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>

3 files changed, 51 insertions, 6 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 9bd4668e2855..2e12b3f98139 100644
--- a/drivers/char/tpm/tpm.c
+++ b/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;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 5d2be8ae1b48..e264de16285f 100644
--- a/drivers/char/tpm/tpm.h
+++ b/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 *);
diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 3f4051a7c5a7..d30d5c3c6c02 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/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;
 }