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SubjectRe: [RESEND PATCH v10 04/10] scsi: ufs: introduce UFSHCD_QUIRK_PRDT_BYTE_GRAN quirk
On Thu, Aug 13, 2020 at 06:51:13AM +0530, Alim Akhtar wrote:
> Hi Eric,
>
> > -----Original Message-----
> > From: Eric Biggers <ebiggers@kernel.org>
> > Sent: 12 August 2020 05:59
> > 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; kishon@ti.com
> > Subject: Re: [RESEND PATCH v10 04/10] scsi: ufs: introduce
> > UFSHCD_QUIRK_PRDT_BYTE_GRAN quirk
> >
> > Hi Alim,
> >
> > On Sat, Jun 13, 2020 at 08:17:00AM +0530, Alim Akhtar wrote:
> > > Some UFS host controllers like Exynos uses granularities of PRDT
> > > length and offset as bytes, whereas others uses actual segment count.
> > >
> > > Reviewed-by: Avri Altman <avri.altman@wdc.com>
> > > 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..ba093d0d0942 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((sg_segments *
> > > + sizeof(struct ufshcd_sg_entry)));
> > > + else
> > > + lrbp->utr_descriptor_ptr->prd_table_length =
> > > + cpu_to_le16((u16) (sg_segments));
> > >
> > > prd_table = (struct ufshcd_sg_entry *)lrbp->ucd_prdt_ptr;
> > >
> > > @@ -3500,11 +3506,21 @@ static void
> > ufshcd_host_memory_configure(struct ufs_hba *hba)
> > >
> > cpu_to_le32(upper_32_bits(cmd_desc_element_addr));
> > >
> > > /* Response upiu and prdt offset should be in double words
> */
> > > - utrdlp[i].response_upiu_offset =
> > > - cpu_to_le16(response_offset >> 2);
> > > - utrdlp[i].prd_table_offset = cpu_to_le16(prdt_offset >> 2);
> > > - utrdlp[i].response_upiu_length =
> > > - cpu_to_le16(ALIGNED_UPIU_SIZE >> 2);
> > > + if (hba->quirks & UFSHCD_QUIRK_PRDT_BYTE_GRAN) {
> > > + utrdlp[i].response_upiu_offset =
> > > + cpu_to_le16(response_offset);
> > > + utrdlp[i].prd_table_offset =
> > > + cpu_to_le16(prdt_offset);
> > > + utrdlp[i].response_upiu_length =
> > > + cpu_to_le16(ALIGNED_UPIU_SIZE);
> > > + } else {
> > > + utrdlp[i].response_upiu_offset =
> > > + cpu_to_le16(response_offset >> 2);
> > > + utrdlp[i].prd_table_offset =
> > > + cpu_to_le16(prdt_offset >> 2);
> > > + utrdlp[i].response_upiu_length =
> > > + cpu_to_le16(ALIGNED_UPIU_SIZE >> 2);
> > > + }
> > >
> > > ufshcd_init_lrb(hba, &hba->lrb[i], i);
> > > }
> >
> > Isn't this patch missing an update to ufshcd_print_trs()? It uses
> > ->prd_table_length as the number of segments, not the number of bytes.
> >
> prd_table_length will be populated before it reaches ufshcd_print_trs()
> based on UFSHCD_QUIRK_PRDT_BYTE_GRAN.
>

Yes, which is why it seems ufshcd_print_trs() needs to be updated to take
UFSHCD_QUIRK_PRDT_BYTE_GRAN into account.

- Eric

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