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Date:   Fri, 26 Aug 2022 07:10:52 +0300
From:   Jarkko Sakkinen <jarkko@kernel.org>
To:     Eddie James <eajames@linux.ibm.com>
Cc:     linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        Alexander.Steffen@infineon.com, jgg@ziepe.ca, peterhuewe@gmx.de,
        joel@jms.id.au
Subject: Re: [PATCH] tpm: tis_i2c: Fix sanity check interrupt enable mask
Message-ID: <YwhHzDL5agT3enUn@kernel.org>
References: <20220817200333.305264-1-eajames@linux.ibm.com>
 <YwhGLZX2+dggWHcI@kernel.org>
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On Fri, Aug 26, 2022 at 07:04:00AM +0300, Jarkko Sakkinen wrote:
> On Wed, Aug 17, 2022 at 03:03:33PM -0500, Eddie James wrote:
> > The sanity check mask for TPM_INT_ENABLE register was off by 8 bits,
> > resulting in failure to probe if the TPM_INT_ENABLE register was a
> > valid value.
> > 
> > Fixes: bbc23a07b072 ("tpm: Add tpm_tis_i2c backend for tpm_tis_core")
> > Signed-off-by: Eddie James <eajames@linux.ibm.com>
> > ---
> >  drivers/char/tpm/tpm_tis_i2c.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c
> > index 0692510dfcab..635a69dfcbbd 100644
> > --- a/drivers/char/tpm/tpm_tis_i2c.c
> > +++ b/drivers/char/tpm/tpm_tis_i2c.c
> > @@ -49,7 +49,7 @@
> >  
> >  /* Masks with bits that must be read zero */
> >  #define TPM_ACCESS_READ_ZERO 0x48
> > -#define TPM_INT_ENABLE_ZERO 0x7FFFFF6
> > +#define TPM_INT_ENABLE_ZERO 0x7FFFFF60
> >  #define TPM_STS_READ_ZERO 0x23
> >  #define TPM_INTF_CAPABILITY_ZERO 0x0FFFF000
> >  #define TPM_I2C_INTERFACE_CAPABILITY_ZERO 0x80000000
> > -- 
> > 2.31.1
> > 
> 
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> 
> Thank you.

I used "6.3 Handling of Multi-Byte Registers" I2C specification
to check this. I do not posses I2C chip.

https://trustedcomputinggroup.org/wp-content/uploads/TCG-TPM-I2C-Interface-Specification-v1.00.pdf

BR, Jarkko