[PATCH] docs/system: document an example booting the versatilepb machine

[Alex Bennée]

There is a bit more out there including Aurelien's excellent write up
and older Debian images here:

  https://www.aurel32.net/info/debian_arm_qemu.php
  https://people.debian.org/~aurel32/qemu/armel/

However the web is transitory and git is forever so lets add something
to the fine manual.

Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 docs/system/arm/versatile.rst | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/docs/system/arm/versatile.rst b/docs/system/arm/versatile.rst
index 51221c30a4..d16f20ccae 100644
--- a/docs/system/arm/versatile.rst
+++ b/docs/system/arm/versatile.rst
@@ -27,3 +27,35 @@ The Arm Versatile baseboard is emulated with the following 
devices:
    devices.
 
 -  PL181 MultiMedia Card Interface with SD card.
+
+Booting a Linux kernel
+----------------------
+
+Building a current Linux kernel with ``versatile_defconfig`` should be
+enough to get something running.
+
+.. code-block:: bash
+
+  $ export ARCH=arm
+  $ export CROSS_COMPILE=arm-linux-gnueabihf-
+  $ make versatile_defconfig
+  $ make
+
+You may want to enable some additional modules if you want to boot
+something from the SCSI interface::
+
+  CONFIG_PCI=y
+  CONFIG_PCI_VERSATILE=y
+  CONFIG_SCSI=y
+  CONFIG_SCSI_SYM53C8XX_2=y
+
+You can then boot with a command line like:
+
+.. code-block:: bash
+
+  $ qemu-system-arm -machine type=versatilepb \
+      -serial mon:stdio \
+      -drive if=scsi,driver=file,filename=debian-buster-armel-rootfs.ext4 \
+      -kernel zImage \
+      -dtb versatile-pb.dtb  \
+      -append "console=ttyAMA0 ro root=/dev/sda"
-- 
2.20.1