Re: [PATCH v2] tpm_ffa_crb: access tpm service over FF-A direct message request v2

[Jarkko Sakkinen <jarkko@kernel.org>]

On Fri, Apr 11, 2025 at 10:08:56AM +0100, Yeoreum Yun wrote:
> For secure partition with multi service, tpm_ffa_crb can access tpm
> service with direct message request v2 interface according to chapter 3.3,
> TPM Service Command Response Buffer Interface Over FF-A specification [0].
> 
> This patch reflects this spec to access tpm service over
> FF-A direct message request v2 ABI.
> 
> Link: https://developer.arm.com/documentation/den0138/latest/ [0]

Sorry, did not notice in the first round:

1. Does not have "[0]" postfix.
2. Only for lore links:
   https://www.kernel.org/doc/html/v6.12/maintainer/configure-git.html#creating-commit-links-to-lore-kernel-org 

> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
> Since v1:
>     - Fix indentation.
>     - https://lore.kernel.org/all/20250410110701.1244965-1-yeoreum.yun@arm.com/
> ---
>  drivers/char/tpm/tpm_crb_ffa.c | 55 ++++++++++++++++++++++++----------
>  1 file changed, 40 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c
> index 3169a87a56b6..fed775cf53ab 100644
> --- a/drivers/char/tpm/tpm_crb_ffa.c
> +++ b/drivers/char/tpm/tpm_crb_ffa.c
> @@ -105,7 +105,10 @@ struct tpm_crb_ffa {
>  	u16 minor_version;
>  	/* lock to protect sending of FF-A messages: */
>  	struct mutex msg_data_lock;
> -	struct ffa_send_direct_data direct_msg_data;
> +	union {
> +		struct ffa_send_direct_data direct_msg_data;
> +		struct ffa_send_direct_data2 direct_msg_data2;
> +	};
>  };
> 
>  static struct tpm_crb_ffa *tpm_crb_ffa;
> @@ -185,18 +188,34 @@ static int __tpm_crb_ffa_send_recieve(unsigned long func_id,
> 
>  	msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops;
> 
> -	memset(&tpm_crb_ffa->direct_msg_data, 0x00,
> -	       sizeof(struct ffa_send_direct_data));
> -
> -	tpm_crb_ffa->direct_msg_data.data1 = func_id;
> -	tpm_crb_ffa->direct_msg_data.data2 = a0;
> -	tpm_crb_ffa->direct_msg_data.data3 = a1;
> -	tpm_crb_ffa->direct_msg_data.data4 = a2;
> +	if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) {
> +		memset(&tpm_crb_ffa->direct_msg_data2, 0x00,
> +		       sizeof(struct ffa_send_direct_data2));
> +
> +		tpm_crb_ffa->direct_msg_data2.data[0] = func_id;
> +		tpm_crb_ffa->direct_msg_data2.data[1] = a0;
> +		tpm_crb_ffa->direct_msg_data2.data[2] = a1;
> +		tpm_crb_ffa->direct_msg_data2.data[3] = a2;
> +
> +		ret = msg_ops->sync_send_receive2(tpm_crb_ffa->ffa_dev,
> +				&tpm_crb_ffa->direct_msg_data2);
> +		if (!ret)
> +			ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data2.data[0]);
> +	} else {
> +		memset(&tpm_crb_ffa->direct_msg_data, 0x00,
> +		       sizeof(struct ffa_send_direct_data));
> +
> +		tpm_crb_ffa->direct_msg_data.data1 = func_id;
> +		tpm_crb_ffa->direct_msg_data.data2 = a0;
> +		tpm_crb_ffa->direct_msg_data.data3 = a1;
> +		tpm_crb_ffa->direct_msg_data.data4 = a2;
> +
> +		ret = msg_ops->sync_send_receive(tpm_crb_ffa->ffa_dev,
> +				&tpm_crb_ffa->direct_msg_data);
> +		if (!ret)
> +			ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data.data1);
> +	}
> 
> -	ret = msg_ops->sync_send_receive(tpm_crb_ffa->ffa_dev,
> -			&tpm_crb_ffa->direct_msg_data);
> -	if (!ret)
> -		ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data.data1);
> 
>  	return ret;
>  }
> @@ -231,8 +250,13 @@ int tpm_crb_ffa_get_interface_version(u16 *major, u16 *minor)
> 
>  	rc = __tpm_crb_ffa_send_recieve(CRB_FFA_GET_INTERFACE_VERSION, 0x00, 0x00, 0x00);
>  	if (!rc) {
> -		*major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa->direct_msg_data.data2);
> -		*minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa->direct_msg_data.data2);
> +		if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) {
> +			*major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa->direct_msg_data2.data[1]);
> +			*minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa->direct_msg_data2.data[1]);
> +		} else {
> +			*major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa->direct_msg_data.data2);
> +			*minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa->direct_msg_data.data2);
> +		}
>  	}
> 
>  	return rc;
> @@ -277,7 +301,8 @@ static int tpm_crb_ffa_probe(struct ffa_device *ffa_dev)
> 
>  	tpm_crb_ffa = ERR_PTR(-ENODEV); // set tpm_crb_ffa so we can detect probe failure
> 
> -	if (!ffa_partition_supports_direct_recv(ffa_dev)) {
> +	if (!ffa_partition_supports_direct_recv(ffa_dev) &&
> +	    !ffa_partition_supports_direct_req2_recv(ffa_dev)) {
>  		pr_err("TPM partition doesn't support direct message receive.\n");
>  		return -EINVAL;
>  	}
> --
> LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
> 

BR, Jarkko