[PATCH v3][ 6/6] boards: tbs2910: add README

[Denis 'GNUtoo' Carikli]

The installation documentation make use of the
"BOOT/UPDATE" mechanism that is documented in the TBS2910
OS installation manual[1].

This is to make sure that they work on the different PCB
revisions of this board.

There is also a boot configuration switch (SW6) but the
one described in the v2.1 schematics has 8 switches whereas
the one present on the v2.3 board has only 4.

Only the v2.1 board schematics are available.

[1]https://www.tbsdtv.com/download/document/tbs2910/How-to-burn-a-new-OS-into-eMMC-on-Matrix-V2.0.pdf

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo at cyberdimension.org>
---
 board/tbs/tbs2910/README | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 board/tbs/tbs2910/README

diff --git a/board/tbs/tbs2910/README b/board/tbs/tbs2910/README
new file mode 100644
index 0000000000..6562897e21
--- /dev/null
+++ b/board/tbs/tbs2910/README
@@ -0,0 +1,37 @@
+How to use U-Boot on the TBS2910
+--------------------------------
+
+Configure and build U-boot for the TBS2910:
+    $ make mrproper
+    $ make tbs2910_defconfig
+    $ make
+
+This will generate the u-boot.imx image.
+
+UART:
+- The UART voltage is at 3.3V and its settings are 115200bps 8N1
+
+Boot from eMMC:
+- Once the board is booted, flash u-boot.imx to mmcblk0boot0:
+    $ sudo echo 0 >/sys/block/mmcblk0boot0/force_ro
+    $ sudo dd if=u-boot.imx of=/dev/mmcblk0boot0 bs=1k seek=1; sync
+  Note that the eMMC card node may vary, so adjust this as needed.
+- Power off the board
+- Make sure that the boot switch is set to "BOOT"
+- Connect the UART cable to the host PC
+- Power up the board and U-Boot messages will appear in the serial console.
+
+Boot from USB:
+- Build imx_usb_loader
+    $ git clone git://github.com/boundarydevices/imx_usb_loader.git
+    $ cd imx_usb_loader
+    $ make
+- Copy u-boot.imx in the imx_usb_loader directory
+- Power off the board
+- Make sure that the boot switch is set to "UPDATE"
+- Connect an USB cable to the host PC
+- Connect the UART cable to the host PC
+- Power on the board
+- Load u-boot.img through USB with imx_usb:
+  $ sudo ./imx_usb -v u-boot.imx
+- U-Boot messages will appear in the serial console
\ No newline at end of file
-- 
2.25.0