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

[Stefan Berger]

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 at linux.intel.com>

Reviewed-by: Stefan Berger <stefanb at linux.ibm.com>


> ---
>   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
> + * * -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
> + */
> +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);