Re: [PATCH v7 15/17] tpm: introduce tpm_chip_start() and tpm_chip_stop()

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On 11/13/18 1:36 PM, Jarkko Sakkinen wrote:
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@xxxxxxxxxxxxxxx>
---
  drivers/char/tpm/tpm-chip.c      | 110 +++++++++++++++++++++++++++++++
  drivers/char/tpm/tpm-interface.c |  87 +-----------------------
  drivers/char/tpm/tpm.h           |   2 +
  3 files changed, 115 insertions(+), 84 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 157505b0f755..65f1561eba81 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -37,6 +37,116 @@ 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
I don't think this is right. Have to withdraw my Reviewed-by on this one.
+ * * -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;
+}
+
+/**
+ * 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

This function doesn't return anything.



+ */
+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);
+}
+
+
  /**
   * tpm_try_get_ops() - Get a ref to the tpm_chip
   * @chip: Chip to ref
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5865b9671d20..888c9923fca1 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/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, u8 *buf, size_t bufsiz,
  				unsigned int flags)
  {
@@ -212,7 +154,6 @@ 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);
@@ -227,34 +168,12 @@ 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);
+		tpm_chip_stop(chip, 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 (ret < 0)
-			break;
  		rc = be32_to_cpu(header->return_code);
  		if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
  			break;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index c7c06de651a0..c42a75710b70 100644
--- a/drivers/char/tpm/tpm.h
+++ b/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);





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