Hi Rob,

Please ignore this version, Grant replied to your v1 comment, so
I'll spin a v3.

-Frank

On 06/28/17 14:53, [email protected] wrote:
> From: Frank Rowand <[email protected]>
> 
> Add ABI documentation for /sys/firmware/fdt
> 
> Change obsolete contact for /sys/firmware/devicetree/* to mail list
> 
> Signed-off-by: Frank Rowand <[email protected]>
> ---
> 
> changes from v1:
>   - Remove obsolete email address as contact for /sys/firmware/devicetree/*
>   - For newly documented /sys/firmware/fdt do not include any individual
>     email for Contact (only provide email list)
> 
>  Documentation/ABI/testing/sysfs-firmware-ofw | 27 ++++++++++++++++++++++++++-
>  1 file changed, 26 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-firmware-ofw 
> b/Documentation/ABI/testing/sysfs-firmware-ofw
> index f562b188e71d..30a6b3621828 100644
> --- a/Documentation/ABI/testing/sysfs-firmware-ofw
> +++ b/Documentation/ABI/testing/sysfs-firmware-ofw
> @@ -1,6 +1,6 @@
>  What:                /sys/firmware/devicetree/*
>  Date:                November 2013
> -Contact:     Grant Likely <[email protected]>
> +Contact:     [email protected]
>  Description:
>               When using OpenFirmware or a Flattened Device Tree to enumerate
>               hardware, the device tree structure will be exposed in this
> @@ -26,3 +26,28 @@ Description:
>               name plus address). Properties are represented as files
>               in the directory. The contents of each file is the exact
>               binary data from the device tree.
> +
> +What:                /sys/firmware/fdt
> +Date:                February 2015
> +KernelVersion:       3.19
> +Contact:     [email protected]
> +Description:
> +             Exports the FDT blob that was passed to the kernel by
> +             the bootloader. This allows userland applications such
> +             as kexec to access the raw binary. This blob is also
> +             useful when debugging since it contains any changes
> +             made to the blob by the bootloader.
> +
> +             The fact that this node does not reside under
> +             /sys/firmware/device-tree is deliberate: FDT is also used
> +             on arm64 UEFI/ACPI systems to communicate just the UEFI
> +             and ACPI entry points, but the FDT is never unflattened
> +             and used to configure the system.
> +
> +             A CRC32 checksum is calculated over the entire FDT
> +             blob, and verified at late_initcall time. The sysfs
> +             entry is instantiated only if the checksum is valid,
> +             i.e., if the FDT blob has not been modified in the mean
> +             time. Otherwise, a warning is printed.
> +Users:               kexec, debugging
> +
> 

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