From: Amir Mizinski <amirmi...@gmail.com>

Using this function while reading/writing data resulted in an aborted
operation.
After investigating the issue according to the TCG TPM Profile (PTP)
Specifications, I found that "request to cancel" should occur only if
TPM_STS.commandReady bit is lit.
Note that i couldn't find a case where the present condition
(in the linux kernel) is valid, so I'm removing the case for
"TPM_VID_WINBOND" since we have no need for it.

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

Fixes: 1f866057291f (tpm: Fix cancellation of TPM commands (polling mode))
Signed-off-by: Amir Mizinski <amirmi...@gmail.com>
---
 drivers/char/tpm/tpm_tis_core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 97eae72..39b28a0 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -694,13 +694,11 @@ 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

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