qualcomm/dragonboard410c/readme.txt

4 # SPDX-License-Identifier:	GPL-2.0+
11 2) Setup CROSS_COMPILE to aarch64 compiler
14 5) generate fake, empty ramdisk (can have 0 bytes)
18 $ dtbTool -o dt.img arch/arm/dts
20 7) Generate Android boot image with mkbootimg [2]:
21 $ mkbootimg --kernel=u-boot-dtb.bin --output=u-boot.img --dt=dt.img  \
22   --pagesize 2048 --base 0x80000000 --ramdisk=rd --cmdline=""
24 8) Enter fastboot (reboot board with vol- button pressed)
27 $ fastboot boot u-boot.img
29 $ fastboot flash boot u-boot.img
34 - UART
35 - GPIO (SoC)
36 - SD
37 - eMMC
38 - Reset
39 - USB in EHCI mode (usb starts does switch device->host, usb stop does the opposite)
40 - PMIC GPIOS (but not in generic subsystem)
41 - PMIC "special" buttons (power, vol-)
44 - SDHCI is slow (~2.5MiB/s for SD and eMMC)
49 Full device tree is not required to boot u-boot. Enough would be:
50 /dts-v1/;
53 	model = "Qualcomm Technologies, Inc. Dragonboard 410c";
54 	compatible = "qcom,dragonboard", "qcom,apq8016-sbc";
55 	qcom,msm-id = <0xce 0x0 0xf8 0x0 0xf9 0x0 0xfa 0x0 0xf7 0x0>;
56 	qcom,board-id = <0x10018 0x0>;
57 	#address-cells = <0x2>;
58 	#size-cells = <0x2>;
64 		reg = <0 0x80000000 0 0x3da00000>;
71 [2] Note that ramdisk is required, even if it is unused.