diff mbox

[v2,02/20] libnd, nd_acpi: initial libnd infrastructure and NFIT support

Message ID 20150428182423.35812.20930.stgit@dwillia2-desk3.amr.corp.intel.com
State Superseded
Delegated to: Dan Williams
Headers show

Commit Message

Dan Williams April 28, 2015, 6:24 p.m. UTC
1/ Autodetect an NFIT table for the ACPI namespace device with _HID of
   "ACPI0012"

2/ libnd bus registration

The NFIT provided by ACPI is one possible method by which platforms will
discover NVDIMM resources.  However, the intent of the nd_bus_descriptor
abstraction is to abstract "provider" specific details, leaving libnd
to be independent of the specific NVDIMM resource discovery mechanism.
This flexibility is later exploited later to implement custom-defined nd
buses.

Cc: <linux-acpi@vger.kernel.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/block/Kconfig         |    2 
 drivers/block/Makefile        |    1 
 drivers/block/nd/Kconfig      |   40 +++
 drivers/block/nd/Makefile     |    6 +
 drivers/block/nd/acpi.c       |  475 +++++++++++++++++++++++++++++++++++++++++
 drivers/block/nd/acpi_nfit.h  |  254 ++++++++++++++++++++++
 drivers/block/nd/core.c       |   67 ++++++
 drivers/block/nd/libnd.h      |   33 +++
 drivers/block/nd/nd-private.h |   23 ++
 9 files changed, 901 insertions(+)
 create mode 100644 drivers/block/nd/Kconfig
 create mode 100644 drivers/block/nd/Makefile
 create mode 100644 drivers/block/nd/acpi.c
 create mode 100644 drivers/block/nd/acpi_nfit.h
 create mode 100644 drivers/block/nd/core.c
 create mode 100644 drivers/block/nd/libnd.h
 create mode 100644 drivers/block/nd/nd-private.h

Comments

Rafael J. Wysocki April 30, 2015, 11:23 p.m. UTC | #1
On Tuesday, April 28, 2015 02:24:23 PM Dan Williams wrote:
> 1/ Autodetect an NFIT table for the ACPI namespace device with _HID of
>    "ACPI0012"
> 
> 2/ libnd bus registration
> 
> The NFIT provided by ACPI is one possible method by which platforms will
> discover NVDIMM resources.  However, the intent of the nd_bus_descriptor
> abstraction is to abstract "provider" specific details, leaving libnd
> to be independent of the specific NVDIMM resource discovery mechanism.
> This flexibility is later exploited later to implement custom-defined nd
> buses.
> 
> Cc: <linux-acpi@vger.kernel.org>
> Cc: Robert Moore <robert.moore@intel.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  drivers/block/Kconfig         |    2 
>  drivers/block/Makefile        |    1 
>  drivers/block/nd/Kconfig      |   40 +++
>  drivers/block/nd/Makefile     |    6 +
>  drivers/block/nd/acpi.c       |  475 +++++++++++++++++++++++++++++++++++++++++
>  drivers/block/nd/acpi_nfit.h  |  254 ++++++++++++++++++++++
>  drivers/block/nd/core.c       |   67 ++++++
>  drivers/block/nd/libnd.h      |   33 +++
>  drivers/block/nd/nd-private.h |   23 ++
>  9 files changed, 901 insertions(+)
>  create mode 100644 drivers/block/nd/Kconfig
>  create mode 100644 drivers/block/nd/Makefile
>  create mode 100644 drivers/block/nd/acpi.c
>  create mode 100644 drivers/block/nd/acpi_nfit.h
>  create mode 100644 drivers/block/nd/core.c
>  create mode 100644 drivers/block/nd/libnd.h
>  create mode 100644 drivers/block/nd/nd-private.h
> 
> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> index eb1fed5bd516..dfe40e5ca9bd 100644
> --- a/drivers/block/Kconfig
> +++ b/drivers/block/Kconfig
> @@ -321,6 +321,8 @@ config BLK_DEV_NVME
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called nvme.
>  
> +source "drivers/block/nd/Kconfig"
> +
>  config BLK_DEV_SKD
>  	tristate "STEC S1120 Block Driver"
>  	depends on PCI
> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
> index 9cc6c18a1c7e..07a6acecf4d8 100644
> --- a/drivers/block/Makefile
> +++ b/drivers/block/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
>  obj-$(CONFIG_MG_DISK)		+= mg_disk.o
>  obj-$(CONFIG_SUNVDC)		+= sunvdc.o
>  obj-$(CONFIG_BLK_DEV_NVME)	+= nvme.o
> +obj-$(CONFIG_ND_DEVICES)	+= nd/
>  obj-$(CONFIG_BLK_DEV_SKD)	+= skd.o
>  obj-$(CONFIG_BLK_DEV_OSD)	+= osdblk.o
>  
> diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig
> new file mode 100644
> index 000000000000..6d5d6b732f82
> --- /dev/null
> +++ b/drivers/block/nd/Kconfig
> @@ -0,0 +1,40 @@
> +menuconfig ND_DEVICES
> +	bool "NVDIMM Support"
> +	depends on PHYS_ADDR_T_64BIT
> +	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 libnd
> +	  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 ND_DEVICES
> +
> +config LIBND
> +	tristate "LIBND: libnd device driver support"
> +	help
> +	  Platform agnostic device model for a libnd bus.  Publishes
> +	  resources for a PMEM (persistent-memory) driver and/or BLK
> +	  (sliding mmio window(s)) driver to attach.  Exposes a device
> +	  topology under a "ndX" bus device, a "/dev/ndctlX" bus-ioctl
> +	  message passing interface, and a "/dev/nmemX" dimm-ioctl
> +	  message interface for each memory device registered on the
> +	  bus.  instance.  A userspace library "ndctl" provides an API
> +	  to enumerate/manage this subsystem.
> +
> +config ND_ACPI
> +	tristate "ACPI: NFIT to libnd bus support"
> +	select LIBND
> +	depends on ACPI
> +	help
> +	  Infrastructure to probe ACPI 6 compliant platforms for
> +	  NVDIMMs (NFIT) and register a libnd device tree.  In
> +	  addition to storage devices this also enables libnd craft
> +	  ACPI._DSM messages for platform/dimm configuration.

I'm wondering if the two CONFIG options above really need to be user-selectable?

For example, what reason people (who've already selected ND_DEVICES) may have
for not selecting ND_ACPI if ACPI is set?

> +
> +endif
> diff --git a/drivers/block/nd/Makefile b/drivers/block/nd/Makefile
> new file mode 100644
> index 000000000000..944b5947c0cb
> --- /dev/null
> +++ b/drivers/block/nd/Makefile
> @@ -0,0 +1,6 @@
> +obj-$(CONFIG_LIBND) += libnd.o
> +obj-$(CONFIG_ND_ACPI) += nd_acpi.o
> +
> +nd_acpi-y := acpi.o
> +
> +libnd-y := core.o

OK, so it looks like no modules, just built-in code, right?

> diff --git a/drivers/block/nd/acpi.c b/drivers/block/nd/acpi.c
> new file mode 100644
> index 000000000000..9f0b24390d1b
> --- /dev/null
> +++ b/drivers/block/nd/acpi.c
> @@ -0,0 +1,475 @@
> +/*
> + * 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/module.h>
> +#include <linux/list.h>
> +#include <linux/acpi.h>
> +#include "acpi_nfit.h"
> +#include "libnd.h"
> +
> +static bool warn_checksum;
> +module_param(warn_checksum, bool, S_IRUGO|S_IWUSR);
> +MODULE_PARM_DESC(warn_checksum, "Turn checksum errors into warnings");
> +
> +enum {
> +	NFIT_ACPI_NOTIFY_TABLE = 0x80,
> +};
> +
> +static int nd_acpi_ctl(struct nd_bus_descriptor *nd_desc,
> +		struct nd_dimm *nd_dimm, unsigned int cmd, void *buf,
> +		unsigned int buf_len)
> +{
> +	return -ENOTTY;
> +}

Why -ENOTTY?  And why not to leave a NULL entry for this instead and
make the library fail it in that case?

> +
> +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_spa *spa)
> +{
> +	if (memcmp(&nfit_spa_uuid_volatile, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_VOLATILE;
> +
> +	if (memcmp(&nfit_spa_uuid_pm, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_PM;
> +
> +	if (memcmp(&nfit_spa_uuid_dcr, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_DCR;
> +
> +	if (memcmp(&nfit_spa_uuid_bdw, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_BDW;
> +
> +	if (memcmp(&nfit_spa_uuid_vdisk, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_VDISK;
> +
> +	if (memcmp(&nfit_spa_uuid_vcd, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_VCD;
> +
> +	if (memcmp(&nfit_spa_uuid_pdisk, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_PDISK;
> +
> +	if (memcmp(&nfit_spa_uuid_pcd, spa->type_uuid, 16) == 0)
> +		return NFIT_SPA_PCD;
> +
> +	return -1;
> +}
> +
> +struct nfit_table_header {
> +	__le16 type;
> +	__le16 length;
> +};

That you'll be able to get from ACPICA I suppose?

> +
> +static void *add_table(struct acpi_nfit_desc *acpi_desc, void *table, const void *end)
> +{
> +	struct device *dev = acpi_desc->dev;
> +	struct nfit_table_header *hdr;
> +	void *err = ERR_PTR(-ENOMEM);
> +
> +	if (table >= end)
> +		return NULL;
> +
> +	hdr = (struct nfit_table_header *) table;
> +	switch (hdr->type) {
> +	case NFIT_TABLE_SPA: {
> +		struct nfit_spa *nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa),
> +				GFP_KERNEL);
> +		struct acpi_nfit_spa *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->spa_index,
> +				spa_type_name(nfit_spa_type(spa)));
> +		break;
> +	}
> +	case NFIT_TABLE_MEM: {
> +		struct nfit_memdev *nfit_memdev = devm_kzalloc(dev,
> +				sizeof(*nfit_memdev), GFP_KERNEL);
> +		struct acpi_nfit_memdev *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->nfit_handle, memdev->spa_index,
> +				memdev->dcr_index);
> +		break;
> +	}
> +	case NFIT_TABLE_DCR: {
> +		struct nfit_dcr *nfit_dcr = devm_kzalloc(dev, sizeof(*nfit_dcr),
> +				GFP_KERNEL);
> +		struct acpi_nfit_dcr *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 num_bcw: %d\n", __func__,
> +				dcr->dcr_index, dcr->num_bcw);
> +		break;
> +	}
> +	case NFIT_TABLE_BDW: {
> +		struct nfit_bdw *nfit_bdw = devm_kzalloc(dev, sizeof(*nfit_bdw),
> +				GFP_KERNEL);
> +		struct acpi_nfit_bdw *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 num_bdw: %d\n", __func__,
> +				bdw->dcr_index, bdw->num_bdw);
> +		break;
> +	}
> +	/* TODO */
> +	case NFIT_TABLE_IDT:
> +		dev_dbg(dev, "%s: idt\n", __func__);
> +		break;
> +	case NFIT_TABLE_FLUSH:
> +		dev_dbg(dev, "%s: flush\n", __func__);
> +		break;
> +	case NFIT_TABLE_SMBIOS:
> +		dev_dbg(dev, "%s: smbios\n", __func__);
> +		break;
> +	default:
> +		dev_err(dev, "unknown table '%d' parsing nfit\n", hdr->type);
> +		return ERR_PTR(-ENXIO);
> +	}
> +
> +	return table + hdr->length;
> +}
> +
> +static void nfit_mem_find_spa_bdw(struct acpi_nfit_desc *acpi_desc,
> +		struct nfit_mem *nfit_mem)
> +{
> +	u32 nfit_handle = __to_nfit_memdev(nfit_mem)->nfit_handle;
> +	u16 dcr_index = nfit_mem->dcr->dcr_index;
> +	struct nfit_spa *nfit_spa;
> +
> +	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
> +		u16 spa_index = nfit_spa->spa->spa_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->spa_index != spa_index)
> +				continue;
> +			if (nfit_memdev->memdev->nfit_handle != nfit_handle)
> +				continue;
> +			if (nfit_memdev->memdev->dcr_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->spa_index);
> +	nfit_mem->bdw = NULL;
> +}
> +
> +static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
> +		struct nfit_mem *nfit_mem, struct acpi_nfit_spa *spa)
> +{
> +	u16 dcr_index = __to_nfit_memdev(nfit_mem)->dcr_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->dcr_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->spa_index,
> +				__to_nfit_memdev(nfit_mem) ? "" : " MEMDEV",
> +				nfit_mem->dcr ? "" : " DCR");
> +		return -ENODEV;
> +	}
> +
> +	/*
> +	 * We've found enough to create an nd_dimm, 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->dcr_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_spa *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->spa_index != spa->spa_index)
> +			continue;
> +		found = NULL;
> +		dcr_index = nfit_memdev->memdev->dcr_index;
> +		list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
> +			if (__to_nfit_memdev(nfit_mem)->dcr_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)->nfit_handle;
> +	handleB = __to_nfit_memdev(b)->nfit_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 nd_acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, acpi_size sz)
> +{
> +	struct device *dev = acpi_desc->dev;
> +	const void *end;
> +	u8 *data, sum;
> +	acpi_size i;
> +
> +	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;
> +	for (i = 0, sum = 0; i < sz; i++)
> +		sum += readb(data + i);
> +	if (sum != 0 && !warn_checksum) {
> +		dev_dbg(dev, "%s: nfit checksum failure\n", __func__);
> +		return -ENXIO;
> +	}
> +	WARN_TAINT_ONCE(sum != 0, TAINT_FIRMWARE_WORKAROUND,
> +			"nfit checksum failure, continuing...\n");
> +
> +	end = data + sz;
> +	data += sizeof(struct acpi_nfit);
> +	while (!IS_ERR_OR_NULL(data))
> +		data = add_table(acpi_desc, data, end);

