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@xxxxxxxxx> --- Changes in v2: - Add descriptions for range_index and ecc_unit_size - Edit various descriptions as suggested Documentation/ABI/testing/sysfs-bus-nfit | 233 +++++++++++++++++++++++++++++++ 1 file changed, 233 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-bus-nfit diff --git a/Documentation/ABI/testing/sysfs-bus-nfit b/Documentation/ABI/testing/sysfs-bus-nfit new file mode 100644 index 000000000000..619eb8ca0f99 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-nfit @@ -0,0 +1,233 @@ +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +Description: + (RO) ACPI NFIT table revision number. + + +What: /sys/bus/nd/devices/ndbusX/nfit/scrub +Date: Sep, 2016 +KernelVersion: v4.9 +Contact: linux-nvdimm@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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@xxxxxxxxxxxx +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. -- 2.16.2 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
