[PATCH 4.9 012/164] tpm_tis_spi: Abort transfer when too many wait states are signaled

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Huewe <peter.huewe@xxxxxxxxxxxx>

commit 975094ddc369a32f27210248bdd9bbd153061b00 upstream.

Abort the transfer with ETIMEDOUT when the TPM signals more than
TPM_RETRY wait states. Continuing with the transfer in this state
will only lead to arbitrary failures in other parts of the code.

Fixes: 0edbfea537d1 ("tpm/tpm_tis_spi: Add support for spi phy")
Signed-off-by: Alexander Steffen <Alexander.Steffen@xxxxxxxxxxxx>
Signed-off-by: Peter Huewe <peter.huewe@xxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Tested-by: Benoit Houyere <benoit.houyere@xxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/char/tpm/tpm_tis_spi.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/char/tpm/tpm_tis_spi.c
+++ b/drivers/char/tpm/tpm_tis_spi.c
@@ -102,6 +102,11 @@ static int tpm_tis_spi_transfer(struct t
 			goto exit;
 	}
 
+	if (i == TPM_RETRY) {
+		ret = -ETIMEDOUT;
+		goto exit;
+	}
+
 	spi_xfer.cs_change = 0;
 	spi_xfer.len = len;