This looks like we are expecting a series of tables here and we're going to
fail the whole discovery if just one of them in invalid.

I wonder if it would be practical to skip just the invalid ones instead?

> +
> +	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 nd_acpi_add(struct acpi_device *adev)
> +{
> +	struct nd_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_nfit *) tbl;
> +	nd_desc = &acpi_desc->nd_desc;
> +	nd_desc->provider_name = "ACPI.NFIT";
> +	nd_desc->ndctl = nd_acpi_ctl;
> +
> +	acpi_desc->nd_bus = nd_bus_register(dev, nd_desc);
> +	if (!acpi_desc->nd_bus)
> +		return -ENXIO;
> +
> +	rc = nd_acpi_nfit_init(acpi_desc, sz);
> +	if (rc) {
> +		nd_bus_unregister(acpi_desc->nd_bus);
> +		return rc;
> +	}
> +	return 0;
> +}
> +
> +static int nd_acpi_remove(struct acpi_device *adev)
> +{
> +	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
> +
> +	nd_bus_unregister(acpi_desc->nd_bus);
> +	return 0;
> +}
> +
> +static void nd_acpi_notify(struct acpi_device *adev, u32 event)
> +{
> +	/* TODO: handle ACPI_NOTIFY_BUS_CHECK notification */
> +	dev_dbg(&adev->dev, "%s: event: %d\n", __func__, event);
> +}
> +
> +static const struct acpi_device_id nd_acpi_ids[] = {
> +	{ "ACPI0012", 0 },
> +	{ "", 0 },
> +};
> +MODULE_DEVICE_TABLE(acpi, nd_acpi_ids);
> +
> +static struct acpi_driver nd_acpi_driver = {
> +	.name = KBUILD_MODNAME,
> +	.ids = nd_acpi_ids,
> +	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
> +	.ops = {
> +		.add = nd_acpi_add,
> +		.remove = nd_acpi_remove,
> +		.notify = nd_acpi_notify
> +	},
> +};

Since this is going to be non-modular built-in code, please use an ACPI
scan handler instead of using a driver here.  acpi_memhotplug.c does that,
you can use it as an example, but I guess you don't need to enable hotplug
for it to start with.

> +
> +static __init int nd_acpi_init(void)
> +{
> +	BUILD_BUG_ON(sizeof(struct acpi_nfit) != 40);
> +	BUILD_BUG_ON(sizeof(struct acpi_nfit_spa) != 56);
> +	BUILD_BUG_ON(sizeof(struct acpi_nfit_memdev) != 48);
> +	BUILD_BUG_ON(sizeof(struct acpi_nfit_idt) != 16);
> +	BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 8);
> +	BUILD_BUG_ON(sizeof(struct acpi_nfit_dcr) != 80);
> +	BUILD_BUG_ON(sizeof(struct acpi_nfit_bdw) != 40);
> +
> +	return acpi_bus_register_driver(&nd_acpi_driver);
> +}
> +
> +static __exit void nd_acpi_exit(void)
> +{
> +	acpi_bus_unregister_driver(&nd_acpi_driver);
> +}
> +
> +module_init(nd_acpi_init);
> +module_exit(nd_acpi_exit);
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Intel Corporation");
> diff --git a/drivers/block/nd/acpi_nfit.h b/drivers/block/nd/acpi_nfit.h
> new file mode 100644
> index 000000000000..e0b0f12736bf
> --- /dev/null
> +++ b/drivers/block/nd/acpi_nfit.h

I'm assuming that the below is coordinated with Bob and David and will be
changed to use ACPICA-provided definitions going forward.

Is that correct?

