scsi: ufs: core: Remove HPB support

Interest among UFS users in HPB has reduced significantly. I am not aware
of any current users of the HPB functionality. Hence remove HPB support
from the kernel.

A note: the work in JEDEC on a successor for HPB is nearing completion.
Zoned storage for UFS or ZUFS combines the UFS standard with ZBC-2.

Acked-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: ChanWoo Lee <cw9316.lee@samsung.com>
Cc: Daejun Park <daejun7.park@samsung.com>
Cc: Keoseong Park <keosung.park@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230719165758.2787573-1-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 0 insertions, 247 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index d5f44fc5b9dc..106687f4f6b7 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1437,180 +1437,6 @@ Description:
 		If avail_wb_buff < wb_flush_threshold, it indicates that WriteBooster buffer needs to
 		be flushed, otherwise it is not necessary.
 
-What:		/sys/bus/platform/drivers/ufshcd/*/device_descriptor/hpb_version
-What:		/sys/bus/platform/devices/*.ufs/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
-What:		/sys/bus/platform/devices/*.ufs/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
-What:		/sys/bus/platform/devices/*.ufs/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
-What:		/sys/bus/platform/devices/*.ufs/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
-What:		/sys/bus/platform/devices/*.ufs/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
-What:		/sys/bus/platform/devices/*.ufs/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/rcmd_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/rcmd_active_cnt
-Date:		June 2021
-Contact:	Daejun Park <daejun7.park@samsung.com>
-Description:	For the HPB device control mode, this entry shows the number of
-        active sub-regions recommended by response UPIUs. For the HPB host control
-        mode, this entry shows the number of active sub-regions recommended by the
-        HPB host control mode heuristic algorithm.
-
-		The file is read only.
-
-What:		/sys/class/scsi_device/*/device/hpb_stats/rcmd_inactive_cnt
-Date:		June 2021
-Contact:	Daejun Park <daejun7.park@samsung.com>
-Description:	For the HPB device control mode, this entry shows the number of
-        inactive regions recommended by response UPIUs. For the HPB host control
-        mode, this entry shows the number of inactive regions recommended by the
-        HPB host control mode heuristic algorithm.
-
-		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
-What:		/sys/bus/platform/devices/*.ufs/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
-What:		/sys/bus/platform/devices/*.ufs/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.
-
 Contact:	Daniil Lunev <dlunev@chromium.org>
 What:		/sys/bus/platform/drivers/ufshcd/*/capabilities/
 What:		/sys/bus/platform/devices/*.ufs/capabilities/
@@ -1648,76 +1474,3 @@ Description:	Indicates status of Write Booster.
 
 		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.