CC: linux-mmc
Hi Alexander,
> 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.
Your Chromebook supports SDIO high speed mode (SDIO 2.0 spec). So 50MHz is correct.
>
> 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.
What are you trying to do here? Are you trying to run a mainline kernel on your Chromebook?
>
> 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.
You said mmc_attach_sdio function fails. The mwifiex_sdio driver and the firmware will not be loaded at all.
>
> I am ready to do further research, but I need some assistance.
CONFIG_MMC_DEBUG=y, and collect the debug logs.
Regards,
Bing
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