James Bottomley @ 2020-10-01 11:09 MST:
> There are two problems with our current interrupt probing: firstly the
> TPM_CHIP_FLAG_IRQ never gets set initially, so a check for interrupts
> is never done. Fix this by setting the flag before we generate and
> interrupt for probing. Secondly our IRQ setup may be ineffective on a
> TPM without legacy access cycles becuase according to the TPM
> Interface Specification the interrupt registers are only writeable in
> the current locality, so issue a request_locality before setting up
> the interrupts.
>
> Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
>
> ---
>
> v2: improved description
> ---
> 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 0c07da8cd680..12b657ed3a39 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -809,6 +809,19 @@ 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)
> @@ -836,6 +849,7 @@ 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
Reviewed-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
