Marc Gonzalez <mgonzalez@xxxxxxxxxx> writes:
> On 01/03/2024 09:10, Kalle Valo wrote:
>
>> Marc Gonzalez wrote:
>>
>>> Kalle Valo wrote:
>>>
>>>> Here's one example where in ath10k we use a feature bit as a workaround:
>>>>
>>>> /* Don't trust error code from otp.bin */
>>>> ATH10K_FW_FEATURE_IGNORE_OTP_RESULT = 7,
>>>>
>>>> ....
>>>>
>>>> if (!(skip_otp || test_bit(ATH10K_FW_FEATURE_IGNORE_OTP_RESULT,
>>>> ar->running_fw->fw_file.fw_features)) &&
>>>> result != 0) {
>>>> ath10k_err(ar, "otp calibration failed: %d", result);
>>>> return -EINVAL;
>>>> }
>>>>
>>>> BTW for modifying firmware-N.bin files we have a script here:
>>>>
>>>> https://github.com/qca/qca-swiss-army-knife/blob/master/tools/scripts/ath10k/ath10k-fwencoder
>>>
>>> If I understand correctly, you are saying that there is
>>> (maybe... probably) a bug in the FW, so it makes sense to
>>> tag that specific FW file with a special bit which the kernel
>>> will interpret as "this FW is broken in a specific way;
>>> and here's how to work around the issue."
>>>
>>> So this bit would serve the same purpose as my proposed
>>> "qcom,no-msa-ready-indicator" bit (that bit existed instead
>>> in my board's device tree).
>>>
>>> The problem I see is that the firmware files are signed.
>>> Thus, changing a single bit breaks the verification...
>>> UNLESS the FW format allows for a signed section ALONG-SIDE
>>> an unsigned section?
>>
>> firmware-N.bin is ath10k specific container file format and we (the
>> Linux community) have full access to it using ath10k-fwencoder, there's
>> no signing or anything like that. One of the major reasons why it was
>> designed was to handle differences between firmware branches, just like
>> in this case.
>>
>> Of course plan A should be to fix the firmware but if that doesn't work
>> out then plan B could be using the feature bit in firmware-N.bin.
>>
>> BTW related to this Dmitry is extending firmware-N.bin handling for
>> WCN3990, you will most likely need to use that:
>>
>> https://patchwork.kernel.org/project/linux-wireless/cover/20240130-wcn3990-firmware-path-v1-0-826b93202964@xxxxxxxxxx/
>
>
> If I understand correctly (happy to have anyone correct any
> misunderstandings), if the FW cannot be fixed (for any reason),
> then we would have to do something like this:
Thanks, this is exactly what I'm proposing.
> diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> index 0032f8aa892ff..c8778ebe922af 100644
> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -769,6 +769,7 @@ static const char *const ath10k_core_fw_feature_str[] = {
> [ATH10K_FW_FEATURE_SINGLE_CHAN_INFO_PER_CHANNEL] = "single-chan-info-per-channel",
> [ATH10K_FW_FEATURE_PEER_FIXED_RATE] = "peer-fixed-rate",
> [ATH10K_FW_FEATURE_IRAM_RECOVERY] = "iram-recovery",
> + [ATH10K_FW_FEATURE_NO_MSA_READY] = "no-msa-ready-indicator",
For consistency I would have just "no-msa-ready".
> @@ -1151,6 +1154,9 @@ struct ath10k {
> u8 cfg_tx_chainmask;
> u8 cfg_rx_chainmask;
>
> + /* FW does not send MSA_READY indicator. Fake it */
> + bool fake_msa_ready; /* bool or u8? or s8? or bitfield? */
Hopefully not needed, see below.
> struct completion install_key_done;
>
> int last_wmi_vdev_start_status;
> diff --git a/drivers/net/wireless/ath/ath10k/qmi.c b/drivers/net/wireless/ath/ath10k/qmi.c
> index 38e939f572a9e..0776e79b25f3a 100644
> --- a/drivers/net/wireless/ath/ath10k/qmi.c
> +++ b/drivers/net/wireless/ath/ath10k/qmi.c
> @@ -1040,6 +1040,8 @@ static void ath10k_qmi_driver_event_work(struct work_struct *work)
> switch (event->type) {
> case ATH10K_QMI_EVENT_SERVER_ARRIVE:
> ath10k_qmi_event_server_arrive(qmi);
> + if (ar->fake_msa_ready)
> + ath10k_qmi_event_msa_ready(qmi);
Unless I'm missing something I would use here test_bit() directly:
if (test_bit(ATH10K_FW_FEATURE_NO_MSA_READY, ar->running_fw->fw_file.fw_features))
ath10k_qmi_event_msa_ready(qmi);
--
https://patchwork.kernel.org/project/linux-wireless/list/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
