mwifiex_sdio on chromebook

[Alexander Varnin <fenixk19@mail.ru>]

Hello.
I am trying to debug the issue with incorrect initialization of WiFi
chip on Samsung ARM Chromebook. And I search for assistance. I have
posted my investigation results on launchpad.net (bug #1247512). Here is
copy:

Marvell SDIO WiFi chip doesn't get initialized correctly on Chromebook.
After some research I have managed to find that when Linux is doing
initialization, it tries setting clock and power to SDIO controller for
that chip. It is trying frequences hardcoded in
linux/drivers/mmc/core/core.c: 400000, 300000, 200000, 100000 Hz.
Opposed to that, chrome os kernel tries other frequences: 784314Hz and
50000000Hz. The last is staying as working frequency. I don't know, if
it is matter for card what frequency does the host tries to gate.

When mainline kernel runs mmc_attach_sdio function it should get correct
answer from card and so process card as SDIO. However it fails with
timeout in that function.

I wonder if this depends on firmware loading. I see, that chrome os 3.4
kernel requires firmware. And mainline is probably simply doesn't load
it by default. Currently, I don't know how to check it and how to
configure kernel to load firmware for mwifiex_sdio.

I am ready to do further research, but I need some assistance.

Is there any manual on marvell chip?