Re: [PATCH v1 7/9] scsi: ufs: add UFS power collapse support during hibern8

[Asutosh Das (asd)]

On 7/21/2018 5:28 AM, Subhash Jadavani wrote:
> On 2018-07-06 05:30, Asutosh Das wrote:
> > From: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
> >
> > UFS host controller hardware may allow the host controller
> > to be power collapsed when UFS link is hibern8 state, this
> > change allows the UFS host controller to be power collapsed
> > during hibern8.
> >
> > Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
> > Signed-off-by: Venkat Gopalakrishnan <venkatg@xxxxxxxxxxxxxx>
> > Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> > Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
> > ---
> > Âdrivers/scsi/ufs/ufshcd.c |Â 8 ++++++--
> > Âdrivers/scsi/ufs/ufshcd.h | 13 ++++++++++++-
> > Â2 files changed, 18 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index 40d9c35..50588cf 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -7673,13 +7673,17 @@ static int ufshcd_vreg_set_hpm(struct ufs_hba 
> > *hba)
> >
> > Âstatic void ufshcd_hba_vreg_set_lpm(struct ufs_hba *hba)
> > Â{
> > -ÂÂÂ if (ufshcd_is_link_off(hba))
> > +ÂÂÂ if (ufshcd_is_link_off(hba) ||
> > +ÂÂÂÂÂÂÂ (ufshcd_is_link_hibern8(hba)
> > +ÂÂÂÂÂÂÂÂ && ufshcd_is_power_collapse_during_hibern8_allowed(hba)))
> > ÂÂÂÂÂÂÂÂ ufshcd_setup_hba_vreg(hba, false);
>
> I guess we have to handle the UFS host controller power collapse via 
> "power-domains" which would requires us to specify the "power-domains" 
> attribute under UFS controller's DT node and then linux core power 
> framework should automatically collapse the UFS controller post runtime 
> suspend. This also means we can't power collapse UFS controller 
> aggressively (as part of clock gating) but it should still be fine from 
> power point of view.
>
> > Â}
> >
> > Âstatic void ufshcd_hba_vreg_set_hpm(struct ufs_hba *hba)
> > Â{
> > -ÂÂÂ if (ufshcd_is_link_off(hba))
> > +ÂÂÂ if (ufshcd_is_link_off(hba) ||
> > +ÂÂÂÂÂÂÂ (ufshcd_is_link_hibern8(hba)
> > +ÂÂÂÂÂÂÂÂ && ufshcd_is_power_collapse_during_hibern8_allowed(hba)))
> > ÂÂÂÂÂÂÂÂ ufshcd_setup_hba_vreg(hba, true);
> > Â}
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> > index f79a639..8c5f987 100644
> > --- a/drivers/scsi/ufs/ufshcd.h
> > +++ b/drivers/scsi/ufs/ufshcd.h
> > @@ -728,7 +728,12 @@ struct ufs_hba {
> > ÂÂÂÂÂ * to do background operation when it's active but it might degrade
> > ÂÂÂÂÂ * the performance of ongoing read/write operations.
> > ÂÂÂÂÂ */
> > -#define UFSHCD_CAP_KEEP_AUTO_BKOPS_ENABLED_EXCEPT_SUSPEND (1 << 5)
> > +#define UFSHCD_CAP_KEEP_AUTO_BKOPS_ENABLED_EXCEPT_SUSPEND (1 << 6)
> > +ÂÂÂ /*
> > +ÂÂÂÂ * If host controller hardware can be power collapsed when UFS 
> > link is
> > +ÂÂÂÂ * in hibern8 then enable this cap.
> > +ÂÂÂÂ */
> > +#define UFSHCD_CAP_POWER_COLLAPSE_DURING_HIBERN8 (1 << 7)
> >
> > ÂÂÂÂ struct devfreq *devfreq;
> > ÂÂÂÂ struct ufs_clk_scaling clk_scaling;
> > @@ -764,6 +769,12 @@ static inline bool
> > ufshcd_is_hibern8_on_idle_allowed(struct ufs_hba *hba)
> > ÂÂÂÂ return hba->caps & UFSHCD_CAP_HIBERN8_ENTER_ON_IDLE;
> > Â}
> >
> > +static inline bool ufshcd_is_power_collapse_during_hibern8_allowed(
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ struct ufs_hba *hba)
> > +{
> > +ÂÂÂ return !!(hba->caps & UFSHCD_CAP_POWER_COLLAPSE_DURING_HIBERN8);
> > +}
> > +
> > Âstatic inline bool ufshcd_is_intr_aggr_allowed(struct ufs_hba *hba)
> > Â{
> > Â/* DWC UFS Core has the Interrupt aggregation feature but is not 
> > detectable*/

Thanks. I'll check the 'power-domains' part and get back with the changes.


--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project