Re: [PATCH v4 04/15] firmware: qcom: Add a PAS TEE service

[Sumit Garg <sumit.garg@kernel.org>]

On Mon, May 04, 2026 at 03:33:06PM +0530, Harshal Dev wrote:
> Hi Sumit,
> 
> On 4/27/2026 3:25 PM, Sumit Garg via OP-TEE wrote:
> > From: Sumit Garg <sumit.garg@oss.qualcomm.com>
> > 
> > Add support for Peripheral Authentication Service (PAS) driver based
> > on TEE bus with OP-TEE providing the backend PAS service implementation.
> > 
> > The TEE PAS service ABI is designed to be extensible with additional API
> > as PTA_QCOM_PAS_CAPABILITIES. This allows to accommodate any future
> > extensions of the PAS service needed while still maintaining backwards
> > compatibility.
> > 
> > Signed-off-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
> > ---
> >  drivers/firmware/qcom/Kconfig        |  10 +
> >  drivers/firmware/qcom/Makefile       |   1 +
> >  drivers/firmware/qcom/qcom_pas_tee.c | 479 +++++++++++++++++++++++++++
> >  3 files changed, 490 insertions(+)
> >  create mode 100644 drivers/firmware/qcom/qcom_pas_tee.c
> 
> [...]
> 
> > diff --git a/drivers/firmware/qcom/qcom_pas_tee.c b/drivers/firmware/qcom/qcom_pas_tee.c
> 
> > +static int qcom_pas_tee_mem_setup(struct device *dev, u32 pas_id,
> > +				  phys_addr_t addr, phys_addr_t size)
> > +{
> 
> [...]
> 
> > +
> > +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> > +	if (ret < 0 || inv_arg.ret != 0) {
> > +		dev_err(dev, "PAS mem setup failed, pas_id: %d, ret: %d, err: 0x%x\n",
> > +			pas_id, ret, inv_arg.ret);
> > +		return ret ?: -EINVAL;
> 
> Following the example from qcom_scm_pas_mem_setup() here:
> https://elixir.bootlin.com/linux/v7.0.1/source/drivers/firmware/qcom/qcom_scm.c#L778
> 
> I think it should be:
> return ret ?: inv_arg.ret;

inv_arg.ret return a GP TEE error code which doesn't map 1:1 to kernel
error codes. The client drivers won't benefit without having a way to
decode those errors. So just printing here can help the user to debug
any issues.

> 
> This way the client (say mdt_loader) knows what error OPTEE PAS service returned.
> I can see that is tries to print this error:
> https://elixir.bootlin.com/linux/v7.0.1/source/drivers/soc/qcom/mdt_loader.c#L286
> 
> With that,
> Reviewed-by: Harshal Dev <harshal.dev@oss.qualcomm.com>
> 

Thanks, I hope with above I can keep your tag.

-Sumit