Messages in this thread | | | From | "Alim Akhtar" <> | Subject | RE: [PATCH v6 04/10] scsi: ufs: introduce UFSHCD_QUIRK_PRDT_BYTE_GRAN quirk | Date | Sun, 26 Apr 2020 21:26:08 +0530 |
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Hi Christoph,
> -----Original Message----- > From: Christoph Hellwig <hch@infradead.org> > Sent: 22 April 2020 12:24 > To: Alim Akhtar <alim.akhtar@samsung.com> > Cc: robh@kernel.org; devicetree@vger.kernel.org; linux-scsi@vger.kernel.org; > krzk@kernel.org; avri.altman@wdc.com; martin.petersen@oracle.com; > kwmad.kim@samsung.com; stanley.chu@mediatek.com; > cang@codeaurora.org; linux-samsung-soc@vger.kernel.org; linux-arm- > kernel@lists.infradead.org; linux-kernel@vger.kernel.org > Subject: Re: [PATCH v6 04/10] scsi: ufs: introduce > UFSHCD_QUIRK_PRDT_BYTE_GRAN quirk > > On Fri, Apr 17, 2020 at 11:29:38PM +0530, Alim Akhtar wrote: > > Some UFS host controllers may think granularities of PRDT length and > > offset as bytes, not double words. > > > > Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com> > > Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com> > > --- > > drivers/scsi/ufs/ufshcd.c | 30 +++++++++++++++++++++++------- > > drivers/scsi/ufs/ufshcd.h | 6 ++++++ > > 2 files changed, 29 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > > index ee30ed6cc805..b32fcedcdcb9 100644 > > --- a/drivers/scsi/ufs/ufshcd.c > > +++ b/drivers/scsi/ufs/ufshcd.c > > @@ -2151,8 +2151,14 @@ static int ufshcd_map_sg(struct ufs_hba *hba, > struct ufshcd_lrb *lrbp) > > return sg_segments; > > > > if (sg_segments) { > > - lrbp->utr_descriptor_ptr->prd_table_length = > > - cpu_to_le16((u16)sg_segments); > > + > > + if (hba->quirks & UFSHCD_QUIRK_PRDT_BYTE_GRAN) > > + lrbp->utr_descriptor_ptr->prd_table_length = > > + cpu_to_le16((u16)(sg_segments * > > + sizeof(struct ufshcd_sg_entry))); > > + else > > + lrbp->utr_descriptor_ptr->prd_table_length = > > + cpu_to_le16((u16) (sg_segments)); > > No double words here. "Normal" UFS uses the actual segment count, while > Samsumg uses bytes. Also no need fo the u16 count in either the old or new > version. Ok, will update the commit message and take your suggestion in the next version.
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