Re: [PATCH 3/4] tpm_tis: fix IRQ probing

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Tue, Sep 29, 2020 at 03:32:15PM -0700, James Bottomley wrote:
> Unless the TPM_CHIP_FLAG_IRQ is set somewhere, an initial probe of the
> IRQ never gets done.
> 
> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

Please add a clear statement what the patch does in imperative form.

> ---
>  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 02cc384fdaea..b8ab26077cb1 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -808,6 +808,19 @@ 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;
> +	}
> +
>  	rc = tpm_tis_read8(priv, TPM_INT_VECTOR(priv->locality),
>  			   &original_int_vec);
>  	if (rc < 0)
> @@ -835,6 +848,7 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip,
>  		return rc;
>  
>  	priv->irq_tested = false;
> +	chip->flags |= TPM_CHIP_FLAG_IRQ;
>  
>  	/* Generate an interrupt by having the core call through to
>  	 * tpm_tis_send
> -- 
> 2.28.0
> 

Agree with the code change tho.

/Jarkko