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https://github.com/brain-hackers/u-boot-brain
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When U-Boot started using SPDX tags we were among the early adopters and there weren't a lot of other examples to borrow from. So we picked the area of the file that usually had a full license text and replaced it with an appropriate SPDX-License-Identifier: entry. Since then, the Linux Kernel has adopted SPDX tags and they place it as the very first line in a file (except where shebangs are used, then it's second line) and with slightly different comment styles than us. In part due to community overlap, in part due to better tag visibility and in part for other minor reasons, switch over to that style. This commit changes all instances where we have a single declared license in the tag as both the before and after are identical in tag contents. There's also a few places where I found we did not have a tag and have introduced one. Signed-off-by: Tom Rini <trini@konsulko.com>
64 lines
2.3 KiB
Plaintext
64 lines
2.3 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0+
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#
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# Copyright (C) 2017, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
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U-Boot on QEMU's 'virt' machine on ARM & AArch64
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================================================
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QEMU for ARM supports a special 'virt' machine designed for emulation and
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virtualization purposes. This document describes how to run U-Boot under it.
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Both 32-bit ARM and AArch64 are supported.
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The 'virt' platform provides the following as the basic functionality:
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- A freely configurable amount of CPU cores
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- U-Boot loaded and executing in the emulated flash at address 0x0
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- A generated device tree blob placed at the start of RAM
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- A freely configurable amount of RAM, described by the DTB
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- A PL011 serial port, discoverable via the DTB
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- An ARMv7/ARMv8 architected timer
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- PSCI for rebooting the system
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- A generic ECAM-based PCI host controller, discoverable via the DTB
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Additionally, a number of optional peripherals can be added to the PCI bus.
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Building U-Boot
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---------------
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Set the CROSS_COMPILE environment variable as usual, and run:
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- For ARM:
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make qemu_arm_defconfig
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make
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- For AArch64:
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make qemu_arm64_defconfig
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make
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Running U-Boot
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--------------
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The minimal QEMU command line to get U-Boot up and running is:
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- For ARM:
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qemu-system-arm -machine virt,highmem=off -bios u-boot.bin
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- For AArch64:
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qemu-system-aarch64 -machine virt,highmem=off -cpu cortex-a57 -bios u-boot.bin
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The 'highmem=off' parameter to the 'virt' machine is required for PCI to work
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in U-Boot. Also, for some odd reason qemu-system-aarch64 needs to be explicitly
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told to use a 64-bit CPU or it will boot in 32-bit mode.
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Additional peripherals that have been tested to work in both U-Boot and Linux
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can be enabled with the following command line parameters:
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- To add a Serial ATA disk via an Intel ICH9 AHCI controller, pass e.g.:
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-drive if=none,file=disk.img,id=mydisk -device ich9-ahci,id=ahci -device ide-drive,drive=mydisk,bus=ahci.0
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- To add an Intel E1000 network adapter, pass e.g.:
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-netdev user,id=net0 -device e1000,netdev=net0
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- To add an EHCI-compliant USB host controller, pass e.g.:
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-device usb-ehci,id=ehci
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- To add a NVMe disk, pass e.g.:
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-drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo
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These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well.
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