On Wed Jun 7, 2023 at 8:14 PM EEST, Alexander Steffen wrote:
> >> - if (status & TPM_STS_DATA_AVAIL) { /* retry? */
> >> + if (status & TPM_STS_DATA_AVAIL) {
> >
> > Please remove (no-op).
>
> You mean I shouldn't change the line and leave the comment in? To me it
> looked like a very brief TODO comment "should we retry here?", and since
> with this change it now actually does retry, I removed it.
Right, ok, point taken, you can keep it.
> >> dev_err(&chip->dev, "Error left over data\n");
> >> size = -EIO;
> >> goto out;
> >> @@ -396,10 +391,39 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
> >> }
> >>
> >> out:
> >> - tpm_tis_ready(chip);
> >> return size;
> >> }
> >>
> >> +static int tpm_tis_recv_with_retries(struct tpm_chip *chip, u8 *buf, size_t count)
> >
> > This *substitutes* the curent tpm_tis_recv(), right?
> >
> > So it *is* tpm_tis_recv(), i.e. no renames thank you :-)
> >
> >> +{
> >> + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> >> + unsigned int try;
> >> + int rc = 0;
> >> +
> >> + if (count < TPM_HEADER_SIZE) {
> >> + rc = -EIO;
> >> + goto out;
> >> + }
> >> +
> >> + for (try = 0; try < TPM_RETRY; try++) {
> >> + rc = tpm_tis_recv(chip, buf, count);
> >
> > I would rename single shot tpm_tis_recv() as tpm_tis_try_recv().
> >
> >> +
> >> + if (rc == -EIO) {
> >> + /* Data transfer errors, indicated by EIO, can be
> >> + * recovered by rereading the response.
> >> + */
> >> + tpm_tis_write8(priv, TPM_STS(priv->locality),
> >> + TPM_STS_RESPONSE_RETRY);
> >> + } else {
> >> + break;
> >> + }
> >
> > And if this should really be managed inside tpm_tis_try_recv(), and
> > then return zero (as the code block consumes the return value).
>
> What exactly should be done in tpm_tis_try_recv()? It could set
> TPM_STS_RESPONSE_RETRY, but then it would still need to return an error
> code, so that this loop knows whether to call it again or not.
So my thinking was to:
- Rename tpm_tis_recv() as tpm_tis_try_recv()
- Rename this new function as tpm_tis_recv().
BR, Jarkko
