From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
robh@kernel.org, boris.brezillon@free-electrons.com,
leoyang.li@nxp.com, oss@buserror.net,
linux-mtd@lists.infradead.org, cyrille.pitchen@wedev4u.fr,
computersforpeace@gmail.com, shawnguo@kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2][v5] dt-bindings: mtd-physmap: Add endianness supports
Date: Thu, 1 Mar 2018 18:12:48 +0100 [thread overview]
Message-ID: <20180301181248.7212a5c5@bbrezillon> (raw)
In-Reply-To: <20180228073335.1758-1-prabhakar.kushwaha@nxp.com>
On Wed, 28 Feb 2018 13:03:34 +0530
Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com> wrote:
> Connection between flash and controller is not necessary to be always
> of same type. It may varies from platform to platform.
>
> Adding endianness (optional) property to provide connection type
> information.
>
> Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
> Reviewed-by: Rob Herring <robh@kernel.org>
> ---
> Changes for v2: updated subject
> Changes for v3: fixed typo for "big-endian"
> Changes for v4: Moved binding definition in mtd-physmap.txt
> as discussed at https://patchwork.ozlabs.org/patch/842543/
> Changes for v5: Sending as it is
>
> Documentation/devicetree/bindings/mtd/mtd-physmap.txt | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt
> index 4a0a48bf4ecb..961a8eed9d0d 100644
> --- a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt
> +++ b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt
> @@ -41,6 +41,11 @@ additional (optional) property is defined:
>
> - erase-size : The chip's physical erase block size in bytes.
>
> + The device tree may optionally contain endianness property.
> + little-endian or big-endian : It represents connection between controller and
> + flash.
Hm, I'm not even sure it has to do with the HW connection of the data
lines (D0:X), probably more something related to how the flash was
programmed (some people program the flash using a dedicated programmer
before soldering it on the board) and the current platform endianness
(which for some platforms, can be changed with a Kconfig option).
> If this property is absent, flash is considered
> + to be host-endian.
The second sentence is no longer valid. Now, if the property is missing
the behavior is platform/configuration dependent, not necessarily
host-endian.
> +
> The device tree may optionally contain sub-nodes describing partitions of the
> address space. See partition.txt for more detail.
>
--
Boris Brezillon, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
prev parent reply other threads:[~2018-03-01 17:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-28 7:33 [PATCH 1/2][v5] dt-bindings: mtd-physmap: Add endianness supports Prabhakar Kushwaha
2018-02-28 7:33 ` [PATCH 2/2][v5] driver: mtd: update struct map_info's swap as per map requirement Prabhakar Kushwaha
2018-03-06 6:02 ` Prabhakar Kushwaha
2018-03-06 8:14 ` Boris Brezillon
2018-03-01 17:12 ` Boris Brezillon [this message]
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