rockchip: add support for Radxa ROCK Pi S

Radxa ROCK Pi S is a small in size, full in features SBC[1] using the
Rockchip RK3308B SoC.

Hardware
--------
- Rockchip RK3308B SoC
- Quad A35 CPU
- 256/512MB DDR3 RAM
- Optional 4/8GB eMMC
- Micro SD Card slot
- Optional WiFi 4 and BT 4 (not supported yet)
- 1x 100M Ethernet with PoE support (additional PoE HAT required)
- 1x USB 2.0 Type-A port (Host)
- 1x USB 2.0 Type-C port (OTG)
- 2x 26 Pin GPIO header

[1] https://radxa.com/products/rockpi/pis

Installation
------------
Uncompress the OpenWrt sysupgrade and write it to a micro SD card or
internal eMMC using dd.

Signed-off-by: FUKAUMI Naoki <naoki@radxa.com>
Link: https://github.com/openwrt/openwrt/pull/15933
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

package/boot/rkbin/Makefile

@@ -25,6 +25,19 @@ define Trusted-Firmware-A/Default
   BUILD_TARGET:=rockchip
 endef
 
+define Trusted-Firmware-A/rk3308
+  BUILD_SUBTARGET:=armv8
+  ATF:=rk33/rk3308_bl31_v2.26.elf
+  TPL:=rk33/rk3308_ddr_589MHz_uart2_m1_v2.07.bin
+endef
+
+define Trusted-Firmware-A/rk3308-rock-pi-s
+  NAME:=Radxa ROCK Pi S
+  BUILD_SUBTARGET:=armv8
+  ATF:=rk33/rk3308_bl31_v2.26.elf
+  TPL:=rk33/rk3308_ddr_589MHz_uart0_m0_v2.07.bin
+endef
+
 define Trusted-Firmware-A/rk3566
   BUILD_SUBTARGET:=armv8
   ATF:=rk35/rk3568_bl31_v1.44.elf
@@ -45,10 +58,28 @@ define Trusted-Firmware-A/rk3568-e25
 endef
 
 TFA_TARGETS:= \
+	rk3308 \
+	rk3308-rock-pi-s \
 	rk3566 \
 	rk3568 \
 	rk3568-e25
 
+ifeq ($(BUILD_VARIANT),rk3308-rock-pi-s)
+  TPL_FILE:=rk3308_ddr_589MHz_uart0_m0_v2.07.bin
+  define Download/rk3308-tpl-rock-pi-s
+    FILE:=$(TPL_FILE)
+    URL:=https://github.com/radxa/rkbin/raw/5696fab20dcac57c1458f72dc7604ba60e553adf/bin/rk33/
+    HASH:=8a1a42df23cccb86a2dabc14a5c0e9227d64a51b9b83e9968ef5af3b30787f7d
+  endef
+
+  define Build/Prepare
+	$(eval $(call Download,rk3308-tpl-rock-pi-s))
+	$(call Build/Prepare/Default)
+
+	$(CP) $(DL_DIR)/$(TPL_FILE) $(PKG_BUILD_DIR)/bin/rk33/
+  endef
+endif
+
 ifeq ($(BUILD_VARIANT),rk3568-e25)
   TPL_FILE:=rk3568_ddr_1560MHz_uart2_m0_115200_v1.21.bin
   define Download/rk3568-tpl-e25

package/boot/uboot-rockchip/Makefile

@@ -24,6 +24,24 @@ define U-Boot/Default
 endef
 
 
+# RK3308 boards
+
+define U-Boot/rk3308/Default
+  BUILD_SUBTARGET:=armv8
+  DEPENDS:=+PACKAGE_u-boot-$(1):trusted-firmware-a-rk3308
+  ATF:=rk3308_bl31_v2.26.elf
+  TPL:=rk3308_ddr_589MHz_uart2_m1_v2.07.bin
+endef
+
+define U-Boot/rock-pi-s-rk3308
+  $(U-Boot/rk3308/Default)
+  DEPENDS:=+PACKAGE_u-boot-$(1):trusted-firmware-a-rk3308-rock-pi-s
+  TPL:=rk3308_ddr_589MHz_uart0_m0_v2.07.bin
+  NAME:=ROCK Pi S
+  BUILD_DEVICES:= \
+    radxa_rock-pi-s
+endef
+
 # RK3328 boards
 
 define U-Boot/rk3328/Default
@@ -186,6 +204,7 @@ UBOOT_TARGETS := \
   nanopi-r4s-rk3399 \
   rock-pi-4-rk3399 \
   rockpro64-rk3399 \
+  rock-pi-s-rk3308 \
   nanopi-r2c-rk3328 \
   nanopi-r2c-plus-rk3328 \
   nanopi-r2s-rk3328 \