doc: board: ti: Update documentation for binman flow

Earlier documentation specified builds for generating bootloader images
using an external TI repository k3-image-gen and core-secdev-k3. Modify
this to using the binman flow so that user understands how to build the
final boot images.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Neha Malcom Francis <n-francis@ti.com>
diff --git a/doc/board/ti/am65x_evm.rst b/doc/board/ti/am65x_evm.rst
new file mode 100644
index 0000000..300cd3e
--- /dev/null
+++ b/doc/board/ti/am65x_evm.rst
@@ -0,0 +1,420 @@
+.. SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+.. sectionauthor:: Neha Francis <n-francis@ti.com>
+
+AM65x Platforms
+===============
+
+Introduction:
+-------------
+The AM65x family of SoCs is the first device family from K3 Multicore
+SoC architecture, targeted for broad market and industrial control with
+aim to meet the complex processing needs of modern embedded products.
+
+The device is built over three domains, each containing specific processing
+cores, voltage domains and peripherals:
+
+1. Wake-up (WKUP) domain:
+        * Device Management and Security Controller (DMSC)
+
+2. Microcontroller (MCU) domain:
+        * Dual Core ARM Cortex-R5F processor
+
+3. MAIN domain:
+        * Quad core 64-bit ARM Cortex-A53
+
+More info can be found in TRM: http://www.ti.com/lit/pdf/spruid7
+
+Boot Flow:
+----------
+On AM65x family devices, ROM supports boot only via MCU(R5). This means that
+bootloader has to run on R5 core. In order to meet this constraint, and for
+the following reasons the boot flow is designed as mentioned:
+
+1. Need to move away from R5 asap, so that we want to start *any*
+firmware on the R5 cores for example autosar can be loaded to receive CAN
+response and other safety operations to be started. This operation is
+very time critical and is applicable for all automotive use cases.
+
+2. U-Boot on A53 should start other remotecores for various
+applications. This should happen before running Linux.
+
+3. In production boot flow, we might not like to use full U-Boot,
+instead use Falcon boot flow to reduce boot time.
+
+.. code-block:: text
+
+ +------------------------------------------------------------------------+
+ |        DMSC            |         R5            |        A53            |
+ +------------------------------------------------------------------------+
+ |    +--------+          |                       |                       |
+ |    |  Reset |          |                       |                       |
+ |    +--------+          |                       |                       |
+ |         :              |                       |                       |
+ |    +--------+          |   +-----------+       |                       |
+ |    | *ROM*  |----------|-->| Reset rls |       |                       |
+ |    +--------+          |   +-----------+       |                       |
+ |    |        |          |         :             |                       |
+ |    |  ROM   |          |         :             |                       |
+ |    |services|          |         :             |                       |
+ |    |        |          |   +-------------+     |                       |
+ |    |        |          |   |  *R5 ROM*   |     |                       |
+ |    |        |          |   +-------------+     |                       |
+ |    |        |<---------|---|Load and auth|     |                       |
+ |    |        |          |   | tiboot3.bin |     |                       |
+ |    |        |          |   +-------------+     |                       |
+ |    |        |          |         :             |                       |
+ |    |        |          |         :             |                       |
+ |    |        |          |         :             |                       |
+ |    |        |          |   +-------------+     |                       |
+ |    |        |          |   |  *R5 SPL*   |     |                       |
+ |    |        |          |   +-------------+     |                       |
+ |    |        |          |   |    Load     |     |                       |
+ |    |        |          |   |  sysfw.itb  |     |                       |
+ |    | Start  |          |   +-------------+     |                       |
+ |    | System |<---------|---|    Start    |     |                       |
+ |    |Firmware|          |   |    SYSFW    |     |                       |
+ |    +--------+          |   +-------------+     |                       |
+ |        :               |   |             |     |                       |
