[PATCH v4 10/10] docs: board: ti: j784s4_evm: Add PCIe boot documentation

[Kumar, Udit]

On 12/1/2025 4:31 PM, Hrushikesh Salunke wrote:
> Add PCIe boot documentation for J784S4-EVM including boot mode switch
> settings, hardware setup requirements, endpoint configuration details
> and step-by-step boot procedure.
>
> Signed-off-by: Hrushikesh Salunke <h-salunke at ti.com>
> ---
>   doc/board/ti/j784s4_evm.rst | 267 ++++++++++++++++++++++++++++++++++++
>   1 file changed, 267 insertions(+)
>
> diff --git a/doc/board/ti/j784s4_evm.rst b/doc/board/ti/j784s4_evm.rst
> index 22442874110..0c9dad122a7 100644
> --- a/doc/board/ti/j784s4_evm.rst
> +++ b/doc/board/ti/j784s4_evm.rst
> @@ -280,6 +280,10 @@ http://www.ti.com/lit/zip/spruj52 under the `Boot Mode Pins` section.
>        - 00000000
>        - 01110000
>   
> +   * - PCIe
> +     - 10001000
> +     - 01010000
> +
>   For SW7 and SW11, the switch state in the "ON" position = 1.
>   
>   Boot Mode Pins for AM69-SK
> @@ -311,6 +315,269 @@ section.
>   
>   For SW2, the switch state in the "ON" position = 1.
>   
> +PCIe Boot
> +---------
> +
> +The J784S4 SoC supports booting over PCIe, allowing the device to function
> +as a PCIe endpoint and receive boot loader images from a PCIe root complex.
> +
> +Hardware Setup
> +^^^^^^^^^^^^^^
> +
> +To boot J784S4 via PCIe, the following hardware setup is required:
> +
> +1. Configure the boot mode switches on J784S4-EVM for PCIe boot:
> +
> +   .. code-block:: text
> +
> +      SW7:  01010000
> +      SW11: 10001000
> +
> +2. Connect the J784S4-EVM (endpoint) to a PCIe root complex (e.g., x86 host)
> +   using a PCIe cable. Both boards should be powered off before making the
> +   connection.
> +
> +Endpoint Configuration
> +^^^^^^^^^^^^^^^^^^^^^^
> +
> +The following configuration options are enabled by default in
> +``j784s4_evm_r5_defconfig`` and ``j784s4_evm_a72_defconfig``:
> +
> +- ``CONFIG_SPL_PCI_DFU_BAR_SIZE``: Size of the PCIe BAR for DFU/boot image download
> +- ``CONFIG_SPL_PCI_DFU_VENDOR_ID``: PCIe vendor ID advertised by the endpoint
> +- ``CONFIG_SPL_PCI_DFU_DEVICE_ID``: PCIe device ID advertised by the endpoint
> +- ``CONFIG_SPL_PCI_DFU_MAGIC_WORD``: Magic word written by root complex to signal image transfer completion
> +- ``CONFIG_SPL_PCI_DFU_BOOT_PHASE``: Current boot phase indicator for root complex
> +
> +By default, PCIe root complex mode is enabled in the device tree. To enable
> +endpoint mode, build the boot loaders with the device tree overlay
> +``k3-j784s4-evm-pcie0-pcie1-ep.dtso``.

Do you think, you need bootph property in pcie_ep node ?


> +
> +PCIe Boot Procedure
> +^^^^^^^^^^^^^^^^^^^
> [..]+
> +The following steps describe how to boot J784S4 over PCIe:

> +
> [..]