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Date:   Tue, 1 Feb 2022 17:39:52 -0600
From:   Rob Herring <robh@kernel.org>
To:     David Brazdil <dbrazdil@google.com>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Frank Rowand <frowand.list@gmail.com>,
        Will Deacon <will@kernel.org>,
        Andrew Scull <ascull@google.com>,
        Wedson Almeida Filho <wedsonaf@google.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v7 1/2] dt-bindings: reserved-memory: Open Profile for
 DICE
Message-ID: <YfnEyB6ZlAj/QI8n@robh.at.kernel.org>
References: <20220126231237.529308-1-dbrazdil@google.com>
 <20220126231237.529308-2-dbrazdil@google.com>
 <YfHW7GcINVlB/3Ur@google.com>
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On Wed, Jan 26, 2022 at 11:19:08PM +0000, David Brazdil wrote:
> Hi Rob,
> 
> On Wed, Jan 26, 2022 at 11:12:36PM +0000, David Brazdil wrote:
> > Add DeviceTree bindings for Open Profile for DICE, an open protocol for
> > measured boot. Firmware uses DICE to measure the hardware/software
> > combination and generates Compound Device Identifier (CDI) certificates.
> > These are stored in memory and the buffer is described in the DT as
> > a reserved memory region compatible with 'google,open-dice'.
> > 
> > 'no-map' is required to ensure the memory region is never treated by
> > the kernel as system memory.
> > 
> > Signed-off-by: David Brazdil <dbrazdil@google.com>
> > ---
> >  .../reserved-memory/google,open-dice.yaml     | 46 +++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/reserved-memory/google,open-dice.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/reserved-memory/google,open-dice.yaml b/Documentation/devicetree/bindings/reserved-memory/google,open-dice.yaml
> > new file mode 100644
> > index 000000000000..257a0b51994a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/reserved-memory/google,open-dice.yaml
> > @@ -0,0 +1,46 @@
> > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/reserved-memory/google,open-dice.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Open Profile for DICE Device Tree Bindings
> > +
> > +description: |
> > +  This binding represents a reserved memory region containing data
> > +  generated by the Open Profile for DICE protocol.
> > +
> > +  See https://pigweed.googlesource.com/open-dice/
> > +
> > +maintainers:
> > +  - David Brazdil <dbrazdil@google.com>
> > +
> > +allOf:
> > +  - $ref: "reserved-memory.yaml"
> > +
> > +properties:
> > +  compatible:
> > +    const: google,open-dice
> > +
> > +  reg:
> > +    description: page-aligned region of memory containing DICE data
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - no-map
> 
> You already gave this a Reviewed-by in v6. Just want to mention that I
> didn't pick it up because I added a required no-map here. It was always
> included in our DTs but I made it required because the kernel should
> never treat that region as system memory. The kernel will warn when the
> driver tries to wipe the memory otherwise.

That's small enough change to keep tags.

Reviewed-by: Rob Herring <robh@kernel.org>