(if the platform supports UFSHCD_CAP_CLK_SCALING). For a
platform that doesn't support UFSHCD_CAP_CLK_SCALING, we can
disable/enable WriteBooster through this sysfs node.
+
+What: /sys/bus/platform/drivers/ufshcd/*/device_descriptor/hpb_version
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the HPB specification version.
+ The full information about the descriptor can be found in the UFS
+ HPB (Host Performance Booster) Extension specifications.
+ Example: version 1.2.3 = 0123h
+
+ The file is read only.
+
+What: /sys/bus/platform/drivers/ufshcd/*/device_descriptor/hpb_control
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows an indication of the HPB control mode.
+ 00h: Host control mode
+ 01h: Device control mode
+
+ The file is read only.
+
+What: /sys/bus/platform/drivers/ufshcd/*/geometry_descriptor/hpb_region_size
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the bHPBRegionSize which can be calculated
+ as in the following (in bytes):
+ HPB Region size = 512B * 2^bHPBRegionSize
+
+ The file is read only.
+
+What: /sys/bus/platform/drivers/ufshcd/*/geometry_descriptor/hpb_number_lu
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the maximum number of HPB LU supported by
+ the device.
+ 00h: HPB is not supported by the device.
+ 01h ~ 20h: Maximum number of HPB LU supported by the device
+
+ The file is read only.
+
+What: /sys/bus/platform/drivers/ufshcd/*/geometry_descriptor/hpb_subregion_size
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the bHPBSubRegionSize, which can be
+ calculated as in the following (in bytes) and shall be a multiple of
+ logical block size:
+ HPB Sub-Region size = 512B x 2^bHPBSubRegionSize
+ bHPBSubRegionSize shall not exceed bHPBRegionSize.
+
+ The file is read only.
+
+What: /sys/bus/platform/drivers/ufshcd/*/geometry_descriptor/hpb_max_active_regions
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the maximum number of active HPB regions that
+ is supported by the device.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/unit_descriptor/hpb_lu_max_active_regions
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the maximum number of HPB regions assigned to
+ the HPB logical unit.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/unit_descriptor/hpb_pinned_region_start_offset
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the start offset of HPB pinned region.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/unit_descriptor/hpb_number_pinned_regions
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the number of HPB pinned regions assigned to
+ the HPB logical unit.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_stats/hit_cnt
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the number of reads that changed to HPB read.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_stats/miss_cnt
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the number of reads that cannot be changed to
+ HPB read.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_stats/rb_noti_cnt
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the number of response UPIUs that has
+ recommendations for activating sub-regions and/or inactivating region.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_stats/rb_active_cnt
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the number of active sub-regions recommended by
+ response UPIUs.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_stats/rb_inactive_cnt
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the number of inactive regions recommended by
+ response UPIUs.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_stats/map_req_cnt
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the number of read buffer commands for
+ activating sub-regions recommended by response UPIUs.
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_params/requeue_timeout_ms
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the requeue timeout threshold for write buffer
+ command in ms. The value can be changed by writing an integer to
+ this entry.
+
+What: /sys/bus/platform/drivers/ufshcd/*/attributes/max_data_size_hpb_single_cmd
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the maximum HPB data size for using a single HPB
+ command.
+
+ === ========
+ 00h 4KB
+ 01h 8KB
+ 02h 12KB
+ ...
+ FFh 1024KB
+ === ========
+
+ The file is read only.
+
+What: /sys/bus/platform/drivers/ufshcd/*/flags/hpb_enable
+Date: June 2021
+Contact: Daejun Park <daejun7.park@samsung.com>
+Description: This entry shows the status of HPB.
+
+ == ============================
+ 0 HPB is not enabled.
+ 1 HPB is enabled
+ == ============================
+
+ The file is read only.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/activation_thld
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: In host control mode, reads are the major source of activation
+ trials. Once this threshold hs met, the region is added to the
+ "to-be-activated" list. Since we reset the read counter upon
+ write, this include sending a rb command updating the region
+ ppn as well.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/normalization_factor
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: In host control mode, we think of the regions as "buckets".
+ Those buckets are being filled with reads, and emptied on write.
+ We use entries_per_srgn - the amount of blocks in a subregion as
+ our bucket size. This applies because HPB1.0 only handles
+ single-block reads. Once the bucket size is crossed, we trigger
+ a normalization work - not only to avoid overflow, but mainly
+ because we want to keep those counters normalized, as we are
+ using those reads as a comparative score, to make various decisions.
+ The normalization is dividing (shift right) the read counter by
+ the normalization_factor. If during consecutive normalizations
+ an active region has exhausted its reads - inactivate it.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/eviction_thld_enter
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: Region deactivation is often due to the fact that eviction took
+ place: A region becomes active at the expense of another. This is
+ happening when the max-active-regions limit has been crossed.
+ In host mode, eviction is considered an extreme measure. We
+ want to verify that the entering region has enough reads, and
+ the exiting region has much fewer reads. eviction_thld_enter is
+ the min reads that a region must have in order to be considered
+ a candidate for evicting another region.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/eviction_thld_exit
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: Same as above for the exiting region. A region is considered to
+ be a candidate for eviction only if it has fewer reads than
+ eviction_thld_exit.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/read_timeout_ms
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: In order not to hang on to "cold" regions, we inactivate
+ a region that has no READ access for a predefined amount of
+ time - read_timeout_ms. If read_timeout_ms has expired, and the
+ region is dirty, it is less likely that we can make any use of
+ HPB reading it so we inactivate it. Still, deactivation has
+ its overhead, and we may still benefit from HPB reading this
+ region if it is clean - see read_timeout_expiries.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/read_timeout_expiries
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: If the region read timeout has expired, but the region is clean,
+ just re-wind its timer for another spin. Do that as long as it
+ is clean and did not exhaust its read_timeout_expiries threshold.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/timeout_polling_interval_ms
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: The frequency with which the delayed worker that checks the
+ read_timeouts is awakened.
+
+What: /sys/class/scsi_device/*/device/hpb_param_sysfs/inflight_map_req
+Date: February 2021
+Contact: Avri Altman <avri.altman@wdc.com>
+Description: In host control mode the host is the originator of map requests.
+ To avoid flooding the device with map requests, use a simple throttling
+ mechanism that limits the number of inflight map requests.
projects / linux-2.6-microblaze.git / blobdiff