> @@ -0,0 +1,254 @@
> +/*
> + * 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/types.h>
> +#include <linux/uuid.h>
> +#include <linux/acpi.h>
> +#include "libnd.h"
> +
> +static const uuid_le nfit_spa_uuid_volatile __maybe_unused = UUID_LE(0x7305944f,
> +		0xfdda, 0x44e3, 0xb1, 0x6c, 0x3f, 0x22, 0xd2, 0x52, 0xe5, 0xd0);
> +
> +static const uuid_le nfit_spa_uuid_pm __maybe_unused = UUID_LE(0x66f0d379,
> +		0xb4f3, 0x4074, 0xac, 0x43, 0x0d, 0x33, 0x18, 0xb7, 0x8c, 0xdb);
> +
> +static const uuid_le nfit_spa_uuid_dcr __maybe_unused = UUID_LE(0x92f701f6,
> +		0x13b4, 0x405d, 0x91, 0x0b, 0x29, 0x93, 0x67, 0xe8, 0x23, 0x4c);
> +
> +static const uuid_le nfit_spa_uuid_bdw __maybe_unused = UUID_LE(0x91af0530,
> +		0x5d86, 0x470e, 0xa6, 0xb0, 0x0a, 0x2d, 0xb9, 0x40, 0x82, 0x49);
> +
> +static const uuid_le nfit_spa_uuid_vdisk __maybe_unused = UUID_LE(0x77ab535a,
> +		0x45fc, 0x624b, 0x55, 0x60, 0xf7, 0xb2, 0x81, 0xd1, 0xf9, 0x6e);
> +
> +static const uuid_le nfit_spa_uuid_vcd __maybe_unused = UUID_LE(0x3d5abd30,
> +		0x4175, 0x87ce, 0x6d, 0x64, 0xd2, 0xad, 0xe5, 0x23, 0xc4, 0xbb);
> +
> +static const uuid_le nfit_spa_uuid_pdisk __maybe_unused = UUID_LE(0x5cea02c9,
> +		0x4d07, 0x69d3, 0x26, 0x9f, 0x44, 0x96, 0xfb, 0xe0, 0x96, 0xf9);
> +
> +static const uuid_le nfit_spa_uuid_pcd __maybe_unused = UUID_LE(0x08018188,
> +		0x42cd, 0xbb48, 0x10, 0x0f, 0x53, 0x87, 0xd5, 0x3d, 0xed, 0x3d);
> +
> +enum {
> +	NFIT_TABLE_SPA = 0,
> +	NFIT_TABLE_MEM = 1,
> +	NFIT_TABLE_IDT = 2,
> +	NFIT_TABLE_SMBIOS = 3,
> +	NFIT_TABLE_DCR = 4,
> +	NFIT_TABLE_BDW = 5,
> +	NFIT_TABLE_FLUSH = 6,
> +	NFIT_SPA_VOLATILE = 0,
> +	NFIT_SPA_PM = 1,
> +	NFIT_SPA_DCR = 2,
> +	NFIT_SPA_BDW = 3,
> +	NFIT_SPA_VDISK = 4,
> +	NFIT_SPA_VCD = 5,
> +	NFIT_SPA_PDISK = 6,
> +	NFIT_SPA_PCD = 7,
> +	NFIT_SPAF_DCR_HOT_ADD = 1 << 0,
> +	NFIT_SPAF_PDVALID = 1 << 1,
> +	NFIT_MEMF_SAVE_FAIL = 1 << 0,
> +	NFIT_MEMF_RESTORE_FAIL = 1 << 1,
> +	NFIT_MEMF_FLUSH_FAIL = 1 << 2,
> +	NFIT_MEMF_UNARMED = 1 << 3,
> +	NFIT_MEMF_NOTIFY_SMART = 1 << 4,
> +	NFIT_MEMF_SMART_READY = 1 << 5,
> +	NFIT_DCRF_BUFFERED = 1 << 0,
> +};
> +
> +/**
> + * struct acpi_nfit - Nvdimm Firmware Interface Table
> + * @signature: "NFIT"
> + * @length: sum of size of this table plus all appended subtables
> + */
> +struct acpi_nfit {
> +	u8 signature[4];
> +	u32 length;
> +	u8 revision;
> +	u8 checksum;
> +	u8 oemid[6];
> +	u64 oem_tbl_id;
> +	u32 oem_revision;
> +	u32 creator_id;
> +	u32 creator_revision;
> +	u32 reserved;
> +};
> +
> +/**
> + * struct acpi_nfit_spa - System Physical Address Range Descriptor Table
> + */
> +struct acpi_nfit_spa {
> +	u16 type;
> +	u16 length;
> +	u16 spa_index;
> +	u16 flags;
> +	u32 reserved;
> +	u32 proximity_domain;
> +	u8 type_uuid[16];
> +	u64 spa_base;
> +	u64 spa_length;
> +	u64 mem_attr;
> +};
> +
> +/**
> + * struct acpi_nfit_mem - Memory Device to SPA Mapping Table
> + */
> +struct acpi_nfit_memdev {
> +	u16 type;
> +	u16 length;
> +	u32 nfit_handle;
> +	u16 phys_id;
> +	u16 region_id;
> +	u16 spa_index;
> +	u16 dcr_index;
> +	u64 region_len;
> +	u64 region_spa_offset;
> +	u64 region_dpa;
> +	u16 idt_index;
> +	u16 interleave_ways;
> +	u16 flags;
> +	u16 reserved;
> +};
> +
> +/**
> + * struct acpi_nfit_idt - Interleave description Table
> + */
> +struct acpi_nfit_idt {
> +	u16 type;
> +	u16 length;
> +	u16 idt_index;
> +	u16 reserved;
> +	u32 num_lines;
> +	u32 line_size;
> +	u32 line_offset[0];
> +};
> +
> +/**
> + * struct acpi_nfit_smbios - SMBIOS Management Information Table
> + */
> +struct acpi_nfit_smbios {
> +	u16 type;
> +	u16 length;
> +	u32 reserved;
> +	u8 data[0];
> +};
> +
> +/**
> + * struct acpi_nfit_dcr - NVDIMM Control Region Table
> + * @fic: Format Interface Code
> + * @cmd_offset: command registers relative to block control window
> + * @status_offset: status registers relative to block control window
> + */
> +struct acpi_nfit_dcr {
> +	u16 type;
> +	u16 length;
> +	u16 dcr_index;
> +	u16 vendor_id;
> +	u16 device_id;
> +	u16 revision_id;
> +	u16 sub_vendor_id;
> +	u16 sub_device_id;
> +	u16 sub_revision_id;
> +	u8 reserved[6];
> +	u32 serial_number;
> +	u16 fic;
> +	u16 num_bcw;
> +	u64 bcw_size;
> +	u64 cmd_offset;
> +	u64 cmd_size;
> +	u64 status_offset;
> +	u64 status_size;
> +	u16 flags;
> +	u8 reserved2[6];
> +};
> +
> +/**
> + * struct acpi_nfit_bdw - NVDIMM Block Data Window Region Table
> + */
> +struct acpi_nfit_bdw {
> +	u16 type;
> +	u16 length;
> +	u16 dcr_index;
> +	u16 num_bdw;
> +	u64 bdw_offset;
> +	u64 bdw_size;
> +	u64 blk_capacity;
> +	u64 blk_offset;
> +};
> +
> +/**
> + * struct acpi_nfit_flush - Flush Hint Address Structure
> + */
> +struct acpi_nfit_flush {
> +	u16 type;
> +	u16 length;
> +	u32 nfit_handle;
> +	u16 num_hints;
> +	u8 reserved[6];
> +	u64 hint_addr[0];
> +};
> +
> +struct nfit_spa {
> +	struct acpi_nfit_spa *spa;
> +	struct list_head list;
> +};
> +
> +struct nfit_dcr {
> +	struct acpi_nfit_dcr *dcr;
> +	struct list_head list;
> +};
> +
> +struct nfit_bdw {
> +	struct acpi_nfit_bdw *bdw;
> +	struct list_head list;
> +};
> +
> +struct nfit_memdev {
> +	struct acpi_nfit_memdev *memdev;
> +	struct list_head list;
> +};
> +
> +/* assembled tables for a given dimm/memory-device */
> +struct nfit_mem {
> +	struct acpi_nfit_memdev *memdev_dcr;
> +	struct acpi_nfit_memdev *memdev_pmem;
> +	struct acpi_nfit_dcr *dcr;
> +	struct acpi_nfit_bdw *bdw;
> +	struct acpi_nfit_spa *spa_dcr;
> +	struct acpi_nfit_spa *spa_bdw;
> +	struct list_head list;
> +};
> +
> +struct acpi_nfit_desc {
> +	struct nd_bus_descriptor nd_desc;
> +	struct acpi_nfit *nfit;
> +	struct list_head memdevs;
> +	struct list_head dimms;
> +	struct list_head spas;
> +	struct list_head dcrs;
> +	struct list_head bdws;
> +	struct nd_bus *nd_bus;
> +	struct device *dev;
> +};
> +
> +static inline struct acpi_nfit_memdev *__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/block/nd/core.c b/drivers/block/nd/core.c
> new file mode 100644
> index 000000000000..3cccdbc0f3b7
> --- /dev/null
> +++ b/drivers/block/nd/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/export.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/slab.h>
> +#include "nd-private.h"
> +#include "libnd.h"
> +
> +static DEFINE_IDA(nd_ida);
> +
> +static void nd_bus_release(struct device *dev)
> +{
> +	struct nd_bus *nd_bus = container_of(dev, struct nd_bus, dev);
> +
> +	ida_simple_remove(&nd_ida, nd_bus->id);
> +	kfree(nd_bus);
> +}
> +
> +struct nd_bus *nd_bus_register(struct device *parent,
> +		struct nd_bus_descriptor *nd_desc)
> +{
> +	struct nd_bus *nd_bus = kzalloc(sizeof(*nd_bus), GFP_KERNEL);
> +	int rc;
> +
> +	if (!nd_bus)
> +		return NULL;
> +	nd_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);
> +	if (nd_bus->id < 0) {
> +		kfree(nd_bus);
> +		return NULL;
> +	}
> +	nd_bus->nd_desc = nd_desc;
> +	nd_bus->dev.parent = parent;
> +	nd_bus->dev.release = nd_bus_release;
> +	dev_set_name(&nd_bus->dev, "ndbus%d", nd_bus->id);
> +	rc = device_register(&nd_bus->dev);
> +	if (rc) {
> +		dev_dbg(&nd_bus->dev, "device registration failed: %d\n", rc);
> +		put_device(&nd_bus->dev);
> +		return NULL;
> +	}
> +
> +	return nd_bus;
> +}
> +EXPORT_SYMBOL_GPL(nd_bus_register);
> +
> +void nd_bus_unregister(struct nd_bus *nd_bus)
> +{
> +	if (!nd_bus)
> +		return;
> +	device_unregister(&nd_bus->dev);
> +}
> +EXPORT_SYMBOL_GPL(nd_bus_unregister);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Intel Corporation");
> diff --git a/drivers/block/nd/libnd.h b/drivers/block/nd/libnd.h
> new file mode 100644
> index 000000000000..163832937e9c
> --- /dev/null
> +++ b/drivers/block/nd/libnd.h
> @@ -0,0 +1,33 @@
> +/*
> + * libnd - 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 __LIBND_H__
> +#define __LIBND_H__
> +struct nd_dimm;
> +struct nd_bus_descriptor;
> +typedef int (*ndctl_fn)(struct nd_bus_descriptor *nd_desc,
> +		struct nd_dimm *nd_dimm, unsigned int cmd, void *buf,
> +		unsigned int buf_len);
> +
> +struct nd_bus_descriptor {
> +	unsigned long dsm_mask;
> +	char *provider_name;
> +	ndctl_fn ndctl;
> +};
> +
> +struct nd_bus;
> +struct nd_bus *nd_bus_register(struct device *parent,
> +		struct nd_bus_descriptor *nfit_desc);
> +void nd_bus_unregister(struct nd_bus *nd_bus);
> +#endif /* __LIBND_H__ */
> diff --git a/drivers/block/nd/nd-private.h b/drivers/block/nd/nd-private.h
> new file mode 100644
> index 000000000000..3dbab29fa0f9
> --- /dev/null
> +++ b/drivers/block/nd/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/device.h>
> +#include "libnd.h"
> +
> +struct nd_bus {
> +	struct nd_bus_descriptor *nd_desc;
> +	struct device dev;
> +	int id;
> +};
> +#endif /* __ND_PRIVATE_H__ */
> 
> --
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> Please read the FAQ at  http://www.tux.org/lkml/
Dan Williams May 1, 2015, 12:39 a.m. UTC | #2
On Thu, Apr 30, 2015 at 4:23 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Tuesday, April 28, 2015 02:24:23 PM Dan Williams wrote:
>> 1/ Autodetect an NFIT table for the ACPI namespace device with _HID of
>>    "ACPI0012"
>>
>> 2/ libnd bus registration
>>
>> The NFIT provided by ACPI is one possible method by which platforms will
>> discover NVDIMM resources.  However, the intent of the nd_bus_descriptor
>> abstraction is to abstract "provider" specific details, leaving libnd
>> to be independent of the specific NVDIMM resource discovery mechanism.
>> This flexibility is later exploited later to implement custom-defined nd
>> buses.
>>
>> Cc: <linux-acpi@vger.kernel.org>
>> Cc: Robert Moore <robert.moore@intel.com>
>> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>> ---
>>  drivers/block/Kconfig         |    2
>>  drivers/block/Makefile        |    1
>>  drivers/block/nd/Kconfig      |   40 +++
>>  drivers/block/nd/Makefile     |    6 +
>>  drivers/block/nd/acpi.c       |  475 +++++++++++++++++++++++++++++++++++++++++
>>  drivers/block/nd/acpi_nfit.h  |  254 ++++++++++++++++++++++
>>  drivers/block/nd/core.c       |   67 ++++++
>>  drivers/block/nd/libnd.h      |   33 +++
>>  drivers/block/nd/nd-private.h |   23 ++
>>  9 files changed, 901 insertions(+)
>>  create mode 100644 drivers/block/nd/Kconfig
>>  create mode 100644 drivers/block/nd/Makefile
>>  create mode 100644 drivers/block/nd/acpi.c
>>  create mode 100644 drivers/block/nd/acpi_nfit.h
>>  create mode 100644 drivers/block/nd/core.c
>>  create mode 100644 drivers/block/nd/libnd.h
>>  create mode 100644 drivers/block/nd/nd-private.h
>>
>> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
>> index eb1fed5bd516..dfe40e5ca9bd 100644
>> --- a/drivers/block/Kconfig
>> +++ b/drivers/block/Kconfig
>> @@ -321,6 +321,8 @@ config BLK_DEV_NVME
>>         To compile this driver as a module, choose M here: the
>>         module will be called nvme.
>>
>> +source "drivers/block/nd/Kconfig"
>> +
>>  config BLK_DEV_SKD
>>       tristate "STEC S1120 Block Driver"
>>       depends on PCI
>> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
>> index 9cc6c18a1c7e..07a6acecf4d8 100644
>> --- a/drivers/block/Makefile
>> +++ b/drivers/block/Makefile
>> @@ -24,6 +24,7 @@ obj-$(CONFIG_CDROM_PKTCDVD) += pktcdvd.o
>>  obj-$(CONFIG_MG_DISK)                += mg_disk.o
>>  obj-$(CONFIG_SUNVDC)         += sunvdc.o
>>  obj-$(CONFIG_BLK_DEV_NVME)   += nvme.o
>> +obj-$(CONFIG_ND_DEVICES)     += nd/
>>  obj-$(CONFIG_BLK_DEV_SKD)    += skd.o
>>  obj-$(CONFIG_BLK_DEV_OSD)    += osdblk.o
>>
>> diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig
>> new file mode 100644
>> index 000000000000..6d5d6b732f82
>> --- /dev/null
>> +++ b/drivers/block/nd/Kconfig
>> @@ -0,0 +1,40 @@
>> +menuconfig ND_DEVICES
>> +     bool "NVDIMM Support"
>> +     depends on PHYS_ADDR_T_64BIT
>> +     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 libnd
>> +       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 ND_DEVICES
>> +
>> +config LIBND
>> +     tristate "LIBND: libnd device driver support"
>> +     help
>> +       Platform agnostic device model for a libnd bus.  Publishes
>> +       resources for a PMEM (persistent-memory) driver and/or BLK
>> +       (sliding mmio window(s)) driver to attach.  Exposes a device
>> +       topology under a "ndX" bus device, a "/dev/ndctlX" bus-ioctl
>> +       message passing interface, and a "/dev/nmemX" dimm-ioctl
>> +       message interface for each memory device registered on the
>> +       bus.  instance.  A userspace library "ndctl" provides an API
>> +       to enumerate/manage this subsystem.
>> +
>> +config ND_ACPI
>> +     tristate "ACPI: NFIT to libnd bus support"
>> +     select LIBND
>> +     depends on ACPI
>> +     help
>> +       Infrastructure to probe ACPI 6 compliant platforms for
>> +       NVDIMMs (NFIT) and register a libnd device tree.  In
>> +       addition to storage devices this also enables libnd craft
>> +       ACPI._DSM messages for platform/dimm configuration.
>
> I'm wondering if the two CONFIG options above really need to be user-selectable?
>
> For example, what reason people (who've already selected ND_DEVICES) may have
> for not selecting ND_ACPI if ACPI is set?


