rk3288: vyasa: Add TPL support

Since the size of SPL can't be exceeded 0x8000 bytes in RK3288,
it is not possible add new SPL features like Falcon mode or etc.

So add TPL stage so-that adding new features to SPL is possible.
- TPL: DRAM init, clocks
- SPL: MMC, falcon, etc

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/doc/README.rockchip b/doc/README.rockchip
index 12fec38..4b7be0b 100644
--- a/doc/README.rockchip
+++ b/doc/README.rockchip
@@ -150,6 +150,24 @@
       debug uart must be disabled
 
 
+Booting from an SD card on RK3288 with TPL
+==========================================
+
+Since the size of SPL can't be exceeded 0x8000 bytes in RK3288, it is not possible add
+new SPL features like Falcon mode or etc.
+
+So introduce TPL so-that adding new features to SPL is possible because now TPL should
+run minimal with code like DDR, clock etc and rest of new features in SPL.
+
+As of now TPL is added on Vyasa-RK3288 board.
+
+To write an image that boots from an SD card (assumed to be /dev/mmcblk0):
+
+   ./tools/mkimage -n rk3288 -T rksd -d ./tpl/u-boot-tpl.bin out &&
+    cat ./spl/u-boot-spl-dtb.bin >> out &&
+    sudo dd if=out of=/dev/mmcblk0 seek=64 &&
+    sudo dd if=u-boot-dtb.img of=/dev/mmcblk0 seek=256
+
 Booting from an SD card on RK3188
 =================================