ath12k: big endian bringup

[Jeff Johnson]

On 6/3/2025 7:31 AM, Alexander Wilhelm wrote:
> Hello devs,
> 
> I need help to bring up the QCN9274 with ath12k driver on big endian PowerPC
> platform. I've already found some issues and fixed the MHI start procedure [1]
> and QMI conversion [2]. Furthermore I added some endianness fixes on 'qmi.c'
> file and could successfully transfer the firmware and boardfile to the wireless
> module. But the firmware does not start properly.
> 
> I'm trying to analyze the error and don't fully understand what is happening.
> While 'ath12k_htc_connect_service' I expect a successful response from
> 'ath12k_htc_send', but the connection then is timeout. It seems that I should
> receive a message with length of 20 and at least I get one. But then the driver
> remains endless in the 'ath12k_ce_recv_process_cb' and I always get a message of
> length 0 from the 'ath12k_hal_ce_dst_status_get_length' until RCU stall happens.
> 
> More interesting is the 'CE_ATTR_BYTE_SWAP_DATA' from ath11k, that is still used
> in ath12k code, but HAL structures now are swapped in driver itself at the same
> time. Is that correct?

That does NOT sound correct.
What happens if you unconditionally keep the BYTE_SWAP flag disabled?

Note that to date the ath12k driver has not been tested internally on a big
endian host. But your message at least has folks talking about it now...

/jeff