board: rockchip: Add Radxa ROCK S0

Radxa ROCK S0 is a single-board computer based on the Rockchip RK3308B
SoC in an ultra-compact form factor. Add a board target for the board.

Features tested on a ROCK S0 v1.2 with 512 MiB RAM and 8 GiB eMMC:
- SD-card boot
- eMMC boot
- Ethernet
- USB gadget
- USB host

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/rock-s0-rk3308_defconfig b/configs/rock-s0-rk3308_defconfig
new file mode 100644
index 0000000..074ec4c
--- /dev/null
+++ b/configs/rock-s0-rk3308_defconfig
@@ -0,0 +1,72 @@
+CONFIG_ARM=y
+CONFIG_SKIP_LOWLEVEL_INIT=y
+CONFIG_COUNTER_FREQUENCY=24000000
+CONFIG_ARCH_ROCKCHIP=y
+CONFIG_DEFAULT_DEVICE_TREE="rockchip/rk3308-rock-s0"
+CONFIG_DM_RESET=y
+CONFIG_ROCKCHIP_RK3308=y
+CONFIG_TARGET_EVB_RK3308=y
+CONFIG_DEBUG_UART_BASE=0xFF0A0000
+CONFIG_DEBUG_UART_CLOCK=24000000
+# CONFIG_DEBUG_UART_BOARD_INIT is not set
+CONFIG_SYS_LOAD_ADDR=0xc00800
+CONFIG_DEBUG_UART=y
+CONFIG_ANDROID_BOOT_IMAGE=y
+CONFIG_FIT=y
+CONFIG_FIT_VERBOSE=y
+CONFIG_DEFAULT_FDT_FILE="rockchip/rk3308-rock-s0.dtb"
+# CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_SPL_MAX_SIZE=0x40000
+CONFIG_SPL_PAD_TO=0x7f8000
+# CONFIG_SPL_RAW_IMAGE_SUPPORT is not set
+CONFIG_CMD_GPIO=y
+CONFIG_CMD_GPT=y
+CONFIG_CMD_MMC=y
+CONFIG_CMD_USB=y
+CONFIG_CMD_ROCKUSB=y
+CONFIG_CMD_USB_MASS_STORAGE=y
+CONFIG_CMD_RNG=y
+CONFIG_CMD_KASLRSEED=y
+CONFIG_CMD_REGULATOR=y
+CONFIG_SPL_OF_CONTROL=y
+CONFIG_OF_LIVE=y
+CONFIG_OF_SPL_REMOVE_PROPS="clock-names interrupt-parent assigned-clocks assigned-clock-rates assigned-clock-parents"
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_REGMAP=y
+CONFIG_SYSCON=y
+CONFIG_CLK=y
+# CONFIG_USB_FUNCTION_FASTBOOT is not set
+CONFIG_ROCKCHIP_GPIO=y
+CONFIG_SYS_I2C_ROCKCHIP=y
+CONFIG_LED=y
+CONFIG_LED_GPIO=y
+CONFIG_ROCKCHIP_IODOMAIN=y
+CONFIG_SUPPORT_EMMC_RPMB=y
+CONFIG_MMC_DW=y
+CONFIG_MMC_DW_ROCKCHIP=y
+CONFIG_PHY_REALTEK=y
+CONFIG_DM_MDIO=y
+CONFIG_DM_ETH_PHY=y
+CONFIG_ETH_DESIGNWARE=y
+CONFIG_GMAC_ROCKCHIP=y
+CONFIG_PHY_ROCKCHIP_INNO_USB2=y
+CONFIG_PINCTRL=y
+CONFIG_REGULATOR_PWM=y
+CONFIG_DM_REGULATOR_FIXED=y
+CONFIG_PWM_ROCKCHIP=y
+CONFIG_RAM=y
+CONFIG_BAUDRATE=1500000
+CONFIG_DEBUG_UART_SHIFT=2
+CONFIG_SYS_NS16550_MEM32=y
+CONFIG_SYSINFO=y
+CONFIG_SYSRESET=y
+CONFIG_USB=y
+CONFIG_DM_USB_GADGET=y
+CONFIG_USB_EHCI_HCD=y
+CONFIG_USB_EHCI_GENERIC=y
+CONFIG_USB_GADGET=y
+CONFIG_USB_GADGET_DWC2_OTG=y
+CONFIG_USB_GADGET_DOWNLOAD=y
+CONFIG_USB_FUNCTION_ROCKUSB=y
+CONFIG_LZO=y
+CONFIG_ERRNO_STR=y