Driver support for QCA6174 chip using SDIO interface

[Kalle Valo]

Erik Stromdahl <erik.stromdahl at gmail.com> writes:

> On 2017-05-12 02:20, Ann Lo wrote:
>> Hi Erik,
>>
>> We are hoping to use your new SDIO patches for QCA9377 on kernel
>> version 4.1.36. There appears to be version 7 patches according to the
>> following email:
>> http://lists.infradead.org/pipermail/ath10k/2017-April/009633.html
>>
>> Would you advise on the followings?
>>
>> 1) What is the status of ath10k SDIO for QCA9377? The above email has
>> the comment "With this patch we have the low level HTC protocol
>> working and it's possible to boot the firmware, but it's still not
>> possible to connect or anything like." Do you have an estimate of the
>> time for full functionality, that wpa_supplicant and hostapd will run
>> successfully? How much further work is needed?
>
> Well, first of all, the patches on the ath10k master only contain the
> HIF layer (which is not that useful by itself). You will need a bunch
> of generic HL (High Latency) patches as well. These patches are common
> for both USB and SDIO and has not yet been integrated into the ath
> mainline.
> These patches are available on my ath repo on github:
>
> https://github.com/erstrom/linux-ath
>
> They should be treated as very experimental though!
> There are a few known issues with the QCA9377 SDIO chip.
> I have as of today not been able to associate with an AP (which
> kind of limits the usefulness of the device, at least when operating
> in STA mode :).
> QCA9377 USB (Linksys WUSB6100M) works much better, but is unfortunately
> not fully stable either since I am only capable of transmit/receive
> ~3Mbytes before it goes deaf (but at least I can associate and authenticate
> to an AP with WPA2 PSK security).
>
> So what remains to be done then?
> Well, it seems as if the sdio chipset won't work that well with the
> generic parts of ath10k. The setup of a device is HIF layer independent
> (mostly implemented in mac.c) and has been tested thoroughly with the
> PCIe devices. When looking at qcacld (another driver that is not part
> of the Linux kernel), the setup is very different (different internal
> parameters are configured and commands are executed in a different order).
>
> From my point of view I think the following things needs to be done:
>
> 1. Make mac.c work with high latency devices (SDIO and USB). I suspect
>    that the setup of SDIO and USB is similar.
> 2. Add support for newer version of the WMI protocol. qcacld uses a
>    different ABI version for the WMI messages.
>
> Since I am doing this work as a spare time activity only, I can't make
> any commitments or estimates of when everything is fully implemented.

I think we should try to get rest of your patches into mainline as well,
even if they are experimental still. Hopefully we get more people
helping that way, Adrian already expressed his interest which is very
cool and others have been also asking especially SDIO support. And with
good luck there are just small fixes needed to SDIO and USB properly
working.

Let's just clearly document that SDIO and USB support is work in
progress, both during driver initialisation and Kconfig documentation.
Maybe we should even depend on BROKEN, dunno?

-- 
Kalle Valo