Changelog: v9 -> v10 1. Fix 64-bit division error 2. Fix problems commentted in Bart's review. v8 -> v9 1. Change sysfs initialization. 2. Change reading descriptor during HPB initialization 3. Fix problems commentted in Bart's review. 4. Change base commit from 5.9/scsi-queue to 5.10/scsi-queue. v7 -> v8 Remove wrongly added tags. v6 -> v7 1. Remove UFS feature layer. 2. Cleanup for sparse error. v5 -> v6 Change base commit to b53293fa662e28ae0cdd40828dc641c09f133405 v4 -> v5 Delete unused macro define. v3 -> v4 1. Cleanup. v2 -> v3 1. Add checking input module parameter value. 2. Change base commit from 5.8/scsi-queue to 5.9/scsi-queue. 3. Cleanup for unused variables and label. v1 -> v2 1. Change the full boilerplate text to SPDX style. 2. Adopt dynamic allocation for sub-region data structure. 3. Cleanup. NAND flash memory-based storage devices use Flash Translation Layer (FTL) to translate logical addresses of I/O requests to corresponding flash memory addresses. Mobile storage devices typically have RAM with constrained size, thus lack in memory to keep the whole mapping table. Therefore, mapping tables are partially retrieved from NAND flash on demand, causing random-read performance degradation. To improve random read performance, JESD220-3 (HPB v1.0) proposes HPB (Host Performance Booster) which uses host system memory as a cache for the FTL mapping table. By using HPB, FTL data can be read from host memory faster than from NAND flash memory. The current version only supports the DCM (device control mode). This patch consists of 3 parts to support HPB feature. 1) HPB probe and initialization process 2) READ -> HPB READ using cached map information 3) L2P (logical to physical) map management In the HPB probe and init process, the device information of the UFS is queried. After checking supported features, the data structure for the HPB is initialized according to the device information. A read I/O in the active sub-region where the map is cached is changed to HPB READ by the HPB. The HPB manages the L2P map using information received from the device. For active sub-region, the HPB caches through ufshpb_map request. For the in-active region, the HPB discards the L2P map. When a write I/O occurs in an active sub-region area, associated dirty bitmap checked as dirty for preventing stale read. HPB is shown to have a performance improvement of 58 - 67% for random read workload. [1] This series patches are based on the 5.9/scsi-queue branch. [1]: https://www.usenix.org/conference/hotstorage17/program/presentation/jeong Daejun park (4): scsi: ufs: Add HPB feature related parameters scsi: ufs: Introduce HPB feature scsi: ufs: L2P map management for HPB read scsi: ufs: Prepare HPB read for cached sub-region drivers/scsi/ufs/Kconfig | 9 + drivers/scsi/ufs/Makefile | 1 + drivers/scsi/ufs/ufs.h | 47 + drivers/scsi/ufs/ufshcd.c | 60 ++ drivers/scsi/ufs/ufshcd.h | 23 +- drivers/scsi/ufs/ufshpb.c | 1845 ++++++++++++++++++++++++++++++++++++++++ drivers/scsi/ufs/ufshpb.h | 229 +++++ 7 files changed, 2213 insertions(+), 1 deletion(-) created mode 100644 drivers/scsi/ufs/ufshpb.c created mode 100644 drivers/scsi/ufs/ufshpb.h
