Re: [PATCH 4/5] dt-bindings: mtd: describe BCM963XX ImageTag format and usage

[Jonas Gorski <jonas.gorski@gmail.com>]

On 4 September 2018 at 02:30, Rob Herring <robh@kernel.org> wrote:
> On Tue, Aug 28, 2018 at 01:19:43PM +0200, Jonas Gorski wrote:
>> Describe how to use the BCM963XX ImageTag format in a mixed flash layout
>> environment.
>>
>> Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
>> ---
>>  .../mtd/partitions/brcm,bcm963xx-imagetag.txt      | 78 ++++++++++++++++++++++
>>  1 file changed, 78 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mtd/partitions/brcm,bcm963xx-imagetag.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mtd/partitions/brcm,bcm963xx-imagetag.txt b/Documentation/devicetree/bindings/mtd/partitions/brcm,bcm963xx-imagetag.txt
>> new file mode 100644
>> index 000000000000..f4a444d69d9a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mtd/partitions/brcm,bcm963xx-imagetag.txt
>> @@ -0,0 +1,78 @@
>> +Broadcom BCM963XX ImageTag Partition Container
>> +==============================================
>> +
>> +Some Broadcom BCM63XX SoC based devices contain additional, non discoverable
>> +partitions or non standard bootloader partition sizes. For these a mixed layout
>> +needs to be used with an explicit firmware partition.
>> +
>> +The BCM963XX ImageTag is a simple firmware header describing the offsets and
>> +sizes of the rootfs and kernel parts contained in the firmware.
>> +
>> +Required properties:
>> +- compatible : must be "brcm,bcm963xx-imagetag"
>> +
>> +Examples:
>> +
>> +flash@1e000000 {
>> +     compatible = "cfi-flash";
>> +     reg = <0x1e000000 0x2000000>;
>> +     bank-width = <2>;
>> +
>> +     partitions {
>> +             compatible = "fixed-partitions";
>> +             #address-cells = <1>;
>> +             #size-cells = <1>;
>> +
>> +             cfe@0 {
>> +                     reg = <0x0 0x10000>;
>> +                     read-only;
>> +             };
>> +
>> +             firmware@10000 {
>> +                     reg = <0x10000 0x7d0000>;
>> +                     compatible = "brcm,bcm963xx-imagetag";
>> +             };
>> +
>> +             caldata@7e0000 {
>> +                     reg = <0x7e0000 0x10000>;
>> +                     read-only;
>> +             };
>> +
>> +             nvram@7f0000 {
>> +                     reg = <0x7f0000 0x10000>;
>> +             };
>> +     };
>> +};
>> +
>> +
>> +flash@1e000000 {
>> +     compatible = "cfi-flash";
>> +     reg = <0x1e000000 0x2000000>;
>> +     bank-width = <2>;
>> +
>> +     partitions {
>> +             compatible = "fixed-partitions";
>> +             #address-cells = <1>;
>> +             #size-cells = <1>;
>> +
>> +             /*
>> +              * Some devices use a flash chip with 64k erase blocks, some
>> +              * use one with 128k erase blocks, so the vendor decided to
>> +              * always use 128k as the firmware offset.
>> +              */
>
> That's a interesting piece of info, but not really a reason to have a
> second example.

Generally, I'd rather have one example too many than one too few, but
I can drop it if you think it's unnecessary. If I do that, can I add
your Ack then here as well for the v2?

>
>> +
>> +             cfe@0 {
>> +                     reg = <0x0 0x20000>;
>> +                     read-only;
>> +             };
>> +
>> +             firmware@20000 {
>> +                     reg = <0x20000 0x7c0000>;
>> +                     compatible = "brcm,bcm963xx-imagetag";
>> +             };
>> +
>> +             nvram@7e0000 {
>> +                     reg = <0x7e0000 0x20000>;
>> +             };
>> +     };
>> +};
>> --
>> 2.13.2
>>
>

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