03fb0958c9
Currently on qemu-arm platforms environment is kept in RAM. Instead
use pflash device 1 to provide persistent environment support across
device reset.
Also (optionally) provide support for persistent environment across
qemu machine OFF/ON using following instructions:
- 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
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
69 lines
2.5 KiB
Plaintext
69 lines
2.5 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 -bios u-boot.bin
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- For AArch64:
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qemu-system-aarch64 -machine virt -cpu cortex-a57 -bios u-boot.bin
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Note that 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 persistent U-boot environment support can be added as follows:
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- Create envstore.img using qemu-img:
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qemu-img create -f raw envstore.img 64M
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- Add a pflash drive parameter to the command line:
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-drive if=pflash,format=raw,index=1,file=envstore.img
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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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