Re: [PATCH v5 09/10] phy: qualcomm: phy-qcom-qmp-ufs: Add High Speed Gear 5 support for SM8550

[Can Guo]

On 11/28/2023 2:47 PM, Manivannan Sadhasivam wrote:
> On Thu, Nov 23, 2023 at 12:46:29AM -0800, Can Guo wrote:
> > On SM8550, two sets of UFS PHY settings are provided, one set is to support
> > HS-G5, another set is to support HS-G4 and lower gears. The two sets of PHY
> > settings are programming different values to different registers, mixing
> > the two sets and/or overwriting one set with another set is definitely not
> > blessed by UFS PHY designers.
> >
> > To add HS-G5 support for SM8550, split the two sets of PHY settings into
> > their dedicated overlay tables, only the common parts of the two sets of
> > PHY settings are left in the .tbls.
> >
> > Consider we are going to add even higher gear support in future, to avoid
> > adding more tables with different names, rename the .tbls_hs_g4 and make it
> > an array, a size of 2 is enough as of now.
> >
> > In this case, .tbls alone is not a complete set of PHY settings, so either
> > tbls_hs_overlay[0] or tbls_hs_overlay[1] must be applied on top of the
> > .tbls to become a complete set of PHY settings.
>
> Thanks for the update! This really helps in minimizing the changes for future
> gears.
>
> > Signed-off-by: Can Guo <quic_cang@xxxxxxxxxxx>
> > ---
> >   drivers/phy/qualcomm/phy-qcom-qmp-pcs-ufs-v6.h     |   2 +
> >   drivers/phy/qualcomm/phy-qcom-qmp-qserdes-com-v6.h |   2 +
> >   .../qualcomm/phy-qcom-qmp-qserdes-txrx-ufs-v6.h    |   9 ++
> >   drivers/phy/qualcomm/phy-qcom-qmp-ufs.c            | 174 ++++++++++++++++++---
> >   4 files changed, 166 insertions(+), 21 deletions(-)
> >
> >   
>
> [...]
>
> > -static void qmp_ufs_init_registers(struct qmp_ufs *qmp, const struct qmp_phy_cfg *cfg)
> > +static bool qmp_ufs_match_gear_overlay(struct qmp_ufs *qmp, const struct qmp_phy_cfg *cfg, int *i)
> > +{
> > +	u32 max_gear, floor_max_gear = cfg->max_supported_gear;
> > +	bool found = false;
> > +	int j;
> > +
> > +	for (j = 0; j < NUM_OVERLAY; j ++) {
> > +		max_gear = cfg->tbls_hs_overlay[j].max_gear;
> > +
> > +		if (max_gear == 0)
>
> Is this condition possible for hs_overlay tables?

Yes, now there are 2 overlays for SM8550, but only one overlay for the 
rest targets. For those who has only one overlay, this check fits them.

> > +			continue;
> > +
> > +		/* Direct matching, bail */
> > +		if (qmp->submode == max_gear) {
> > +			*i = j;
> > +			return true;
> > +		}
> > +
> > +		/* If no direct matching, the lowest gear is the best matching */
> > +		if (max_gear < floor_max_gear) {
>
> Can you start the loop from max? If looks odd to set the matching params in the
> first iteration itself and then checking the next one.

OK, will start from j = NUM_VERLAY - 1; in next version. When I wrote 
the code, I was not expecting the max is always in the last overlay, 
they can come in any orders.

> > +			*i = j;
> > +			found = true;
> > +			floor_max_gear = max_gear;
> > +		}
> > +	}
> > +
> > +	return found;
> > +}
> > +
> > +static int qmp_ufs_init_registers(struct qmp_ufs *qmp, const struct qmp_phy_cfg *cfg)
> >   {
> > +	bool apply_overlay;
> > +	int i;
> > +
> > +	if (qmp->submode > cfg->max_supported_gear || qmp->submode == 0) {
> > +		dev_err(qmp->dev, "Invalid PHY submode %u\n", qmp->submode);
> > +		return -EINVAL;
> > +	}
>
> This check should be moved to qmp_ufs_set_mode().

OK.

Thanks,
Can Guo.

> Rest LGTM.
>
> - Mani