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SubjectRe: [PATCH] of: document /sys/firmware/fdt
On 14 June 2017 at 11:55, Mark Rutland <mark.rutland@arm.com> wrote:
> [Adding Ard, as he added /sys/firmware/fdt]
>

Thanks

> On Tue, Jun 13, 2017 at 09:20:07PM -0700, frowand.list@gmail.com wrote:
>> From: Frank Rowand <frank.rowand@sony.com>
>>
>> Add ABI documentation for /sys/firmware/fdt
>>
>> Update contact for /sys/firmware/devicetree/* to include mail list
>>
>> Signed-off-by: Frank Rowand <frank.rowand@sony.com>
>
> FWIW:
>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

>> ---
>> 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..8e700db6c295 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 <grant.likely@linaro.org>
>> +Contact: Grant Likely <grant.likely@linaro.org>, devicetree@vger.kernel.org
>> 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: Frank Rowand <frank.rowand@sony.com>, devicetree@vger.kernel.org
>> +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
>> +
>> --
>> Frank Rowand <frank.rowand@sony.com>
>>
>> --
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