doc: boards: amlogic: update documentation for ODROID-N2/N2+

Improve documentation. Notably mention the ODROID-N2+ and the option
to use FDTDIR not FDT for automatic device-tree selection.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Link: https://lore.kernel.org/r/20230320114609.930145-19-christianshewitt@gmail.com
[narmstrong: fixed doc build]
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

1 files changed, 66 insertions, 57 deletions

diff --git a/doc/board/amlogic/odroid-n2.rst b/doc/board/amlogic/odroid-n2.rst
index 7aad36e..883720f 100644
--- a/doc/board/amlogic/odroid-n2.rst
+++ b/doc/board/amlogic/odroid-n2.rst
@@ -1,10 +1,10 @@
 .. SPDX-License-Identifier: GPL-2.0+
 
-U-Boot for ODROID-N2
-====================
+U-Boot for ODROID-N2/N2+ (S922X)
+================================
 
-ODROID-N2 is a single board computer manufactured by Hardkernel
-Co. Ltd with the following specifications:
+ODROID-N2 and ODROID-N2+ are a Single Board Computers manufactured by Hardkernel with the
+following specifications:
 
  - Amlogic S922X ARM Cortex-A53 dual-core + Cortex-A73 quad-core SoC
  - 4GB DDR4 SDRAM
@@ -15,9 +15,13 @@ Co. Ltd with the following specifications:
  - eMMC, microSD
  - Infrared receiver
 
-Schematics are available on the manufacturer website.
+ODROID-N2+ uses Rev-C silicon allowing higher CPU opp-points. U-Boot contains logic to
+read the model detail from SARADC and select the correct device-tree file if FDTDIR is
+used instead of an FDT reference to a specfic device-tree.
 
-U-Boot compilation
+Schematics are available on the manufacturer website: https://wiki.odroid.com
+
+U-Boot Compilation
 ------------------
 
 .. code-block:: bash
@@ -26,14 +30,21 @@ U-Boot compilation
     $ make odroid-n2_defconfig
     $ make
 
-Image creation
---------------
+U-Boot Signing with Pre-Built FIP repo
+--------------------------------------
+
+.. code-block:: bash
+
+    $ git clone https://github.com/LibreELEC/amlogic-boot-fip --depth=1
+    $ cd amlogic-boot-fip
+    $ mkdir my-output-dir
+    $ ./build-fip.sh odroid-n2 /path/to/u-boot/u-boot.bin my-output-dir
 
-For simplified usage, pleaser refer to :doc:`pre-generated-fip` with codename `odroid-n2` or `odroid-n2-plus`
+U-Boot Manual Signing
+---------------------
 
-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:
+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
 
@@ -44,16 +55,14 @@ the git tree published by the board vendor:
     $ 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=odroid-n2
-    $ git clone --depth 1 \
-       https://github.com/hardkernel/u-boot.git -b odroidn2-v2015.01 \
-       $DIR
+    $ git clone --depth 1 https://github.com/hardkernel/u-boot.git -b odroidn2-v2015.01 $DIR
 
     $ cd odroid-n2
     $ make odroidn2_defconfig
     $ make
     $ 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
 
@@ -76,57 +85,57 @@ the git tree published by the board vendor:
     $ cp u-boot.bin fip/bl33.bin
 
     $ sh 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
 
     $ sh 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/g12b/aml_encrypt_g12b --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/g12b/aml_encrypt_g12b --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/g12b/aml_encrypt_g12b --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/g12b/aml_encrypt_g12b --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/g12b/aml_encrypt_g12b --bl2sig --input fip/bl2_new.bin \
-    					--output fip/bl2.n.bin.sig
+                                          --output fip/bl2.n.bin.sig
     $ $UBOOTDIR/fip/g12b/aml_encrypt_g12b --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 \
-    		--level v3
-
-and then write the image to SD with:
+                                          --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 \
+                                          --level v3
+
+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