docs(u-boot): Add documentation of Ethernet boot for AM62px SoC

Ethernet boot support has been added to AM62px SoC, add documentation for
the same.

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

Author: chintanv133

configs/AM62PX/AM62PX_linux_config.txt

@@ -31,6 +31,10 @@ Replacement Variables
 '__FEATURINGMATRIX__'            : \
 '__SYSFW_CORE_NAME__'            : 'TIFS'
 '__IMAGE_TYPE__'                 : 'default'
+'__SPL_VCI_STRING_LEN__'         : '20'
+'__SPL_VCI_STRING__'             : 'AM62PX U-Boot R5 SPL'
+'__UBOOT_VCI_STRING_LEN__'       : '21'
+'__UBOOT_VCI_STRING__'           : 'AM62PX U-Boot A53 SPL'
 
 Configuration Values
 --------------------

configs/AM62PX/AM62PX_linux_toc.txt

@@ -34,7 +34,7 @@ linux/Foundational_Components/U-Boot/UG-SPI
 linux/Foundational_Components/U-Boot/UG-QSPI
 linux/Foundational_Components/U-Boot/UG-UART
 linux/Foundational_Components/U-Boot/UG-DDRSS
-#linux/Foundational_Components/U-Boot/UG-Network-K3
+linux/Foundational_Components/U-Boot/UG-Network-K3
 linux/Foundational_Components/U-Boot/UG-Splash-Screen
 linux/Foundational_Components/U-Boot/UG-RemoteProc
 linux/Foundational_Components/U-Boot/UG-Falcon-Mode

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

@@ -601,12 +601,12 @@ Build U-Boot
 
    .. ifconfig:: CONFIG_part_variant in ('AM62PX')
 
-      +-------------+----------------------------------+----------------------------------------------------------+--------------------------------------------------------+
-      |  Board      |            SD Boot               |                       USB DFU                            |                        USB MSC                         |
-      +=============+==================================+==========================================================+========================================================+
-      |  AM62PX SK  |  | ``am62px_evm_r5_defconfig``   |  | ``am62px_evm_r5_defconfig am62x_r5_usbdfu.config``    |  | ``am62px_evm_r5_defconfig am62x_r5_usbmsc.config``  |
-      |             |  | ``am62px_evm_a53_defconfig``  |  | ``am62px_evm_a53_defconfig``                          |  | ``am62px_evm_a53_defconfig``                        |
-      +-------------+----------------------------------+----------------------------------------------------------+--------------------------------------------------------+
+      +-------------+----------------------------------+----------------------------------------------------------+--------------------------------------------------------+-----------------------------------------+
+      |  Board      |            SD Boot               |                       USB DFU                            |                        USB MSC                         |                 Ethernet Boot           |
+      +=============+==================================+==========================================================+========================================================+=========================================+
+      |  AM62PX SK  |  | ``am62px_evm_r5_defconfig``   |  | ``am62px_evm_r5_defconfig am62x_r5_usbdfu.config``    |  | ``am62px_evm_r5_defconfig am62x_r5_usbmsc.config``  |  | ``am62px_evm_r5_ethboot_defconfig``  |
+      |             |  | ``am62px_evm_a53_defconfig``  |  | ``am62px_evm_a53_defconfig``                          |  | ``am62px_evm_a53_defconfig``                        |  | ``am62px_evm_a53_ethboot_defconfig`` |
+      +-------------+----------------------------------+----------------------------------------------------------+--------------------------------------------------------+-----------------------------------------+
 
       .. note::
 

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

@@ -61,7 +61,18 @@ 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')
+.. ifconfig:: CONFIG_part_variant in ('AM62PX')
+
+   Build tiboot3.bin using ``am62px_evm_r5_ethboot_defconfig``. Build tispl.bin and u-boot.img using ``am62px_evm_a53_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 AM62px SoC.
+      - CPSW PHYs should be strapped as per ROM's expectation described in part's TRM.
+      - 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')
 
   If using ISC dhcpd an example host entry would look like this: