[PATCH RFC v3 0/5] scsi: ufs: add UFS Host Performance Booster(HPB) support

[huobean]

From: Bean Huo <beanhuo@xxxxxxxxxx>

This patchset is just an RFC to add UFS HPB support in the upstream Linux.
Before this series, I have submitted two versions [2] and [4] of UFS
HPB driver in the community. The first two series HPB driver patchsets
follow the Samsung HPB driver[1] approach, in which the HPB driver submits
its HPB READ BUFFER  and HPB WRITE BUFFER requests to the SCSI
device->request_queueu to execute. Since this fly submission is unacceptable,
in this RFC version, I changed it, and now the HPB requests will be directly
submitted to UFS device, don't go backwards to SCSI mid-layer. In this
approach, the L2P mapping entries loading path will be shorter, and the
latency is smaller.

Regarding the UFS HPB feature, which is defined in Jedec Standard Universal
Flash (UFS) Host Performance Booster (HPB) Extension Version 1.0, its purpose
is to improve read performance by utilizing the host side memory. For the more
detail information about HPB, you can refer to the HPB Spec. If the approach
in this RFC patchset is accepted and feasible, it is necessary to add a
document to detail HPB feature and its implementation later.

Based on the Avri's comments in the second patchset, to be reviewable patches,
I shortened HPB driver, deleted HPB host control mode. Also, for change tracing,
this patch is RFC v3, including the first two patchsets changes.

This series patch is still based on the [4] branch 5.8/scsi-queue

v2--v3
    1. delete GET_BYTE_* and SHIFT_BYTE_* macro definition , using
       get_unaligned_*()/put_unaligned_*() instead. (Bart Van Assche)
    2. change Kconfig help message (Randy Dunlap)
    3. delete HPB host control mode code
    4. change the way of submission of HPB request, and let the HPB
       driver directly submit HPB request to UFS.

v1--v2:
    1. Rebased the patch on the [3] branch 5.8/scsi-queue
    2. Optimized and simplified several functions
    3. Add parameter read_threshold in HPB sysfs, by which the user can change
       read_threshold for the HPB host control mode
    4. Add HPB memory limitation, let the user adjust its size according to the
       system memory capacity


Bean Huo (5):
  scsi; ufs: add device descriptor for Host Performance Booster
  scsi: ufs: make ufshcd_read_unit_desc_param() non-static func
  scsi: ufs: add ufs_features parameter in structure ufs_dev_info
  scsi: ufs: add unit and geometry parameters for HPB
  scsi: ufs: UFS Host Performance Booster(HPB) driver

 drivers/scsi/ufs/Kconfig  |   62 +
 drivers/scsi/ufs/Makefile |    1 +
 drivers/scsi/ufs/ufs.h    |   15 +
 drivers/scsi/ufs/ufshcd.c |  245 +++-
 drivers/scsi/ufs/ufshcd.h |   28 +-
 drivers/scsi/ufs/ufshpb.c | 2767 +++++++++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshpb.h |  423 ++++++
 7 files changed, 3534 insertions(+), 7 deletions(-)
 create mode 100644 drivers/scsi/ufs/ufshpb.c
 create mode 100644 drivers/scsi/ufs/ufshpb.h

-- 
2.17.1