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

Alim Akhtar
2022-02-03T06:50:56Z

Hi Hoyoung

>-----Original Message-----
>From: Hoyoung SEO [mailto:hy50.seo@samsung.com]
>Sent: Thursday, February 3, 2022 5:43 AM
>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' <lkp@intel.com>
>Subject: RE: [PATCH v2] scsi: ufs: disable auto hibern8 while entering suspend
>
>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.
>>
I am not sure, if this problem is generic and faced by all other UFS vendors.
If not, how about having a vendor specific call back for your platform only?
Just a thought.

>> > -----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;
>
>