Re: [PATCH] usb: dwc3: omap: Fix imprecise external abort and oops on boot

[Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>]

* Felipe Balbi <balbi-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> [161208 12:12]:
> 
> Hi,
> 
> Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> writes:
> > * Felipe Balbi <balbi-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> [161208 11:17]:
> >> Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> writes:
> >> > The call to pm_runtime_get_sync() in dwc3_omap_probe() will use it.
> >> 
> >> right, but there's no runtime suspend until ->remove(). IOW, after
> >> pm_runtime_get_sync(), all necessary clocks should already be
> >> enabled. If they aren't, there's either an erratum or a bug in drivers/clk/ti/
> >
> > I think it's some dependency to the dwc3 core probe. That's because I'm
> > able to read and print out the wrapper interrupt registers just fine
> > before the imprecise external abort happens in probe. So that means it's
> > something dwc3 specific after the TI wrapper module clckctl bit.
> >
> >> > Is there also some dwc3 internal clock? If we assume the usb_otg_ss
> >> > module is properly enabled it could be some dwc3 internal clock not
> >> > enabled?
> >> 
> >> no extra clocks.
> >
> > It seems that if we get an interrupt before dwc3 core has probed with
> > of_platform_populate(), we get the imprecise external abort.
> 
> that's pretty odd. hwmod doesn't know about dwc3 core device, only
> usb_otg_ss (dwc3-omap.c).

It's probably the dwc3_core_soft_reset() that needs to happen before
we enable interrupts.

> >> is IRQ status already 0x2121 from u-boot prompt?
> >
> > Yes md 0x4A020034 shows 0x2121.
> 
> okay, so maybe something left from even earlier? OMAP5 can boot off USB
> peripheral.

I guess yeah it could be :)

Tony
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