docs(u-boot): Add documentation of Ethernet boot for J721s2 SoC

Ethernet boot support has been added to J721s2 SoC, add documentation for
the same.

Signed-off-by: Chintan Vankar <c-vankar@ti.com>

Author: chintanv133

configs/AM68/AM68_linux_config.txt

@@ -32,6 +32,7 @@ Replacement Variables
 '__PCIE_BASE_ADDRESS__'          : '2910000'
 '__PCIE_DEVICE_ID__'             : '0xb00d'
 '__IMAGE_TYPE__'                 : 'default'
+'__VCI_DEVICE_NAME__'            : 'AM68'
 
 Configuration Values
 --------------------

configs/AM68/AM68_linux_toc.txt

@@ -33,6 +33,7 @@ linux/Foundational_Components/U-Boot/UG-UART
 linux/Foundational_Components/U-Boot/UG-SATA
 linux/Foundational_Components/U-Boot/UG-UFS
 linux/Foundational_Components/U-Boot/UG-DDRSS-J7
+linux/Foundational_Components/U-Boot/UG-Network-K3
 linux/Foundational_Components/U-Boot/UG-HyperBus
 linux/Foundational_Components/U-Boot/UG-RemoteProc
 linux/Foundational_Components/U-Boot/Applications

source/linux/Foundational_Components/U-Boot/UG-General-Info.rst

@@ -358,15 +358,15 @@ Build U-Boot
 
    .. ifconfig:: CONFIG_part_variant in ('J721S2')
 
-      +----------------------------+---------------------------------+--------------------------------+--------------------------------+--------------------------------+
-      |  Board                     |            SD/eMMC Boot         |           UART boot            |           OSPI boot            |           USB DFU              |
-      +============================+=================================+================================+================================+================================+
-      |    J721S2 EVM              |    j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |
-      |                            |    j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |
-      +----------------------------+---------------------------------+--------------------------------+--------------------------------+--------------------------------+
-      |    AM68 HS-FS SK           |    j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |                                |
-      |                            |    j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |                                |
-      +----------------------------+---------------------------------+--------------------------------+--------------------------------+--------------------------------+
+      +----------------------------+---------------------------------+--------------------------------+--------------------------------+--------------------------------+--------------------------------------+
+      |  Board                     |            SD/eMMC Boot         |           UART boot            |           OSPI boot            |           USB DFU              |           Ethernet Boot              |
+      +============================+=================================+================================+================================+================================+======================================+
+      |    J721S2 EVM              |    j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |                                      |
+      |                            |    j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |                                      |
+      +----------------------------+---------------------------------+--------------------------------+--------------------------------+--------------------------------+--------------------------------------+
+      |    AM68 HS-FS SK           |    j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |   j721s2\_evm\_r5\_defconfig   |                                |   am68\_sk\_r5\_ethboot\_defconfig   |
+      |                            |    j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |   j721s2\_evm\_a72\_defconfig  |                                |   am68\_sk\_a72\_ethboot\_defconfig  |
+      +----------------------------+---------------------------------+--------------------------------+--------------------------------+--------------------------------+--------------------------------------+
 
    .. ifconfig:: CONFIG_part_variant in ('J784S4')
 

source/linux/Foundational_Components/U-Boot/UG-Network-K3.rst

@@ -72,7 +72,15 @@ binaries files to be sent over TFTP are listed in the table below.
       - When the link info Bootmode pin is enabled, this means no auto-negotiation or reading of the Ethernet PHY is needed since the ROM will assume the link is up at 1Gbps, full duplex mode.
       - Disable link info Bootmode pin so that ROM can identify the PHY and establishes link with the supported speed and duplex mode.
 
-.. ifconfig:: CONFIG_part_variant in ('AM64X','AM62X','J722S','AM62PX')
+.. ifconfig:: CONFIG_part_variant in ('J721S2')
+
+   Build tiboot3.bin using ``am68_evm_r5_ethboot_defconfig``. Build tispl.bin and u-boot.img using ``am68_evm_a72_ethboot_defconfig``. For instructions to build the bootloader images please refer to :ref:`Build-U-Boot-label`.
+
+   .. important::
+
+      - Ethernet RGMII boot is supported over RGMII on J721S2 SoC.
+
+.. ifconfig:: CONFIG_part_variant in ('AM64X','AM62X','J722S','AM62PX','J721S2')
 
   If using ISC dhcpd an example host entry would look like this: