summaryrefslogtreecommitdiffstats
path: root/Documentation/ABI
diff options
context:
space:
mode:
authorDaejun Park <daejun7.park@samsung.com>2021-07-12 11:00:25 +0200
committerMartin K. Petersen <martin.petersen@oracle.com>2021-08-01 22:05:07 +0200
commit41d8a9333cc96f5ad4dd7a52786585338257d9f1 (patch)
tree595fc1295e8565f6220fcc7ee18bf8a400c028a5 /Documentation/ABI
parentscsi: ufs: ufshpb: Prepare HPB read for cached sub-region (diff)
downloadlinux-41d8a9333cc96f5ad4dd7a52786585338257d9f1.tar.xz
linux-41d8a9333cc96f5ad4dd7a52786585338257d9f1.zip
scsi: ufs: ufshpb: Add HPB 2.0 support
Version 2.0 of HBP supports reads of varying sizes from 4KB to 1MB. A read operation <= 32KB is supported as single HPB read. A read between 36KB and 1MB is supported by a combination of write buffer command and HPB read command to deliver more PPN. The write buffer commands may not be issued immediately due to busy tags. To use HPB read more aggressively, the driver can requeue the write buffer command. The requeue threshold is implemented as timeout and can be modified with requeue_timeout_ms entry in sysfs. [mkp: REQ_OP_DRV_* and blk_rq_is_passthrough()] Link: https://lore.kernel.org/r/20210712090025epcms2p3b3d94f6f1b2cfa394e3d9ba130ca0fa7@epcms2p3 Tested-by: Can Guo <cang@codeaurora.org> Tested-by: Stanley Chu <stanley.chu@mediatek.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Can Guo <cang@codeaurora.org> Reviewed-by: Bean Huo <beanhuo@micron.com> Reviewed-by: Stanley Chu <stanley.chu@mediatek.com> Signed-off-by: Daejun Park <daejun7.park@samsung.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/sysfs-driver-ufs35
1 files changed, 35 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 4c1a5d28408d..929460738651 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1425,3 +1425,38 @@ 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/wb_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.