Re: [PATCH v2 02/15] firmware: qcom: Add a generic PAS service

[Krzysztof Kozlowski <krzk@kernel.org>]

On 12/03/2026 07:27, Sumit Garg wrote:
> From: Sumit Garg <sumit.garg@oss.qualcomm.com>
> 
> Qcom platforms has the legacy of using non-standard SCM calls
> splintered over the various kernel drivers. These SCM calls aren't
> compliant with the standard SMC calling conventions which is a
> prerequisite to enable migration to the FF-A specifications from Arm.
> 
> OP-TEE as an alternative trusted OS to Qualcomm TEE (QTEE) can't
> support these non-standard SCM calls. And even for newer architectures
> with S-EL2 and Hafnium support, QTEE won't be able to support SCM
> calls either with FF-A requirements coming in. And with both OP-TEE
> and QTEE drivers well integrated in the TEE subsystem, it makes further
> sense to reuse the TEE bus client drivers infrastructure.
> 
> The added benefit of TEE bus infrastructure is that there is support
> for discoverable/enumerable services. With that client drivers don't
> have to manually invoke a special SCM call to know the service status.
> 
> So enable the generic Peripheral Authentication Service (PAS) provided
> by the firmware. It acts as the common layer with different TZ
> backends plugged in whether it's an SCM implementation or a proper
> TEE bus based PAS service implementation.
> 
> Signed-off-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
> ---
>  drivers/firmware/qcom/Kconfig          |   8 +
>  drivers/firmware/qcom/Makefile         |   1 +
>  drivers/firmware/qcom/qcom_pas.c       | 298 +++++++++++++++++++++++++
>  drivers/firmware/qcom/qcom_pas.h       |  53 +++++
>  include/linux/firmware/qcom/qcom_pas.h |  41 ++++
>  5 files changed, 401 insertions(+)
>  create mode 100644 drivers/firmware/qcom/qcom_pas.c
>  create mode 100644 drivers/firmware/qcom/qcom_pas.h
>  create mode 100644 include/linux/firmware/qcom/qcom_pas.h
> 
> diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig
> index b477d54b495a..8653639d06db 100644
> --- a/drivers/firmware/qcom/Kconfig
> +++ b/drivers/firmware/qcom/Kconfig
> @@ -6,6 +6,14 @@
>  
>  menu "Qualcomm firmware drivers"
>  
> +config QCOM_PAS
> +	tristate
> +	help
> +	  Enable the generic Peripheral Authentication Service (PAS) provided
> +	  by the firmware. It acts as the common layer with different TZ
> +	  backends plugged in whether it's an SCM implementation or a proper
> +	  TEE bus based PAS service implementation.
> +
>  config QCOM_SCM
>  	select QCOM_TZMEM
>  	tristate
> diff --git a/drivers/firmware/qcom/Makefile b/drivers/firmware/qcom/Makefile
> index 0be40a1abc13..dc5ab45f906a 100644
> --- a/drivers/firmware/qcom/Makefile
> +++ b/drivers/firmware/qcom/Makefile
> @@ -8,3 +8,4 @@ qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
>  obj-$(CONFIG_QCOM_TZMEM)	+= qcom_tzmem.o
>  obj-$(CONFIG_QCOM_QSEECOM)	+= qcom_qseecom.o
>  obj-$(CONFIG_QCOM_QSEECOM_UEFISECAPP) += qcom_qseecom_uefisecapp.o
> +obj-$(CONFIG_QCOM_PAS)		+= qcom_pas.o
> diff --git a/drivers/firmware/qcom/qcom_pas.c b/drivers/firmware/qcom/qcom_pas.c
> new file mode 100644
> index 000000000000..beb1bae55546
> --- /dev/null
> +++ b/drivers/firmware/qcom/qcom_pas.c
> @@ -0,0 +1,298 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <linux/device/devres.h>
> +#include <linux/firmware/qcom/qcom_pas.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +
> +#include "qcom_pas.h"
> +
> +struct qcom_pas_ops *ops_ptr;

Same comment as before. Don't create singletons. And for sure not global
ones.

Best regards,
Krzysztof