[PATCH v1 3/3] doc: add AMD NTB support

[Bruce Richardson]

On Sun, Aug 23, 2026 at 07:36:39PM +0530, Raghavendra Ningoji wrote:
> Document AMD EPYC Embedded NTB support in the raw/ntb guide, add a
> release note entry, and claim maintainership of the AMD NTB support.
> 
> Signed-off-by: Raghavendra Ningoji <raghavendra.ningoji at amd.com>
> ---
>  MAINTAINERS                            |  1 +
>  doc/guides/rawdevs/ntb.rst             | 18 +++++++++++++++++-
>  doc/guides/rel_notes/release_26_11.rst |  8 ++++++++
>  3 files changed, 26 insertions(+), 1 deletion(-)
> 

This documentation should be squashed into the prevous patch adding the
support. See also one additional comment below.

Thanks,
/Bruce

> diff --git a/MAINTAINERS b/MAINTAINERS
> index e99a65d197..13306345fd 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1613,6 +1613,7 @@ F: doc/guides/rawdevs/cnxk_rvu_lf.rst
>  
>  NTB
>  M: Jingjing Wu <jingjing.wu at intel.com>
> +M: Bhagyada Modali <bhagyada.modali at amd.com>
>  F: drivers/raw/ntb/
>  F: doc/guides/rawdevs/ntb.rst
>  F: examples/ntb/
> diff --git a/doc/guides/rawdevs/ntb.rst b/doc/guides/rawdevs/ntb.rst
> index 3721b4880e..c89eaccac8 100644
> --- a/doc/guides/rawdevs/ntb.rst
> +++ b/doc/guides/rawdevs/ntb.rst
> @@ -37,10 +37,26 @@ then reboot.
>  - Set ``PCIe PLL SSC (Spread Spectrum Clocking)`` as ``Disabled``, on both hosts.
>    This is a hardware requirement when using Re-timer Cards.
>  
> +AMD EPYC Embedded NTB
> +---------------------
> +
> +The driver also supports the NTB endpoints integrated in AMD EPYC Embedded
> +"Turin", "Genoa" and "Siena" processors. These use a primary/secondary
> +topology rather than the Intel back-to-back topology: one endpoint is
> +enumerated as the primary (device ID ``0x14c0``) and the other as the
> +secondary (device ID ``0x14c3``). The BIOS on both systems performs NTB link
> +training; no additional NTB-specific BIOS options are required beyond enabling
> +the NTB endpoints.
> +
> +The AMD NTB hardware exposes two memory windows (BAR23 and BAR45), 16
> +doorbells and a single shared 16-register scratchpad bank. The scratchpad
> +bank is split into two disjoint 8-register sets, one owned by each side, so
> +the driver uses a packed handshake layout that fits within 8 registers.
> +

The documentation needs an update on the alignment requirements and
handling - either the need for the new alignment API if one is added as I
suggested, or else details on how the app needs to handle it itself (which
is less preferable).

>  Device Setup
>  ------------
>  
> -The Intel NTB devices need to be bound to a DPDK-supported kernel driver
> +The NTB devices need to be bound to a DPDK-supported kernel driver
>  to use, i.e. igb_uio, vfio. The ``dpdk-devbind.py`` script can be used to
>  show devices status and to bind them to a suitable kernel driver. They will
>  appear under the category of "Misc (rawdev) devices".
> diff --git a/doc/guides/rel_notes/release_26_11.rst b/doc/guides/rel_notes/release_26_11.rst
> index c8cc86295d..0b364ccbd4 100644
> --- a/doc/guides/rel_notes/release_26_11.rst
> +++ b/doc/guides/rel_notes/release_26_11.rst
> @@ -55,6 +55,14 @@ New Features
>       Also, make sure to start the actual text at the margin.
>       =======================================================
>  
> +* **Added AMD NTB support to the NTB rawdev driver.**
> +
> +  Added support for the NTB endpoints integrated in AMD EPYC Embedded
> +  "Turin", "Genoa" and "Siena" processors to the ``raw/ntb`` driver.
> +  The NTB rawdev framework was generalized to support multiple vendors,
> +  with AMD-specific hardware access, a primary/secondary topology and a
> +  packed scratchpad handshake.
> +
>  
>  Removed Items
>  -------------
> -- 
> 2.34.1
>