Re: [PATCH 1/3] tpm: cmd_ready command can be issued only after granting locality

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Tue, Jan 23, 2018 at 01:27:29PM +0200, Tomas Winkler wrote:
> The correct sequence is to first request locality and only after
> that perform cmd_ready  handshake, otherwise the hardware will drop
> the subsequent message as from the device point of view the cmd_ready
> handshake wasn't performed. Symmetrically locality has to be relinquished
> only after going idle handshake has completed, this requires that
> go_idle has to poll for the completion.
> 
> The issue is only visible on devices that support multiple localities.
> 
> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>

Thank you!

> ---
>  drivers/char/tpm/tpm-interface.c | 12 ++---
>  drivers/char/tpm/tpm_crb.c       | 95 ++++++++++++++++++++++++++--------------
>  2 files changed, 70 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 76df4fbcf089..197fda39aab5 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -422,8 +422,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
>  	if (!(flags & TPM_TRANSMIT_UNLOCKED))
>  		mutex_lock(&chip->tpm_mutex);
>  
> -	if (chip->dev.parent)
> -		pm_runtime_get_sync(chip->dev.parent);
>  
>  	if (chip->ops->clk_enable != NULL)
>  		chip->ops->clk_enable(chip, true);
> @@ -439,6 +437,9 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
>  		chip->locality = rc;
>  	}
>  
> +	if (chip->dev.parent)
> +		pm_runtime_get_sync(chip->dev.parent);
> +
>  	rc = tpm2_prepare_space(chip, space, ordinal, buf);
>  	if (rc)
>  		goto out;
> @@ -499,17 +500,18 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
>  	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
>  
>  out:
> +	if (chip->dev.parent)
> +		pm_runtime_put_sync(chip->dev.parent);
> +
>  	if (need_locality && chip->ops->relinquish_locality) {
>  		chip->ops->relinquish_locality(chip, chip->locality);
>  		chip->locality = -1;
>  	}
> +
>  out_no_locality:
>  	if (chip->ops->clk_enable != NULL)
>  		chip->ops->clk_enable(chip, false);
>  
> -	if (chip->dev.parent)
> -		pm_runtime_put_sync(chip->dev.parent);
> -
>  	if (!(flags & TPM_TRANSMIT_UNLOCKED))
>  		mutex_unlock(&chip->tpm_mutex);
>  	return rc ? rc : len;
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 7b3c2a8aa9de..d174919c446d 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -112,6 +112,25 @@ struct tpm2_crb_smc {
>  	u32 smc_func_id;
>  };
>  
> +static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> +				unsigned long timeout)
> +{
> +	ktime_t start;
> +	ktime_t stop;
> +
> +	start = ktime_get();
> +	stop = ktime_add(start, ms_to_ktime(timeout));
> +
> +	do {
> +		if ((ioread32(reg) & mask) == value)
> +			return true;
> +
> +		usleep_range(50, 100);
> +	} while (ktime_before(ktime_get(), stop));
> +
> +	return ((ioread32(reg) & mask) == value);

Not sure about the change of return statement. Is this worth of doing?

