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Subject: Re: [PATCH] ath10k: support bus and device specific API 1 BDF
 selection
To:     Robert Marko <robimarko@gmail.com>, kvalo@codeaurora.org,
        davem@davemloft.net, kuba@kernel.org, ath10k@lists.infradead.org,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20211009221711.2315352-1-robimarko@gmail.com>
From:   Christian Lamparter <chunkeey@gmail.com>
Message-ID: <ba520cf0-480e-245b-395f-7d3a5f771521@gmail.com>
Date:   Thu, 14 Oct 2021 13:54:30 +0200
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On 10/10/2021 00:17, Robert Marko wrote:
> Some ath10k IPQ40xx devices like the MikroTik hAP ac2 and ac3 require the
> BDF-s to be extracted from the device storage instead of shipping packaged
> API 2 BDF-s.
> 
> This is required as MikroTik has started shipping boards that require BDF-s
> to be updated, as otherwise their WLAN performance really suffers.
> This is however impossible as the devices that require this are release
> under the same revision and its not possible to differentiate them from
> devices using the older BDF-s.
> 
> In OpenWrt we are extracting the calibration data during runtime and we are
> able to extract the BDF-s in the same manner, however we cannot package the
> BDF-s to API 2 format on the fly and can only use API 1 to provide BDF-s on
> the fly.
> This is an issue as the ath10k driver explicitly looks only for the
> board.bin file and not for something like board-bus-device.bin like it does
> for pre-cal data.
> Due to this we have no way of providing correct BDF-s on the fly, so lets
> extend the ath10k driver to first look for BDF-s in the
> board-bus-device.bin format, for example: board-ahb-a800000.wifi.bin
> If that fails, look for the default board file name as defined previously.
> 
> Signed-off-by: Robert Marko <robimarko@gmail.com>
> ---

As mentioned in Robert's OpenWrt Pull request:
https://github.com/openwrt/openwrt/pull/4679

It looks like the data comes from an mtd-partition parser.
So the board data takes an extra detour through userspace
for this.

Maybe it would be great, if that BDF (and likewise pre-cal)
files could be fetched via an nvmem-consumer there?
(Kalle: like the ath9k-nvmem patches)

This would help with many other devices as well, since currently
in OpenWrt all pre-cal data has to be extracted by userspace
helpers, while it could be easily accessible through nvmem.

What do you think?

Cheers,
Christian