Re: [PATCH] tpm: cr50: Add new device/vendor ID 0x504a6666

[Paul Menzel]

Dear Jarkko,


Am 14.04.22 um 14:08 schrieb Jarkko Sakkinen:
> On Thu, Apr 07, 2022 at 12:21:44PM +0200, Paul Menzel wrote:

> > Thank you for your patch.
> >
> > Am 05.04.22 um 19:37 schrieb Jes B. Klinke:
> > > Accept one additional numerical value of DID:VID for next generation
> > > Google TPM, to be used in future Chromebooks.
> >
> > Maybe extend:
> >
> > … Google TPM with new firmware …
> >
> > The TPM with the new firmware has the code name TI50, and going to use the
> > same interfaces.
> >
> > > This patch touches more lines than may seem necessary, as a result of
> > > the need to move the error case to sit after the two recognized cases.
> > >
> > > Signed-off-by: Jes B. Klinke <jbk@xxxxxxxxxxxx>
> > > ---
> > >
> > >    drivers/char/tpm/tpm_tis_i2c_cr50.c | 21 +++++++++++++--------
> > >    1 file changed, 13 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/char/tpm/tpm_tis_i2c_cr50.c b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> > > index f6c0affbb4567..bf54ebd6724b0 100644
> > > --- a/drivers/char/tpm/tpm_tis_i2c_cr50.c
> > > +++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> > > @@ -31,6 +31,7 @@
> > >    #define TPM_CR50_TIMEOUT_SHORT_MS	2		/* Short timeout during transactions */
> > >    #define TPM_CR50_TIMEOUT_NOIRQ_MS	20		/* Timeout for TPM ready without IRQ */
> > >    #define TPM_CR50_I2C_DID_VID		0x00281ae0L	/* Device and vendor ID reg value */
> > > +#define TPM_TI50_I2C_DID_VID		0x504a6666L	/* Device and vendor ID reg value */
> > >    #define TPM_CR50_I2C_MAX_RETRIES	3		/* Max retries due to I2C errors */
> > >    #define TPM_CR50_I2C_RETRY_DELAY_LO	55		/* Min usecs between retries on I2C */
> > >    #define TPM_CR50_I2C_RETRY_DELAY_HI	65		/* Max usecs between retries on I2C */
> > > @@ -742,16 +743,20 @@ static int tpm_cr50_i2c_probe(struct i2c_client *client)
> > >    	}
> > >    	vendor = le32_to_cpup((__le32 *)buf);
> > > -	if (vendor != TPM_CR50_I2C_DID_VID) {
> > > -		dev_err(dev, "Vendor ID did not match! ID was %08x\n", vendor);
> > > -		tpm_cr50_release_locality(chip, true);
> > > -		return -ENODEV;
> > > +	if (vendor == TPM_CR50_I2C_DID_VID) {
> > > +		dev_info(dev, "cr50 TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
> > > +			 client->addr, client->irq, vendor >> 16);
> > > +		return tpm_chip_register(chip);
> > > +	}
> > > +	if (vendor == TPM_TI50_I2C_DID_VID) {
> > > +		dev_info(dev, "ti50 TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
> > > +			 client->addr, client->irq, vendor >> 16);
> > > +		return tpm_chip_register(chip);
> > >    	}
> >
> > Both branches are quite similar. Can a ternary operator be used?
> >
> >      dev_info(dev, "%s TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
> >      	 (vendor == TPM_CR50_I2C_DID_VID) ? "cr50" : "ti50", client->addr,
> > client->irq, vendor >> 16);
> >      return tpm_chip_register(chip);
> >
> > and the original flow be left? (A separate variable can also be added.)
> >
> > > -	dev_info(dev, "cr50 TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
> > > -		 client->addr, client->irq, vendor >> 16);
> > > -
> > > -	return tpm_chip_register(chip);
> > > +	dev_err(dev, "Vendor ID did not match! ID was %08x\n", vendor);
> > > +	tpm_cr50_release_locality(chip, true);
> > > +	return -ENODEV;
> > >    }
> > >    /**

> OK, these are legit suggestions. Paul, can you do these changes and add my
> reviewed-by for the +1 version?

I guess you mean Jes?


Kind regards,

Paul