* Marc Zyngier <marc.zyngier@xxxxxxx> [150224 01:08]:
> On 23/02/15 23:02, Tony Lindgren wrote:
> > * Marc Zyngier <marc.zyngier@xxxxxxx> [150223 09:48]:
> >> This series is extracted from [4], which is trying to remove all
> >> traces of gic_arch_extn from the tree. As some maintainers are more
> >> responsive than others (understatement of the year...), I've decided
> >> to split it per sub-arch, and get it moving, at least partially.
> >>
> >> This series addresses OMAP{4,5} by converting the WUGEN to stacked
> >> domains. The DRA7 crossbar gets the same treatment.
> >>
> >> It is worth realizing that:
> >>
> >> - I haven't been able to test this as much as I would have wanted to
> >> (it's only been tested on omap4 and omap5).
> >>
> >> - This actively *breaks* existing setups. Once you boot a new kernel
> >> with an old DT, suspend/resume *will* be broken. Old kernels on a
> >> new DT won't even boot! You've been warned. This really outline the
> >> necessity of actually describing the HW in device trees...
> >
> > Could we parse still the old binding and produce warning for the
> > case when a new kernel is booted with the old DT? That would make
> > it easier for people to debug what's going on.
>
> There's a number of strategies:
> - Looking up the default, top-level interrupt controller:
> if that's the GIC, scream.
> - Lookup the crossbar:
> if it exists, but is not an interrupt controller, scream as well.
> - Lookup the WUGEN:
> if it doesn't exist, scream again.
>
> The last one is pretty easy to implement:
>
> diff --git a/arch/arm/mach-omap2/omap4-common.c b/arch/arm/mach-omap2/omap4-common.c
> index fba1ba7..7bb116a 100644
> --- a/arch/arm/mach-omap2/omap4-common.c
> +++ b/arch/arm/mach-omap2/omap4-common.c
> @@ -277,6 +277,12 @@ void __init omap_gic_of_init(void)
> {
> struct device_node *np;
>
> + intc_node = of_find_matching_node(NULL, intc_match);
> + if (WARN_ON(!intc_node)) {
> + pr_err("No WUGEN found in DT, system will misbehave.\n");
> + pr_err("UPDATE YOUR DEVICE TREE!\n");
> + }
> +
> /* Extract GIC distributor and TWD bases for OMAP4460 ROM Errata WA */
> if (!cpu_is_omap446x())
> goto skip_errata_init;
>
> This should cover both OMAP4, OMAP5 and DRA7.
>
> What do you think?
This should do the job for the case of old dtb and people trying to
suspend the device.
Thanks,
Tony
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