Later on in the series we introduce ND_E820 which supports creating a
libnd-bus from e820-type-12 memory ranges on pre-NFIT systems.  I'm
also considering a configfs defined libnd-bus because e820 types are
not nearly enough information to safely define nvdimm resources
outside of NFIT.


>> +
>> +endif
>> diff --git a/drivers/block/nd/Makefile b/drivers/block/nd/Makefile
>> new file mode 100644
>> index 000000000000..944b5947c0cb
>> --- /dev/null
>> +++ b/drivers/block/nd/Makefile
>> @@ -0,0 +1,6 @@
>> +obj-$(CONFIG_LIBND) += libnd.o
>> +obj-$(CONFIG_ND_ACPI) += nd_acpi.o
>> +
>> +nd_acpi-y := acpi.o
>> +
>> +libnd-y := core.o
>
> OK, so it looks like no modules, just built-in code, right?
>

Um, no, both CONFIG_ND_ACPI and CONFIG_LIBND can be =m.

>> diff --git a/drivers/block/nd/acpi.c b/drivers/block/nd/acpi.c
>> new file mode 100644
>> index 000000000000..9f0b24390d1b
>> --- /dev/null
>> +++ b/drivers/block/nd/acpi.c
>> @@ -0,0 +1,475 @@
>> +/*
>> + * 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/module.h>
>> +#include <linux/list.h>
>> +#include <linux/acpi.h>
>> +#include "acpi_nfit.h"
>> +#include "libnd.h"
>> +
>> +static bool warn_checksum;
>> +module_param(warn_checksum, bool, S_IRUGO|S_IWUSR);
>> +MODULE_PARM_DESC(warn_checksum, "Turn checksum errors into warnings");
>> +
>> +enum {
>> +     NFIT_ACPI_NOTIFY_TABLE = 0x80,
>> +};
>> +
>> +static int nd_acpi_ctl(struct nd_bus_descriptor *nd_desc,
>> +             struct nd_dimm *nd_dimm, unsigned int cmd, void *buf,
>> +             unsigned int buf_len)
>> +{
>> +     return -ENOTTY;
>> +}
>
> Why -ENOTTY?  And why not to leave a NULL entry for this instead and
> make the library fail it in that case?


Yes, I should have deferred this to the patch that fills in
nd_acpi_ctl later in the series.  Having this stub here in this patch
just trips up reviewers, sorry.


>> +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_spa *spa)
>> +{
>> +     if (memcmp(&nfit_spa_uuid_volatile, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_VOLATILE;
>> +
>> +     if (memcmp(&nfit_spa_uuid_pm, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_PM;
>> +
>> +     if (memcmp(&nfit_spa_uuid_dcr, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_DCR;
>> +
>> +     if (memcmp(&nfit_spa_uuid_bdw, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_BDW;
>> +
>> +     if (memcmp(&nfit_spa_uuid_vdisk, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_VDISK;
>> +
>> +     if (memcmp(&nfit_spa_uuid_vcd, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_VCD;
>> +
>> +     if (memcmp(&nfit_spa_uuid_pdisk, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_PDISK;
>> +
>> +     if (memcmp(&nfit_spa_uuid_pcd, spa->type_uuid, 16) == 0)
>> +             return NFIT_SPA_PCD;
>> +
>> +     return -1;
>> +}
>> +
>> +struct nfit_table_header {
>> +     __le16 type;
>> +     __le16 length;
>> +};
>
> That you'll be able to get from ACPICA I suppose?


Yes.


>> +
>> +static void *add_table(struct acpi_nfit_desc *acpi_desc, void *table, const void *end)
>> +{
>> +     struct device *dev = acpi_desc->dev;
>> +     struct nfit_table_header *hdr;
>> +     void *err = ERR_PTR(-ENOMEM);
>> +
>> +     if (table >= end)
>> +             return NULL;
>> +
>> +     hdr = (struct nfit_table_header *) table;
>> +     switch (hdr->type) {
>> +     case NFIT_TABLE_SPA: {
>> +             struct nfit_spa *nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa),
>> +                             GFP_KERNEL);
>> +             struct acpi_nfit_spa *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->spa_index,
>> +                             spa_type_name(nfit_spa_type(spa)));
>> +             break;
>> +     }
>> +     case NFIT_TABLE_MEM: {
>> +             struct nfit_memdev *nfit_memdev = devm_kzalloc(dev,
>> +                             sizeof(*nfit_memdev), GFP_KERNEL);
>> +             struct acpi_nfit_memdev *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->nfit_handle, memdev->spa_index,
>> +                             memdev->dcr_index);
>> +             break;
>> +     }
>> +     case NFIT_TABLE_DCR: {
>> +             struct nfit_dcr *nfit_dcr = devm_kzalloc(dev, sizeof(*nfit_dcr),
>> +                             GFP_KERNEL);
>> +             struct acpi_nfit_dcr *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 num_bcw: %d\n", __func__,
>> +                             dcr->dcr_index, dcr->num_bcw);
>> +             break;
>> +     }
>> +     case NFIT_TABLE_BDW: {
>> +             struct nfit_bdw *nfit_bdw = devm_kzalloc(dev, sizeof(*nfit_bdw),
>> +                             GFP_KERNEL);
>> +             struct acpi_nfit_bdw *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 num_bdw: %d\n", __func__,
>> +                             bdw->dcr_index, bdw->num_bdw);
>> +             break;
>> +     }
>> +     /* TODO */
>> +     case NFIT_TABLE_IDT:
>> +             dev_dbg(dev, "%s: idt\n", __func__);
>> +             break;
>> +     case NFIT_TABLE_FLUSH:
>> +             dev_dbg(dev, "%s: flush\n", __func__);
>> +             break;
>> +     case NFIT_TABLE_SMBIOS:
>> +             dev_dbg(dev, "%s: smbios\n", __func__);
>> +             break;
>> +     default:
>> +             dev_err(dev, "unknown table '%d' parsing nfit\n", hdr->type);
>> +             return ERR_PTR(-ENXIO);
>> +     }
>> +
>> +     return table + hdr->length;
>> +}
>> +
>> +static void nfit_mem_find_spa_bdw(struct acpi_nfit_desc *acpi_desc,
>> +             struct nfit_mem *nfit_mem)
>> +{
>> +     u32 nfit_handle = __to_nfit_memdev(nfit_mem)->nfit_handle;
>> +     u16 dcr_index = nfit_mem->dcr->dcr_index;
>> +     struct nfit_spa *nfit_spa;
>> +
>> +     list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
>> +             u16 spa_index = nfit_spa->spa->spa_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->spa_index != spa_index)
>> +                             continue;
>> +                     if (nfit_memdev->memdev->nfit_handle != nfit_handle)
>> +                             continue;
>> +                     if (nfit_memdev->memdev->dcr_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->spa_index);
>> +     nfit_mem->bdw = NULL;
>> +}
>> +
>> +static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
>> +             struct nfit_mem *nfit_mem, struct acpi_nfit_spa *spa)
>> +{
>> +     u16 dcr_index = __to_nfit_memdev(nfit_mem)->dcr_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->dcr_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->spa_index,
>> +                             __to_nfit_memdev(nfit_mem) ? "" : " MEMDEV",
>> +                             nfit_mem->dcr ? "" : " DCR");
>> +             return -ENODEV;
>> +     }
>> +
>> +     /*
>> +      * We've found enough to create an nd_dimm, 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->dcr_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_spa *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->spa_index != spa->spa_index)
>> +                     continue;
>> +             found = NULL;
>> +             dcr_index = nfit_memdev->memdev->dcr_index;
>> +             list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
>> +                     if (__to_nfit_memdev(nfit_mem)->dcr_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)->nfit_handle;
>> +     handleB = __to_nfit_memdev(b)->nfit_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 nd_acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, acpi_size sz)
>> +{
>> +     struct device *dev = acpi_desc->dev;
>> +     const void *end;
>> +     u8 *data, sum;
>> +     acpi_size i;
>> +
>> +     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;
>> +     for (i = 0, sum = 0; i < sz; i++)
>> +             sum += readb(data + i);
>> +     if (sum != 0 && !warn_checksum) {
>> +             dev_dbg(dev, "%s: nfit checksum failure\n", __func__);
>> +             return -ENXIO;
>> +     }
>> +     WARN_TAINT_ONCE(sum != 0, TAINT_FIRMWARE_WORKAROUND,
>> +                     "nfit checksum failure, continuing...\n");
>> +
>> +     end = data + sz;
>> +     data += sizeof(struct acpi_nfit);
>> +     while (!IS_ERR_OR_NULL(data))
>> +             data = add_table(acpi_desc, data, end);
>
> This looks like we are expecting a series of tables here and we're going to
> fail the whole discovery if just one of them in invalid.
>
> I wonder if it would be practical to skip just the invalid ones instead?


Yes, for future-proofing we should just ignore tables that we don't
understand.  Will fix.


>
>> +
>> +     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 nd_acpi_add(struct acpi_device *adev)
>> +{
>> +     struct nd_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_nfit *) tbl;
>> +     nd_desc = &acpi_desc->nd_desc;
>> +     nd_desc->provider_name = "ACPI.NFIT";
>> +     nd_desc->ndctl = nd_acpi_ctl;
>> +
>> +     acpi_desc->nd_bus = nd_bus_register(dev, nd_desc);
>> +     if (!acpi_desc->nd_bus)
>> +             return -ENXIO;
>> +
>> +     rc = nd_acpi_nfit_init(acpi_desc, sz);
>> +     if (rc) {
>> +             nd_bus_unregister(acpi_desc->nd_bus);
>> +             return rc;
>> +     }
>> +     return 0;
>> +}
>> +
>> +static int nd_acpi_remove(struct acpi_device *adev)
>> +{
>> +     struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
>> +
>> +     nd_bus_unregister(acpi_desc->nd_bus);
>> +     return 0;
>> +}
>> +
>> +static void nd_acpi_notify(struct acpi_device *adev, u32 event)
>> +{
>> +     /* TODO: handle ACPI_NOTIFY_BUS_CHECK notification */
>> +     dev_dbg(&adev->dev, "%s: event: %d\n", __func__, event);
>> +}
>> +
>> +static const struct acpi_device_id nd_acpi_ids[] = {
>> +     { "ACPI0012", 0 },
>> +     { "", 0 },
>> +};
>> +MODULE_DEVICE_TABLE(acpi, nd_acpi_ids);
>> +
>> +static struct acpi_driver nd_acpi_driver = {
>> +     .name = KBUILD_MODNAME,
>> +     .ids = nd_acpi_ids,
>> +     .flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
>> +     .ops = {
>> +             .add = nd_acpi_add,
>> +             .remove = nd_acpi_remove,
>> +             .notify = nd_acpi_notify
>> +     },
>> +};
>
> Since this is going to be non-modular built-in code, please use an ACPI
> scan handler instead of using a driver here.  acpi_memhotplug.c does that,
> you can use it as an example, but I guess you don't need to enable hotplug
> for it to start with.


No, you misunderstood, this will certainly be modular and loaded on-demand.


>
>> +
>> +static __init int nd_acpi_init(void)
>> +{
>> +     BUILD_BUG_ON(sizeof(struct acpi_nfit) != 40);
>> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_spa) != 56);
>> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_memdev) != 48);
>> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_idt) != 16);
>> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 8);
>> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_dcr) != 80);
>> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_bdw) != 40);
>> +
>> +     return acpi_bus_register_driver(&nd_acpi_driver);
>> +}
>> +
>> +static __exit void nd_acpi_exit(void)
>> +{
>> +     acpi_bus_unregister_driver(&nd_acpi_driver);
>> +}
>> +
>> +module_init(nd_acpi_init);
>> +module_exit(nd_acpi_exit);
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_AUTHOR("Intel Corporation");
>> diff --git a/drivers/block/nd/acpi_nfit.h b/drivers/block/nd/acpi_nfit.h
>> new file mode 100644
>> index 000000000000..e0b0f12736bf
>> --- /dev/null
>> +++ b/drivers/block/nd/acpi_nfit.h
>
> I'm assuming that the below is coordinated with Bob and David and will be
> changed to use ACPICA-provided definitions going forward.
>
> Is that correct?

