Date:   Wed, 15 Dec 2021 21:08:29 +0000
From:   David Brazdil <dbrazdil@google.com>
To:     Rob Herring <robh@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>, Will Deacon <will@kernel.org>,
        Andrew Scull <ascull@google.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/2] dt-bindings: firmware: Add Open Profile for DICE
Message-ID: <YbpZTSpmnieCNZ9a@google.com>
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 <YbpPYG4rzPmJmwA6@robh.at.kernel.org>
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Hi Rob,

> > +        dice_reserved: dice@12340000 {
> > +            reg = <0x00 0x12340000 0x2000>;
> > +            no-map;
> > +        };
> > +    };
> > +
> > +    dice {
> > +        compatible = "google,open-dice";
> > +        memory-region = <&dice_reserved>;
> 
> There's no need for this indirection. Just add the compatible to the 
> dice@12340000 node. You can bind drivers to /reserved-memory nodes.

I have not found a way to make that work for kernel modules. Built-in
drivers can bind with RESERVEDMEM_OF_DECLARE, which puts an entry in
__reservedmem_of_table and __reserved_mem_init_node() iterates find it
there. A good case study might be CONFIG_TEGRA210_EMC, where the driver
itself can be a module but the rmem parsing is always built-in under
CONFIG_TEGRA210_EMC_TABLE. I don't think that's worth the trouble with
this driver.

David