tpm_tis: Only probe iTPMs

Detect iTPMs through the vendor ID on the hardware interface and only
probe the device if the manufacturer is found to be Intel. This
obsoletes a previously added delay necessary for some TPMs but not iTPMs.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>

2 files changed, 7 insertions, 3 deletions

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 010547138281..b1c5280ac159 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -99,6 +99,8 @@ struct tpm_vendor_specific {
 	wait_queue_head_t int_queue;
 };
 
+#define TPM_VID_INTEL    0x8086
+
 struct tpm_chip {
 	struct device *dev;	/* Device stuff */
 
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index a1748621111b..47ba9c213cc1 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -368,6 +368,11 @@ static int probe_itpm(struct tpm_chip *chip)
 	};
 	size_t len = sizeof(cmd_getticks);
 	int rem_itpm = itpm;
+	u16 vendor = ioread16(chip->vendor.iobase + TPM_DID_VID(0));
+
+	/* probe only iTPMS */
+	if (vendor != TPM_VID_INTEL)
+		return 0;
 
 	itpm = 0;
 
@@ -390,9 +395,6 @@ static int probe_itpm(struct tpm_chip *chip)
 out:
 	itpm = rem_itpm;
 	tpm_tis_ready(chip);
-	/* some TPMs need a break here otherwise they will not work
-	 * correctly on the immediately subsequent command */
-	msleep(chip->vendor.timeout_b);
 	release_locality(chip, chip->vendor.locality, 0);
 
 	return rc;