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authorAishwarya Pant <aishpant@gmail.com>2018-02-23 18:24:48 +0530
committerJonathan Corbet <corbet@lwn.net>2018-03-21 09:23:31 -0600
commit014d8fd8805b29186448bc4e5a697b34b604587a (patch)
tree284be36ad990a0cc720efd62014018bdfccfb421 /Documentation/ABI
parentbd15134a73d8226f1961164d450016a05e9222af (diff)
acpi: nfit: document sysfs interface
This is an attempt to document the nfit sysfs interface. The descriptions have been collected from git commit logs and the ACPI specification 6.2. Signed-off-by: Aishwarya Pant <aishpant@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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+For all of the nmem device attributes under nfit/*, see the 'NVDIMM Firmware
+Interface Table (NFIT)' section in the ACPI specification
+(http://www.uefi.org/specifications) for more details.
+
+What: /sys/bus/nd/devices/nmemX/nfit/serial
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Serial number of the NVDIMM (non-volatile dual in-line
+ memory module), assigned by the module vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/handle
+Date: Apr, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The address (given by the _ADR object) of the device on its
+ parent bus of the NVDIMM device containing the NVDIMM region.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/device
+Date: Apr, 2015
+KernelVersion: v4.1
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Device id for the NVDIMM, assigned by the module vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/rev_id
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Revision of the NVDIMM, assigned by the module vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/phys_id
+Date: Apr, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Handle (i.e., instance number) for the SMBIOS (system
+ management BIOS) Memory Device structure describing the NVDIMM
+ containing the NVDIMM region.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/flags
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The flags in the NFIT memory device sub-structure indicate
+ the state of the data on the nvdimm relative to its energy
+ source or last "flush to persistence".
+
+ The attribute is a translation of the 'NVDIMM State Flags' field
+ in section 5.2.25.3 'NVDIMM Region Mapping' Structure of the
+ ACPI specification 6.2.
+
+ The health states are "save_fail", "restore_fail", "flush_fail",
+ "not_armed", "smart_event", "map_fail" and "smart_notify".
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/format
+What: /sys/bus/nd/devices/nmemX/nfit/format1
+What: /sys/bus/nd/devices/nmemX/nfit/formats
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The interface codes indicate support for persistent memory
+ mapped directly into system physical address space and / or a
+ block aperture access mechanism to the NVDIMM media.
+ The 'formats' attribute displays the number of supported
+ interfaces.
+
+ This layout is compatible with existing libndctl binaries that
+ only expect one code per-dimm as they will ignore
+ nmemX/nfit/formats and nmemX/nfit/formatN.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/vendor
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Vendor id of the NVDIMM.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/dsm_mask
+Date: May, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The bitmask indicates the supported device specific control
+ functions relative to the NVDIMM command family supported by the
+ device
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/family
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Displays the NVDIMM family command sets. Values
+ 0, 1, 2 and 3 correspond to NVDIMM_FAMILY_INTEL,
+ NVDIMM_FAMILY_HPE1, NVDIMM_FAMILY_HPE2 and NVDIMM_FAMILY_MSFT
+ respectively.
+
+ See the specifications for these command families here:
+ http://pmem.io/documents/NVDIMM_DSM_Interface-V1.6.pdf
+ https://github.com/HewlettPackard/hpe-nvm/blob/master/Documentation/
+ https://msdn.microsoft.com/library/windows/hardware/mt604741"
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/id
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) ACPI specification 6.2 section 5.2.25.9, defines an
+ identifier for an NVDIMM, which refelects the id attribute.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/subsystem_vendor
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Sub-system vendor id of the NVDIMM non-volatile memory
+ subsystem controller.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/subsystem_rev_id
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Sub-system revision id of the NVDIMM non-volatile memory subsystem
+ controller, assigned by the non-volatile memory subsystem
+ controller vendor.
+
+
+What: /sys/bus/nd/devices/nmemX/nfit/subsystem_device
+Date: Apr, 2016
+KernelVersion: v4.7
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Sub-system device id for the NVDIMM non-volatile memory
+ subsystem controller, assigned by the non-volatile memory
+ subsystem controller vendor.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/revision
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) ACPI NFIT table revision number.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/scrub
+Date: Sep, 2016
+KernelVersion: v4.9
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RW) This shows the number of full Address Range Scrubs (ARS)
+ that have been completed since driver load time. Userspace can
+ wait on this using select/poll etc. A '+' at the end indicates
+ an ARS is in progress
+
+ Writing a value of 1 triggers an ARS scan.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/hw_error_scrub
+Date: Sep, 2016
+KernelVersion: v4.9
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RW) Provides a way to toggle the behavior between just adding
+ the address (cache line) where the MCE happened to the poison
+ list and doing a full scrub. The former (selective insertion of
+ the address) is done unconditionally.
+
+ This attribute can have the following values written to it:
+
+ '0': Switch to the default mode where an exception will only
+ insert the address of the memory error into the poison and
+ badblocks lists.
+ '1': Enable a full scrub to happen if an exception for a memory
+ error is received.
+
+
+What: /sys/bus/nd/devices/ndbusX/nfit/dsm_mask
+Date: Jun, 2017
+KernelVersion: v4.13
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) The bitmask indicates the supported bus specific control
+ functions. See the section named 'NVDIMM Root Device _DSMs' in
+ the ACPI specification.
+
+
+What: /sys/bus/nd/devices/regionX/nfit/range_index
+Date: Jun, 2015
+KernelVersion: v4.2
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) A unique number provided by the BIOS to identify an address
+ range. Used by NVDIMM Region Mapping Structure to uniquely refer
+ to this structure. Value of 0 is reserved and not used as an
+ index.
+
+
+What: /sys/bus/nd/devices/regionX/nfit/ecc_unit_size
+Date: Aug, 2017
+KernelVersion: v4.14
+Contact: linux-nvdimm@lists.01.org
+Description:
+ (RO) Size of a write request to a DIMM that will not incur a
+ read-modify-write cycle at the memory controller.
+
+ When the nfit driver initializes it runs an ARS (Address Range
+ Scrub) operation across every pmem range. Part of that process
+ involves determining the ARS capabilities of a given address
+ range. One of the capabilities that is reported is the 'Clear
+ Uncorrectable Error Range Length Unit Size' (see: ACPI 6.2
+ section 9.20.7.4 Function Index 1 - Query ARS Capabilities).
+ This property indicates the boundary at which the NVDIMM may
+ need to perform read-modify-write cycles to maintain ECC (Error
+ Correcting Code) blocks.