Re: [PATCH] ath10k: support bus and device specific API 1 BDF selection

From: Robert Marko <robimarko@gmail.com>
To: Christian Lamparter <chunkeey@gmail.com>
Cc: Kalle Valo <kvalo@kernel.org>,
	kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org,
	ath10k@lists.infradead.org, linux-wireless@vger.kernel.org,
	netdev@vger.kernel.org, open list <linux-kernel@vger.kernel.org>,
	Thibaut <hacks@slashdirt.org>
Subject: Re: [PATCH] ath10k: support bus and device specific API 1 BDF selection
Date: Fri, 17 Dec 2021 13:06:26 +0100	[thread overview]
Message-ID: <CAOX2RU6qaZ7NkeRe1bukgH6OxXOPvJS=z9PRp=UYAxMfzwD2oQ@mail.gmail.com> (raw)
In-Reply-To: <09a27912-9ea4-fe75-df72-41ba0fa5fd4e@gmail.com>

On Wed, 8 Dec 2021 at 15:07, Christian Lamparter <chunkeey@gmail.com> wrote:
>
> On 08/12/2021 13:21, Robert Marko wrote:
> > On Tue, 7 Dec 2021 at 19:06, Kalle Valo <kvalo@kernel.org> wrote:
> >>
> >> Robert Marko <robimarko@gmail.com> 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>
> >>
> >> Can someone review this, please? I understand the need for this, but the board
> >> handling is getting quite complex in ath10k so I'm hesitant.
> >>
> >> What about QCA6390 and other devices. Will they still work?
> > Hi Kalle,
> > everything else should just continue working as before unless the
> > board-bus-device.bin file
> > exists it will just use the current method to fetch the BDF.
> >
> > Also, this only applies to API1 BDF-s.
> >
> > We are really needing this as currently there are devices with the
> > wrong BDF being loaded as
> > we have no way of knowing where MikroTik changed it and dynamic
> > loading would resolve
> > all of that since they are one of the rare vendors that embed the
> > BDF-s next to calibration data.
>
> Isn't the only user of this the non-upstreamable rb_hardconfig
> mikrotik platform driver? So, in your case the devices in question
> needs to setup a detour through the userspace firmware (helper+scripts)
> to pull on the sysfs of that mikrotik platform driver? Wouldn't it
> be possible to do this more directly?

Yes, its the sole current user as its the only vendor shipping the BDF
as part of the
factory data and not like a userspace blob.

I don't see how can it be more direct, its the same setup as when
getting pre-cal
data for most devices currently.

I am adding Thibaut who is the author of the platform driver.

Regards,
Robert
>
> Cheers,
> Christian