Re: [PATCH v6 2/3] DT/arm,gic-v3-its: add reset-on-suspend property

From: Mark Rutland
Date: Thu Feb 08 2018 - 08:47:03 EST


On Wed, Feb 07, 2018 at 06:36:47PM -0800, Derek Basehore wrote:
> This adds documentation for the new reset-on-suspend property. This
> property enables saving and restoring the ITS for when it loses state
> in system suspend.
>
> Signed-off-by: Derek Basehore <dbasehore@xxxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
> index 0a57f2f4167d..a470147d4f14 100644
> --- a/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
> +++ b/Documentation/devicetree/bindings/interrupt-controller/arm,gic-v3.txt
> @@ -78,6 +78,9 @@ These nodes must have the following properties:
> Optional:
> - socionext,synquacer-pre-its: (u32, u32) tuple describing the untranslated
> address and size of the pre-ITS window.
> +- reset-on-suspend: Boolean property. Indicates that the ITS state is
> + reset on suspend. The state is then saved on suspend and restored on
> + resume.

The latter sentence reads like a description of SW policy, rather than a
description of what the HW does. I don't think that should be here
(though it might be worth noting the FW will not restore state).

Which state is lost? Is "ITS state" a well-defined term?

By suspend do you mean a PSCI_SYSTEM_SUSPEND, or potentially other
cases?

Thanks,
Mark.