Re: [PATCH v6 04/10] scsi: ufs: ufs-qcom: Allow the first init start with the maximum supported gear

[Can Guo]

On 11/30/2023 2:42 PM, Manivannan Sadhasivam wrote:
> On Wed, Nov 29, 2023 at 12:28:29AM -0800, Can Guo wrote:
> > During host driver init, the phy_gear is set to the minimum supported gear
> > (HS_G2). Then, during the first power mode change, the negotiated gear, say
> > HS-G4, is updated to the phy_gear variable so that in the second init the
> > updated phy_gear can be used to program the PHY.
> >
> > But the current code only allows update the phy_gear to a higher value. If
> > one wants to start the first init with the maximum support gear, say HS-G4,
> > the phy_gear is not updated to HS-G3 if the device only supports HS-G3.
> >
> > The original check added there is intend to make sure the phy_gear won't be
> > updated when gear is scaled down (during clock scaling). Update the check
> > so that one can start the first init with the maximum support gear without
> > breaking the original fix by checking the ufshcd_state, that is, allow
> > update to phy_gear only if power mode change is invoked from
> > ufshcd_probe_hba().
> >
> > This change is a preparation patch for the next patches in the same series.
>
> If you happen to respin the series, please remove this line. When the patches
> get merged, there will be no concept of patches/series as all will be git
> commits.
>
> You can have this information in the comment section (below --- line) though.

Sure, will remove it in next version.

Thanks,
Can Guo.

> > Signed-off-by: Can Guo <quic_cang@xxxxxxxxxxx>
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
>
> - Mani
>
> > ---
> >   drivers/ufs/host/ufs-qcom.c | 9 +++++----
> >   1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> > index 9a90019..81056b9 100644
> > --- a/drivers/ufs/host/ufs-qcom.c
> > +++ b/drivers/ufs/host/ufs-qcom.c
> > @@ -916,11 +916,12 @@ static int ufs_qcom_pwr_change_notify(struct ufs_hba *hba,
> >   		}
> >   
> >   		/*
> > -		 * Update phy_gear only when the gears are scaled to a higher value. This is
> > -		 * because, the PHY gear settings are backwards compatible and we only need to
> > -		 * change the PHY gear settings while scaling to higher gears.
> > +		 * During UFS driver probe, always update the PHY gear to match the negotiated
> > +		 * gear, so that, if quirk UFSHCD_QUIRK_REINIT_AFTER_MAX_GEAR_SWITCH is enabled,
> > +		 * the second init can program the optimal PHY settings. This allows one to start
> > +		 * the first init with either the minimum or the maximum support gear.
> >   		 */
> > -		if (dev_req_params->gear_tx > host->phy_gear)
> > +		if (hba->ufshcd_state == UFSHCD_STATE_RESET)
> >   			host->phy_gear = dev_req_params->gear_tx;
> >   
> >   		/* enable the device ref clock before changing to HS mode */
> > --
> > 2.7.4