doc: boards: amlogic: update documentation for Khadas VIM3L

Improve documentation.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Link: https://lore.kernel.org/r/20230320114609.930145-12-christianshewitt@gmail.com
[narmstrong: fixed doc build]
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
diff --git a/doc/board/amlogic/khadas-vim3l.rst b/doc/board/amlogic/khadas-vim3l.rst
index 692ab3d..cd21466 100644
--- a/doc/board/amlogic/khadas-vim3l.rst
+++ b/doc/board/amlogic/khadas-vim3l.rst
@@ -1,10 +1,10 @@
 .. SPDX-License-Identifier: GPL-2.0+
 
-U-Boot for Khadas VIM3L
-=======================
+U-Boot for Khadas VIM3L (S905D3)
+================================
 
-Khadas VIM3L is a single board computer manufactured by Shenzhen Wesion
-Technology Co., Ltd. with the following specifications:
+Khadas VIM3L is a Single Board Computer manufactured by Shenzhen Wesion Technology Co. Ltd
+with the following specifications:
 
  - Amlogic S905D3 Arm Cortex-A55 quad-core SoC
  - 2GB LPDDR4 SDRAM
@@ -20,32 +20,27 @@
 
 PCIe Setup
 ----------
-The VIM3 on-board  MCU can mux the PCIe/USB3.0 shared differential
-lines using a FUSB340TMX USB 3.1 SuperSpeed Data Switch between
-an USB3.0 Type A connector and a M.2 Key M slot.
-The PHY driving these differential lines is shared between
-the USB3.0 controller and the PCIe Controller, thus only
-a single controller can use it.
 
-To setup for PCIe, run the following commands from U-Boot:
+The on-board MCU can mux the PCIe/USB3.0 shared differential lines using a FUSB340TMX USB
+3.1 SuperSpeed Data Switch between a USB3.0 Type-A connector and an M.2 Key-M slot. The
+PHY driving these differential lines is shared between the USB3.0 controller and the PCIe
+Controller, thus only a single controller can use it.
+
+To setup for PCIe run the following commands from U-Boot then power-cycle the board:
 
 .. code-block:: none
 
     i2c dev i2c@5000
     i2c mw 0x18 0x33 1
 
-Then power-cycle the board.
-
-To set back to USB3.0, run the following commands from U-Boot:
+To revert to USB3.0 run the following commands from U-Boot then power-cycle the board:
 
 .. code-block:: none
 
     i2c dev i2c@5000
     i2c mw 0x18 0x33 0
 
-Then power-cycle the board.
-
-U-Boot compilation
+U-Boot Compilation
 ------------------
 
 .. code-block:: bash
@@ -54,14 +49,21 @@
     $ make khadas-vim3l_defconfig
     $ make
 
-Image creation
---------------
+U-Boot Signing with Pre-Built FIP repo
+--------------------------------------
 
-For simplified usage, pleaser refer to :doc:`pre-generated-fip` with codename `khadas-vim3l`
+.. code-block:: bash
 
-Amlogic doesn't provide sources for the firmware and for tools needed
-to create the bootloader image, so it is necessary to obtain them from
-the git tree published by the board vendor:
+    $ git clone https://github.com/LibreELEC/amlogic-boot-fip --depth=1
+    $ cd amlogic-boot-fip
+    $ mkdir my-output-dir
+    $ ./build-fip.sh khadas-vim3l /path/to/u-boot/u-boot.bin my-output-dir
+
+U-Boot Manual Signing
+---------------------
+
+Amlogic does not provide sources for the firmware and tools needed to create a bootloader
+image so it is necessary to obtain binaries from sources published by the board vendor:
 
 .. code-block:: bash
 
@@ -72,16 +74,14 @@
     $ export PATH=$PWD/gcc-linaro-aarch64-none-elf-4.8-2013.11_linux/bin:$PWD/gcc-linaro-arm-none-eabi-4.8-2013.11_linux/bin:$PATH
 
     $ DIR=vim3l-u-boot
-    $ git clone --depth 1 \
-       https://github.com/khadas/u-boot.git -b khadas-vims-v2015.01 \
-       $DIR
+    $ git clone --depth 1 https://github.com/khadas/u-boot.git -b khadas-vims-v2015.01 $DIR
 
     $ cd vim3l-u-boot
     $ make kvim3l_defconfig
     $ make CROSS_COMPILE=aarch64-none-elf-
     $ export UBOOTDIR=$PWD
 
-Go back to mainline U-Boot source tree then :
+Go back to the mainline U-Boot source tree then:
 
