Re: [PATCH v9 16/19] tpm: Add ability to set the preferred locality the TPM chip uses

[ross . philipson]

On 6/4/24 1:27 PM, Jarkko Sakkinen wrote:
> On Fri May 31, 2024 at 4:03 AM EEST, Ross Philipson wrote:
> > Curently the locality is hard coded to 0 but for DRTM support, access
> > is needed to localities 1 through 4.
> >
> > Signed-off-by: Ross Philipson <ross.philipson@xxxxxxxxxx>
> > ---
> >   drivers/char/tpm/tpm-chip.c      | 24 +++++++++++++++++++++++-
> >   drivers/char/tpm/tpm-interface.c | 15 +++++++++++++++
> >   drivers/char/tpm/tpm.h           |  1 +
> >   include/linux/tpm.h              |  4 ++++
> >   4 files changed, 43 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> > index 854546000c92..73eac54d61fb 100644
> > --- a/drivers/char/tpm/tpm-chip.c
> > +++ b/drivers/char/tpm/tpm-chip.c
> > @@ -44,7 +44,7 @@ static int tpm_request_locality(struct tpm_chip *chip)
> >   	if (!chip->ops->request_locality)
> >   		return 0;
> >   
> > -	rc = chip->ops->request_locality(chip, 0);
> > +	rc = chip->ops->request_locality(chip, chip->pref_locality);
> >   	if (rc < 0)
> >   		return rc;
> >   
> > @@ -143,6 +143,27 @@ void tpm_chip_stop(struct tpm_chip *chip)
> >   }
> >   EXPORT_SYMBOL_GPL(tpm_chip_stop);
> >   
> > +/**
> > + * tpm_chip_preferred_locality() - set the TPM chip preferred locality to open
> > + * @chip:	a TPM chip to use
> > + * @locality:   the preferred locality
> > + *
> > + * Return:
> > + * * true      - Preferred locality set
> > + * * false     - Invalid locality specified
> > + */
> > +bool tpm_chip_preferred_locality(struct tpm_chip *chip, int locality)
> > +{
> > +	if (locality < 0 || locality >=TPM_MAX_LOCALITY)
> > +		return false;
> > +
> > +	mutex_lock(&chip->tpm_mutex);
> > +	chip->pref_locality = locality;
> > +	mutex_unlock(&chip->tpm_mutex);
> > +	return true;
> > +}
> > +EXPORT_SYMBOL_GPL(tpm_chip_preferred_locality);
> > +
> >   /**
> >    * tpm_try_get_ops() - Get a ref to the tpm_chip
> >    * @chip: Chip to ref
> > @@ -374,6 +395,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
> >   	}
> >   
> >   	chip->locality = -1;
> > +	chip->pref_locality = 0;
> >   	return chip;
> >   
> >   out:
> > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> > index 5da134f12c9a..35f14ccecf0e 100644
> > --- a/drivers/char/tpm/tpm-interface.c
> > +++ b/drivers/char/tpm/tpm-interface.c
> > @@ -274,6 +274,21 @@ int tpm_is_tpm2(struct tpm_chip *chip)
> >   }
> >   EXPORT_SYMBOL_GPL(tpm_is_tpm2);
> >   
> > +/**
> > + * tpm_preferred_locality() - set the TPM chip preferred locality to open
> > + * @chip:	a TPM chip to use
> > + * @locality:   the preferred locality
> > + *
> > + * Return:
> > + * * true      - Preferred locality set
> > + * * false     - Invalid locality specified
> > + */
> > +bool tpm_preferred_locality(struct tpm_chip *chip, int locality)
> > +{
> > +	return tpm_chip_preferred_locality(chip, locality);
> > +}
> > +EXPORT_SYMBOL_GPL(tpm_preferred_locality);
>
>   What good does this extra wrapping do?
>
>   tpm_set_default_locality() and default_locality would make so much more
>   sense in any case.

Are you mainly just talking about my naming choices here and in the 
follow-on response? Can you clarify what you are requesting?

Thanks
Ross

>   BR, Jarkko