ath11k WiFi bringup on Milos SoC

[Luca Weiss]

On Fri Jul 18, 2025 at 3:23 PM CEST, Luca Weiss wrote:
> 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

To conclude this, this was missing a pinctrl for gpio5 of pmk8550 which
provides sleep clock to the LF_CLK_IN_GPIO pin of the WCN6755 PMU.

Downstream does define this but not in any way connected to anything
related to the WCN6755.

    &pmk8550_gpios {
    	pinctrl-0 = <&alt_sleep_clk_default>;
    	pinctrl-names = "default";

    	alt_sleep_clk {
    		alt_sleep_clk_default: alt_sleep_clk_default {
    			pins = "gpio5";
    			function = "func1";
    			input-disable;
    			output-enable;
    			bias-disable;
    			power-source = <0>;
    		};
    	};
    };

This is the upstream patch with the pinctrl defined:
https://lore.kernel.org/linux-arm-msm/20260116-milos-fp6-bt-wifi-v1-5-27b4fbb77e9c@fairphone.com/

With this added, the WPSS doesn't crash anymore and WiFi starts working.

Regards
Luca

>
> 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