Yes, as soon as definitions those are available we will drop this
header and rebase on the ACPICA implementation.

[..]
Rafael J. Wysocki May 1, 2015, 1:21 a.m. UTC | #3
On Thursday, April 30, 2015 05:39:06 PM Dan Williams wrote:
> On Thu, Apr 30, 2015 at 4:23 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> > On Tuesday, April 28, 2015 02:24:23 PM Dan Williams wrote:
> >> 1/ Autodetect an NFIT table for the ACPI namespace device with _HID of
> >>    "ACPI0012"
> >>
> >> 2/ libnd bus registration
> >>
> >> The NFIT provided by ACPI is one possible method by which platforms will
> >> discover NVDIMM resources.  However, the intent of the nd_bus_descriptor
> >> abstraction is to abstract "provider" specific details, leaving libnd
> >> to be independent of the specific NVDIMM resource discovery mechanism.
> >> This flexibility is later exploited later to implement custom-defined nd
> >> buses.
> >>
> >> Cc: <linux-acpi@vger.kernel.org>
> >> Cc: Robert Moore <robert.moore@intel.com>
> >> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> >> ---
> >>  drivers/block/Kconfig         |    2
> >>  drivers/block/Makefile        |    1
> >>  drivers/block/nd/Kconfig      |   40 +++
> >>  drivers/block/nd/Makefile     |    6 +
> >>  drivers/block/nd/acpi.c       |  475 +++++++++++++++++++++++++++++++++++++++++
> >>  drivers/block/nd/acpi_nfit.h  |  254 ++++++++++++++++++++++
> >>  drivers/block/nd/core.c       |   67 ++++++
> >>  drivers/block/nd/libnd.h      |   33 +++
> >>  drivers/block/nd/nd-private.h |   23 ++
> >>  9 files changed, 901 insertions(+)
> >>  create mode 100644 drivers/block/nd/Kconfig
> >>  create mode 100644 drivers/block/nd/Makefile
> >>  create mode 100644 drivers/block/nd/acpi.c
> >>  create mode 100644 drivers/block/nd/acpi_nfit.h
> >>  create mode 100644 drivers/block/nd/core.c
> >>  create mode 100644 drivers/block/nd/libnd.h
> >>  create mode 100644 drivers/block/nd/nd-private.h
> >>
> >> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> >> index eb1fed5bd516..dfe40e5ca9bd 100644
> >> --- a/drivers/block/Kconfig
> >> +++ b/drivers/block/Kconfig
> >> @@ -321,6 +321,8 @@ config BLK_DEV_NVME
> >>         To compile this driver as a module, choose M here: the
> >>         module will be called nvme.
> >>
> >> +source "drivers/block/nd/Kconfig"
> >> +
> >>  config BLK_DEV_SKD
> >>       tristate "STEC S1120 Block Driver"
> >>       depends on PCI
> >> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
> >> index 9cc6c18a1c7e..07a6acecf4d8 100644
> >> --- a/drivers/block/Makefile
> >> +++ b/drivers/block/Makefile
> >> @@ -24,6 +24,7 @@ obj-$(CONFIG_CDROM_PKTCDVD) += pktcdvd.o
> >>  obj-$(CONFIG_MG_DISK)                += mg_disk.o
> >>  obj-$(CONFIG_SUNVDC)         += sunvdc.o
> >>  obj-$(CONFIG_BLK_DEV_NVME)   += nvme.o
> >> +obj-$(CONFIG_ND_DEVICES)     += nd/
> >>  obj-$(CONFIG_BLK_DEV_SKD)    += skd.o
> >>  obj-$(CONFIG_BLK_DEV_OSD)    += osdblk.o
> >>
> >> diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig
> >> new file mode 100644
> >> index 000000000000..6d5d6b732f82
> >> --- /dev/null
> >> +++ b/drivers/block/nd/Kconfig
> >> @@ -0,0 +1,40 @@
> >> +menuconfig ND_DEVICES
> >> +     bool "NVDIMM Support"
> >> +     depends on PHYS_ADDR_T_64BIT
> >> +     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 libnd
> >> +       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 ND_DEVICES
> >> +
> >> +config LIBND
> >> +     tristate "LIBND: libnd device driver support"
> >> +     help
> >> +       Platform agnostic device model for a libnd bus.  Publishes
> >> +       resources for a PMEM (persistent-memory) driver and/or BLK
> >> +       (sliding mmio window(s)) driver to attach.  Exposes a device
> >> +       topology under a "ndX" bus device, a "/dev/ndctlX" bus-ioctl
> >> +       message passing interface, and a "/dev/nmemX" dimm-ioctl
> >> +       message interface for each memory device registered on the
> >> +       bus.  instance.  A userspace library "ndctl" provides an API
> >> +       to enumerate/manage this subsystem.
> >> +
> >> +config ND_ACPI
> >> +     tristate "ACPI: NFIT to libnd bus support"
> >> +     select LIBND
> >> +     depends on ACPI
> >> +     help
> >> +       Infrastructure to probe ACPI 6 compliant platforms for
> >> +       NVDIMMs (NFIT) and register a libnd device tree.  In
> >> +       addition to storage devices this also enables libnd craft
> >> +       ACPI._DSM messages for platform/dimm configuration.
> >
> > I'm wondering if the two CONFIG options above really need to be user-selectable?
> >
> > For example, what reason people (who've already selected ND_DEVICES) may have
> > for not selecting ND_ACPI if ACPI is set?
> 
> 
> Later on in the series we introduce ND_E820 which supports creating a
> libnd-bus from e820-type-12 memory ranges on pre-NFIT systems.  I'm
> also considering a configfs defined libnd-bus because e820 types are
> not nearly enough information to safely define nvdimm resources
> outside of NFIT.

I hope these are not mutually exclusive with ND_ACPI?  Otherwise distros
will have problems with supporting them in one kernel.

If ND_E820 and ND_ACPI aren't mutually exclusive, I still don't see a good
enough reason for asking users about ND_ACPI.  Why would I ever say "No"
here if I said "Yes" or "Module" to ND_DEVICES?


> >> +
> >> +endif
> >> diff --git a/drivers/block/nd/Makefile b/drivers/block/nd/Makefile
> >> new file mode 100644
> >> index 000000000000..944b5947c0cb
> >> --- /dev/null
> >> +++ b/drivers/block/nd/Makefile
> >> @@ -0,0 +1,6 @@
> >> +obj-$(CONFIG_LIBND) += libnd.o
> >> +obj-$(CONFIG_ND_ACPI) += nd_acpi.o
> >> +
> >> +nd_acpi-y := acpi.o
> >> +
> >> +libnd-y := core.o
> >
> > OK, so it looks like no modules, just built-in code, right?
> >
> 
> Um, no, both CONFIG_ND_ACPI and CONFIG_LIBND can be =m.

OK

[cut]

> >> +static int nd_acpi_remove(struct acpi_device *adev)
> >> +{
> >> +     struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
> >> +
> >> +     nd_bus_unregister(acpi_desc->nd_bus);
> >> +     return 0;
> >> +}
> >> +
> >> +static void nd_acpi_notify(struct acpi_device *adev, u32 event)
> >> +{
> >> +     /* TODO: handle ACPI_NOTIFY_BUS_CHECK notification */
> >> +     dev_dbg(&adev->dev, "%s: event: %d\n", __func__, event);
> >> +}
> >> +
> >> +static const struct acpi_device_id nd_acpi_ids[] = {
> >> +     { "ACPI0012", 0 },
> >> +     { "", 0 },
> >> +};
> >> +MODULE_DEVICE_TABLE(acpi, nd_acpi_ids);
> >> +
> >> +static struct acpi_driver nd_acpi_driver = {
> >> +     .name = KBUILD_MODNAME,
> >> +     .ids = nd_acpi_ids,
> >> +     .flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
> >> +     .ops = {
> >> +             .add = nd_acpi_add,
> >> +             .remove = nd_acpi_remove,
> >> +             .notify = nd_acpi_notify
> >> +     },
> >> +};
> >
> > Since this is going to be non-modular built-in code, please use an ACPI
> > scan handler instead of using a driver here.  acpi_memhotplug.c does that,
> > you can use it as an example, but I guess you don't need to enable hotplug
> > for it to start with.
> 
> 
> No, you misunderstood, this will certainly be modular and loaded on-demand.

OK

So please drop the .notify thing at least for now.  It most likely doesn't do
what you need anyway.

> >
> >> +
> >> +static __init int nd_acpi_init(void)
> >> +{
> >> +     BUILD_BUG_ON(sizeof(struct acpi_nfit) != 40);
> >> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_spa) != 56);
> >> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_memdev) != 48);
> >> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_idt) != 16);
> >> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 8);
> >> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_dcr) != 80);
> >> +     BUILD_BUG_ON(sizeof(struct acpi_nfit_bdw) != 40);
> >> +
> >> +     return acpi_bus_register_driver(&nd_acpi_driver);
> >> +}
> >> +
> >> +static __exit void nd_acpi_exit(void)
> >> +{
> >> +     acpi_bus_unregister_driver(&nd_acpi_driver);
> >> +}
> >> +
> >> +module_init(nd_acpi_init);
> >> +module_exit(nd_acpi_exit);
> >> +MODULE_LICENSE("GPL v2");
> >> +MODULE_AUTHOR("Intel Corporation");
> >> diff --git a/drivers/block/nd/acpi_nfit.h b/drivers/block/nd/acpi_nfit.h
> >> new file mode 100644
> >> index 000000000000..e0b0f12736bf
> >> --- /dev/null
> >> +++ b/drivers/block/nd/acpi_nfit.h
> >
> > I'm assuming that the below is coordinated with Bob and David and will be
> > changed to use ACPICA-provided definitions going forward.
> >
> > Is that correct?
> 
> Yes, as soon as definitions those are available we will drop this
> header and rebase on the ACPICA implementation.
> 
> [..]

OK
Dan Williams May 1, 2015, 4:23 p.m. UTC | #4
On Thu, Apr 30, 2015 at 6:21 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Thursday, April 30, 2015 05:39:06 PM Dan Williams wrote:
>> On Thu, Apr 30, 2015 at 4:23 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
[..]
>> >> +if ND_DEVICES
>> >> +
>> >> +config LIBND
>> >> +     tristate "LIBND: libnd device driver support"
>> >> +     help
>> >> +       Platform agnostic device model for a libnd bus.  Publishes
>> >> +       resources for a PMEM (persistent-memory) driver and/or BLK
>> >> +       (sliding mmio window(s)) driver to attach.  Exposes a device
>> >> +       topology under a "ndX" bus device, a "/dev/ndctlX" bus-ioctl
>> >> +       message passing interface, and a "/dev/nmemX" dimm-ioctl
>> >> +       message interface for each memory device registered on the
>> >> +       bus.  instance.  A userspace library "ndctl" provides an API
>> >> +       to enumerate/manage this subsystem.
>> >> +
>> >> +config ND_ACPI
>> >> +     tristate "ACPI: NFIT to libnd bus support"
>> >> +     select LIBND
>> >> +     depends on ACPI
>> >> +     help
>> >> +       Infrastructure to probe ACPI 6 compliant platforms for
>> >> +       NVDIMMs (NFIT) and register a libnd device tree.  In
>> >> +       addition to storage devices this also enables libnd craft
>> >> +       ACPI._DSM messages for platform/dimm configuration.
>> >
>> > I'm wondering if the two CONFIG options above really need to be user-selectable?
>> >
>> > For example, what reason people (who've already selected ND_DEVICES) may have
>> > for not selecting ND_ACPI if ACPI is set?
>>
>>
>> Later on in the series we introduce ND_E820 which supports creating a
>> libnd-bus from e820-type-12 memory ranges on pre-NFIT systems.  I'm
>> also considering a configfs defined libnd-bus because e820 types are
>> not nearly enough information to safely define nvdimm resources
>> outside of NFIT.
>
> I hope these are not mutually exclusive with ND_ACPI?  Otherwise distros
> will have problems with supporting them in one kernel.

