tpm: clean up tpm_try_transmit() error handling flow

Move locking, locality handling and power management to tpm_transmit()
in order to simplify the flow.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Alexander Steffen <Alexander.Steffen@infineon.com>

drivers/char/tpm/tpm-interface.c

@@ -167,7 +167,6 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	ssize_t len = 0;
 	u32 count, ordinal;
 	unsigned long stop;
-	bool need_locality;
 
 	rc = tpm_validate_command(chip, space, buf, bufsiz);
 	if (rc == -EINVAL)
@@ -197,37 +196,16 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, struct tpm_space *space,
 		return -E2BIG;
 	}
 
-	if (!(flags & TPM_TRANSMIT_UNLOCKED) && !(flags & TPM_TRANSMIT_NESTED))
-		mutex_lock(&chip->tpm_mutex);
-
-	if (chip->ops->clk_enable != NULL)
-		chip->ops->clk_enable(chip, true);
-
-	/* Store the decision as chip->locality will be changed. */
-	need_locality = chip->locality == -1;
-
-	if (need_locality) {
-		rc = tpm_request_locality(chip, flags);
-		if (rc < 0) {
-			need_locality = false;
-			goto out_locality;
-		}
-	}
-
-	rc = tpm_cmd_ready(chip, flags);
-	if (rc)
-		goto out_locality;
-
 	rc = tpm2_prepare_space(chip, space, ordinal, buf);
 	if (rc)
-		goto out;
+		return rc;
 
 	rc = chip->ops->send(chip, buf, count);
 	if (rc < 0) {
 		if (rc != -EPIPE)
 			dev_err(&chip->dev,
 				"%s: send(): error %d\n", __func__, rc);
-		goto out;
+		goto out_rc;
 	}
 
 	/* A sanity check. send() should just return zero on success e.g.
@@ -252,7 +230,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, struct tpm_space *space,
 		if (chip->ops->req_canceled(chip, status)) {
 			dev_err(&chip->dev, "Operation Canceled\n");
 			rc = -ECANCELED;
-			goto out;
+			goto out_rc;
 		}
 
 		tpm_msleep(TPM_TIMEOUT_POLL);
@@ -262,40 +240,20 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	chip->ops->cancel(chip);
 	dev_err(&chip->dev, "Operation Timed out\n");
 	rc = -ETIME;
-	goto out;
+	goto out_rc;
 
 out_recv:
 	len = chip->ops->recv(chip, buf, bufsiz);
 	if (len < 0) {
 		rc = len;
-		dev_err(&chip->dev,
-			"tpm_transmit: tpm_recv: error %d\n", rc);
-		goto out;
-	} else if (len < TPM_HEADER_SIZE) {
-		rc = -EFAULT;
-		goto out;
-	}
-
-	if (len != be32_to_cpu(header->length)) {
+		dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);
+	} else if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
 		rc = -EFAULT;
-		goto out;
-	}
 
+out_rc:
+	if (!rc)
 		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
 
-out:
-	/* may fail but do not override previous error value in rc */
-	tpm_go_idle(chip, flags);
-
-out_locality:
-	if (need_locality)
-		tpm_relinquish_locality(chip, flags);
-
-	if (chip->ops->clk_enable != NULL)
-		chip->ops->clk_enable(chip, false);
-
-	if (!(flags & TPM_TRANSMIT_UNLOCKED) && !(flags & TPM_TRANSMIT_NESTED))
-		mutex_unlock(&chip->tpm_mutex);
 	return rc ? rc : len;
 }
 
@@ -325,6 +283,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	/* space for header and handles */
 	u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
 	unsigned int delay_msec = TPM2_DURATION_SHORT;
+	bool has_locality = false;
 	u32 rc = 0;
 	ssize_t ret;
 	const size_t save_size = min(space ? sizeof(save) : TPM_HEADER_SIZE,
@@ -340,7 +299,40 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	memcpy(save, buf, save_size);
 
 	for (;;) {
+		if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
+		    !(flags & TPM_TRANSMIT_NESTED))
+			mutex_lock(&chip->tpm_mutex);
+
+		if (chip->ops->clk_enable != NULL)
+			chip->ops->clk_enable(chip, true);
+
+		if (chip->locality == -1) {
+			ret = tpm_request_locality(chip, flags);
+			if (ret)
+				goto out_locality;
+			has_locality = true;
+		}
+
+		ret = tpm_cmd_ready(chip, flags);
+		if (ret)
+			goto out_locality;
+
 		ret = tpm_try_transmit(chip, space, buf, bufsiz, flags);
+
+		/* This may fail but do not override ret. */
+		tpm_go_idle(chip, flags);
+
+out_locality:
+		if (has_locality)
+			tpm_relinquish_locality(chip, flags);
+
+		if (chip->ops->clk_enable != NULL)
+			chip->ops->clk_enable(chip, false);
+
+		if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
+		    !(flags & TPM_TRANSMIT_NESTED))
+			mutex_unlock(&chip->tpm_mutex);
+
 		if (ret < 0)
 			break;
 		rc = be32_to_cpu(header->return_code);

drivers/char/tpm/tpm.h

@@ -576,6 +576,7 @@ int tpm2_probe(struct tpm_chip *chip);
 int tpm2_find_cc(struct tpm_chip *chip, u32 cc);
 int tpm2_init_space(struct tpm_space *space);
 void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space);
+void tpm2_flush_space(struct tpm_chip *chip);
 int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
 		       u8 *cmd);
 int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,

drivers/char/tpm/tpm2-space.c

@@ -162,7 +162,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
 	return 0;
 }
 
-static void tpm2_flush_space(struct tpm_chip *chip)
+void tpm2_flush_space(struct tpm_chip *chip)
 {
 	struct tpm_space *space = &chip->work_space;
 	int i;