docs/system/arm/imx8m.rst

NXP i.MX 8M Plus and i.MX 8M Mini Evaluation Kits (``imx8mp-evk``, ``imx8mm-evk``)
==================================================================================

The ``imx8mp-evk`` and ``imx8mm-evk`` machine models the i.MX 8M Plus
and i.MX 8M Mini Evaluation Kits, based on i.MX 8M Plus and i.MX8M
Mini SoCs.

Supported devices
-----------------

The ``imx8mp-evk`` and ``imx8mm-evk`` machines implement the
following devices:

 * Up to 4 Cortex-A53 cores
 * Generic Interrupt Controller (GICv3)
 * 4 UARTs
 * 3 USDHC Storage Controllers
 * 1 Designware PCI Express Controller
 * 1 Ethernet Controller
 * 2 Designware USB 3 Controllers
 * 2 FlexCAN 3 CAN Controllers (``imx8mp-evk`` only)
 * 5 GPIO Controllers
 * 6 I2C Controllers
 * 3 SPI Controllers
 * 3 Watchdogs
 * 6 General Purpose Timers
 * Secure Non-Volatile Storage (SNVS) including an RTC
 * Clock Tree

Boot options
------------

The ``imx8mp-evk`` and ``imx8mm-evk`` machines can start a Linux
kernel directly using the standard ``-kernel`` functionality.

Direct Linux Kernel Boot
''''''''''''''''''''''''

Probably the easiest way to get started with a whole Linux system on the machine
is to generate an image with Buildroot. Version 2024.11.1 is tested at the time
of writing and involves two steps. First run the following commands in the
toplevel directory of the Buildroot source tree:

For i.MX 8M Plus EVK:

.. code-block:: bash

  $ make freescale_imx8mpevk_defconfig
  $ make

For i.MX 8M Mini EVK:

.. code-block:: bash

  $ make freescale_imx8mmevk_defconfig
  $ make

Once finished successfully there is an ``output/image`` subfolder. Navigate into
it and resize the SD card image to a power of two:

.. code-block:: bash

  $ qemu-img resize sdcard.img 256M

Now that everything is prepared the machine can be started as follows:

For i.MX 8M Plus EVK:

.. code-block:: bash

  $ qemu-system-aarch64 -M imx8mp-evk \
      -display none -serial null -serial stdio \
      -kernel Image \
      -dtb imx8mp-evk.dtb \
      -append "root=/dev/mmcblk2p2" \
      -drive file=sdcard.img,if=sd,bus=2,format=raw,id=mmcblk2

For i.MX 8M Mini EVK:

.. code-block:: bash

  $ qemu-system-aarch64 -M imx8mm-evk -smp 4 -m 2G \
      -display none -serial null -serial stdio \
      -kernel Image \
      -dtb imx8mm-evk.dtb \
      -append "root=/dev/mmcblk2p2" \
      -drive file=sdcard.img,if=sd,bus=2,format=raw,id=mmcblk2

KVM Acceleration
----------------

To enable hardware-assisted acceleration via KVM, append
``-accel kvm`` to the command line. While this speeds up performance
significantly, be aware of the following limitations:

* The ``imx8mp-evk`` and ``imx8mm-evk`` machines are not included
  under the "virtualization use case" of :doc:`QEMU's security
  policy </system/security>`.  This means that you should not trust that
  it can contain malicious guests, whether it is run using TCG or KVM.
  If you don't trust your guests and you're relying on QEMU to be the
  security boundary, you want to choose another machine such as
  ``virt``.
* Rather than Cortex-A53 CPUs, the same CPU type as the host's will be used.
  This is a limitation of KVM and may not work with guests with a tight
  dependency on Cortex-A53.
* No EL2 and EL3 exception levels are available which is also a KVM limitation.
  Direct kernel boot should work but running U-Boot, TF-A, etc. won't succeed.