You can have ND_E820 support and ND_ACPI support in the same system.
Likely an NFIT enabled system will never have e820-type-12 ranges, but
if a user messes up and uses the new memmap=ss!nn command line to
overlap NFIT-defined memory then the request_mem_region() calls in the
driver will collide.  First to load wins in that scenario.

> If ND_E820 and ND_ACPI aren't mutually exclusive, I still don't see a good
> enough reason for asking users about ND_ACPI.  Why would I ever say "No"
> here if I said "Yes" or "Module" to ND_DEVICES?

I agree that if the user selects ND_DEVICES then ND_ACPI should
probably default on, but otherwise turning it off is a useful option.
If you know your system is pre-ACPI-6 then why bother including
support?

>> >> +
>> >> +endif
>> >> diff --git a/drivers/block/nd/Makefile b/drivers/block/nd/Makefile
>> >> new file mode 100644
>> >> index 000000000000..944b5947c0cb
>> >> --- /dev/null
>> >> +++ b/drivers/block/nd/Makefile
>> >> @@ -0,0 +1,6 @@
>> >> +obj-$(CONFIG_LIBND) += libnd.o
>> >> +obj-$(CONFIG_ND_ACPI) += nd_acpi.o
>> >> +
>> >> +nd_acpi-y := acpi.o
>> >> +
>> >> +libnd-y := core.o
>> >
>> > OK, so it looks like no modules, just built-in code, right?
>> >
>>
>> Um, no, both CONFIG_ND_ACPI and CONFIG_LIBND can be =m.
>
> OK
>
> [cut]
>
>> >> +static int nd_acpi_remove(struct acpi_device *adev)
>> >> +{
>> >> +     struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
>> >> +
>> >> +     nd_bus_unregister(acpi_desc->nd_bus);
>> >> +     return 0;
>> >> +}
>> >> +
>> >> +static void nd_acpi_notify(struct acpi_device *adev, u32 event)
>> >> +{
>> >> +     /* TODO: handle ACPI_NOTIFY_BUS_CHECK notification */
>> >> +     dev_dbg(&adev->dev, "%s: event: %d\n", __func__, event);
>> >> +}
>> >> +
>> >> +static const struct acpi_device_id nd_acpi_ids[] = {
>> >> +     { "ACPI0012", 0 },
>> >> +     { "", 0 },
>> >> +};
>> >> +MODULE_DEVICE_TABLE(acpi, nd_acpi_ids);
>> >> +
>> >> +static struct acpi_driver nd_acpi_driver = {
>> >> +     .name = KBUILD_MODNAME,
>> >> +     .ids = nd_acpi_ids,
>> >> +     .flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
>> >> +     .ops = {
>> >> +             .add = nd_acpi_add,
>> >> +             .remove = nd_acpi_remove,
>> >> +             .notify = nd_acpi_notify
>> >> +     },
>> >> +};
>> >
>> > Since this is going to be non-modular built-in code, please use an ACPI
>> > scan handler instead of using a driver here.  acpi_memhotplug.c does that,
>> > you can use it as an example, but I guess you don't need to enable hotplug
>> > for it to start with.
>>
>>
>> No, you misunderstood, this will certainly be modular and loaded on-demand.
>
> OK
>
> So please drop the .notify thing at least for now.  It most likely doesn't do
> what you need anyway.

The .notify handler will eventually be filled in to handle hot-add of
NFIT structures, but yes I'll drop it for now.
Dan Williams May 4, 2015, 11:46 p.m. UTC | #5
On Mon, May 4, 2015 at 4:58 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Friday, May 01, 2015 09:23:38 AM Dan Williams wrote:
>> On Thu, Apr 30, 2015 at 6:21 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>> > On Thursday, April 30, 2015 05:39:06 PM Dan Williams wrote:
>> >> On Thu, Apr 30, 2015 at 4:23 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
[..]
>> > If ND_E820 and ND_ACPI aren't mutually exclusive, I still don't see a good
>> > enough reason for asking users about ND_ACPI.  Why would I ever say "No"
>> > here if I said "Yes" or "Module" to ND_DEVICES?
>>
>> I agree that if the user selects ND_DEVICES then ND_ACPI should
>> probably default on, but otherwise turning it off is a useful option.
>> If you know your system is pre-ACPI-6 then why bother including
>> support?
>
> If you're a distro, you don't care.  You have to support it regardless.
>
> You might care if you're an end user building a kernel for yourself and just
> for this particular specific machine.  Honestly, how many *server* users do
> that?
>
> And fewer user-selectable options means fewer combination of options to test
> during development/validation.
>
> Also unrelated, but applies to this patch.
>
> Since your new driver will handle device ID ACPI0012 which is defined by the
> spec proper, it should go into drivers/acpi/, because there's where such things
> go as a rule.

Ok, I think the move to drivers/acpi/ will kill two birds with one
stone as selecting ACPI_NFIT from there will select the libnd support
without prompting.
Rafael J. Wysocki May 4, 2015, 11:58 p.m. UTC | #6
On Friday, May 01, 2015 09:23:38 AM Dan Williams wrote:
> On Thu, Apr 30, 2015 at 6:21 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> > On Thursday, April 30, 2015 05:39:06 PM Dan Williams wrote:
> >> On Thu, Apr 30, 2015 at 4:23 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> [..]
> >> >> +if ND_DEVICES
> >> >> +
> >> >> +config LIBND
> >> >> +     tristate "LIBND: libnd device driver support"
> >> >> +     help
> >> >> +       Platform agnostic device model for a libnd bus.  Publishes
> >> >> +       resources for a PMEM (persistent-memory) driver and/or BLK
> >> >> +       (sliding mmio window(s)) driver to attach.  Exposes a device
> >> >> +       topology under a "ndX" bus device, a "/dev/ndctlX" bus-ioctl
> >> >> +       message passing interface, and a "/dev/nmemX" dimm-ioctl
> >> >> +       message interface for each memory device registered on the
> >> >> +       bus.  instance.  A userspace library "ndctl" provides an API
> >> >> +       to enumerate/manage this subsystem.
> >> >> +
> >> >> +config ND_ACPI
> >> >> +     tristate "ACPI: NFIT to libnd bus support"
> >> >> +     select LIBND
> >> >> +     depends on ACPI
> >> >> +     help
> >> >> +       Infrastructure to probe ACPI 6 compliant platforms for
> >> >> +       NVDIMMs (NFIT) and register a libnd device tree.  In
> >> >> +       addition to storage devices this also enables libnd craft
> >> >> +       ACPI._DSM messages for platform/dimm configuration.
> >> >
> >> > I'm wondering if the two CONFIG options above really need to be user-selectable?
> >> >
> >> > For example, what reason people (who've already selected ND_DEVICES) may have
> >> > for not selecting ND_ACPI if ACPI is set?
> >>
> >>
> >> Later on in the series we introduce ND_E820 which supports creating a
> >> libnd-bus from e820-type-12 memory ranges on pre-NFIT systems.  I'm
> >> also considering a configfs defined libnd-bus because e820 types are
> >> not nearly enough information to safely define nvdimm resources
> >> outside of NFIT.
> >
> > I hope these are not mutually exclusive with ND_ACPI?  Otherwise distros
> > will have problems with supporting them in one kernel.
> 
> You can have ND_E820 support and ND_ACPI support in the same system.
> Likely an NFIT enabled system will never have e820-type-12 ranges, but
> if a user messes up and uses the new memmap=ss!nn command line to
> overlap NFIT-defined memory then the request_mem_region() calls in the
> driver will collide.  First to load wins in that scenario.
> 
> > If ND_E820 and ND_ACPI aren't mutually exclusive, I still don't see a good
> > enough reason for asking users about ND_ACPI.  Why would I ever say "No"
> > here if I said "Yes" or "Module" to ND_DEVICES?
> 
> I agree that if the user selects ND_DEVICES then ND_ACPI should
> probably default on, but otherwise turning it off is a useful option.
> If you know your system is pre-ACPI-6 then why bother including
> support?

If you're a distro, you don't care.  You have to support it regardless.

You might care if you're an end user building a kernel for yourself and just
for this particular specific machine.  Honestly, how many *server* users do
that?

And fewer user-selectable options means fewer combination of options to test
during development/validation.

Also unrelated, but applies to this patch.

Since your new driver will handle device ID ACPI0012 which is defined by the
spec proper, it should go into drivers/acpi/, because there's where such things
go as a rule.
Jeff Moyer May 15, 2015, 7:44 p.m. UTC | #7
Dan Williams <dan.j.williams@intel.com> writes:

Looks like the Kconfig stuff has been worked out between you and Rafael,
so I won't comment on that.

> diff --git a/drivers/block/nd/acpi.c b/drivers/block/nd/acpi.c
> new file mode 100644
> index 000000000000..9f0b24390d1b
> --- /dev/null
> +++ b/drivers/block/nd/acpi.c
> @@ -0,0 +1,475 @@
> +/*
> + * 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/module.h>
> +#include <linux/list.h>
> +#include <linux/acpi.h>
> +#include "acpi_nfit.h"
> +#include "libnd.h"
> +
> +static bool warn_checksum;
> +module_param(warn_checksum, bool, S_IRUGO|S_IWUSR);
> +MODULE_PARM_DESC(warn_checksum, "Turn checksum errors into warnings");

Is this just a debugging option?

> +
> +enum {
> +	NFIT_ACPI_NOTIFY_TABLE = 0x80,
> +};

This is unused by this patch.

The rest looks ok to me.

-Jeff
Dan Williams May 15, 2015, 8:41 p.m. UTC | #8
On Fri, May 15, 2015 at 12:44 PM, Jeff Moyer <jmoyer@redhat.com> wrote:
> Dan Williams <dan.j.williams@intel.com> writes:
>
> Looks like the Kconfig stuff has been worked out between you and Rafael,
> so I won't comment on that.
>
>> diff --git a/drivers/block/nd/acpi.c b/drivers/block/nd/acpi.c
>> new file mode 100644
>> index 000000000000..9f0b24390d1b
>> --- /dev/null
>> +++ b/drivers/block/nd/acpi.c
>> @@ -0,0 +1,475 @@
>> +/*
>> + * 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/module.h>
>> +#include <linux/list.h>
>> +#include <linux/acpi.h>
>> +#include "acpi_nfit.h"
>> +#include "libnd.h"
>> +
>> +static bool warn_checksum;
>> +module_param(warn_checksum, bool, S_IRUGO|S_IWUSR);
>> +MODULE_PARM_DESC(warn_checksum, "Turn checksum errors into warnings");
>
> Is this just a debugging option?

Yes, but I've deleted it in the next rev of the code since the ACPI
core will have already done the checksum.  The driver need not
implement it's own checksum.

>> +
>> +enum {
>> +     NFIT_ACPI_NOTIFY_TABLE = 0x80,
>> +};
>
> This is unused by this patch.

Yes.  I went ahead and deleted all the ACPI notification
infrastructure until we're ready to implement hot-add.

> The rest looks ok to me.

