode 100644
index 000000000000..eeec6dd2fed1
--- /dev/null
+++ b/drivers/nvdimm/core.c
@@ -0,0 +1,67 @@ 
+/*
+ * 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/libnvdimm.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include "nd-private.h"
+
+static DEFINE_IDA(nd_ida);
+
+static void nvdimm_bus_release(struct device *dev)
+{
+	struct nvdimm_bus *nvdimm_bus = container_of(dev, struct nvdimm_bus, dev);
+
+	ida_simple_remove(&nd_ida, nvdimm_bus->id);
+	kfree(nvdimm_bus);
+}
+
+struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
+		struct nvdimm_bus_descriptor *nd_desc)
+{
+	struct nvdimm_bus *nvdimm_bus = kzalloc(sizeof(*nvdimm_bus), GFP_KERNEL);
+	int rc;
+
+	if (!nvdimm_bus)
+		return NULL;
+	nvdimm_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);
+	if (nvdimm_bus->id < 0) {
+		kfree(nvdimm_bus);
+		return NULL;
+	}
+	nvdimm_bus->nd_desc = nd_desc;
+	nvdimm_bus->dev.parent = parent;
+	nvdimm_bus->dev.release = nvdimm_bus_release;
+	dev_set_name(&nvdimm_bus->dev, "ndbus%d", nvdimm_bus->id);
+	rc = device_register(&nvdimm_bus->dev);
+	if (rc) {
+		dev_dbg(&nvdimm_bus->dev, "device registration failed: %d\n", rc);
+		put_device(&nvdimm_bus->dev);
+		return NULL;
+	}
+
+	return nvdimm_bus;
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_register);
+
+void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
+{
+	if (!nvdimm_bus)
+		return;
+	device_unregister(&nvdimm_bus->dev);
+}
+EXPORT_SYMBOL_GPL(nvdimm_bus_unregister);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Intel Corporation");
diff --git a/drivers/nvdimm/nd-private.h b/drivers/nvdimm/nd-private.h
new file mode 100644
index 000000000000..e7c4e99a22a4
--- /dev/null
+++ b/drivers/nvdimm/nd-private.h
@@ -0,0 +1,23 @@ 
+/*
+ * 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 __ND_PRIVATE_H__
+#define __ND_PRIVATE_H__
+#include <linux/libnvdimm.h>
+#include <linux/device.h>
+
+struct nvdimm_bus {
+	struct nvdimm_bus_descriptor *nd_desc;
+	struct device dev;
+	int id;
+};
+#endif /* __ND_PRIVATE_H__ */
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
new file mode 100644
index 000000000000..2b3c63950c91
--- /dev/null
+++ b/include/linux/libnvdimm.h
@@ -0,0 +1,34 @@ 
+/*
+ * libnvdimm - Non-volatile-memory Devices Subsystem
+ *
+ * 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 __LIBNVDIMM_H__
+#define __LIBNVDIMM_H__
+struct nvdimm;
+struct nvdimm_bus_descriptor;
+typedef int (*ndctl_fn)(struct nvdimm_bus_descriptor *nd_desc,
+		struct nvdimm *nvdimm, unsigned int cmd, void *buf,
+		unsigned int buf_len);
+
+struct nvdimm_bus_descriptor {
+	unsigned long dsm_mask;
+	char *provider_name;
+	ndctl_fn ndctl;
+};
+
+struct device;
+struct nvdimm_bus;
+struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
+		struct nvdimm_bus_descriptor *nfit_desc);
+void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus);
+#endif /* __LIBNVDIMM_H__ */