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From:   "Seunghui Lee" <sh043.lee@samsung.com>
To:     "'Avri Altman'" <Avri.Altman@wdc.com>, <alim.akhtar@samsung.com>,
        <bvanassche@acm.org>, <jejb@linux.ibm.com>,
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Subject: RE: [PATCH] scsi: ufs: no sw reset after last linkstartup fail
Date:   Tue, 5 Jul 2022 16:49:42 +0900
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> -----Original Message-----
> From: Avri Altman <Avri.Altman=40wdc.com>
> Sent: Tuesday, July 5, 2022 3:51 PM
> To: Seunghui Lee <sh043.lee=40samsung.com>; alim.akhtar=40samsung.com;
> bvanassche=40acm.org; jejb=40linux.ibm.com; martin.petersen=40oracle.com;=
 linux-
> scsi=40vger.kernel.org; linux-kernel=40vger.kernel.org
> Cc: grant.jung=40samsung.com; jt77.jang=40samsung.com;
> dh0421.hwang=40samsung.com; junwoo80.lee=40samsung.com; jangsub.yi=40sams=
ung.com;
> cw9316.lee=40samsung.com; sh8267.baek=40samsung.com; wkon.kim=40samsung.c=
om;
> seunghwan.hyun=40samsung.com
> Subject: RE: =5BPATCH=5D scsi: ufs: no sw reset after last linkstartup fa=
il
>=20
>=20
> > As we know, the ufs host controller is disabled and enabled in the
> > ufshcd_hba_enable(). So, host controller registers are clear after sw
> reset.
> >
> > Once the host fails to link startup 3 times, all host's controller can
> > be clear due to executing last ufshcd_hba_enable()(s/w reset).
> > That's why we need to skip last sw reset to get valid host register
> values.
> >
> > Before
> > (ufshcd_dme_link_startup() -> ufshcd_hba_enable() -> retries--) * 3
> times.
> >
> > After
> > (ufshcd_dme_link_startup() -> if retries is 0, break. ->
> > ufshcd_hba_enable()
> > -> retries--) * 3 times.
> > In this case, ufshcd_print_host_state(), ufshcd_print_pwr_info(),
> > ufshcd_print_evt_hist() are valid.
> If you find it necessary to elaborate the commit log, why not do just tha=
t?
> Also maybe make the title more indicative of what you want to achieve:
> =22skip last hci reset to get valid register values=22 or something.
>=20
> Thanks,
> Avri

Thank you for your comment.
I'll modify the commit log and update it again.

>=20
>=20
> >
> > > -----Original Message-----
> > > From: Seunghui Lee <sh043.lee=40samsung.com>
> > > Sent: Thursday, June 30, 2022 1:48 PM
> > > To: alim.akhtar=40samsung.com; avri.altman=40wdc.com;
> > bvanassche=40acm.org;
> > > jejb=40linux.ibm.com; martin.petersen=40oracle.com; linux-
> > scsi=40vger.kernel.org;
> > > linux-kernel=40vger.kernel.org
> > > Cc: grant.jung=40samsung.com; jt77.jang=40samsung.com;
> > > dh0421.hwang=40samsung.com; junwoo80.lee=40samsung.com;
> > jangsub.yi=40samsung.com;
> > > cw9316.lee=40samsung.com; sh8267.baek=40samsung.com;
> > wkon.kim=40samsung.com;
> > > Seunghui Lee <sh043.lee=40samsung.com>
> > > Subject: =5BPATCH=5D scsi: ufs: no sw reset after last linkstartup fa=
il
> > >
> > > Host driver resets the host(ufshcd_hba_enable) after last
> > > linkstartup command failed. All of the member or host dump after
> > > linkstartup fail are reset value because of sw reset.
> > >
> > > Signed-off-by: Junwoo Lee <junwoo80.lee=40samsung.com>
> > > Signed-off-by: Seunghui Lee <sh043.lee=40samsung.com>
> > > ---
> > >  drivers/ufs/core/ufshcd.c =7C 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> > > index
> > > 7c1d7bb9c579..2cdc14675443 100644
> > > --- a/drivers/ufs/core/ufshcd.c
> > > +++ b/drivers/ufs/core/ufshcd.c
> > > =40=40 -4753,7 +4753,7 =40=40 static int ufshcd_link_startup(struct u=
fs_hba
> > *hba)
> > >                * but we can't be sure if the link is up until link st=
artup
> > >                * succeeds. So reset the local Uni-Pro and try again.
> > >                */
> > > -             if (ret && ufshcd_hba_enable(hba)) =7B
> > > +             if (ret && retries && ufshcd_hba_enable(hba)) =7B
> > >                       ufshcd_update_evt_hist(hba,
> > >                                              UFS_EVT_LINK_STARTUP_FAI=
L,
> > >                                              (u32)ret);
> > > --
> > > 2.29.0
> >