+ |    +---------+         |   |   Load      |     |                       |
+ |    | *SYSFW* |         |   |   system    |     |                       |
+ |    +---------+         |   | Config data |     |                       |
+ |    |         |<--------|---|             |     |                       |
+ |    |         |         |   +-------------+     |                       |
+ |    |         |         |   |             |     |                       |
+ |    |         |         |   |    DDR      |     |                       |
+ |    |         |         |   |   config    |     |                       |
+ |    |         |         |   +-------------+     |                       |
+ |    |         |         |   |             |     |                       |
+ |    |         |<--------|---| Start A53   |     |                       |
+ |    |         |         |   |  and Reset  |     |                       |
+ |    |         |         |   +-------------+     |                       |
+ |    |         |         |                       |     +-----------+     |
+ |    |         |---------|-----------------------|---->| Reset rls |     |
+ |    |         |         |                       |     +-----------+     |
+ |    |  DMSC   |         |                       |          :            |
+ |    |Services |         |                       |     +------------+    |
+ |    |         |<--------|-----------------------|---->|*ATF/OP-TEE*|    |
+ |    |         |         |                       |     +------------+    |
+ |    |         |         |                       |          :            |
+ |    |         |         |                       |     +-----------+     |
+ |    |         |<--------|-----------------------|---->| *A53 SPL* |     |
+ |    |         |         |                       |     +-----------+     |
+ |    |         |         |                       |     |   Load    |     |
+ |    |         |         |                       |     | u-boot.img|     |
+ |    |         |         |                       |     +-----------+     |
+ |    |         |         |                       |          :            |
+ |    |         |         |                       |     +-----------+     |
+ |    |         |<--------|-----------------------|---->| *U-Boot*  |     |
+ |    |         |         |                       |     +-----------+     |
+ |    |         |         |                       |     |  prompt   |     |
+ |    |         |         |                       |     +-----------+     |
+ |    +---------+         |                       |                       |
+ |                        |                       |                       |
+ +------------------------------------------------------------------------+
+
+- Here DMSC acts as master and provides all the critical services. R5/A53
+  requests DMSC to get these services done as shown in the above diagram.
+
+Sources:
+--------
+1. Trusted Firmware-A:
+        Tree: https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/
+        Branch: master
+
+2. OP-TEE:
+        Tree: https://github.com/OP-TEE/optee_os.git
+        Branch: master
+
+3. U-Boot:
+        Tree: https://source.denx.de/u-boot/u-boot
+        Branch: master
+
+4. TI Linux Firmware:
+        Tree: git://git.ti.com/processor-firmware/ti-linux-firmware.git
+        Branch: ti-linux-firmware
+
+Build procedure:
+----------------
+1. Trusted Firmware-A:
+
+.. code-block:: bash
+
+ $ make CROSS_COMPILE=aarch64-linux-gnu- ARCH=aarch64 PLAT=k3 \
+        TARGET_BOARD=generic SPD=opteed
+
+2. OP-TEE:
+
+.. code-block:: bash
+
+ $ make PLATFORM=k3-am65x CFG_ARM64_core=y
+
+3. U-Boot:
+
+* 4.1 R5:
+
+.. code-block:: bash
+
+ $ make am65x_evm_r5_defconfig
+ $ make CROSS_COMPILE=arm-linux-gnueabihf- \
+        BINMAN_INDIRS=<path/to/ti-linux-firmware>
+
+* 4.2 A53:
+
+.. code-block:: bash
+
+ $ make am65x_evm_a53_defconfig
+ $ make CROSS_COMPILE=aarch64-linux-gnu- \
+        BL31=<path/to/trusted-firmware-a/dir>/build/k3/generic/release/bl31.bin \
+        TEE=<path/to/optee_os/dir>/out/arm-plat-k3/core/tee-raw.bin \
+        BINMAN_INDIRS=<path/to/ti-linux-firmware>
+
+Target Images
+--------------
+Copy the below images to an SD card and boot:
+
+- GP
+
+        * tiboot3-am65x_sr2-gp-evm.bin, sysfw-am65x_sr2-gp-evm.itb from step 4.1
+        * tispl.bin_unsigned, u-boot.img_unsigned from step 4.2
+
+- HS
+
+        * tiboot3-am65x_sr2-hs-evm.bin, sysfw-am65x_sr2-hs-evm.itb from step 4.1
+        * tispl.bin, u-boot.img from step 4.2
+
+Image formats:
+--------------
+
+- tiboot3.bin:
+
+.. code-block:: text
+
