Re: [PATCH V2 2/2] scsi: ufs: introduce quirk to extend PA_HIBERN8TIME for UFS devices

[MANISH PANDEY]

On 4/7/2025 12:05 AM, Manivannan Sadhasivam wrote:
> On Fri, Apr 04, 2025 at 11:15:39PM +0530, Manish Pandey wrote:
> > Some UFS devices need additional time in hibern8 mode before exiting,
> > beyond the negotiated handshaking phase between the host and device.
> > Introduce a quirk to increase the PA_HIBERN8TIME parameter by 100 µs
> > to ensure proper hibernation process.
>
> This commit message didn't mention the UFS device for which this quirk is being
> applied.
Since it's a quirk and may be applicable to other vendors also in 
future, so i thought to keep it general.

Will update in next patch set if required.
 >> Signed-off-by: Manish Pandey <quic_mapa@xxxxxxxxxxx>
> > ---
> >   drivers/ufs/core/ufshcd.c | 31 +++++++++++++++++++++++++++++++
> >   include/ufs/ufs_quirks.h  |  6 ++++++
> >   2 files changed, 37 insertions(+)
> >
> > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> > index 464f13da259a..2b8203fe7b8c 100644
> > --- a/drivers/ufs/core/ufshcd.c
> > +++ b/drivers/ufs/core/ufshcd.c
> > @@ -278,6 +278,7 @@ static const struct ufs_dev_quirk ufs_fixups[] = {
> >   	  .model = UFS_ANY_MODEL,
> >   	  .quirk = UFS_DEVICE_QUIRK_DELAY_BEFORE_LPM |
> >   		   UFS_DEVICE_QUIRK_HOST_PA_TACTIVATE |
> > +		   UFS_DEVICE_QUIRK_PA_HIBER8TIME |
> >   		   UFS_DEVICE_QUIRK_RECOVERY_FROM_DL_NAC_ERRORS },
> >   	{ .wmanufacturerid = UFS_VENDOR_SKHYNIX,
> >   	  .model = UFS_ANY_MODEL,
> > @@ -8384,6 +8385,33 @@ static int ufshcd_quirk_tune_host_pa_tactivate(struct ufs_hba *hba)
> >   	return ret;
> >   }
> >   
> > +/**
> > + * ufshcd_quirk_override_pa_h8time - Ensures proper adjustment of PA_HIBERN8TIME.
> > + * @hba: per-adapter instance
> > + *
> > + * Some UFS devices require specific adjustments to the PA_HIBERN8TIME parameter
> > + * to ensure proper hibernation timing. This function retrieves the current
> > + * PA_HIBERN8TIME value and increments it by 100us.
> > + */
> > +static void ufshcd_quirk_override_pa_h8time(struct ufs_hba *hba)
> > +{
> > +	u32 pa_h8time = 0;
>
> Why do you need to initialize it?
Agree.. Not needed, will update.>> +	int ret;
> > +
> > +	ret = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_HIBERN8TIME),
> > +			&pa_h8time);
> > +	if (ret) {
> > +		dev_err(hba->dev, "Failed to get PA_HIBERN8TIME: %d\n", ret);
> > +		return;
> > +	}
> > +
> > +	/* Increment by 1 to increase hibernation time by 100 µs */
>
>  From where the value of 100us adjustment is coming from?
>
> - Mani
These values are derived from experiments on Qualcomm SoCs.
However this is also matching with ufs-exynos.c

fsd_ufs_post_link() {
    ufshcd_dme_get(hba,UIC_ARG_MIB(PA_HIBERN8TIME),  		 
&max_rx_hibern8_time_cap);
    .......
    ufshcd_dme_set(hba, UIC_ARG_MIB(PA_HIBERN8TIME), 	 
max_rx_hibern8_time_cap + 1);
    ...
}

Thanks
Manish