[PATCH v19 2/5] tpm: tpm_tis: Rewrite "tpm_tis_req_canceled()"

[amirmizi6@gmail.com]

From: Amir Mizinski <amirmizi6@gmail.com>

tpm_tis_req_canceled() function is used to check if the caller requested
to abort the current operation. It was found that in some cases
tpm_tis_req_canceled() wrongly returned true.
Since a cancel request sets the TPM_STS.commandReady field to TRUE, the
tpm_tis_req_canceled() function should check only the TPM_STS.commandReady
field value.
The case for TPM_VID_WINBOND is wrong and was therefore removed.

Also, the default comparison is wrong. Only cmdReady bit needs to be
compared instead of the full lower status register byte.

Signed-off-by: Amir Mizinski <amirmizi6@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index f833f35..6ff8b44 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -661,13 +661,10 @@ static bool tpm_tis_req_canceled(struct tpm_chip *chip, u8 status)
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 
 	switch (priv->manufacturer_id) {
-	case TPM_VID_WINBOND:
-		return ((status == TPM_STS_VALID) ||
-			(status == (TPM_STS_VALID | TPM_STS_COMMAND_READY)));
 	case TPM_VID_STM:
 		return (status == (TPM_STS_VALID | TPM_STS_COMMAND_READY));
 	default:
-		return (status == TPM_STS_COMMAND_READY);
+		return (status & TPM_STS_COMMAND_READY) == TPM_STS_COMMAND_READY;
 	}
 }
 
-- 
2.7.4