Re: [PATCH v2 4/5] tpm_tis: fix IRQ probing

[Jarkko Sakkinen <jarkko@kernel.org>]

On Sat, Oct 24, 2020 at 03:17:18PM +0300, Jarkko Sakkinen wrote:
> On Mon, Oct 19, 2020 at 04:41:35PM -0700, Jerry Snitselaar wrote:
> > 
> > James Bottomley @ 2020-10-01 11:09 MST:
> > 
> > > There are two problems with our current interrupt probing: firstly the
> > > TPM_CHIP_FLAG_IRQ never gets set initially, so a check for interrupts
> > > is never done.  Fix this by setting the flag before we generate and
> > > interrupt for probing.  Secondly our IRQ setup may be ineffective on a
> > > TPM without legacy access cycles becuase according to the TPM
> > > Interface Specification the interrupt registers are only writeable in
> > > the current locality, so issue a request_locality before setting up
> > > the interrupts.
> > >
> > > Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
> > >
> > > ---
> > >
> > > v2: improved description
> > > ---
> > >  drivers/char/tpm/tpm_tis_core.c | 14 ++++++++++++++
> > >  1 file changed, 14 insertions(+)
> > >
> > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> > > index 0c07da8cd680..12b657ed3a39 100644
> > > --- a/drivers/char/tpm/tpm_tis_core.c
> > > +++ b/drivers/char/tpm/tpm_tis_core.c
> > > @@ -809,6 +809,19 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip,
> > >  	}
> > >  	priv->irq = irq;
> > >  
> > > +	/*
> > > +	 * note writes to the interrupt registers are only effective
> > > +	 * when the TPM is in the active locality, so we have to
> > > +	 * request the locality here to get the interrupt set up.
> > > +	 * This request has no corresponding release, because the
> > > +	 * locality will be relinquished at the end of the tpm command
> > > +	 * that probes the interrupts
> > > +	 */
> > > +	if (request_locality(chip, 0) != 0) {
> > > +		dev_err(&chip->dev, "failed to gain locality for irq probe\n");
> > > +		return -EBUSY;
> > > +	}
> 
> Appreciate the comment a lot, but s/note/Note/

I tested this with:

- https://ark.intel.com/content/www/us/en/ark/products/84861/intel-nuc-kit-nuc5i5myhe.html
  dTPM 1.2
- https://ark.intel.com/content/www/us/en/ark/products/74483/intel-nuc-kit-dc53427hye.html
  dTPM 2.0

I did not get "TPM interrupt not working, polling instead" to klog.
But I neither see tpm0 in /proc/interrupts. What I'm doing wrong?

/Jarkko