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
+
--
Frank Rowand <[email protected]>
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
> +
>