Re: [PATCH ath-next 1/2] wifi: ath12k: Add support for handling incumbent signal interference in 6 GHz

[Amith A <amith.a@oss.qualcomm.com>]

On 5/8/2026 11:43 AM, Rameshkumar Sundaram wrote:
> On 5/5/2026 8:08 PM, Amith A wrote:
>> From: Aishwarya R <aishwarya.r@oss.qualcomm.com>
>>
>> When incumbent signal interference is detected by an AP/mesh interface
>> operating in the 6 GHz band, as mandated by the FCC, it is expected to
>> vacate the affected channels. The firmware indicates the interference to
>> the host using the WMI_DCS_INTERFERENCE_EVENT.
>>
>> To handle the new WMI event, first parse it to retrieve the interference
>> information. Next, validate the interference-detected channel and
>> the interference bitmap. The interference bitmap received from the
>> firmware uses a mapping where bit 0 corresponds to the primary
>> 20 MHz segment, regardless of its position within the operating
>> bandwidth. Bit 1 represents the next adjacent 20 MHz segment, bit 2
>> the lower 20 MHz segment of the adjacent 40 MHz segment, and so
>> on, progressing sequentially across the bandwidth. However, for
>> userspace
>> consumption via mac80211, this bitmap must be transformed into a
>> standardized format such that each bit position directly maps to the
>> corresponding sub-channel index within the operating bandwidth.
>> Finally, indicate the transformed interference bitmap to mac80211, which
>> then notifies userspace of the interference. Once the incumbent signal
>> interference is detected, firmware suspends TX internally on the
>> affected
>> operating channel while userspace decides the mitigation action.
>> Userspace
>> is expected to trigger a channel switch or bandwidth reduction to
>> mitigate
>> the interference. Also, add a flag handling_in_progress to indicate that
>> handling of interference is in progress. Set it to true after
>> indicating to mac80211 about the interference. Reset the flag to false
>> after the operating channel is switched by userspace. This prevents
>> processing any further interference events when there is already a
>> previous event being handled. Hence, further events are processed only
>> after a channel switch request is received from userspace for the
>> previous event.
>>
>> Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.5-01651-QCAHKSWPL_SILICONZ-1
>>
>> Signed-off-by: Aishwarya R <aishwarya.r@oss.qualcomm.com>
>> Co-developed-by: Hari Chandrakanthan <quic_haric@quicinc.com>
>> Signed-off-by: Hari Chandrakanthan <quic_haric@quicinc.com>
>> Signed-off-by: Amith A <amith.a@oss.qualcomm.com>
>> ---
>>   drivers/net/wireless/ath/ath12k/core.h |   8 +
>>   drivers/net/wireless/ath/ath12k/mac.c  |  46 +++
>>   drivers/net/wireless/ath/ath12k/wmi.c  | 382 +++++++++++++++++++++++++
>>   drivers/net/wireless/ath/ath12k/wmi.h  |  58 +++-
>>   4 files changed, 493 insertions(+), 1 deletion(-)
>>
>
> { ... }
>
>
>> +static int
>> +ath12k_wmi_incumbent_signal_interference_subtlv_parser(struct
>> ath12k_base *ab,
>> +                               u16 tag, u16 len,
>> +                               const void *ptr,
>> +                               void *data)
>> +{
>> +    const struct ath12k_wmi_incumbent_signal_interference_params *info;
>> +    struct ath12k_wmi_incumbent_signal_interference_arg *arg = data;
>> +
>> +    switch (tag) {
>> +    case WMI_TAG_DCS_INCUMBENT_SIGNAL_INTERFERENCE_TYPE:
>> +        info = ptr;
>> +
>
> should we validate len before accessing info ? or may be add an entry
> for WMI_TAG_DCS_INCUMBENT_SIGNAL_INTERFERENCE_TYPE in
> ath12k_wmi_tlv_policies so that ath12k_wmi_tlv_iter() can take care of
> the validation.
Will add an explicit len < sizeof(*info) check in the parser before
accessing info.
>
>> +        arg->chan_width = le32_to_cpu(info->chan_width);
>> +        arg->chan_freq = le32_to_cpu(info->chan_freq);
>> +        arg->center_freq0 = le32_to_cpu(info->center_freq0);
>> +        arg->center_freq1 = le32_to_cpu(info->center_freq1);
>> +        arg->chan_bw_interference_bitmap =
>> +            le32_to_cpu(info->chan_bw_interference_bitmap);
>> +
>> +        ath12k_dbg(ab, ATH12K_DBG_WMI,
>> +               "incumbent signal interference chan width %u freq %u
>> center_freq0 %u center_freq1 %u bitmap 0x%x\n",
>> +               arg->chan_width, arg->chan_freq,
>> +               arg->center_freq0, arg->center_freq1,
>> +               arg->chan_bw_interference_bitmap);
>> +        break;
>> +    default:
>> +        ath12k_warn(ab, "Received invalid tag 0x%x for WMI DCS
>> interference in subtlvs\n",
>> +                tag);
>> +        return -EINVAL;
>> +    }
>> +
>> +    return 0;
>> +}
>
> -- 
> Ramesh