Re: [PATCH v4] wifi: ath12k: fix endianness handling for SRNG ring pointer accesses

[Baochen Qiang]

On 3/11/2026 6:24 PM, Alexander Wilhelm wrote:
> The SRNG head and tail ring pointers are stored in device memory as
> little-endian values. On big-endian systems, direct dereferencing of these
> pointers leads to incorrect values being read or written, causing ring
> management issues and potentially breaking data flow.
> 
> This patch ensures all accesses to SRNG ring pointers use the appropriate
> endianness conversions. This affects both read and write paths for source
> and destination rings, as well as debug output. The changes guarantee
> correct operation on both little- and big-endian architectures.
> 
> Signed-off-by: Alexander Wilhelm <alexander.wilhelm@xxxxxxxxxxxx>
> Reviewed-by: Baochen Qiang <baochen.qiang@xxxxxxxxxxxxxxxx>
> ---
> Changes in v4:
> - Rebase on latest 'ath' master
> - Remove volatile from `hp_addr` due to the `checkpatch.pl` warning

by 'cgeckpatch.pl wanring' did you mean below ?

"
WARNING: Use of volatile is usually wrong: see
Documentation/process/volatile-considered-harmful.rst
#64: FILE: drivers/net/wireless/ath/ath12k/hal.c:504:
+                       *(volatile __le32 *)srng->u.src_ring.tp_addr);
"

But the documentation clearly says that the case here is one of a few rare situations
where volatile makes sense:

"
  - Pointers to data structures in coherent memory which might be modified
    by I/O devices can, sometimes, legitimately be volatile.  A ring buffer
    used by a network adapter, where that adapter changes pointers to
    indicate which descriptors have been processed, is an example of this
    type of situation.
"