 .. code-block:: bash
 
@@ -105,58 +105,58 @@
     $ cp u-boot.bin fip/bl33.bin
 
     $ bash fip/blx_fix.sh \
-    	fip/bl30.bin \
-    	fip/zero_tmp \
-    	fip/bl30_zero.bin \
-    	fip/bl301.bin \
-    	fip/bl301_zero.bin \
-    	fip/bl30_new.bin \
-    	bl30
+           fip/bl30.bin \
+           fip/zero_tmp \
+           fip/bl30_zero.bin \
+           fip/bl301.bin \
+           fip/bl301_zero.bin \
+           fip/bl30_new.bin \
+           bl30
 
     $ bash fip/blx_fix.sh \
-    	fip/bl2.bin \
-    	fip/zero_tmp \
-    	fip/bl2_zero.bin \
-    	fip/acs.bin \
-    	fip/bl21_zero.bin \
-    	fip/bl2_new.bin \
-    	bl2
+           fip/bl2.bin \
+           fip/zero_tmp \
+           fip/bl2_zero.bin \
+           fip/acs.bin \
+           fip/bl21_zero.bin \
+           fip/bl2_new.bin \
+           bl2
 
     $ $UBOOTDIR/fip/g12a/aml_encrypt_g12a --bl30sig --input fip/bl30_new.bin \
-    					--output fip/bl30_new.bin.g12a.enc \
-    					--level v3
+                                          --output fip/bl30_new.bin.g12a.enc \
+                                          --level v3
     $ $UBOOTDIR/fip/g12a/aml_encrypt_g12a --bl3sig --input fip/bl30_new.bin.g12a.enc \
-    					--output fip/bl30_new.bin.enc \
-    					--level v3 --type bl30
+                                          --output fip/bl30_new.bin.enc \
+                                          --level v3 --type bl30
     $ $UBOOTDIR/fip/g12a/aml_encrypt_g12a --bl3sig --input fip/bl31.img \
-    					--output fip/bl31.img.enc \
-    					--level v3 --type bl31
+                                          --output fip/bl31.img.enc \
+                                          --level v3 --type bl31
     $ $UBOOTDIR/fip/g12a/aml_encrypt_g12a --bl3sig --input fip/bl33.bin --compress lz4 \
-    					--output fip/bl33.bin.enc \
-    					--level v3 --type bl33 --compress lz4
+                                          --output fip/bl33.bin.enc \
+                                          --level v3 --type bl33 --compress lz4
     $ $UBOOTDIR/fip/g12a/aml_encrypt_g12a --bl2sig --input fip/bl2_new.bin \
-    					--output fip/bl2.n.bin.sig
+                                          --output fip/bl2.n.bin.sig
     $ $UBOOTDIR/fip/g12a/aml_encrypt_g12a --bootmk \
-    		--output fip/u-boot.bin \
-    		--bl2 fip/bl2.n.bin.sig \
-    		--bl30 fip/bl30_new.bin.enc \
-    		--bl31 fip/bl31.img.enc \
-    		--bl33 fip/bl33.bin.enc \
-    		--ddrfw1 fip/ddr4_1d.fw \
-    		--ddrfw2 fip/ddr4_2d.fw \
-    		--ddrfw3 fip/ddr3_1d.fw \
-    		--ddrfw4 fip/piei.fw \
-    		--ddrfw5 fip/lpddr4_1d.fw \
-    		--ddrfw6 fip/lpddr4_2d.fw \
-    		--ddrfw7 fip/diag_lpddr4.fw \
-    		--ddrfw8 fip/aml_ddr.fw \
-    		--ddrfw9 fip/lpddr3_1d.fw \
-    		--level v3
+                                          --output fip/u-boot.bin \
+                                          --bl2 fip/bl2.n.bin.sig \
+                                          --bl30 fip/bl30_new.bin.enc \
+                                          --bl31 fip/bl31.img.enc \
+                                          --bl33 fip/bl33.bin.enc \
+                                          --ddrfw1 fip/ddr4_1d.fw \
+                                          --ddrfw2 fip/ddr4_2d.fw \
+                                          --ddrfw3 fip/ddr3_1d.fw \
+                                          --ddrfw4 fip/piei.fw \
+                                          --ddrfw5 fip/lpddr4_1d.fw \
+                                          --ddrfw6 fip/lpddr4_2d.fw \
+                                          --ddrfw7 fip/diag_lpddr4.fw \
+                                          --ddrfw8 fip/aml_ddr.fw \
+                                          --ddrfw9 fip/lpddr3_1d.fw \
+                                          --level v3
 
-and then write the image to SD with:
+Then write U-Boot to SD or eMMC with:
 
 .. code-block:: bash
 
-    $ DEV=/dev/your_sd_device
+    $ DEV=/dev/boot_device
     $ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=512 skip=1 seek=1
-    $ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=1 count=444
+    $ dd if=fip/u-boot.bin.sd.bin of=$DEV conv=fsync,notrunc bs=1 count=440