tpm: fix (ACPI S3) suspend regression

This patch fixes an (ACPI S3) suspend regression introduced in commit
68d6e6713fcb ("tpm: Introduce function to poll for result of self test")
and occurring with an Infineon TPM and tpm_tis and tpm_infineon drivers
active.

The suspend problem occurred if the TPM was disabled and/or deactivated
and therefore the TPM_PCRRead checking the result of the (asynchronous)
self test returned an error code which then caused the tpm_tis driver to
become inactive and this then seemed to have negatively influenced the
suspend support by the tpm_infineon driver...  Besides that the tpm_tis
drive may stay active even if the TPM is disabled and/or deactivated.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 12 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 6a8771f47a55..32362cf35b8d 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -846,6 +846,15 @@ int tpm_do_selftest(struct tpm_chip *chip)
 
 	do {
 		rc = __tpm_pcr_read(chip, 0, digest);
+		if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) {
+			dev_info(chip->dev,
+				 "TPM is disabled/deactivated (0x%X)\n", rc);
+			/* TPM is disabled and/or deactivated; driver can
+			 * proceed and TPM does handle commands for
+			 * suspend/resume correctly
+			 */
+			return 0;
+		}
 		if (rc != TPM_WARN_DOING_SELFTEST)
 			return rc;
 		msleep(delay_msec);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 8c1df302fbb6..010547138281 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -39,6 +39,9 @@ enum tpm_addr {
 };
 
 #define TPM_WARN_DOING_SELFTEST 0x802
+#define TPM_ERR_DEACTIVATED     0x6
+#define TPM_ERR_DISABLED        0x7
+
 #define TPM_HEADER_SIZE		10
 extern ssize_t tpm_show_pubek(struct device *, struct device_attribute *attr,
 				char *);