Hi,
The code looks good to me and I encourage you to submit your patches.
I just want to make some general remarks:
- The way you use the clock scaling to set WB on/off, is IMO, an elegant design choice.
- You should add a platform capability for WB
- As for setting user space configuration options - I think you've got it wrong.
You should read it from bSupportedWriteBoosterBufferUserSpaceReductionTypes
(offset 0x55 in the device descriptor).
This is a configurable parameter that the chipset vendor control and can set during provisioning.
- I agree with your approach toward flush during runtime suspend (keep-vcc-on):
it is the host's interest to assist the device with some extra idle time if needed for WB flush.
This way you will assure consistent write performance.
Thanks,
Avri
>
>
> Still a RFC patch, because I'm still expecting some comments
> on the design.
>
> v1 -> v2:
> - Addressed comments on v1
>
> - Supports shared buffer mode only
>
> - Didn't use exception event as suggested.
> The reason being while testing I saw that the WriteBooster
> available buffer remains at 0x1 for a longer time if flush is
> enabled all the time as compared to an event-based enablement.
> This essentially means that writes go to the WriteBooster buffer
> more. Spec says that the if flush is enabled, the device would
> flush when it sees the command queue empty. So I guess that'd trigger
> flush more than an event based approach.
> Anyway the Vcc would be turned-off during system suspend, so flush
> would stop anyway.
> In this patchset, I never turn-off flush.
> Hence the RFC.
>
> Asutosh Das (3):
> scsi: ufs: add write booster feature support
> ufs-qcom: scsi: configure write booster type
> ufs: sysfs: add sysfs entries for write booster
>
> drivers/scsi/ufs/ufs-qcom.c | 7 ++
> drivers/scsi/ufs/ufs-sysfs.c | 39 ++++++-
> drivers/scsi/ufs/ufs.h | 37 ++++++-
> drivers/scsi/ufs/ufshcd.c | 238
> ++++++++++++++++++++++++++++++++++++++++++-
> drivers/scsi/ufs/ufshcd.h | 9 ++
> 5 files changed, 324 insertions(+), 6 deletions(-)
>
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
> Linux Foundation Collaborative Project.
