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- .. SPDX-License-Identifier: GPL-2.0+
- .. Copyright (C) 2017, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
- QEMU ARM
- ========
- QEMU for ARM supports a special 'virt' machine designed for emulation and
- virtualization purposes. This document describes how to run U-Boot under it.
- Both 32-bit ARM and AArch64 are supported.
- The 'virt' platform provides the following as the basic functionality:
- - A freely configurable amount of CPU cores
- - U-Boot loaded and executing in the emulated flash at address 0x0
- - A generated device tree blob placed at the start of RAM
- - A freely configurable amount of RAM, described by the DTB
- - A PL011 serial port, discoverable via the DTB
- - An ARMv7/ARMv8 architected timer
- - PSCI for rebooting the system
- - A generic ECAM-based PCI host controller, discoverable via the DTB
- Additionally, a number of optional peripherals can be added to the PCI bus.
- Building U-Boot
- ---------------
- Set the CROSS_COMPILE environment variable as usual, and run:
- - For ARM::
- make qemu_arm_defconfig
- make
- - For AArch64::
- make qemu_arm64_defconfig
- make
- Running U-Boot
- --------------
- The minimal QEMU command line to get U-Boot up and running is:
- - For ARM::
- qemu-system-arm -machine virt -bios u-boot.bin
- - For AArch64::
- qemu-system-aarch64 -machine virt -cpu cortex-a57 -bios u-boot.bin
- Note that for some odd reason qemu-system-aarch64 needs to be explicitly
- told to use a 64-bit CPU or it will boot in 32-bit mode.
- Additional persistent U-boot environment support can be added as follows:
- - Create envstore.img using qemu-img::
- qemu-img create -f raw envstore.img 64M
- - Add a pflash drive parameter to the command line::
- -drive if=pflash,format=raw,index=1,file=envstore.img
- Additional peripherals that have been tested to work in both U-Boot and Linux
- can be enabled with the following command line parameters:
- - To add a Serial ATA disk via an Intel ICH9 AHCI controller, pass e.g.::
- -drive if=none,file=disk.img,id=mydisk -device ich9-ahci,id=ahci -device ide-drive,drive=mydisk,bus=ahci.0
- - To add an Intel E1000 network adapter, pass e.g.::
- -netdev user,id=net0 -device e1000,netdev=net0
- - To add an EHCI-compliant USB host controller, pass e.g.::
- -device usb-ehci,id=ehci
- - To add a NVMe disk, pass e.g.::
- -drive if=none,file=disk.img,id=mydisk -device nvme,drive=mydisk,serial=foo
- These have been tested in QEMU 2.9.0 but should work in at least 2.5.0 as well.
- Debug UART
- ----------
- The debug UART on the ARM virt board uses these settings::
- CONFIG_DEBUG_UART=y
- CONFIG_DEBUG_UART_PL010=y
- CONFIG_DEBUG_UART_BASE=0x9000000
- CONFIG_DEBUG_UART_CLOCK=0
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