1 files changed, 61 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index a69a02366c32..3bd9f1fa77ce 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -666,3 +666,64 @@ out:
 		rc = -ENODEV;
 	return rc;
 }
+
+#define TPM_ORD_SAVESTATE 152
+#define SAVESTATE_RESULT_SIZE 10
+static const struct tpm_input_header savestate_header = {
+	.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
+	.length = cpu_to_be32(10),
+	.ordinal = cpu_to_be32(TPM_ORD_SAVESTATE)
+};
+
+/**
+ * tpm1_pm_suspend() - pm suspend handler
+ * @chip: TPM chip to use.
+ * @tpm_suspend_pcr: flush pcr for buggy TPM chips.
+ *
+ * The functions saves the TPM state to be restored on resume.
+ *
+ * Return:
+ * * 0 on success,
+ * * < 0 on error.
+ */
+int tpm1_pm_suspend(struct tpm_chip *chip, int tpm_suspend_pcr)
+{
+	u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 };
+	struct tpm_cmd_t cmd;
+	int rc, try;
+
+	/* for buggy tpm, flush pcrs with extend to selected dummy */
+	if (tpm_suspend_pcr)
+		rc = tpm1_pcr_extend(chip, tpm_suspend_pcr, dummy_hash,
+				     "extending dummy pcr before suspend");
+
+	/* now do the actual savestate */
+	for (try = 0; try < TPM_RETRY; try++) {
+		cmd.header.in = savestate_header;
+		rc = tpm_transmit_cmd(chip, NULL, &cmd, SAVESTATE_RESULT_SIZE,
+				      0, 0, 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;
+		tpm_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;
+}