On Thu, Mar 06, 2025 at 09:00:56AM +0000, Jonathan McDowell wrote: > From: Jonathan McDowell <noodles@xxxxxxxx> > > Some Infineon devices have a issue where the status register will get > stuck with a quick REQUEST_USE / COMMAND_READY sequence. This is not > simply a matter of requiring a longer timeout; the work around is to > retry the command submission. Add appropriate logic to do this in the > send path. > > This is fixed in later firmware revisions, but those are not always > available, and cannot generally be easily updated from outside a > firmware environment. > > Testing has been performed with a simple repeated loop of doing a > TPM2_CC_GET_CAPABILITY for TPM_CAP_PROP_MANUFACTURER using the Go code > at: > > https://the.earth.li/~noodles/tpm-stuff/timeout-reproducer-simple.go > > It can take several hours to reproduce, and millions of operations. > > Signed-off-by: Jonathan McDowell <noodles@xxxxxxxx> > --- > drivers/char/tpm/tpm_tis_core.c | 17 ++++++++++++++--- > drivers/char/tpm/tpm_tis_core.h | 1 + > include/linux/tpm.h | 1 + > 3 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 167d71747666..e4eae206a353 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -464,7 +464,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > > if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, > &priv->int_queue, false) < 0) { > - rc = -ETIME; > + if (test_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags)) > + rc = -EAGAIN; > + else > + rc = -ETIME; > goto out_err; > } > status = tpm_tis_status(chip); > @@ -481,7 +484,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len) > > if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c, > &priv->int_queue, false) < 0) { > - rc = -ETIME; > + if (test_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags)) > + rc = -EAGAIN; > + else > + rc = -ETIME; I'd encapsulate this inside wait_for_tpm_stat(). > goto out_err; > } > status = tpm_tis_status(chip); > @@ -546,9 +552,11 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len) > if (rc >= 0) > /* Data transfer done successfully */ > break; > - else if (rc != -EIO) > + else if (rc != EAGAIN && rc != -EIO) > /* Data transfer failed, not recoverable */ > return rc; > + > + usleep_range(priv->timeout_min, priv->timeout_max); > } > > /* go and do it */ > @@ -1144,6 +1152,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > priv->timeout_max = TIS_TIMEOUT_MAX_ATML; > } > > + if (priv->manufacturer_id == TPM_VID_IFX) > + set_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags); > + > if (is_bsw()) { > priv->ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR, > ILB_REMAP_SIZE); > diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h > index 690ad8e9b731..ce97b58dc005 100644 > --- a/drivers/char/tpm/tpm_tis_core.h > +++ b/drivers/char/tpm/tpm_tis_core.h > @@ -89,6 +89,7 @@ enum tpm_tis_flags { > TPM_TIS_INVALID_STATUS = 1, > TPM_TIS_DEFAULT_CANCELLATION = 2, > TPM_TIS_IRQ_TESTED = 3, > + TPM_TIS_STATUS_WORKAROUND = 4, TPM_TIS_TIMEOUT_AGAIN or maybe *_REPEAT? The current name does not tell anything. > }; > > struct tpm_tis_data { > diff --git a/include/linux/tpm.h b/include/linux/tpm.h > index 20a40ade8030..6c3125300c00 100644 > --- a/include/linux/tpm.h > +++ b/include/linux/tpm.h > @@ -335,6 +335,7 @@ enum tpm2_cc_attrs { > #define TPM_VID_WINBOND 0x1050 > #define TPM_VID_STM 0x104A > #define TPM_VID_ATML 0x1114 > +#define TPM_VID_IFX 0x15D1 > > enum tpm_chip_flags { > TPM_CHIP_FLAG_BOOTSTRAPPED = BIT(0), > -- > 2.48.1 > BR, Jarkko
