Re: [PATCH v6 14/16] wifi: ath12k: Switch to generic PAS TZ APIs

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The transition from `QCOM_SCM` to the generic `QCOM_PAS` framework introduces an asynchronous probing bug where `ath12k` fails to check if the PAS backend is available, causing permanent probe failures.
--

commit 9d619dc2a0265a4c4b222e1e790293c324c3c591
Author: Sumit Garg <sumit.garg@oss.qualcomm.com>

wifi: ath12k: Switch to generic PAS TZ APIs

This commit switches the ath12k client driver over to the generic PAS TZ
APIs. This abstracts the TZ implementation, allowing the driver to support
multiple backends such as the QTEE based SCM PAS service or OP-TEE based
PAS service.

> diff --git a/drivers/net/wireless/ath/ath12k/ahb.c b/drivers/net/wireless/ath/ath12k/ahb.c
> --- a/drivers/net/wireless/ath/ath12k/ahb.c
> +++ b/drivers/net/wireless/ath/ath12k/ahb.c

[ ... ]

> @@ -420,7 +420,7 @@ static int ath12k_ahb_power_up(struct ath12k_base *ab)
>  
>  	if (ab_ahb->scm_auth_enabled) {
>  		/* Authenticate FW image using peripheral ID */
> -		ret = qcom_scm_pas_auth_and_reset(pasid);
> +		ret = qcom_pas_auth_and_reset(pasid);
>  		if (ret) {
>  			ath12k_err(ab, "failed to boot the remote processor %d\n", ret);
>  			goto err_fw2;

Does this change introduce an asynchronous probing failure?

Since the generic QCOM_PAS layer allows its backends (like QCOM_SCM or
QCOM_PAS_TEE) to be built as loadable modules, the ath12k_ahb driver might
probe before the backend has registered its operations.

If that happens, qcom_pas_auth_and_reset() returns -ENODEV:

drivers/firmware/qcom/qcom_pas.c:qcom_pas_auth_and_reset() {
	if (!ops_ptr)
		return -ENODEV;

	return ops_ptr->auth_and_reset(ops_ptr->dev, pas_id);
}

Because this returns -ENODEV instead of -EPROBE_DEFER, the ath12k_ahb driver
will treat this as a fatal hardware initialization error. The kernel driver
core will not retry the probe, resulting in a permanent failure.

Should the driver be updated to check if the PAS backend is available and
explicitly return -EPROBE_DEFER if it is not yet registered?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260518072856.22790-1-sumit.garg@kernel.org?part=14