Re: [PATCH v5 06/10] scsi: ufs: ufs-qcom: Limit HS-G5 Rate-A to hosts with HW version 5

[Can Guo]

Hi Mani,

On 11/28/2023 1:55 PM, Manivannan Sadhasivam wrote:
> On Thu, Nov 23, 2023 at 12:46:26AM -0800, Can Guo wrote:
> > Qcom UFS hosts, with HW ver 5, can only support up to HS-G5 Rate-A due to
> > HW limitations. If the HS-G5 PHY gear is used, update host_params->hs_rate
> > to Rate-A, so that the subsequent power mode changes shall stick to Rate-A.
> >
> > Signed-off-by: Can Guo <quic_cang@xxxxxxxxxxx>
>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
>
> One question below...
>
> > ---
> >   drivers/ufs/host/ufs-qcom.c | 18 +++++++++++++++++-
> >   1 file changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
> > index 9613ad9..6756f8d 100644
> > --- a/drivers/ufs/host/ufs-qcom.c
> > +++ b/drivers/ufs/host/ufs-qcom.c
> > @@ -442,9 +442,25 @@ static u32 ufs_qcom_get_hs_gear(struct ufs_hba *hba)
> >   static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
> >   {
> >   	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
> > +	struct ufs_host_params *host_params = &host->host_params;
> >   	struct phy *phy = host->generic_phy;
> > +	enum phy_mode mode;
> >   	int ret;
> >   
> > +	/*
> > +	 * HW ver 5 can only support up to HS-G5 Rate-A due to HW limitations.
> > +	 * If the HS-G5 PHY gear is used, update host_params->hs_rate to Rate-A,
> > +	 * so that the subsequent power mode change shall stick to Rate-A.
> > +	 */
> > +	if (host->hw_ver.major == 0x5) {
> > +		if (host->phy_gear == UFS_HS_G5)
> > +			host_params->hs_rate = PA_HS_MODE_A;
> > +		else
> > +			host_params->hs_rate = PA_HS_MODE_B;
>
> Is this 'else' part really needed? Since there wouldn't be any 2nd init, I think
> we can skip that.

We need it because, even there is only one init, if a UFS3.1 device is 
attached, phy_gear is given as UFS_HS_G4 in ufs_qcom_set_phy_gear(), 
hence we need to put the UFS at HS-G4 Rate B, not Rate A.

Thanks,
Can Guo.

> - Mani
>
> > +	}
> > +
> > +	mode = host_params->hs_rate == PA_HS_MODE_B ? PHY_MODE_UFS_HS_B : PHY_MODE_UFS_HS_A;
> > +
> >   	/* Reset UFS Host Controller and PHY */
> >   	ret = ufs_qcom_host_reset(hba);
> >   	if (ret)
> > @@ -459,7 +475,7 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
> >   		return ret;
> >   	}
> >   
> > -	phy_set_mode_ext(phy, PHY_MODE_UFS_HS_B, host->phy_gear);
> > +	phy_set_mode_ext(phy, mode, host->phy_gear);
> >   
> >   	/* power on phy - start serdes and phy's power and clocks */
> >   	ret = phy_power_on(phy);
> > --
> > 2.7.4