Re: [PATCH 1/1] dma: actions: Fix lockdep splat for owl-dma

[Andreas FÃrber]

Am 28.04.20 um 20:18 schrieb Manivannan Sadhasivam:
> On Tue, Apr 28, 2020 at 09:11:15PM +0300, Cristian Ciocaltea wrote:
> > On Tue, Apr 28, 2020 at 10:19:21PM +0530, Manivannan Sadhasivam wrote:
> > > On Tue, Apr 28, 2020 at 01:56:12PM +0300, Cristian Ciocaltea wrote:
> > > > When the kernel is build with lockdep support and the owl-dma driver is
> > > > used, the following message is shown:
[...]
> > > > The required fix is to use spin_lock_init() on the pchan lock before
> > > > attempting to call any spin_lock_irqsave() in owl_dma_get_pchan().
> > >
> > > Right, this is a bug. But while looking at the code now, I feel that we don't
> > > need 'pchan->lock'. The idea was to protect 'pchan->vchan', but I think
> > > 'od->lock' is the better candidate for that since it already protects it in
> > > 'owl_dma_terminate_pchan'.
> > >
> > > So I'd be happy if you remove the lock from 'pchan' and just directly use the
> > > one in 'od'.
> > >
> > > Out of curiosity, on which platform you're testing this?
> >
> > Totally agree, I will send a new patch revision as soon as I do some
> > more testing.
>
> Coo[l], thanks!
>
> > I'm currently experimenting on an Actions S500 based board (Roseapple Pi)
> > trying to extend, if possible, the existing mainline support for those
> > SoCs.
>
> Awesome! It's great to see that Actions platform is seeing some attention
> these days :)
>
> > I don't have much progress so far, since I started quite recently
> > and I also lack experience in the kernel development area, but I do my
> > best to come back with more patches once I get a consistent functionality.
>
> No worries. Feel free to reach out to me if you have any questions. There is
> a lot of work to do and for sure it will be a good learning curve.
>
> We do have an IRC channel (##linux-actions) for quick discussions. Fee[l] free
> to join!

Please also CC the linux-actions mailing list on any patches:

https://lists.infradead.org/mailman/listinfo/linux-actions

Mani, do you have a 5.7-rc1 tree set up or should I queue patches this 
round? It still seems missing in MAINTAINERS, and then there's Matheus' 
patches in review.

Thanks,
Andreas

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