RE: [PATCH v2] scsi: ufs: disable auto hibern8 while entering suspend

[Avri Altman <Avri.Altman@wdc.com>]

> Hi,
> Please check this patch.
> If there is any other opinion, please give me comments Thanks
> 
> > -----Original Message-----
> > From: 서호영 [mailto:hy50.seo@samsung.com]
> > Sent: Wednesday, January 26, 2022 2:35 PM
> > To: 'linux-scsi@vger.kernel.org'; 'linux-kernel@vger.kernel.org';
> > 'alim.akhtar@samsung.com'; 'avri.altman@wdc.com';
> > 'jejb@linux.ibm.com'; 'martin.petersen@oracle.com';
> > 'beanhuo@micron.com'; 'asutoshd@codeaurora.org';
> > 'cang@codeaurora.org'; 'bvanassche@acm.org';
> 'bhoon95.kim@samsung.com'; 'kwmad.kim@samsung.com'
> > Cc: 'kernel test robot'
> > Subject: RE: [PATCH v2] scsi: ufs: disable auto hibern8 while entering
> > suspend
> >
> > Hi,
> > I think content is lacking in the UFSHCI spec.
> > In the process, AH8 is in operation, and it seems that sending the
> > command
> > hibern8 by manual has a defeat.
> > I don't know what the all hci vendor's hardware design will be, but
> > there is a possibility that ah8 and manual hibern8 may overlap.
> > So if is operating in ah8, it is thought that it will be safer to
> > disable
> > ah8 before sending hibern8 command.
Hi,
Thank you for your patch.
Maybe better to promote your idea in JEDEC first.

Thanks,
Avri
> >
> > > -----Original Message-----
> > > From: Stanley Chu [mailto:stanley.chu@mediatek.com]
> > > Sent: Wednesday, January 26, 2022 10:22 AM
> > > To: SEO HOYOUNG; linux-scsi@vger.kernel.org;
> > > linux-kernel@vger.kernel.org; alim.akhtar@samsung.com;
> > > avri.altman@wdc.com; jejb@linux.ibm.com;
> martin.petersen@oracle.com;
> > > beanhuo@micron.com; asutoshd@codeaurora.org;
> cang@codeaurora.org;
> > > bvanassche@acm.org; bhoon95.kim@samsung.com;
> kwmad.kim@samsung.com
> > > Cc: kernel test robot; peter.wang@mediatek.com
> > > Subject: Re: [PATCH v2] scsi: ufs: disable auto hibern8 while
> > > entering suspend
> > >
> > > Hi Hoyoung,
> > >
> > > On Tue, 2022-01-25 at 03:06 +0900, SEO HOYOUNG wrote:
> > > > v1-> v2: fixed no previous prototype warning
> > > > Reported-by: kernel test robot <lkp@intel.com>
> > > >
> > > > All warnings (new ones prefixed by >>):
> > > > > > drivers/scsi/ufs/ufshcd.c:4207:6: warning: no previous
> > > > > > prototype
> > > >
> > > > for 'ufshcd_auto_hibern8_disable' [-Wmissing-prototypes]
> > > > 4207 | void ufshcd_auto_hibern8_disable(struct ufs_hba *hba)
> > > >
> > > > If using auto hibern8 mode, need to disable auto hibern8 while
> > > > entering suspend.
> > > > When using auto hibern8 mode, it does not seem right to send a uic
> > > > command
> > >
> > > The UFSHCI spec does not mention the above rule.
> > > Why would you need to disable AH8 before using UIC command to enter
> H8?
> > >
> > > > for entry into hibern8 in the next
> > > > line(ufshcd_lik_state_transition(..))
> > > > It seem right to send after disable auto hibern8.
> > > >
> > > > In addition, if the auto hibern8 mode supported, it is enabled in
> > > > resume.
> > > > So it seems that it will be paired only when auto hibern8 is
> > > > disabled while entering suspend.
> > > >
> > > > Signed-off-by: SEO HOYOUNG <hy50.seo@samsung.com>
> > > > ---
> > > >  drivers/scsi/ufs/ufshcd.c | 14 ++++++++++++++
> > > >  1 file changed, 14 insertions(+)
> > > >
> > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > > > index 460d2b440d2e..a6edbbd8ca2c 100644
> > > > --- a/drivers/scsi/ufs/ufshcd.c
> > > > +++ b/drivers/scsi/ufs/ufshcd.c
> > > > @@ -254,6 +254,7 @@ static void
> > > > ufshcd_wb_toggle_flush_during_h8(struct ufs_hba *hba, bool set);
> > > > static inline void ufshcd_wb_toggle_flush(struct ufs_hba *hba,
> > > > bool enable);  static void ufshcd_hba_vreg_set_lpm(struct ufs_hba
> > > > *hba); static void ufshcd_hba_vreg_set_hpm(struct ufs_hba *hba);
> > > > +static void ufshcd_auto_hibern8_disable(struct ufs_hba *hba);
> > > >
> > > >  static inline void ufshcd_enable_irq(struct ufs_hba *hba)  { @@
> > > > -4204,6 +4205,18 @@ void ufshcd_auto_hibern8_update(struct
> ufs_hba
> > > > *hba, u32 ahit)  }
> EXPORT_SYMBOL_GPL(ufshcd_auto_hibern8_update);
> > > >
> > > > +static void ufshcd_auto_hibern8_disable(struct ufs_hba *hba) {
> > > > +unsigned long flags;
> > > > +
> > > > + if (!ufshcd_is_auto_hibern8_supported(hba))
> > > > +         return;
> > > > +
> > > > + spin_lock_irqsave(hba->host->host_lock, flags);
> > > > + ufshcd_writel(hba, 0, REG_AUTO_HIBERNATE_IDLE_TIMER);
> > > > + spin_unlock_irqrestore(hba->host->host_lock, flags); }
> > > > +
> > > >  void ufshcd_auto_hibern8_enable(struct ufs_hba *hba)  {
> > > >   unsigned long flags;
> > > > @@ -8925,6 +8938,7 @@ static int __ufshcd_wl_suspend(struct
> > > > ufs_hba *hba, enum ufs_pm_op pm_op)
> > > >    * with the link off, so do not check for bkops.
> > > >    */
> > > >   check_for_bkops = !ufshcd_is_ufs_dev_deepsleep(hba);
> > > > + ufshcd_auto_hibern8_disable(hba);
> > > >   ret = ufshcd_link_state_transition(hba, req_link_state,
> > > > check_for_bkops);
> > > >   if (ret)
> > > >           goto set_dev_active;
> 
>