[PATCH] tpm_tis: fix iTPM probe via probe_itpm() function

[Maciej S. Szmigiero]

probe_itpm() function is supposed to send command without an itpm flag set
and if this fails to repeat it, this time with the itpm flag set.

However, commit 41a5e1cf1fe15 ("tpm/tpm_tis: Split tpm_tis driver into a
core and TCG TIS compliant phy") moved the itpm flag from an "itpm"
variable to a TPM_TIS_ITPM_POSSIBLE chip flag, so setting the
(now function-local) itpm variable no longer had any effect.

Finally, this function-local itpm variable was removed by
commit 56af322156dbe9 ("tpm/tpm_tis: remove unused itpm variable")

Tested only on non-iTPM TIS TPM.

Signed-off-by: Maciej S. Szmigiero <m...@maciej.szmigiero.name>

Fixes: 41a5e1cf1fe15 ("Split tpm_tis driver into a core and TCG TIS compliant 
phy")
Cc: sta...@vger.kernel.org
---
 drivers/char/tpm/tpm_tis_core.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index e42e5a6a3c2f..401f1228547c 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -467,6 +467,9 @@ static int probe_itpm(struct tpm_chip *chip)
        size_t len = sizeof(cmd_getticks);
        u16 vendor;
 
+       if (priv->flags & TPM_TIS_ITPM_POSSIBLE)
+               return 0;
+
        rc = tpm_tis_read16(priv, TPM_DID_VID(0), &vendor);
        if (rc < 0)
                return rc;
@@ -482,12 +485,15 @@ static int probe_itpm(struct tpm_chip *chip)
        tpm_tis_ready(chip);
        release_locality(chip, priv->locality, 0);
 
+       priv->flags |= TPM_TIS_ITPM_POSSIBLE;
+
        rc = tpm_tis_send_data(chip, cmd_getticks, len);
-       if (rc == 0) {
+       if (rc == 0)
                dev_info(&chip->dev, "Detected an iTPM.\n");
-               rc = 1;
-       } else
+       else {
+               priv->flags &= ~TPM_TIS_ITPM_POSSIBLE;
                rc = -EFAULT;
+       }
 
 out:
        tpm_tis_ready(chip);
@@ -743,15 +749,10 @@ int tpm_tis_core_init(struct device *dev, struct 
tpm_tis_data *priv, int irq,
                 (chip->flags & TPM_CHIP_FLAG_TPM2) ? "2.0" : "1.2",
                 vendor >> 16, rid);
 
-       if (!(priv->flags & TPM_TIS_ITPM_POSSIBLE)) {
-               probe = probe_itpm(chip);
-               if (probe < 0) {
-                       rc = -ENODEV;
-                       goto out_err;
-               }
-
-               if (!!probe)
-                       priv->flags |= TPM_TIS_ITPM_POSSIBLE;
+       probe = probe_itpm(chip);
+       if (probe < 0) {
+               rc = -ENODEV;
+               goto out_err;
        }
 
        /* Figure out the capabilities */