[PATCH v2 2/2] tpm: tpm_tis: stop transmit if retries are exhausted

Jacqueline Wong
2026-04-11T00:34:32Z

tpm_tis_send_main() will attempt to retry sending data TPM_RETRY times.
Currently, if those retries are exhausted, the driver will attempt to
call execute. The TPM will be in the wrong state, leading to the
operation simply timing out.

Instead, if there is still an error after retries are exhausted, return
that error immediately.

Fixes: 280db21e153d8 ("tpm_tis: Resend command to recover from data transfer errors")
Signed-off-by: Jacqueline Wong <jacqwong@google.com>
Signed-off-by: Jordan Hand <jhand@google.com>
---
drivers/char/tpm/tpm_tis_core.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index c79b696086fe..ecda3c1085c7 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -556,11 +556,16 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
break;
else if (rc != -EAGAIN && rc != -EIO)
/* Data transfer failed, not recoverable */
- return rc;
+ goto out_err;

usleep_range(priv->timeout_min, priv->timeout_max);
}

+ if (rc == -EAGAIN || rc == -EIO) {
+ dev_err(&chip->dev, "Exhausted %d tpm_tis_send_data retries\n", TPM_RETRY);
+ goto out_err;
+ }
+
/* go and do it */
rc = tpm_tis_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);
if (rc < 0)
--
2.53.0.1213.gd9a14994de-goog