tpm: introduce tpm_chip_start() and tpm_chip_stop()

Encapsulate power gating and locality functionality to tpm_chip_start()
and tpm_chip_stop() in order to clean up the branching mess in
tpm_transmit().

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-chip.c

@@ -37,6 +37,117 @@ struct class *tpm_class;
 struct class *tpmrm_class;
 dev_t tpm_devt;
 
+static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
+{
+	int rc;
+
+	if (flags & TPM_TRANSMIT_NESTED)
+		return 0;
+
+	if (!chip->ops->request_locality)
+		return 0;
+
+	rc = chip->ops->request_locality(chip, 0);
+	if (rc < 0)
+		return rc;
+
+	chip->locality = rc;
+	return 0;
+}
+
+static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
+{
+	int rc;
+
+	if (flags & TPM_TRANSMIT_NESTED)
+		return;
+
+	if (!chip->ops->relinquish_locality)
+		return;
+
+	rc = chip->ops->relinquish_locality(chip, chip->locality);
+	if (rc)
+		dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
+
+	chip->locality = -1;
+}
+
+static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
+{
+	if (flags & TPM_TRANSMIT_NESTED)
+		return 0;
+
+	if (!chip->ops->cmd_ready)
+		return 0;
+
+	return chip->ops->cmd_ready(chip);
+}
+
+static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
+{
+	if (flags & TPM_TRANSMIT_NESTED)
+		return 0;
+
+	if (!chip->ops->go_idle)
+		return 0;
+
+	return chip->ops->go_idle(chip);
+}
+
+/**
+ * tpm_chip_start() - power on the TPM
+ * @chip:	a TPM chip to use
+ * @flags:	TPM transmit flags
+ *
+ * Return:
+ * * The response length	- OK
+ * * -errno			- A system error
+ */
+int tpm_chip_start(struct tpm_chip *chip, unsigned int flags)
+{
+	int ret;
+
+	if (chip->ops->clk_enable)
+		chip->ops->clk_enable(chip, true);
+
+	if (chip->locality == -1) {
+		ret = tpm_request_locality(chip, flags);
+		if (ret) {
+			chip->ops->clk_enable(chip, false);
+			return ret;
+		}
+	}
+
+	ret = tpm_cmd_ready(chip, flags);
+	if (ret) {
+		tpm_relinquish_locality(chip, flags);
+		if (chip->ops->clk_enable)
+			chip->ops->clk_enable(chip, false);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tpm_chip_start);
+
+/**
+ * tpm_chip_stop() - power off the TPM
+ * @chip:	a TPM chip to use
+ * @flags:	TPM transmit flags
+ *
+ * Return:
+ * * The response length	- OK
+ * * -errno			- A system error
+ */
+void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags)
+{
+	tpm_go_idle(chip, flags);
+	tpm_relinquish_locality(chip, flags);
+	if (chip->ops->clk_enable)
+		chip->ops->clk_enable(chip, false);
+}
+EXPORT_SYMBOL_GPL(tpm_chip_stop);
+
 /**
  * tpm_try_get_ops() - Get a ref to the tpm_chip
  * @chip: Chip to ref

drivers/char/tpm/tpm-interface.c

@@ -62,64 +62,6 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
 }
 EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
 
-static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
-{
-	int rc;
-
-	if (flags & TPM_TRANSMIT_NESTED)
-		return 0;
-
-	if (!chip->ops->request_locality)
-		return 0;
-
-	rc = chip->ops->request_locality(chip, 0);
-	if (rc < 0)
-		return rc;
-
-	chip->locality = rc;
-
-	return 0;
-}
-
-static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
-{
-	int rc;
-
-	if (flags & TPM_TRANSMIT_NESTED)
-		return;
-
-	if (!chip->ops->relinquish_locality)
-		return;
-
-	rc = chip->ops->relinquish_locality(chip, chip->locality);
-	if (rc)
-		dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
-
-	chip->locality = -1;
-}
-
-static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
-{
-	if (flags & TPM_TRANSMIT_NESTED)
-		return 0;
-
-	if (!chip->ops->cmd_ready)
-		return 0;
-
-	return chip->ops->cmd_ready(chip);
-}
-
-static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
-{
-	if (flags & TPM_TRANSMIT_NESTED)
-		return 0;
-
-	if (!chip->ops->go_idle)
-		return 0;
-
-	return chip->ops->go_idle(chip);
-}
-
 static ssize_t tpm_try_transmit(struct tpm_chip *chip, void *buf, size_t bufsiz,
 				unsigned int flags)
 {
@@ -221,7 +163,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
 	/* 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(sizeof(save), bufsiz);
@@ -236,32 +177,13 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
 	memcpy(save, buf, save_size);
 
 	for (;;) {
-		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);
+		ret = tpm_chip_start(chip, flags);
 		if (ret)
-			goto out_locality;
+			return ret;
 
 		ret = tpm_try_transmit(chip, 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);
-
+		tpm_chip_stop(chip, flags);
 		if (ret < 0)
 			break;
 		rc = be32_to_cpu(header->return_code);

drivers/char/tpm/tpm.h

@@ -523,6 +523,8 @@ static inline void tpm_msleep(unsigned int delay_msec)
 		     delay_msec * 1000);
 };
 
+int tpm_chip_start(struct tpm_chip *chip, unsigned int flags);
+void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags);
 struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
 __must_check int tpm_try_get_ops(struct tpm_chip *chip);
 void tpm_put_ops(struct tpm_chip *chip);