+                +-----------------------+
+                |        X.509          |
+                |      Certificate      |
+                | +-------------------+ |
+                | |                   | |
+                | |        R5         | |
+                | |   u-boot-spl.bin  | |
+                | |                   | |
+                | +-------------------+ |
+                | |                   | |
+                | |     FIT header    | |
+                | | +---------------+ | |
+                | | |               | | |
+                | | |   DTB 1...N   | | |
+                | | +---------------+ | |
+                | +-------------------+ |
+                +-----------------------+
+
+- tispl.bin
+
+.. code-block:: text
+
+                +-----------------------+
+                |                       |
+                |       FIT HEADER      |
+                | +-------------------+ |
+                | |                   | |
+                | |      A53 ATF      | |
+                | +-------------------+ |
+                | |                   | |
+                | |     A53 OP-TEE    | |
+                | +-------------------+ |
+                | |                   | |
+                | |      A53 SPL      | |
+                | +-------------------+ |
+                | |                   | |
+                | |   SPL DTB 1...N   | |
+                | +-------------------+ |
+                +-----------------------+
+
+- sysfw.itb
+
+.. code-block:: text
+
+                +-----------------------+
+                |                       |
+                |       FIT HEADER      |
+                | +-------------------+ |
+                | |                   | |
+                | |     sysfw.bin     | |
+                | +-------------------+ |
+                | |                   | |
+                | |    board config   | |
+                | +-------------------+ |
+                | |                   | |
+                | |     PM config     | |
+                | +-------------------+ |
+                | |                   | |
+                | |     RM config     | |
+                | +-------------------+ |
+                | |                   | |
+                | |    Secure config  | |
+                | +-------------------+ |
+                +-----------------------+
+
+eMMC:
+-----
+ROM supports booting from eMMC from boot0 partition offset 0x0
+
+Flashing images to eMMC:
+
+The following commands can be used to download tiboot3.bin, tispl.bin,
+u-boot.img, and sysfw.itb from an SD card and write them to the eMMC boot0
+partition at respective addresses.
+
+.. code-block:: text
+
+ => mmc dev 0 1
+ => fatload mmc 1 ${loadaddr} tiboot3.bin
+ => mmc write ${loadaddr} 0x0 0x400
+ => fatload mmc 1 ${loadaddr} tispl.bin
+ => mmc write ${loadaddr} 0x400 0x1000
+ => fatload mmc 1 ${loadaddr} u-boot.img
+ => mmc write ${loadaddr} 0x1400 0x2000
+ => fatload mmc 1 ${loadaddr} sysfw.itb
+ => mmc write ${loadaddr} 0x3600 0x800
+
+To give the ROM access to the boot partition, the following commands must be
+used for the first time:
+
+.. code-block:: text
+
+ => mmc partconf 0 1 1 1
+ => mmc bootbus 0 1 0 0
+
+To create a software partition for the rootfs, the following command can be
+used:
+
+.. code-block:: text
+
+ => gpt write mmc 0 ${partitions}
+
+eMMC layout:
+
+.. code-block:: text
+
+            boot0 partition (8 MB)                        user partition
+    0x0+----------------------------------+      0x0+-------------------------+
+       |     tiboot3.bin (512 KB)         |         |                         |
+  0x400+----------------------------------+         |                         |
+       |       tispl.bin (2 MB)           |         |                         |
+ 0x1400+----------------------------------+         |        rootfs           |
+       |       u-boot.img (4 MB)          |         |                         |
+ 0x3400+----------------------------------+         |                         |
+       |      environment (128 KB)        |         |                         |
+ 0x3500+----------------------------------+         |                         |
+       |   backup environment (128 KB)    |         |                         |
+ 0x3600+----------------------------------+         |                         |
+       |          sysfw (1 MB)            |         |                         |
+ 0x3E00+----------------------------------+         +-------------------------+
+
+Kernel image and DT are expected to be present in the /boot folder of rootfs.
