[PATCH 2/5] tpm_tis_spi: Abort transfer when too many wait states are signaled

[Peter Huewe]

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.

Cc: <stable@xxxxxxxxxxxxxxx>
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>
---
 drivers/char/tpm/tpm_tis_spi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/char/tpm/tpm_tis_spi.c b/drivers/char/tpm/tpm_tis_spi.c
index 6e1a3c43f621..d782b9974c14 100644
--- a/drivers/char/tpm/tpm_tis_spi.c
+++ b/drivers/char/tpm/tpm_tis_spi.c
@@ -101,6 +101,11 @@ static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u8 len,
 			goto exit;
 	}
 
+	if (i == TPM_RETRY) {
+		ret = -ETIMEDOUT;
+		goto exit;
+	}
+
 	spi_xfer.cs_change = 0;
 	spi_xfer.len = len;
 
-- 
2.7.4