2 files changed, 30 insertions, 4 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 0d2e82f95577..7c3b3dcbfbc8 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1337,7 +1337,7 @@ int tpm_pm_suspend(struct device *dev)
 {
         struct tpm_chip *chip = dev_get_drvdata(dev);
         struct tpm_cmd_t cmd;
-        int rc;
+        int rc, try;
 
         u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
 
@@ -1355,9 +1355,32 @@ int tpm_pm_suspend(struct device *dev)
         }
 
         /* now do the actual savestate */
-        cmd.header.in = savestate_header;
-        rc = transmit_cmd(chip, &cmd, SAVESTATE_RESULT_SIZE,
-                          "sending savestate before suspend");
+        for (try = 0; try < TPM_RETRY; try++) {
+                cmd.header.in = savestate_header;
+                rc = transmit_cmd(chip, &cmd, SAVESTATE_RESULT_SIZE, NULL);
+
+                /*
+                 * If the TPM indicates that it is too busy to respond to
+                 * this command then retry before giving up.  It can take
+                 * several seconds for this TPM to be ready.
+                 *
+                 * This can happen if the TPM has already been sent the
+                 * SaveState command before the driver has loaded.  TCG 1.2
+                 * specification states that any communication after SaveState
+                 * may cause the TPM to invalidate previously saved state.
+                 */
+                if (rc != TPM_WARN_RETRY)
+                        break;
+                msleep(TPM_TIMEOUT_RETRY);
+        }
+
+        if (rc)
+                dev_err(chip->dev,
+                        "Error (%d) sending savestate before suspend\n", rc);
+        else if (try > 0)
+                dev_warn(chip->dev, "TPM savestate took %dms\n",
+                         try * TPM_TIMEOUT_RETRY);
+
         return rc;
 }
 EXPORT_SYMBOL_GPL(tpm_pm_suspend);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 81b52015f669..0770d1d79366 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -32,10 +32,12 @@ enum tpm_const {
         TPM_MINOR = 224,        /* officially assigned */
         TPM_BUFSIZE = 4096,
         TPM_NUM_DEVICES = 256,
+        TPM_RETRY = 50,         /* 5 seconds */
 };
 
 enum tpm_timeout {
         TPM_TIMEOUT = 5,        /* msecs */
+        TPM_TIMEOUT_RETRY = 100 /* msecs */
 };
 
 /* TPM addresses */
@@ -44,6 +46,7 @@ enum tpm_addr {
         TPM_ADDR = 0x4E,
 };
 
+#define TPM_WARN_RETRY          0x800
 #define TPM_WARN_DOING_SELFTEST 0x802
 #define TPM_ERR_DEACTIVATED     0x6
 #define TPM_ERR_DISABLED        0x7