Patch Set 16:

(19 comments)

Thank you for your reviews. I add a documentation, deleted cpu/armltd/cortex-a53, and updated files.
I have some things I don't understand yet.

1.
I'm trying to add a payload LinuxBoot by selecting it via 'make menuconfig'.
However, I got the following error:
make LINUXBOOT_CROSS_COMPILE=aarch64-linux-gnu-
...
cp: -r not specified; omitting directory '../../../'
make[2]: *** [targets/linux.mk:112: linuxboot/target.dtb] Error 1
make[1]: *** [Makefile:55: kernel] Error 2
make: *** [payloads/external/Makefile.inc:266: linuxboot] Error 2

I think this error relates to the second question about FDT.

2.
What is an FDT and how can I use it? I looked it up and found an FDT is a flattened device tree which is used especially for ARM system. We can configure peripherals via an FDT dynamically.
How can I pass an FDT when building the image?

When generating the uImage, you must include a DTB.
When you build LinuxBoot, you need to specify a "Compiled devicetree file", that is a DTB. too.

You can gernate one from qemu by runing qemu-system-aarch64 -machine virt-2.9,dumpdtb=file.dtb ...
Please convert the DTB to DTS and store it in the mainboard directory.

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3 comments:

• File src/mainboard/emulation/qemu-aarch64/bootblock_custom.S:

  • Patch Set #15, Line 11: ENTRY(_start)

    Sorry, I only have a few knowledge about FDT. […]

    boot rom is the code run by the SoC itself, before coreboot's bootblock is executed.
    I guess qemu passes a pointer to FDT in x0.
    As Julius said it's likely easier to add a static DTS file to the mainboard directory.

• File src/mainboard/emulation/qemu-aarch64/mainboard.c:

  • Patch Set #15, Line 28: ram_resource(dev, 0, VIRT_DRAM_START >> 10, discovered << 10);

    Sorry, does "discover resources" mean BS_DEV_RESOURCES?

    have a look at "mainboard/emulation/qemu-i440fx/northbridge.c"
    It calls ram_resource in "cpu_pci_domain_read_resources":

    static struct device_operations pci_domain_ops = {
            .read_resources = cpu_pci_domain_read_resources,

• File src/mainboard/emulation/qemu-aarch64/timer.c:

  • Patch Set #15, Line 9: void udelay(unsigned int n);

    src/arch/arm64/arch_timer.c will be enable when we select CONFIG_ARM64_USE_ARCH_TIMER. […]

    Have a look at "soc/qualcomm/sdm845/timer.c"
    It just implements init_timer().
    You can do that in a similar way.

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