Re: [PATCH 2/3] net: irda: pxaficp_ir: convert to readl and writel

From: Robert Jarzmik
Date: Fri Sep 11 2015 - 02:23:13 EST


Petr Cvek <petr.cvek@xxxxxx> writes:

>> Should have been posted to linux arm kernel mailing list, unless my mailer
>> failed ...
>>
> Searching for:
>
> "ARM: pxa: add resources to pxaficp_ir"
>
> did not found anything, same was for "ficp" in the linux-arm-kernel/netdev/linux-kernel
> mailing list archive.
Ah ok, I'll resend it then.

>>> BTW This patch required update of my kernel repo. It seems that my:
>>>
>>> magician.c patches + ficp patch + new dma engine
>>>
>>> does not work for me at all. Kernel throws some panic about interrupts and then
>>> it ends in an infinite stack dumping loop. Fault occurs before rootfs is
>>> mounted, so probably around MMC init (with removed SD card it fails normally
>>> with no rootfs found error).
>> Could you send me (privately) the stack you're getting please. This is something
>> I'd like to catch up early in the -rc releases.
>
> Well this will be problem as I cannot save anything to an SD card after and
> during the failure. Only viable interfaces would be earlycon on an infraport
> or high speed camera on LCD :-).
Ah just as on my mioa701. I ended up soldering a JTAG cable :)

> But I was able to revert this commit:
>
> 6464b71409511939efce1ae4fb4ec6e3483b11b2 mmc: pxamci: switch over to dmaengine use
>
> and after that I am able to boot.
Okay. I'll try to reproduce this failure then. If I fail, well, before using the
JTAG cable, I used another trick: I was taking a movie from the LCD with a
smartphone, and it worked. It was an horrible thing to decrypt ... Let's hope
I'll be lucky on one of my platforms.

>> Now with your stack, could you also give me the upstream commit id of the tip of
>> the tree you're using (before your patches) please ?
>
> It is probably irelevant now, but for complete information:
>
> Discovered on my working repo: mainline b8889c4fc6ba03e289cec6a4d692f6f080a55e53
> Still present on fresh downloaded: linux-next
> 22dc312d56ba077db27a9798b340e7d161f1df05
Ok, thanks.

>> And it is true I have not tested the rootfs special case, where drivers are not
>> yet initialized (and more specifically gpio and interrupt chip). Your backtrace
>> should tell me if you fall into this category of issues ... but I digress, this
>> has no link with pxaficp.
>
> Should I start new thread? (same bug can be present in the FICP too)
Yes, this pxamci bothers me, it deserves a thread.

> I will try to configure an initrd rootfs this should create more ways to save
> kernel log.
Great idea.

>
> Anyway after mmc dma revert I was still not able to start FICP. There is an error:
>
> Unable to handle kernel paging request at virtual address 32e00004
>
> from pxa_irda_startup() and it seems it is caused by register definitions. For example:
>
> writel_relaxed((val), (irda)->stuart_base + (off));
>
> is called by
>
> stuart_writel(si, 0, STIER);
>
> but STIER is not just an offset, but full register address:
>
> __REG(0x40700004)
>
> So the definition should be changed, unless there is another patch I did not
> received (in that case, send me full patchset again please) :-).
Agreed, this is a bug in this patch. With this fix, is the pxaficp working or do
you need a bit more time to experiment ?

Cheers.

--
Robert
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