rockchip: add option to change method of loading u-boot
If we would like to boot from SD card, we have to implement mmc driver
in SPL stage, and get a slightly large SPL binary. Rockchip SoC's
bootrom code has the ability to load spl and u-boot, then boot.
If CONFIG_ROCKCHIP_SPL_BACK_TO_BROM is enabled, the spl will return to
bootrom in board_init_f(), then bootrom loads u-boot binary.
Loading sequence after rework:
bootrom ==> spl ==> bootrom ==> u-boot
Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
Fixed up spelling of U-Boot, boorom, opinion->option, Rochchip:
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.rockchip b/doc/README.rockchip
index e0572c8..182e3ae 100644
--- a/doc/README.rockchip
+++ b/doc/README.rockchip
@@ -119,6 +119,20 @@
Hit any key to stop autoboot: 0
=>
+The rockchip bootrom can load and boot an initial spl, then continue to
+load a second-level bootloader(ie. U-BOOT) as soon as it returns to bootrom.
+Therefore RK3288 has another loading sequence like RK3036. The option of
+U-Boot is controlled with this setting in U-Boot:
+
+ #define CONFIG_ROCKCHIP_SPL_BACK_TO_BROM
+
+You can create the image via the following operations:
+
+ ./firefly-rk3288/tools/mkimage -n rk3288 -T rksd -d \
+ firefly-rk3288/spl/u-boot-spl-dtb.bin out && \
+ cat firefly-rk3288/u-boot-dtb.bin >> out && \
+ sudo dd if=out of=/dev/sdc seek=64
+
If you have an HDMI cable attached you should see a video console.
For evb_rk3036 board: