From:   =?UTF-8?B?7ISc7Zi47JiB?= <hy50.seo@samsung.com>
To:     "'Avri Altman'" <Avri.Altman@wdc.com>,
        <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <alim.akhtar@samsung.com>, <jejb@linux.ibm.com>,
        <martin.petersen@oracle.com>, <beanhuo@micron.com>,
        <asutoshd@codeaurora.org>, <cang@codeaurora.org>,
        <bvanassche@acm.org>
In-Reply-To: <DM6PR04MB657535F7CC817A0E2893F668FC4D9@DM6PR04MB6575.namprd04.prod.outlook.com>
Subject: RE: [PATCH v2] scsi: ufs: modify Tactive time setting conditions
Date:   Mon, 10 Jan 2022 11:05:16 +0900
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References: <CGME20220107095451epcas2p2d06b23e50cbd46e910532e2d9078c912@epcas2p2.samsung.com>
        <20220106213924.186263-1-hy50.seo@samsung.com>
        <DM6PR04MB657535F7CC817A0E2893F668FC4D9@DM6PR04MB6575.namprd04.prod.outlook.com>
Precedence: bulk

Hi,
If register =22UFS_DEVICE_QUIRK_HOST_PA_TACTIVATE=22 quirk,
using this Tact time function.
And I mean all Samsung device use UFS_DEVICE_QUIRK_HOST_PA_TACTIVATE quirk =
below this. so I told that.
static struct ufs_dev_fix ufs_fixups=5B=5D =3D =7B                   =20
         /* UFS cards deviations table */                     =20
         UFS_FIX(UFS_VENDOR_MICRON, UFS_ANY_MODEL,            =20
                 UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM =7C          =20
                 UFS_DEVICE_QUIRK_SWAP_L2P_ENTRY_FOR_HPB_READ),
         UFS_FIX(UFS_VENDOR_SAMSUNG, UFS_ANY_MODEL,           =20
                 UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM =7C          =20
                 UFS_DEVICE_QUIRK_HOST_PA_TACTIVATE =7C

Other vendors can use it if necessary.
And for stability, the device tact time must be longer than host tact time.
(I already check Major device vendors)
That's reason why use this function.
But the Host tact time and Device tact time same, stability may not be sati=
sfied.
So I changed this way

Thanks,
HOYOUNG.

> -----Original Message-----
> From: Avri Altman =5Bmailto:Avri.Altman=40wdc.com=5D
> Sent: Friday, January 7, 2022 7:57 PM
> To: SEO HOYOUNG; linux-scsi=40vger.kernel.org; linux-kernel=40vger.kernel=
.org;
> alim.akhtar=40samsung.com; jejb=40linux.ibm.com; martin.petersen=40oracle=
.com;
> beanhuo=40micron.com; asutoshd=40codeaurora.org; cang=40codeaurora.org;
> bvanassche=40acm.org
> Subject: RE: =5BPATCH v2=5D scsi: ufs: modify Tactive time setting condit=
ions
>=20
> > The Tactive time determine the waiting time before burst at hibern8
> > exit and is determined by H/W at linkup state However, in the case of
> > samsung devices, guided host's Tactive time
> > +100us for stability.
> > If the HCI's Tactive time is equal or greater than the device,
> > +100us should be set.
> This way you are changing this for everyone - not just for Samsung.
> e.g. Qualcomm are using this quirk as well for WDC devices.
>=20
> Thanks,
> Avri
>=20
> >
> > Signed-off-by: SEO HOYOUNG <hy50.seo=40samsung.com>
> > ---
> >  drivers/scsi/ufs/ufshcd.c =7C 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index 1049e41abd5b..460d2b440d2e 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > =40=40 -7815,7 +7815,7 =40=40 static int
> > ufshcd_quirk_tune_host_pa_tactivate(struct
> > ufs_hba *hba)
> >         peer_pa_tactivate_us =3D peer_pa_tactivate *
> >                              gran_to_us_table=5Bpeer_granularity - 1=5D=
;
> >
> > -       if (pa_tactivate_us > peer_pa_tactivate_us) =7B
> > +       if (pa_tactivate_us >=3D peer_pa_tactivate_us) =7B
> >                 u32 new_peer_pa_tactivate;
> >
> >                 new_peer_pa_tactivate =3D pa_tactivate_us /
> > --
> > 2.26.0