[PATCH] wifi: ath12k: Fix Tx Completion Ring(WBM2SW) Setup Failure

[Jeff Johnson]

On 4/9/2024 12:09 PM, Nithyanantham Paramasivam wrote:
> We observe intermittent ping failures from the access point (AP) to
> station (STA) in any mode(AP-STA or Mesh) configured. Specifically,
> the transmission completion status is not received at Tx completion
> ring id-4(WBM2SW ring4) for the packets transmitted via TCL DATA
> ring id-3. This prevents freeing up Tx descriptors and leads
> to buffer exhaustion.
> 
> Currently, during initialization of the WBM2SW ring, we are directly
> mapping the ring number to the ring mask to obtain the ring mask
> group index. This approach is causing setup failures for WBM2SW
> ring-4. Similarly, during runtime, when receiving incoming
> transmission completion status, the validation of the ring number by
> mapping the interrupted ring mask. This is resulting in
> validation failure. Thereby preventing entry into the completion
> handler(ath12k_dp_tx_completion_handler()).
> 
> The existing design assumed that the ring numbers would always be
> sequential and could be directly mapped with the ring mask. However,
> this assumption does not hold true for WBM2SW ring-4. Therefore,
> modify the design such that, instead of mapping the ring number,
> the ring ID is mapped with the ring mask.
> 
> According to this design:
> 1. During initialization of the WBM2SW ring, mapping the ring ID
> to the ring mask will ensure obtaining the correct ring mask group
> ID.
> 2. During runtime, validating the interrupted ring mask group ID
> within the transmission completion group is sufficient. This
> approach allows the ring ID to be derived from the interrupted ring
> mask and enables entry into the completion handler.
> 
> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
> 
> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
> Signed-off-by: Nithyanantham Paramasivam <quic_nithp at quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson at quicinc.com>