RE: [PATCH v1] ufs: introduce UFSHCI_QUIRK_SKIP_INTR_AGGR quirk

[Kiwoong Kim <kwmad.kim@samsung.com>]

Hi, Subhash

I'll update this patch referring what you said (including adding comments of
other quirks)

> > If UFS driver resets interrupt aggregation timer and counter when
> > there is a pending doorbell, an interrupt of IO completion of a
> > corresponding task may be missed.
> > That would cause a command timeout.
> >
> > If UFS driver resets interrupt aggregation timer and counter when
> > there is a pending doorbell, a competion interrupt of a corresponing
> > task may be issued.
> > That would casue a command timeout.
> >
> > Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> > ---
> >  drivers/scsi/ufs/ufshcd.c | 4 +++-
> >  drivers/scsi/ufs/ufshcd.h | 1 +
> >  2 files changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index c904854..65bbf59 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -3730,7 +3730,9 @@ static void ufshcd_transfer_req_compl(struct
> > ufs_hba *hba)
> >  	 * false interrupt if device completes another request after
> > resetting
> >  	 * aggregation and before reading the DB.
> >  	 */
> > -	if (ufshcd_is_intr_aggr_allowed(hba))
> > +	if ((ufshcd_is_intr_aggr_allowed(hba))
> > +		&& !(hba->quirks & UFSHCI_QUIRK_SKIP_INTR_AGGR))
> 
> Why do we need this new quirk? If controller has the issue with interrupt
> aggregation, you can remove this UFSHCD_CAP_INTR_AGGR to disable the
> aggregation altogether.
> 
> > +		ufshcd_reset_intr_aggr(hba);
> >  		ufshcd_reset_intr_aggr(hba);
> >
> >  	tr_doorbell = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
> > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> > index 6a96f24..6a9c6e9 100644
> > --- a/drivers/scsi/ufs/ufshcd.h
> > +++ b/drivers/scsi/ufs/ufshcd.h
> > @@ -497,6 +497,7 @@ struct ufs_hba {
> >  	#define UFSHCD_QUIRK_BROKEN_DWORD_UTRD                  UFS_BIT(7)
> >  	#define UFSHCD_QUIRK_BROKEN_REQ_LIST_CLR                UFS_BIT(8)
> >  	#define UFSHCD_QUIRK_USE_OF_HCE				UFS_BIT(9)
> > +	#define UFSHCI_QUIRK_SKIP_INTR_AGGR			UFS_BIT(10)
> >
> >
> >  	unsigned int quirks;	/* Deviations from standard UFSHCI spec.
> */
> 
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