linux-kernel - Re: [PATCH] tpm_tis: turn on TPM before calling tpm_get

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Date:   Tue, 12 Nov 2019 13:23:33 -0700
From:   Jerry Snitselaar <jsnitsel@...hat.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     linux-integrity <linux-integrity@...r.kernel.org>,
        Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>,
        linux-stable@...r.kernel.org,
        Christian Bundy <christianbundy@...ction.io>
Subject: Re: [PATCH] tpm_tis: turn on TPM before calling tpm_get_timeouts

On Tue, Nov 12, 2019 at 1:03 PM Jarkko Sakkinen
<jarkko.sakkinen@...ux.intel.com> wrote:
>
> On Mon, Nov 11, 2019 at 04:34:18PM -0700, Jerry Snitselaar wrote:
> > With power gating moved out of the tpm_transmit code we need
> > to power on the TPM prior to calling tpm_get_timeouts.
> >
> > Cc: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> > Cc: Peter Huewe <peterhuewe@....de>
> > Cc: Jason Gunthorpe <jgg@...pe.ca>
> > Cc: linux-kernel@...r.kernel.org
> > Cc: linux-stable@...r.kernel.org
> > Fixes: a3fbfae82b4c ("tpm: take TPM chip power gating out of tpm_transmit()")
> > Reported-by: Christian Bundy <christianbundy@...ction.io>
> > Signed-off-by: Jerry Snitselaar <jsnitsel@...hat.com>
> > ---
> >  drivers/char/tpm/tpm_tis_core.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> > index 270f43acbb77..cb101cec8f8b 100644
> > --- a/drivers/char/tpm/tpm_tis_core.c
> > +++ b/drivers/char/tpm/tpm_tis_core.c
> > @@ -974,13 +974,14 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
> >                * to make sure it works. May as well use that command to set the
> >                * proper timeouts for the driver.
> >                */
> > +             tpm_chip_start(chip);
> >               if (tpm_get_timeouts(chip)) {
> >                       dev_err(dev, "Could not get TPM timeouts and durations\n");
> >                       rc = -ENODEV;
> > +                     tpm_stop_chip(chip);
> >                       goto out_err;
> >               }
>
> Couldn't this call just be removed?
>
> /Jarkko
>

Probably. It will eventually get called when tpm_chip_register
happens. I don't know what the reason was for trying it prior to the
irq probe.