ath11k WiFi bringup on Milos SoC

[Luca Weiss]

Hi,

I'm trying to bring up WiFi on the Milos SoC (on my device: SM7635)
which is paired with a WCN6755.

There's also the WPSS remoteproc on this SoC, similar to SC7280/Kodiak.

Using the qcom,wcn6750-wifi compatible in dt makes the wpss firmware
crash soon after boot with the following errors:

[ 1263.547381] ath11k 17110040.wifi: wcn6750 hw1.0
[ 1263.577281] remoteproc remoteproc2: powering up wpss
[ 1263.814337] remoteproc remoteproc2: Booting fw image qcom/milos/fairphone/fp6/wpss.mbn, size 8229144
[ 1263.817861] PDM: no support for the platform, userspace daemon might be required.
[ 1264.523796] remoteproc remoteproc2: remote processor wpss is now up
[ 1264.773557] ath11k 17110040.wifi: chip_id 0x1 chip_family 0xb board_id 0xff soc_id 0x40140120
[ 1264.774484] ath11k 17110040.wifi: fw_version 0x3014ffff fw_build_timestamp 2025-04-09 08:57 fw_build_id WLAN.MSL.3.0.1-00328.3-QCAMSLSWPLZ-1.105949.2
[ 1272.362281] ath11k 17110040.wifi: htt event 48 not handled
[ 1273.499832] qcom_q6v5_pas 8a00000.remoteproc: fatal error received: cmnos_assert.c:400:Asserted in whal_wmac_recipes.c:whal_wmac_transition_to_fw_control:1734
[ 1273.500231] remoteproc remoteproc2: crash detected in wpss: type fatal error
[ 1273.501114] remoteproc remoteproc2: handling crash #1 in wpss
[ 1273.501153] remoteproc remoteproc2: recovering wpss

That "htt event 48" should be HTT_T2H_PPDU_ID_FMT_IND, I have briefly
looked in the WiFi driver from the downstream 6.1 kernel and while I
might definitely be wrong here, I'm guessing it's not related to the
crash.

Anyone have an idea how to debug this? Unfortunately my AMSS sources do
not include any sources for WiFi, it's just prebuilts.

Regards
Luca