Thanks Jeff.
diff mbox

Patch

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index eb1fed5bd516..dfe40e5ca9bd 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -321,6 +321,8 @@  config BLK_DEV_NVME
 	  To compile this driver as a module, choose M here: the
 	  module will be called nvme.
 
+source "drivers/block/nd/Kconfig"
+
 config BLK_DEV_SKD
 	tristate "STEC S1120 Block Driver"
 	depends on PCI
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 9cc6c18a1c7e..07a6acecf4d8 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -24,6 +24,7 @@  obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
 obj-$(CONFIG_MG_DISK)		+= mg_disk.o
 obj-$(CONFIG_SUNVDC)		+= sunvdc.o
 obj-$(CONFIG_BLK_DEV_NVME)	+= nvme.o
+obj-$(CONFIG_ND_DEVICES)	+= nd/
 obj-$(CONFIG_BLK_DEV_SKD)	+= skd.o
 obj-$(CONFIG_BLK_DEV_OSD)	+= osdblk.o
 
diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig
new file mode 100644
index 000000000000..6d5d6b732f82
--- /dev/null
+++ b/drivers/block/nd/Kconfig
@@ -0,0 +1,40 @@ 
+menuconfig ND_DEVICES
+	bool "NVDIMM Support"
+	depends on PHYS_ADDR_T_64BIT
+	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 libnd
+	  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 ND_DEVICES
+
+config LIBND
+	tristate "LIBND: libnd device driver support"
+	help
+	  Platform agnostic device model for a libnd bus.  Publishes
+	  resources for a PMEM (persistent-memory) driver and/or BLK
+	  (sliding mmio window(s)) driver to attach.  Exposes a device
+	  topology under a "ndX" bus device, a "/dev/ndctlX" bus-ioctl
+	  message passing interface, and a "/dev/nmemX" dimm-ioctl
+	  message interface for each memory device registered on the
+	  bus.  instance.  A userspace library "ndctl" provides an API
+	  to enumerate/manage this subsystem.
+
+config ND_ACPI
+	tristate "ACPI: NFIT to libnd bus support"
+	select LIBND
+	depends on ACPI
+	help
+	  Infrastructure to probe ACPI 6 compliant platforms for
+	  NVDIMMs (NFIT) and register a libnd device tree.  In
+	  addition to storage devices this also enables libnd craft
+	  ACPI._DSM messages for platform/dimm configuration.
+
+endif
diff --git a/drivers/block/nd/Makefile b/drivers/block/nd/Makefile
new file mode 100644
index 000000000000..944b5947c0cb
--- /dev/null
+++ b/drivers/block/nd/Makefile
@@ -0,0 +1,6 @@ 
+obj-$(CONFIG_LIBND) += libnd.o
+obj-$(CONFIG_ND_ACPI) += nd_acpi.o
+
+nd_acpi-y := acpi.o
+
+libnd-y := core.o
diff --git a/drivers/block/nd/acpi.c b/drivers/block/nd/acpi.c
new file mode 100644
index 000000000000..9f0b24390d1b
--- /dev/null
+++ b/drivers/block/nd/acpi.c
@@ -0,0 +1,475 @@ 
+/*
+ * 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/module.h>
+#include <linux/list.h>
+#include <linux/acpi.h>
+#include "acpi_nfit.h"
+#include "libnd.h"
+
+static bool warn_checksum;
+module_param(warn_checksum, bool, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(warn_checksum, "Turn checksum errors into warnings");
+
+enum {
+	NFIT_ACPI_NOTIFY_TABLE = 0x80,
+};
+
+static int nd_acpi_ctl(struct nd_bus_descriptor *nd_desc,
+		struct nd_dimm *nd_dimm, 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_spa *spa)
+{
+	if (memcmp(&nfit_spa_uuid_volatile, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_VOLATILE;
+
+	if (memcmp(&nfit_spa_uuid_pm, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_PM;
+
+	if (memcmp(&nfit_spa_uuid_dcr, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_DCR;
+
+	if (memcmp(&nfit_spa_uuid_bdw, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_BDW;
+
+	if (memcmp(&nfit_spa_uuid_vdisk, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_VDISK;
+
+	if (memcmp(&nfit_spa_uuid_vcd, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_VCD;
+
+	if (memcmp(&nfit_spa_uuid_pdisk, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_PDISK;
+
+	if (memcmp(&nfit_spa_uuid_pcd, spa->type_uuid, 16) == 0)
+		return NFIT_SPA_PCD;
+
+	return -1;
+}
+
+struct nfit_table_header {
+	__le16 type;
+	__le16 length;
+};
+
+static void *add_table(struct acpi_nfit_desc *acpi_desc, void *table, const void *end)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nfit_table_header *hdr;
+	void *err = ERR_PTR(-ENOMEM);
+
+	if (table >= end)
+		return NULL;
+
+	hdr = (struct nfit_table_header *) table;
+	switch (hdr->type) {
+	case NFIT_TABLE_SPA: {
+		struct nfit_spa *nfit_spa = devm_kzalloc(dev, sizeof(*nfit_spa),
+				GFP_KERNEL);
+		struct acpi_nfit_spa *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->spa_index,
+				spa_type_name(nfit_spa_type(spa)));
+		break;
+	}
+	case NFIT_TABLE_MEM: {
+		struct nfit_memdev *nfit_memdev = devm_kzalloc(dev,
+				sizeof(*nfit_memdev), GFP_KERNEL);
+		struct acpi_nfit_memdev *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->nfit_handle, memdev->spa_index,
+				memdev->dcr_index);
+		break;
+	}
+	case NFIT_TABLE_DCR: {
+		struct nfit_dcr *nfit_dcr = devm_kzalloc(dev, sizeof(*nfit_dcr),
+				GFP_KERNEL);
+		struct acpi_nfit_dcr *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 num_bcw: %d\n", __func__,
+				dcr->dcr_index, dcr->num_bcw);
+		break;
+	}
+	case NFIT_TABLE_BDW: {
+		struct nfit_bdw *nfit_bdw = devm_kzalloc(dev, sizeof(*nfit_bdw),
+				GFP_KERNEL);
+		struct acpi_nfit_bdw *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 num_bdw: %d\n", __func__,
+				bdw->dcr_index, bdw->num_bdw);
+		break;
+	}
+	/* TODO */
+	case NFIT_TABLE_IDT:
+		dev_dbg(dev, "%s: idt\n", __func__);
+		break;
+	case NFIT_TABLE_FLUSH:
+		dev_dbg(dev, "%s: flush\n", __func__);
+		break;
+	case NFIT_TABLE_SMBIOS:
+		dev_dbg(dev, "%s: smbios\n", __func__);
+		break;
+	default:
+		dev_err(dev, "unknown table '%d' parsing nfit\n", hdr->type);
+		return ERR_PTR(-ENXIO);
+	}
+
+	return table + hdr->length;
+}
+
+static void nfit_mem_find_spa_bdw(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_mem *nfit_mem)
+{
+	u32 nfit_handle = __to_nfit_memdev(nfit_mem)->nfit_handle;
+	u16 dcr_index = nfit_mem->dcr->dcr_index;
+	struct nfit_spa *nfit_spa;
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		u16 spa_index = nfit_spa->spa->spa_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->spa_index != spa_index)
+				continue;
+			if (nfit_memdev->memdev->nfit_handle != nfit_handle)
+				continue;
+			if (nfit_memdev->memdev->dcr_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->spa_index);
+	nfit_mem->bdw = NULL;
+}
+
+static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_mem *nfit_mem, struct acpi_nfit_spa *spa)
+{
+	u16 dcr_index = __to_nfit_memdev(nfit_mem)->dcr_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->dcr_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->spa_index,
+				__to_nfit_memdev(nfit_mem) ? "" : " MEMDEV",
+				nfit_mem->dcr ? "" : " DCR");
+		return -ENODEV;
+	}
+
+	/*
+	 * We've found enough to create an nd_dimm, 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->dcr_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_spa *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->spa_index != spa->spa_index)
+			continue;
+		found = NULL;
+		dcr_index = nfit_memdev->memdev->dcr_index;
+		list_for_each_entry(nfit_mem, &acpi_desc->dimms, list)
+			if (__to_nfit_memdev(nfit_mem)->dcr_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)->nfit_handle;
+	handleB = __to_nfit_memdev(b)->nfit_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 nd_acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, acpi_size sz)
+{
+	struct device *dev = acpi_desc->dev;
+	const void *end;
+	u8 *data, sum;
+	acpi_size i;
+
+	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;
+	for (i = 0, sum = 0; i < sz; i++)
+		sum += readb(data + i);
+	if (sum != 0 && !warn_checksum) {
+		dev_dbg(dev, "%s: nfit checksum failure\n", __func__);
+		return -ENXIO;
+	}
+	WARN_TAINT_ONCE(sum != 0, TAINT_FIRMWARE_WORKAROUND,
+			"nfit checksum failure, continuing...\n");
+
+	end = data + sz;
+	data += sizeof(struct acpi_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 nd_acpi_add(struct acpi_device *adev)
+{
+	struct nd_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_nfit *) tbl;
+	nd_desc = &acpi_desc->nd_desc;
+	nd_desc->provider_name = "ACPI.NFIT";
+	nd_desc->ndctl = nd_acpi_ctl;
+
+	acpi_desc->nd_bus = nd_bus_register(dev, nd_desc);
+	if (!acpi_desc->nd_bus)
+		return -ENXIO;
+
+	rc = nd_acpi_nfit_init(acpi_desc, sz);
+	if (rc) {
+		nd_bus_unregister(acpi_desc->nd_bus);
+		return rc;
+	}
+	return 0;
+}
+
+static int nd_acpi_remove(struct acpi_device *adev)
+{
+	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(&adev->dev);
+
+	nd_bus_unregister(acpi_desc->nd_bus);
+	return 0;
+}
+
+static void nd_acpi_notify(struct acpi_device *adev, u32 event)
+{
+	/* TODO: handle ACPI_NOTIFY_BUS_CHECK notification */
+	dev_dbg(&adev->dev, "%s: event: %d\n", __func__, event);
+}
+
+static const struct acpi_device_id nd_acpi_ids[] = {
+	{ "ACPI0012", 0 },
+	{ "", 0 },
+};
+MODULE_DEVICE_TABLE(acpi, nd_acpi_ids);
+
+static struct acpi_driver nd_acpi_driver = {
+	.name = KBUILD_MODNAME,
+	.ids = nd_acpi_ids,
