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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-driver-ufs | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs index b4a5d55fa19f..ec3a7149ced5 100644 --- a/Documentation/ABI/testing/sysfs-driver-ufs +++ b/Documentation/ABI/testing/sysfs-driver-ufs @@ -1298,3 +1298,239 @@ Description: This node is used to set or display whether UFS WriteBooster is (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. |