[PATCH 1/2] Only probe iTPMs

From: Stefan Berger
Date: Fri Jan 20 2012 - 12:59:45 EST


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@xxxxxxxxxxxxxxxxxx>

---
drivers/char/tpm/tpm.h | 2 ++
drivers/char/tpm/tpm_tis.c | 8 +++++---
2 files changed, 7 insertions(+), 3 deletions(-)

Index: linux-2.6/drivers/char/tpm/tpm.h
===================================================================
--- linux-2.6.orig/drivers/char/tpm/tpm.h
+++ linux-2.6/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 */

Index: linux-2.6/drivers/char/tpm/tpm_tis.c
===================================================================
--- linux-2.6.orig/drivers/char/tpm/tpm_tis.c
+++ linux-2.6/drivers/char/tpm/tpm_tis.c
@@ -368,6 +368,11 @@ static int probe_itpm(struct tpm_chip *c
};
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 *c
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;

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