Messages in this thread | | | Date | Thu, 1 Mar 2018 11:41:45 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH v7 1/3] irqchip/gic-v3-its: add ability to save/restore ITS state |
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On Wed, Feb 28, 2018 at 09:48:18PM -0800, Derek Basehore wrote: > Some platforms power off GIC logic in suspend, so we need to > save/restore state. The distributor and redistributor registers need > to be handled in platform code due to access permissions on those > registers, but the ITS registers can be restored in the kernel. > > Signed-off-by: Derek Basehore <dbasehore@chromium.org>
How much state do we have to save/restore?
Given we can apparently read all this state, couldn't we *always* save the state, then upon resume detect if the state has been lost, restoring it if so?
That way, we don't need a property in FW tables for DT or ACPI.
[...]
> @@ -3261,6 +3363,9 @@ static int __init its_probe_one(struct resource *res, > ctlr |= GITS_CTLR_ImDe; > writel_relaxed(ctlr, its->base + GITS_CTLR); > > + if (fwnode_property_present(handle, "reset-on-suspend")) > + its->flags |= ITS_FLAGS_SAVE_SUSPEND_STATE;
Does this allow this property on an ACPI system?
If we need this on ACPI, we need a spec update to handle this properly, and shouldn't use device properties like this.
Thanks, Mark.
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