+To boot kernel from eMMC, use the following commands:
+
+.. code-block:: text
+
+ => setenv mmcdev 0
+ => setenv bootpart 0
+ => boot
+
+OSPI:
+-----
+ROM supports booting from OSPI from offset 0x0.
+
+Flashing images to OSPI:
+
+Below commands can be used to download tiboot3.bin, tispl.bin, u-boot.img,
+and sysfw.itb over tftp and then flash those to OSPI at their respective
+addresses.
+
+.. code-block:: text
+
+ => sf probe
+ => tftp ${loadaddr} tiboot3.bin
+ => sf update $loadaddr 0x0 $filesize
+ => tftp ${loadaddr} tispl.bin
+ => sf update $loadaddr 0x80000 $filesize
+ => tftp ${loadaddr} u-boot.img
+ => sf update $loadaddr 0x280000 $filesize
+ => tftp ${loadaddr} sysfw.itb
+ => sf update $loadaddr 0x6C0000 $filesize
+
+Flash layout for OSPI:
+
+.. code-block:: text
+
+         0x0 +----------------------------+
+             |     ospi.tiboot3(512K)     |
+             |                            |
+     0x80000 +----------------------------+
+             |     ospi.tispl(2M)         |
+             |                            |
+    0x280000 +----------------------------+
+             |     ospi.u-boot(4M)        |
+             |                            |
+    0x680000 +----------------------------+
+             |     ospi.env(128K)         |
+             |                            |
+    0x6A0000 +----------------------------+
+             |   ospi.env.backup (128K)   |
+             |                            |
+    0x6C0000 +----------------------------+
+             |      ospi.sysfw(1M)        |
+             |                            |
+    0x7C0000 +----------------------------+
+             |      padding (256k)        |
+    0x800000 +----------------------------+
+             |     ospi.rootfs(UBIFS)     |
+             |                            |
+             +----------------------------+
+
+Kernel Image and DT are expected to be present in the /boot folder of UBIFS
+ospi.rootfs just like in SD card case. U-Boot looks for UBI volume named
+"rootfs" for rootfs.
+
+To boot kernel from OSPI, at the U-Boot prompt:
+
+.. code-block:: text
+
+ => setenv boot ubi
+ => boot
+
+UART:
+-----
+ROM supports booting from MCU_UART0 via X-Modem protocol. The entire UART-based
+boot process up to U-Boot (proper) prompt goes through different stages and uses
+different UART peripherals as follows:
+
+.. code-block:: text
+
+ +---------+---------------+-------------+------------+
+ | WHO     | Loading WHAT  |  HW Module  |  Protocol  |
+ +---------+---------------+-------------+------------+
+ |Boot ROM |  tiboot3.bin  |  MCU_UART0  |  X-Modem(*)|
+ |R5 SPL   |  sysfw.itb    |  MCU_UART0  |  Y-Modem(*)|
+ |R5 SPL   |  tispl.bin    |  MAIN_UART0 |  Y-Modem   |
+ |A53 SPL  |  u-boot.img   |  MAIN_UART0 |  Y-Modem   |
+ +---------+---------------+-------------+------------+
+
+Note that in addition to X/Y-Modem related protocol timeouts the DMSC
+watchdog timeout of 3min (typ.) needs to be observed until System Firmware
+is fully loaded (from sysfw.itb) and started.
+
+Example bash script sequence for running on a Linux host PC feeding all boot
+artifacts needed to the device:
+
+.. code-block:: text
+
+ MCU_DEV=/dev/ttyUSB1
+ MAIN_DEV=/dev/ttyUSB0
+
+ stty -F $MCU_DEV 115200 cs8 -cstopb -parenb
+ stty -F $MAIN_DEV 115200 cs8 -cstopb -parenb
+
+ sb --xmodem tiboot3.bin > $MCU_DEV < $MCU_DEV
+ sb --ymodem sysfw.itb > $MCU_DEV < $MCU_DEV
+ sb --ymodem tispl.bin > $MAIN_DEV < $MAIN_DEV
+ sleep 1
+ sb --xmodem u-boot.img > $MAIN_DEV < $MAIN_DEV