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SubjectRE: [PATCH v19 3/3] scsi: ufs: Prepare HPB read for cached sub-region
Date
> 
>
> > > > + put_unaligned_be64(ppn, &cdb[6]);
> > >
> > > You are assuming the HPB entries read out by "HPB Read Buffer" cmd
> > > are
> > > in Little
> > > Endian, which is why you are using put_unaligned_be64 here. However,
> > > this assumption
> > > is not right for all the other flash vendors - HPB entries read out
> > > by
> > > "HPB Read Buffer"
> > > cmd may come in Big Endian, if so, their random read performance are
> > > screwed.
> >
> > For this question, it is very hard to make a correct format since the
> > Spec doesn't give a clear definition. Should we have a default format,
> > if there is conflict, and then add quirk or add a vendor-specific
> > table?
> >
> > Hi Avri
> > Do you have a good idea?
> I don't know. Better let Daejun answer this.
> This was working for me for both Galaxy S20 (Exynos) as well as Xiaomi Mi10
> (8250).
As for the endianity issue -
I don't think that any fix is needed in the hpb driver.
It is readily seen that the ppn from get_ppn, and the one in the upiu cdb (upiu trace) are identical.
Therefore, if an issue exist, it is IMHO a device issue.

kworker/u16:10-315 [001] d..2 62.283264: ufshpb_get_ppn: Avri ppn 480d2f8244c21abd
kworker/u16:10-315 [001] d..2 62.283336: ufshcd_upiu: v:1.10 send: T:62283314922, HDR:014000000000000000000000, CDB:8800002ddaac480d2f8244c21abd0100, D:

Again, verified on both gs20 (exynos) and mi10 (8250).
Thanks,
Avri
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