Masahiro Yamada b75d8dc564 treewide: convert bd_t to struct bd_info by coccinelle 3 years ago
..
Kconfig 626f048bbc board: Add Qualcomm Dragonboard 410C support 8 years ago
MAINTAINERS 0dfe442e87 MAINTAINERS: change Ramon Fried email address 4 years ago
Makefile 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 6 years ago
dragonboard410c.c b75d8dc564 treewide: convert bd_t to struct bd_info by coccinelle 3 years ago
head.S 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 6 years ago
lowlevel_init.S 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 6 years ago
readme.txt 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style 6 years ago
u-boot.lds 7e21fbca26 efi_loader: Rename sections to allow for implicit data 5 years ago

readme.txt

# SPDX-License-Identifier: GPL-2.0+
#
# (C) Copyright 2015 Mateusz Kulikowski

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.