Re: [PATCH v5 6/7] tpm_crb: Factor crb_send()/crb_recv() bodies into helpers

[Jarkko Sakkinen]

On Thu, Oct 29, 2026 at 11:45:40PM +0530, Arun Menon wrote:
> From: Arun Menon <armenon@xxxxxxxxxx>
> 
> A later patch adds CRB chunking, which needs its own send/receive
> loops alongside the existing single-shot transfer. Move the body of
> crb_send() into tpm_crb_send_no_chunks() and the body of crb_recv()
> into tpm_crb_recv_no_chunks().
> 
> Pure code motion, no behavior change. Also fix the block comment to the
> kernel's preferred multi-line style.
> 
> Signed-off-by: Arun Menon <armenon@xxxxxxxxxx>
> ---
>  drivers/char/tpm/tpm_crb.c | 71 ++++++++++++++++++++++++--------------
>  1 file changed, 45 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 30ca8192d3a8..f0bac9e1f1e8 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -369,24 +369,13 @@ static u8 crb_status(struct tpm_chip *chip)
>  	return sts;
>  }
>  
> -static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
> +static int tpm_crb_recv_no_chunks(struct tpm_chip *chip, u8 *buf, size_t count)
>  {
>  	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
>  	unsigned int expected;
>  
> -	/* A sanity check that the upper layer wants to get at least the header
> -	 * as that is the minimum size for any TPM response.
> -	 */
> -	if (count < TPM_HEADER_SIZE)
> -		return -EIO;
> -
> -	/* If this bit is set, according to the spec, the TPM is in
> -	 * unrecoverable condition.
> -	 */
> -	if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR)
> -		return -EIO;
> -
> -	/* Read the first 8 bytes in order to get the length of the response.
> +	/*
> +	 * Read the first 8 bytes in order to get the length of the response.
>  	 * We read exactly a quad word in order to make sure that the remaining
>  	 * reads will be aligned.
>  	 */
> @@ -399,6 +388,28 @@ static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
>  	memcpy_fromio(&buf[8], &priv->rsp[8], expected - 8);
>  
>  	return expected;
> +
> +}
> +
> +static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
> +{
> +	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> +	/*
> +	 * A sanity check that the upper layer wants to get at least the header
> +	 * as that is the minimum size for any TPM response.
> +	 */
> +	if (count < TPM_HEADER_SIZE)
> +		return -EIO;
> +
> +	/*
> +	 * If this bit is set, according to the spec, the TPM is in
> +	 * unrecoverable condition.
> +	 */
> +	if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR)
> +		return -EIO;
> +
> +	return tpm_crb_recv_no_chunks(chip, buf, count);
>  }
>  
>  static int crb_do_acpi_start(struct tpm_chip *chip)
> @@ -474,12 +485,29 @@ static int tpm_crb_start(struct tpm_chip *chip, u32 start_cmd)
>  	return rc;
>  }
>  
> -static int crb_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz, size_t len)
> +static int tpm_crb_send_no_chunks(struct tpm_chip *chip, u8 *buf, size_t len)
>  {
>  	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
>  	int rc = 0;
>  
> -	/* Zero the cancel register so that the next command will not get
> +	memcpy_toio(priv->cmd, buf, len);
> +
> +	/* Make sure that cmd is populated before issuing start. */
> +	wmb();
> +
> +	rc = tpm_crb_start(chip, CRB_START_INVOKE);
> +	if (rc)
> +		return rc;
> +
> +	return crb_try_pluton_doorbell(priv, false);
> +}
> +
> +static int crb_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz, size_t len)
> +{
> +	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> +	/*
> +	 * Zero the cancel register so that the next command will not get
>  	 * canceled.
>  	 */
>  	iowrite32(0, &priv->regs_t->ctrl_cancel);
> @@ -494,16 +522,7 @@ static int crb_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz, size_t len)
>  	if (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON)
>  		__crb_cmd_ready(&chip->dev, priv, chip->locality);
>  
> -	memcpy_toio(priv->cmd, buf, len);
> -
> -	/* Make sure that cmd is populated before issuing start. */
> -	wmb();
> -
> -	rc = tpm_crb_start(chip, CRB_START_INVOKE);
> -	if (rc)
> -		return rc;
> -
> -	return crb_try_pluton_doorbell(priv, false);
> +	return tpm_crb_send_no_chunks(chip, buf, len);
>  }
>  
>  static void crb_cancel(struct tpm_chip *chip)
> -- 
> 2.56.0
> 


Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>

Br, Jarkko