+	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
+	.ops = {
+		.add = nd_acpi_add,
+		.remove = nd_acpi_remove,
+		.notify = nd_acpi_notify
+	},
+};
+
+static __init int nd_acpi_init(void)
+{
+	BUILD_BUG_ON(sizeof(struct acpi_nfit) != 40);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_spa) != 56);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_memdev) != 48);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_idt) != 16);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_smbios) != 8);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_dcr) != 80);
+	BUILD_BUG_ON(sizeof(struct acpi_nfit_bdw) != 40);
+
+	return acpi_bus_register_driver(&nd_acpi_driver);
+}
+
+static __exit void nd_acpi_exit(void)
+{
+	acpi_bus_unregister_driver(&nd_acpi_driver);
+}
+
+module_init(nd_acpi_init);
+module_exit(nd_acpi_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Intel Corporation");
diff --git a/drivers/block/nd/acpi_nfit.h b/drivers/block/nd/acpi_nfit.h
new file mode 100644
index 000000000000..e0b0f12736bf
--- /dev/null
+++ b/drivers/block/nd/acpi_nfit.h
@@ -0,0 +1,254 @@ 
+/*
+ * 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/types.h>
+#include <linux/uuid.h>
+#include <linux/acpi.h>
+#include "libnd.h"
+
+static const uuid_le nfit_spa_uuid_volatile __maybe_unused = UUID_LE(0x7305944f,
+		0xfdda, 0x44e3, 0xb1, 0x6c, 0x3f, 0x22, 0xd2, 0x52, 0xe5, 0xd0);
+
+static const uuid_le nfit_spa_uuid_pm __maybe_unused = UUID_LE(0x66f0d379,
+		0xb4f3, 0x4074, 0xac, 0x43, 0x0d, 0x33, 0x18, 0xb7, 0x8c, 0xdb);
+
+static const uuid_le nfit_spa_uuid_dcr __maybe_unused = UUID_LE(0x92f701f6,
+		0x13b4, 0x405d, 0x91, 0x0b, 0x29, 0x93, 0x67, 0xe8, 0x23, 0x4c);
+
+static const uuid_le nfit_spa_uuid_bdw __maybe_unused = UUID_LE(0x91af0530,
+		0x5d86, 0x470e, 0xa6, 0xb0, 0x0a, 0x2d, 0xb9, 0x40, 0x82, 0x49);
+
+static const uuid_le nfit_spa_uuid_vdisk __maybe_unused = UUID_LE(0x77ab535a,
+		0x45fc, 0x624b, 0x55, 0x60, 0xf7, 0xb2, 0x81, 0xd1, 0xf9, 0x6e);
+
+static const uuid_le nfit_spa_uuid_vcd __maybe_unused = UUID_LE(0x3d5abd30,
+		0x4175, 0x87ce, 0x6d, 0x64, 0xd2, 0xad, 0xe5, 0x23, 0xc4, 0xbb);
+
+static const uuid_le nfit_spa_uuid_pdisk __maybe_unused = UUID_LE(0x5cea02c9,
+		0x4d07, 0x69d3, 0x26, 0x9f, 0x44, 0x96, 0xfb, 0xe0, 0x96, 0xf9);
+
+static const uuid_le nfit_spa_uuid_pcd __maybe_unused = UUID_LE(0x08018188,
+		0x42cd, 0xbb48, 0x10, 0x0f, 0x53, 0x87, 0xd5, 0x3d, 0xed, 0x3d);
+
+enum {
+	NFIT_TABLE_SPA = 0,
+	NFIT_TABLE_MEM = 1,
+	NFIT_TABLE_IDT = 2,
+	NFIT_TABLE_SMBIOS = 3,
+	NFIT_TABLE_DCR = 4,
+	NFIT_TABLE_BDW = 5,
+	NFIT_TABLE_FLUSH = 6,
+	NFIT_SPA_VOLATILE = 0,
+	NFIT_SPA_PM = 1,
+	NFIT_SPA_DCR = 2,
+	NFIT_SPA_BDW = 3,
+	NFIT_SPA_VDISK = 4,
+	NFIT_SPA_VCD = 5,
+	NFIT_SPA_PDISK = 6,
+	NFIT_SPA_PCD = 7,
+	NFIT_SPAF_DCR_HOT_ADD = 1 << 0,
+	NFIT_SPAF_PDVALID = 1 << 1,
+	NFIT_MEMF_SAVE_FAIL = 1 << 0,
+	NFIT_MEMF_RESTORE_FAIL = 1 << 1,
+	NFIT_MEMF_FLUSH_FAIL = 1 << 2,
+	NFIT_MEMF_UNARMED = 1 << 3,
+	NFIT_MEMF_NOTIFY_SMART = 1 << 4,
+	NFIT_MEMF_SMART_READY = 1 << 5,
+	NFIT_DCRF_BUFFERED = 1 << 0,
+};
+
+/**
+ * struct acpi_nfit - Nvdimm Firmware Interface Table
+ * @signature: "NFIT"
+ * @length: sum of size of this table plus all appended subtables
+ */
+struct acpi_nfit {
+	u8 signature[4];
+	u32 length;
+	u8 revision;
+	u8 checksum;
+	u8 oemid[6];
+	u64 oem_tbl_id;
+	u32 oem_revision;
+	u32 creator_id;
+	u32 creator_revision;
+	u32 reserved;
+};
+
+/**
+ * struct acpi_nfit_spa - System Physical Address Range Descriptor Table
+ */
+struct acpi_nfit_spa {
+	u16 type;
+	u16 length;
+	u16 spa_index;
+	u16 flags;
+	u32 reserved;
+	u32 proximity_domain;
+	u8 type_uuid[16];
+	u64 spa_base;
+	u64 spa_length;
+	u64 mem_attr;
+};
+
+/**
+ * struct acpi_nfit_mem - Memory Device to SPA Mapping Table
+ */
+struct acpi_nfit_memdev {
+	u16 type;
+	u16 length;
+	u32 nfit_handle;
+	u16 phys_id;
+	u16 region_id;
+	u16 spa_index;
+	u16 dcr_index;
+	u64 region_len;
+	u64 region_spa_offset;
+	u64 region_dpa;
+	u16 idt_index;
+	u16 interleave_ways;
+	u16 flags;
+	u16 reserved;
+};
+
+/**
+ * struct acpi_nfit_idt - Interleave description Table
+ */
+struct acpi_nfit_idt {
+	u16 type;
+	u16 length;
+	u16 idt_index;
+	u16 reserved;
+	u32 num_lines;
+	u32 line_size;
+	u32 line_offset[0];
+};
+
+/**
+ * struct acpi_nfit_smbios - SMBIOS Management Information Table
+ */
+struct acpi_nfit_smbios {
+	u16 type;
+	u16 length;
+	u32 reserved;
+	u8 data[0];
+};
+
+/**
+ * struct acpi_nfit_dcr - NVDIMM Control Region Table
+ * @fic: Format Interface Code
+ * @cmd_offset: command registers relative to block control window
+ * @status_offset: status registers relative to block control window
+ */
+struct acpi_nfit_dcr {
+	u16 type;
+	u16 length;
+	u16 dcr_index;
+	u16 vendor_id;
+	u16 device_id;
+	u16 revision_id;
+	u16 sub_vendor_id;
+	u16 sub_device_id;
+	u16 sub_revision_id;
+	u8 reserved[6];
+	u32 serial_number;
+	u16 fic;
+	u16 num_bcw;
+	u64 bcw_size;
+	u64 cmd_offset;
+	u64 cmd_size;
+	u64 status_offset;
+	u64 status_size;
+	u16 flags;
+	u8 reserved2[6];
+};
+
+/**
+ * struct acpi_nfit_bdw - NVDIMM Block Data Window Region Table
+ */
+struct acpi_nfit_bdw {
+	u16 type;
+	u16 length;
+	u16 dcr_index;
+	u16 num_bdw;
+	u64 bdw_offset;
+	u64 bdw_size;
+	u64 blk_capacity;
+	u64 blk_offset;
+};
+
+/**
+ * struct acpi_nfit_flush - Flush Hint Address Structure
+ */
+struct acpi_nfit_flush {
+	u16 type;
+	u16 length;
+	u32 nfit_handle;
+	u16 num_hints;
+	u8 reserved[6];
+	u64 hint_addr[0];
+};
+
+struct nfit_spa {
+	struct acpi_nfit_spa *spa;
+	struct list_head list;
+};
+
+struct nfit_dcr {
+	struct acpi_nfit_dcr *dcr;
+	struct list_head list;
+};
+
+struct nfit_bdw {
+	struct acpi_nfit_bdw *bdw;
+	struct list_head list;
+};
+
+struct nfit_memdev {
+	struct acpi_nfit_memdev *memdev;
+	struct list_head list;
+};
+
+/* assembled tables for a given dimm/memory-device */
+struct nfit_mem {
+	struct acpi_nfit_memdev *memdev_dcr;
+	struct acpi_nfit_memdev *memdev_pmem;
+	struct acpi_nfit_dcr *dcr;
+	struct acpi_nfit_bdw *bdw;
+	struct acpi_nfit_spa *spa_dcr;
+	struct acpi_nfit_spa *spa_bdw;
+	struct list_head list;
+};
+
+struct acpi_nfit_desc {
+	struct nd_bus_descriptor nd_desc;
+	struct acpi_nfit *nfit;
+	struct list_head memdevs;
+	struct list_head dimms;
+	struct list_head spas;
+	struct list_head dcrs;
+	struct list_head bdws;
+	struct nd_bus *nd_bus;
+	struct device *dev;
+};
+
+static inline struct acpi_nfit_memdev *__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/block/nd/core.c b/drivers/block/nd/core.c
new file mode 100644
index 000000000000..3cccdbc0f3b7
--- /dev/null
+++ b/drivers/block/nd/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/export.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include "nd-private.h"
+#include "libnd.h"
+
+static DEFINE_IDA(nd_ida);
+
+static void nd_bus_release(struct device *dev)
+{
+	struct nd_bus *nd_bus = container_of(dev, struct nd_bus, dev);
+
+	ida_simple_remove(&nd_ida, nd_bus->id);
+	kfree(nd_bus);
+}
+
+struct nd_bus *nd_bus_register(struct device *parent,
+		struct nd_bus_descriptor *nd_desc)
+{
+	struct nd_bus *nd_bus = kzalloc(sizeof(*nd_bus), GFP_KERNEL);
+	int rc;
+
+	if (!nd_bus)
+		return NULL;
+	nd_bus->id = ida_simple_get(&nd_ida, 0, 0, GFP_KERNEL);
+	if (nd_bus->id < 0) {
+		kfree(nd_bus);
+		return NULL;
+	}
+	nd_bus->nd_desc = nd_desc;
+	nd_bus->dev.parent = parent;
+	nd_bus->dev.release = nd_bus_release;
+	dev_set_name(&nd_bus->dev, "ndbus%d", nd_bus->id);
+	rc = device_register(&nd_bus->dev);
+	if (rc) {
+		dev_dbg(&nd_bus->dev, "device registration failed: %d\n", rc);
+		put_device(&nd_bus->dev);
+		return NULL;
+	}
+
+	return nd_bus;
+}
+EXPORT_SYMBOL_GPL(nd_bus_register);
+
+void nd_bus_unregister(struct nd_bus *nd_bus)
+{
+	if (!nd_bus)
+		return;
+	device_unregister(&nd_bus->dev);
+}
+EXPORT_SYMBOL_GPL(nd_bus_unregister);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Intel Corporation");
diff --git a/drivers/block/nd/libnd.h b/drivers/block/nd/libnd.h
new file mode 100644
index 000000000000..163832937e9c
--- /dev/null
+++ b/drivers/block/nd/libnd.h
@@ -0,0 +1,33 @@ 
+/*
+ * libnd - 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 __LIBND_H__
+#define __LIBND_H__
+struct nd_dimm;
+struct nd_bus_descriptor;
+typedef int (*ndctl_fn)(struct nd_bus_descriptor *nd_desc,
+		struct nd_dimm *nd_dimm, unsigned int cmd, void *buf,
+		unsigned int buf_len);
+
+struct nd_bus_descriptor {
+	unsigned long dsm_mask;
+	char *provider_name;
+	ndctl_fn ndctl;
+};
+
+struct nd_bus;
+struct nd_bus *nd_bus_register(struct device *parent,
+		struct nd_bus_descriptor *nfit_desc);
+void nd_bus_unregister(struct nd_bus *nd_bus);
+#endif /* __LIBND_H__ */
diff --git a/drivers/block/nd/nd-private.h b/drivers/block/nd/nd-private.h
new file mode 100644
index 000000000000..3dbab29fa0f9
--- /dev/null
+++ b/drivers/block/nd/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/device.h>
+#include "libnd.h"
+
+struct nd_bus {
+	struct nd_bus_descriptor *nd_desc;
+	struct device dev;
+	int id;
+};
+#endif /* __ND_PRIVATE_H__ */