Date:   Thu, 23 Feb 2023 11:41:13 +0100
From:   =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= <clement.leger@bootlin.com>
To:     Frank Rowand <frowand.list@gmail.com>
Cc:     Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Lizhi Hou <lizhi.hou@xilinx.com>,
        Allan Nielsen <allan.nielsen@microchip.com>,
        Horatiu Vultur <horatiu.vultur@microchip.com>,
        Steen Hegelund <steen.hegelund@microchip.com>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v2 0/2] of: populate of_root_node if not set (alternate)
Message-ID: <20230223114113.7865938b@fixe.home>
In-Reply-To: <20230222221051.809091-1-frowand.list@gmail.com>
References: <20230222221051.809091-1-frowand.list@gmail.com>
Organization: Bootlin
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Le Wed, 22 Feb 2023 16:10:49 -0600,
Frank Rowand <frowand.list@gmail.com> a =C3=A9crit :

> This series is a different implementation to achieve the goals of
> https://lore.kernel.org/r/20220623105044.152832-1-clement.leger@bootlin.c=
om
>=20
> In order to apply overlays or create new nodes under the root node, the
> kernel expects of_root to be set. On some system where a device-tree was
> not provided by firmware (x86 for instance) if CONFIG_OF is enabled,
> then we will end up with a null of_root. This series adds support to
> create this root node using a builtin dtb and removes the manual
> creation of the root node done in unittests.c.

Hi Frank, I'm currently testing your series and I encountered some
crashes at boot. Looks like it comes from the
early_init_dt_alloc_memory_arch() that calls panic. Maybe the memblock
allocator is not ready yet. Please note that I'm testing it on a x86
kernel. I'll investigate that.

Regarding the series itself it seems ok to me.

Thanks,

Cl=C3=A9ment

>=20
> Changes since version 1: (patch 1/2)
>   - refresh for 6.2-rc1
>   - update Signed-off-by
>   - fix typo in of_fdt.h: s/of_setup/setup_of
>   - unflatten_device_tree(): validate size in header field dtb_empty_root
>     that will be used to copy dtb_empty_root
>   - add Kconfig option to manually select CONFIG_OF_EARLY_FLATTREE
>=20
> Changes since version 1: (patch 2/2)
>   - refresh for 6.2-rc1
>   - update Signed-off-by
>   - fix formatting error (leading space) in patch comment
>=20
> Frank Rowand (2):
>   of: create of_root if no dtb provided
>   of: unittest: treat missing of_root as error instead of fixing up
>=20
>  drivers/of/Kconfig        |  7 ++++++-
>  drivers/of/Makefile       |  2 +-
>  drivers/of/empty_root.dts |  6 ++++++
>  drivers/of/fdt.c          | 27 ++++++++++++++++++++++++++-
>  drivers/of/unittest.c     | 16 ++++++----------
>  include/linux/of_fdt.h    |  2 ++
>  init/main.c               |  2 ++
>  7 files changed, 49 insertions(+), 13 deletions(-)
>  create mode 100644 drivers/of/empty_root.dts
>=20


--=20
Cl=C3=A9ment L=C3=A9ger,
Embedded Linux and Kernel engineer at Bootlin
https://bootlin.com