Re: [PATCH v6 5/9] tpm, tpm_tis: Only handle supported interrupts

Jarkko Sakkinen
2022-06-26T06:44:11Z

On Sun, Jun 26, 2022 at 09:40:43AM +0300, Jarkko Sakkinen wrote:
> On Tue, Jun 21, 2022 at 03:24:43PM +0200, Lino Sanfilippo wrote:
> > From: Lino Sanfilippo <l.sanfilippo@kunbus.com>
> >
> > According to the TPM Interface Specification (TIS) support for "stsValid"
> > and "commandReady" interrupts is only optional.
> > This has to be taken into account when handling the interrupts in functions
> > like wait_for_tpm_stat(). To determine the supported interrupts use the
> > capability query.
> >
> > Also adjust wait_for_tpm_stat() to only wait for interrupt reported status
> > changes. After that process all the remaining status changes by polling
> > the status register.
> >
> > Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
> > ---
> > drivers/char/tpm/tpm_tis_core.c | 119 +++++++++++++++++++-------------
> > drivers/char/tpm/tpm_tis_core.h | 1 +
> > 2 files changed, 72 insertions(+), 48 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> > index 09d8f04cbc81..cb469591373a 100644
> > --- a/drivers/char/tpm/tpm_tis_core.c
> > +++ b/drivers/char/tpm/tpm_tis_core.c
> > @@ -53,41 +53,63 @@ static int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
> > long rc;
> > u8 status;
> > bool canceled = false;
> > + u8 sts_mask = 0;
> > + int ret = 0;
> >
> > /* check current status */
> > status = chip->ops->status(chip);
> > if ((status & mask) == mask)
> > return 0;
> >
> > - stop = jiffies + timeout;
> > + /* check what status changes can be handled by irqs */
> > + if (priv->int_mask & TPM_INTF_STS_VALID_INT)
> > + sts_mask |= TPM_STS_VALID;
> >
> > - if (chip->flags & TPM_CHIP_FLAG_IRQ) {
> > + if (priv->int_mask & TPM_INTF_DATA_AVAIL_INT)
> > + sts_mask |= TPM_STS_DATA_AVAIL;
> > +
> > + if (priv->int_mask & TPM_INTF_CMD_READY_INT)
> > + sts_mask |= TPM_STS_COMMAND_READY;
> > +
> > + sts_mask &= mask;
>
> I would instead mask out bits and write a helper function
> taking care of this:
>
> static u8 tpm_tis_filter_sts_mask(u8 int_mask, u8 sts_mask)
> {
> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);

Ignore this line (wrote this out of top of my head).

> if (!(int_mask & TPM_INTF_STS_VALID_INT))
> sts_mask &= ~TPM_STS_VALID;
>
> if (!(int_mask & TPM_INTF_DATA_AVAIL_INT))
> sts_mask &= ~TPM_STS_DATA_AVAIL;
>
> if (!(int_mask & TPM_INTF_CMD_READY_INT))
> sts_mask &= ~TPM_STS_COMMAND_READY;
>
> return sts_mask;
> }
>
> Less operations and imho somewhat cleaner structure.
>
> Add suggested-by if you want.
>
> BR, Jarkko