u-boot/board/qualcomm/dragonboard410c
Ramon Fried aa043ee91a db410c: automatically launch fastboot
If during boot the key-vol-down press is detected
we'll fall back to fastboot.

Signed-off-by: Ramon Fried <ramon.fried@gmail.com>
2018-09-30 13:00:37 -04:00
..
dragonboard410c.c db410c: automatically launch fastboot 2018-09-30 13:00:37 -04:00
head.S SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
Kconfig
lowlevel_init.S SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
MAINTAINERS MAINTAINERS: Take over DB410c maintainership 2018-06-04 11:25:30 -04:00
Makefile SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
readme.txt SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
u-boot.lds efi_loader: Rename sections to allow for implicit data 2018-07-25 14:57:44 +02:00

# SPDX-License-Identifier: GPL-2.0+
#
# (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>

Build & Run instructions:

1) Install mkbootimg and dtbTool from
   git://codeaurora.org/quic/kernel/skales (15ece94f09 worked for me)
2) Setup CROSS_COMPILE to aarch64 compiler
3) make dragonboard410c_config
4) make
5) generate fake, empty ramdisk (can have 0 bytes)
$ touch rd

6) Generate qualcomm device tree table with dtbTool [1]
$ dtbTool -o dt.img arch/arm/dts

7) Generate Android boot image with mkbootimg [2]:
$ mkbootimg --kernel=u-boot-dtb.bin --output=u-boot.img --dt=dt.img  \
  --pagesize 2048 --base 0x80000000 --ramdisk=rd --cmdline=""

8) Enter fastboot (reboot board with vol- button pressed)

9) Boot it:
$ fastboot boot u-boot.img
or flash as kernel:
$ fastboot flash boot u-boot.img
$ fastboot reboot


What is working:
- UART
- GPIO (SoC)
- SD
- eMMC
- Reset
- USB in EHCI mode (usb starts does switch device->host, usb stop does the opposite)
- PMIC GPIOS (but not in generic subsystem)
- PMIC "special" buttons (power, vol-)

What is not working / known bugs:
- SDHCI is slow (~2.5MiB/s for SD and eMMC)

[1] To boot any kernel image, Little Kernel requires valid device tree for the
platform it runs on. dtbTool creates device tree table that Little Kernel scans.
Later on proper device tree is passed to next boot stage.
Full device tree is not required to boot u-boot. Enough would be:
/dts-v1/;

/ {
	model = "Qualcomm Technologies, Inc. Dragonboard 410c";
	compatible = "qcom,dragonboard", "qcom,apq8016-sbc";
	qcom,msm-id = <0xce 0x0 0xf8 0x0 0xf9 0x0 0xfa 0x0 0xf7 0x0>;
	qcom,board-id = <0x10018 0x0>;
	#address-cells = <0x2>;
	#size-cells = <0x2>;
	chosen { };
	aliases { };

	memory {
		device_type = "memory";
		reg = <0 0x80000000 0 0x3da00000>;
	};
};

but for simplicity (and because size of image is not that critical) we use
existing Qualcomm device trees.

[2] Note that ramdisk is required, even if it is unused.