Re: [PATCH v2] tpm_crb: ffa_tpm: fix/update comments describing the CRB over FFA ABI

[Jarkko Sakkinen <jarkko@kernel.org>]

On Wed, Apr 30, 2025 at 10:47:23AM -0500, Stuart Yoder wrote:
> -Fix the comment describing the 'start' function, which was a cut/paste
>  mistake for a different function.
> 
> -The comment for DIRECT_REQ and DIRECT_RESP only mentioned AArch32
>  and listed 32-bit function IDs.  Update to include 64-bit.
> 
> Signed-off-by: Stuart Yoder <stuart.yoder@arm.com>
> ---
> v2:
>   -squashed the two comment updates into a single patch
> 
>  drivers/char/tpm/tpm_crb_ffa.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c
> index 3169a87a56b60..134747911ba38 100644
> --- a/drivers/char/tpm/tpm_crb_ffa.c
> +++ b/drivers/char/tpm/tpm_crb_ffa.c
> @@ -38,9 +38,11 @@
>   * messages.
>   *
>   * All requests with FFA_MSG_SEND_DIRECT_REQ and FFA_MSG_SEND_DIRECT_RESP
> - * are using the AArch32 SMC calling convention with register usage as
> - * defined in FF-A specification:
> - * w0:    Function ID (0x8400006F or 0x84000070)
> + * are using the AArch32 or AArch64 SMC calling convention with register usage
> + * as defined in FF-A specification:
> + * w0:    Function ID
> + *          -for 32-bit: 0x8400006F or 0x84000070
> + *          -for 64-bit: 0xC400006F or 0xC4000070
>   * w1:    Source/Destination IDs
>   * w2:    Reserved (MBZ)
>   * w3-w7: Implementation defined, free to be used below
> @@ -68,7 +70,8 @@
>  #define CRB_FFA_GET_INTERFACE_VERSION 0x0f000001
>  
>  /*
> - * Return information on a given feature of the TPM service
> + * Notifies the TPM service that a TPM command or TPM locality request is
> + * ready to be processed, and allows the TPM service to process it.
>   * Call register usage:
>   * w3:    Not used (MBZ)
>   * w4:    TPM service function ID, CRB_FFA_START
> -- 
> 2.34.1
> 

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko