Wow, thank you for taking a look at this! Always nice to get an unexpected documentation gift. Some comments below: On Mon, Feb 19, 2018 at 10:07 AM, Aishwarya Pant <aishpant@xxxxxxxxx> wrote: > 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. There are still two undocumented attributes- > range_index and ecc_unit_size, for which I couldn't collect complete > information. 'range_index' is taken directly from the ACPI specification. It's a unique number provided by the BIOS to identify an address range. Here's a quote from ACPI 6.2a [1] section '5.2.25.2 System Physical Address (SPA) Range Structure' "SPA Range Structure Index: Used by NVDIMM Region Mapping Structure to uniquely refer to this structure. Value of 0 is Reserved and shall not be used as an index." 'ecc_unit_size' is the size of a write request to a DIMM that will not incur a read-modify-write cycle at the memory controller. More details from the commit log here [2] [1]: http://www.uefi.org/sites/default/files/resources/ACPI%206_2_A_Sept29.pdf [2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a15797f4bef > > Signed-off-by: Aishwarya Pant <aishpant@xxxxxxxxx> > --- > Documentation/ABI/testing/sysfs-bus-nfit | 202 +++++++++++++++++++++++++++++++ > 1 file changed, 202 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..758d8d0d4c37 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-bus-nfit > @@ -0,0 +1,202 @@ > +What: /sys/bus/nd/devices/nmemX/nfit/serial > +Date: Apr, 2015 > +KernelVersion: v4.1 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) Serial number of the NVDIMM (non-volatile dual in-line > + memory module), assigned by the module vendor. For all of these nfit/* attributes it would be helpful to include a reference to the ACPI specification. I.e. for all of these nfit/* attributes add a sentence "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/handle > +Date: Apr, 2015 > +KernelVersion: v4.1 > +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) Identifier for the NVDIMM, assigned by the module vendor. s/Identifier/Device Id/ > + > + > +What: /sys/bus/nd/devices/nmemX/nfit/rev_id > +Date: Apr, 2015 > +KernelVersion: v4.1 > +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: v4.1 > +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: v4.1 > +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: v4.6 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) Identifiers for the programming interface. Starting with "Identifiers for one or more programming interfaces, format interface codes, supported by the NVDIMM." > + ACPI 6.1 an NFIT table reports multiple 'NVDIMM Control Region > + Structure' instances per-dimm, one for each supported format > + interface. That code is represented in the sysfs as follows: > + nmemX/nfit/formats, nmemX/nfit/format, nmemX/nfit/format1, > + nmemX/nfit/format2 ... nmemX/nfit/formatN, where format2 - > + formatN are theoretical as there are no known DIMMs with support > + for more than two interface formats. I'd delete the above since those are kernel / specification implementation details that don't help explain what the attribute is. > The 'formats' attribute > + displays the number of supported interfaces. "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." > + > + 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: v4.6 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) Identifier indicating the vendor of the NVDIMM. > + s/Identifier indicating the vendor/Vendor Id/ > + > +What: /sys/bus/nd/devices/nmemX/nfit/dsm_mask > +Date: Apr, 2016 > +KernelVersion: v4.6 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) The bitmask indicates the supported device specific control > + functions. s/functions/functions relative to the NVDIMM command family supported by the device./ > + > + > +What: /sys/bus/nd/devices/nmemX/nfit/family > +Date: Apr, 2016 > +KernelVersion: v4.6 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) Displays the NVDIMM family (and the command sets). Values s/and the command sets/command set/ > + 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: v4.6 > +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. > + > + If the manufacturing location and manufacturing date fields are > + valid, then 'id' is composed of the vendor id (bytes 0-1), > + manufacturing location byte, manufacturing date (bytes 0-1) and > + the serial number(bytes 0-3), otherwise it is composed of vendor > + id (bytes 0-1) and serial number (bytes 0-3) I'd drop this section, this first sentence that refers to the ACPI section is enough. > + > + > +What: /sys/bus/nd/devices/nmemX/nfit/subsystem_vendor > +Date: Apr, 2016 > +KernelVersion: v4.6 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) Vendor of the NVDIMM non-volatile memory subsystem > + controller. s/Vendor/Sub-system Vendor Id/ > + > + > +What: /sys/bus/nd/devices/nmemX/nfit/subsystem_rev_id > +Date: Apr, 2016 > +KernelVersion: v4.6 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) Revision of the NVDIMM non-volatile memory subsystem > + controller, assigned by the non-volatile memory subsystem > + controller vendor. s/Revision/Sub-system Revision Id/ > + > + > +What: /sys/bus/nd/devices/nmemX/nfit/subsystem_device > +Date: Apr, 2016 > +KernelVersion: v4.6 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) Identifier for the NVDIMM non-volatile memory subsystem > + controller, assigned by the non-volatile memory subsystem > + controller vendor. s/Identifier/Sub-system Device Id/ > + > + > +What: /sys/bus/nd/devices/ndbusX/nfit/revision > +Date: Apr, 2015 > +KernelVersion: v4.1 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) ACPI Specification minor version number. "ACPI NFIT table revision number" > + > + > +What: /sys/bus/nd/devices/ndbusX/nfit/scrub > +Date: Sep, 2016 > +KernelVersion: v4.8 > +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: v4.8 > +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: v4.12 > +Contact: linux-nvdimm@xxxxxxxxxxxx > +Description: > + (RO) The bitmask indicates the supported bus specific control > + functions. I'd add: "See the section named 'NVDIMM Root Device _DSMs' in the ACPI specification." So, this looks great and is something I've had on my backlog for a while. That said this is a bit incomplete. These attributes are relative to the the "nd" bus which is the libnvdimm sub-system sysfs interface. This document describes that sysfs layout [3]. Ideally that content would be converted into Documentation/ABI format and merged with what you have done here into an overall Documentation/ABI/testing/sysfs-bus-nvdimm file. I realize that's quite a bit more work, so I'm fine if we start with the nfit attributes and save that follow on work for a separate patch in the future. [3]: https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git/tree/Documentation/nvdimm/nvdimm.txt?h=libnvdimm-for-next -- 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
