tpm: Introduce function to poll for result of self test

This patch introduces a function that runs the TPM_ContinueSelfTest()
function and then polls the TPM to check whether it finished the selftest
and can receive new commands.

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

drivers/char/tpm/tpm.c

@@ -627,7 +627,7 @@ static struct tpm_input_header continue_selftest_header = {
  * Returns 0 on success, < 0 in case of fatal error or a value > 0 representing
  * a TPM error code.
  */
-int tpm_continue_selftest(struct tpm_chip *chip)
+static int tpm_continue_selftest(struct tpm_chip *chip)
 {
 	int rc;
 	struct tpm_cmd_t cmd;
@@ -637,7 +637,6 @@ int tpm_continue_selftest(struct tpm_chip *chip)
 			  "continue selftest");
 	return rc;
 }
-EXPORT_SYMBOL_GPL(tpm_continue_selftest);
 
 ssize_t tpm_show_enabled(struct device * dev, struct device_attribute * attr,
 			char *buf)
@@ -732,7 +731,7 @@ static struct tpm_input_header pcrread_header = {
 	.ordinal = TPM_ORDINAL_PCRREAD
 };
 
-int __tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
+static int __tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 {
 	int rc;
 	struct tpm_cmd_t cmd;
@@ -812,6 +811,45 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
 }
 EXPORT_SYMBOL_GPL(tpm_pcr_extend);
 
+/**
+ * tpm_do_selftest - have the TPM continue its selftest and wait until it
+ *                   can receive further commands
+ * @chip: TPM chip to use
+ *
+ * Returns 0 on success, < 0 in case of fatal error or a value > 0 representing
+ * a TPM error code.
+ */
+int tpm_do_selftest(struct tpm_chip *chip)
+{
+	int rc;
+	u8 digest[TPM_DIGEST_SIZE];
+	unsigned int loops;
+	unsigned int delay_msec = 1000;
+	unsigned long duration;
+
+	duration = tpm_calc_ordinal_duration(chip,
+	                                     TPM_ORD_CONTINUE_SELFTEST);
+
+	loops = jiffies_to_msecs(duration) / delay_msec;
+
+	rc = tpm_continue_selftest(chip);
+	/* This may fail if there was no TPM driver during a suspend/resume
+	 * cycle; some may return 10 (BAD_ORDINAL), others 28 (FAILEDSELFTEST)
+	 */
+	if (rc)
+		return rc;
+
+	do {
+		rc = __tpm_pcr_read(chip, 0, digest);
+		if (rc != TPM_WARN_DOING_SELFTEST)
+			return rc;
+		msleep(delay_msec);
+	} while (--loops > 0);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(tpm_do_selftest);
+
 int tpm_send(u32 chip_num, void *cmd, size_t buflen)
 {
 	struct tpm_chip *chip;

drivers/char/tpm/tpm.h

@@ -38,6 +38,8 @@ enum tpm_addr {
 	TPM_ADDR = 0x4E,
 };
 
+#define TPM_WARN_DOING_SELFTEST 0x802
+
 extern ssize_t tpm_show_pubek(struct device *, struct device_attribute *attr,
 				char *);
 extern ssize_t tpm_show_pcrs(struct device *, struct device_attribute *attr,
@@ -281,7 +283,7 @@ ssize_t	tpm_getcap(struct device *, __be32, cap_t *, const char *);
 
 extern int tpm_get_timeouts(struct tpm_chip *);
 extern void tpm_gen_interrupt(struct tpm_chip *);
-extern int tpm_continue_selftest(struct tpm_chip *);
+extern int tpm_do_selftest(struct tpm_chip *);
 extern unsigned long tpm_calc_ordinal_duration(struct tpm_chip *, u32);
 extern struct tpm_chip* tpm_register_hardware(struct device *,
 				 const struct tpm_vendor_specific *);

drivers/char/tpm/tpm_tis.c

@@ -616,6 +616,12 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
 	/* get the timeouts before testing for irqs */
 	tpm_get_timeouts(chip);
 
+	if (tpm_do_selftest(chip)) {
+		dev_err(dev, "TPM self test failed\n");
+		rc = -ENODEV;
+		goto out_err;
+	}
+
 	/* INTERRUPT Setup */
 	init_waitqueue_head(&chip->vendor.read_queue);
 	init_waitqueue_head(&chip->vendor.int_queue);
@@ -722,7 +728,6 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
 	list_add(&chip->vendor.list, &tis_chips);
 	spin_unlock(&tis_lock);
 
-	tpm_continue_selftest(chip);
 
 	return 0;
 out_err:
@@ -790,7 +795,7 @@ static int tpm_tis_pnp_resume(struct pnp_dev *dev)
 
 	ret = tpm_pm_resume(&dev->dev);
 	if (!ret)
-		tpm_continue_selftest(chip);
+		tpm_do_selftest(chip);
 
 	return ret;
 }