> +}
> +
>  /**
>   * crb_go_idle - request tpm crb device to go the idle state
>   *
> @@ -128,7 +147,7 @@ struct tpm2_crb_smc {
>   *
>   * Return: 0 always
>   */
> -static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
> +static int crb_go_idle(struct device *dev, struct crb_priv *priv)
>  {
>  	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
>  	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
> @@ -136,30 +155,17 @@ static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
>  		return 0;
>  
>  	iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
> -	/* we don't really care when this settles */
>  
> +	if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
> +				 CRB_CTRL_REQ_GO_IDLE/* mask */,
> +				 0, /* value */
> +				 TPM2_TIMEOUT_C)) {
> +		dev_warn(dev, "goIdle timed out\n");
> +		return -ETIME;
> +	}
>  	return 0;
>  }
>  
> -static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
> -				unsigned long timeout)
> -{
> -	ktime_t start;
> -	ktime_t stop;
> -
> -	start = ktime_get();
> -	stop = ktime_add(start, ms_to_ktime(timeout));
> -
> -	do {
> -		if ((ioread32(reg) & mask) == value)
> -			return true;
> -
> -		usleep_range(50, 100);
> -	} while (ktime_before(ktime_get(), stop));
> -
> -	return false;
> -}
> -
>  /**
>   * crb_cmd_ready - request tpm crb device to enter ready state
>   *
> @@ -175,8 +181,7 @@ static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
>   *
>   * Return: 0 on success -ETIME on timeout;
>   */
> -static int __maybe_unused crb_cmd_ready(struct device *dev,
> -					struct crb_priv *priv)
> +static int crb_cmd_ready(struct device *dev, struct crb_priv *priv)
>  {
>  	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
>  	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
> @@ -195,11 +200,11 @@ static int __maybe_unused crb_cmd_ready(struct device *dev,
>  	return 0;
>  }
>  
> -static int crb_request_locality(struct tpm_chip *chip, int loc)
> +static int __crb_request_locality(struct device *dev,
> +				  struct crb_priv *priv, int loc)
>  {
> -	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
>  	u32 value = CRB_LOC_STATE_LOC_ASSIGNED |
> -		CRB_LOC_STATE_TPM_REG_VALID_STS;
> +		    CRB_LOC_STATE_TPM_REG_VALID_STS;
>  
>  	if (!priv->regs_h)
>  		return 0;
> @@ -207,23 +212,36 @@ static int crb_request_locality(struct tpm_chip *chip, int loc)
>  	iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
>  	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
>  				 TPM2_TIMEOUT_C)) {
> -		dev_warn(&chip->dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
> +		dev_warn(dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
>  		return -ETIME;
>  	}
>  
>  	return 0;
>  }
>  
> -static void crb_relinquish_locality(struct tpm_chip *chip, int loc)
> +static int crb_request_locality(struct tpm_chip *chip, int loc)
>  {
>  	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
>  
> +	return __crb_request_locality(&chip->dev, priv, loc);
> +}
> +
> +static void __crb_relinquish_locality(struct device *dev,
> +				      struct crb_priv *priv, int loc)
> +{
>  	if (!priv->regs_h)
>  		return;
>  
>  	iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
>  }
>  
> +static void crb_relinquish_locality(struct tpm_chip *chip, int loc)
> +{
> +	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> +	__crb_relinquish_locality(&chip->dev, priv, loc);
> +}
> +
>  static u8 crb_status(struct tpm_chip *chip)
>  {
>  	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> @@ -475,6 +493,10 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
>  			dev_warn(dev, FW_BUG "Bad ACPI memory layout");
>  	}
>  
> +	ret = __crb_request_locality(dev, priv, 0);
> +	if (ret)
> +		return ret;
> +
>  	priv->regs_t = crb_map_res(dev, priv, &io_res, buf->control_address,
>  				   sizeof(struct crb_regs_tail));
>  	if (IS_ERR(priv->regs_t))
> @@ -531,6 +553,8 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
>  
>  	crb_go_idle(dev, priv);
>  
> +	__crb_relinquish_locality(dev, priv, 0);
> +
>  	return ret;
>  }
>  
> @@ -588,10 +612,14 @@ static int crb_acpi_add(struct acpi_device *device)
>  	chip->acpi_dev_handle = device->handle;
>  	chip->flags = TPM_CHIP_FLAG_TPM2;
>  
> -	rc  = crb_cmd_ready(dev, priv);
> +	rc = __crb_request_locality(dev, priv, 0);
>  	if (rc)
>  		return rc;
>  
> +	rc  = crb_cmd_ready(dev, priv);
> +	if (rc)
> +		goto out;
> +
>  	pm_runtime_get_noresume(dev);
>  	pm_runtime_set_active(dev);
>  	pm_runtime_enable(dev);
> @@ -601,12 +629,15 @@ static int crb_acpi_add(struct acpi_device *device)
>  		crb_go_idle(dev, priv);
>  		pm_runtime_put_noidle(dev);
>  		pm_runtime_disable(dev);
> -		return rc;
> +		goto out;
>  	}
>  
> -	pm_runtime_put(dev);
> +	pm_runtime_put_sync(dev);

Change to put_sync is needed so that the idle handshake gets completed?

>  
> -	return 0;
> +out:
> +	__crb_relinquish_locality(dev, priv, 0);
> +
> +	return rc;
>  }
>  
>  static int crb_acpi_remove(struct acpi_device *device)
> -- 
> 2.14.3
> 

/Jarkko