linux-kernel - Re: [PATCH v3] tpm_tis: turn on TPM before calling tpm_get

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Message-ID: <20191114165927.GB11107@linux.intel.com>
Date:   Thu, 14 Nov 2019 18:59:27 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Jerry Snitselaar <jsnitsel@...hat.com>
Cc:     linux-integrity@...r.kernel.org, Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org,
        Christian Bundy <christianbundy@...ction.io>
Subject: Re: [PATCH v3] tpm_tis: turn on TPM before calling tpm_get_timeouts

On Tue, Nov 12, 2019 at 05:02:43PM -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: 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>
> ---
> v3: call tpm_chip_stop in error path
> v2: fix stable cc to correct address
> 
>  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..806acc666696 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_chip_stop(chip);
>  			goto out_err;
>  		}
>  
> -		tpm_chip_start(chip);

As the commit describes the call is not there for any other reason than
pinging the TPM.

/Jarkko