docs/system/ppc: Document running Linux on AmigaNG machines

Documentation on how to run Linux on the amigaone, pegasos2 and
sam460ex machines is currently buried in the depths of the qemu-devel
mailing list and in the source code. Let's collect the information in
the QEMU handbook for a one stop solution.

Tested-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Co-authored-by: Bernhard Beschow <shentey@gmail.com>
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

MAINTAINERS

@@ -1572,6 +1572,7 @@ F: hw/rtc/m41t80.c
 F: pc-bios/canyonlands.dt[sb]
 F: pc-bios/u-boot-sam460ex-20100605.bin
 F: roms/u-boot-sam460ex
+F: docs/system/ppc/amigang.rst
 
 pegasos2
 M: BALATON Zoltan <balaton@eik.bme.hu>

docs/system/ppc/amigang.rst

@@ -0,0 +1,161 @@
+=========================================================
+AmigaNG boards (``amigaone``, ``pegasos2``, ``sam460ex``)
+=========================================================
+
+These PowerPC machines emulate boards that are primarily used for
+running Amiga like OSes (AmigaOS 4, MorphOS and AROS) but these can
+also run Linux which is what this section documents.
+
+Eyetech AmigaOne/Mai Logic Teron (``amigaone``)
+===============================================
+
+The ``amigaone`` machine emulates an AmigaOne XE mainboard by Eyetech
+which is a rebranded Mai Logic Teron board with modified U-Boot
+firmware to support AmigaOS 4.
+
+Emulated devices
+----------------
+
+ * PowerPC 7457 CPU (can also use``-cpu g3, 750cxe, 750fx`` or ``750gx``)
+ * Articia S north bridge
+ * VIA VT82C686B south bridge
+ * PCI VGA compatible card (guests may need other card instead)
+ * PS/2 keyboard and mouse
+
+Firmware
+--------
+
+A firmware binary is necessary for the boot process. It is a modified
+U-Boot under GPL but its source is lost so it cannot be included in
+QEMU. A binary is available at
+https://www.hyperion-entertainment.com/index.php/downloads?view=files&parent=28.
+The ROM image is in the last 512kB which can be extracted with the
+following command:
+
+.. code-block:: bash
+
+  $ tail -c 524288 updater.image > u-boot-amigaone.bin
+
+The BIOS emulator in the firmware is unable to run QEMU‘s standard
+vgabios so ``VGABIOS-lgpl-latest.bin`` is needed instead which can be
+downloaded from http://www.nongnu.org/vgabios.
+
+Running Linux
+-------------
+
+There are some Linux images under the following link that work on the
+``amigaone`` machine:
+https://sourceforge.net/projects/amigaone-linux/files/debian-installer/.
+To boot the system run:
+
+.. code-block:: bash
+
+  $ qemu-system-ppc -machine amigaone -bios u-boot-amigaone.bin \
+                    -cdrom "A1 Linux Net Installer.iso" \
+                    -device ati-vga,model=rv100,romfile=VGABIOS-lgpl-latest.bin
+
+From the firmware menu that appears select ``Boot sequence`` →
+``Amiga Multiboot Options`` and set ``Boot device 1`` to
+``Onboard VIA IDE CDROM``. Then hit escape until the main screen appears again,
+hit escape once more and from the exit menu that appears select either
+``Save settings and exit`` or ``Use settings for this session only``. It may
+take a long time loading the kernel into memory but eventually it boots and the
+installer becomes visible. The ``ati-vga`` RV100 emulation is not
+complete yet so only frame buffer works, DRM and 3D is not available.
+
+Genesi/bPlan Pegasos II (``pegasos2``)
+======================================
+
+The ``pegasos2`` machine emulates the Pegasos II sold by Genesi and
+designed by bPlan. Its schematics are available at
+https://www.powerdeveloper.org/platforms/pegasos/schematics.
+
+Emulated devices
+----------------
+
+ * PowerPC 7457 CPU (can also use``-cpu g3`` or ``750cxe``)
+ * Marvell MV64361 Discovery II north bridge
+ * VIA VT8231 south bridge
+ * PCI VGA compatible card (guests may need other card instead)
+ * PS/2 keyboard and mouse
+
+Firmware
+--------
+
+The Pegasos II board has an Open Firmware compliant ROM based on
+SmartFirmware with some changes that are not open-sourced therefore
+the ROM binary cannot be included in QEMU. An updater was available
+from bPlan, it can be found in the `Internet Archive
+<http://web.archive.org/web/20071021223056/http://www.bplan-gmbh.de/up050404/up050404>`_.
+The ROM image can be extracted from it with the following command:
+
+.. code-block:: bash
+
+  $ tail -c +85581 up050404 | head -c 524288 > pegasos2.rom
+
+Running Linux
+-------------
+
+The PowerPC version of Debian 8.11 supported Pegasos II. The BIOS
+emulator in the firmware binary is unable to run QEMU‘s standard
+vgabios so it needs to be disabled. To boot the system run:
+
+.. code-block:: bash
+
+  $ qemu-system-ppc -machine pegasos2 -bios pegasos2.rom \
+                    -cdrom debian-8.11.0-powerpc-netinst.iso \
+                    -device VGA,romfile="" -serial stdio
+
+At the firmware ``ok`` prompt enter ``boot cd install/pegasos``.
+
+Alternatively, it is possible to boot the kernel directly without
+firmware ROM using the QEMU built-in minimal Virtual Open Firmware
+(VOF) emulation which is also supported on ``pegasos2``. For this,
+extract the kernel ``install/powerpc/vmlinuz-chrp.initrd`` from the CD
+image, then run:
+
+.. code-block:: bash
+
+  $ qemu-system-ppc -machine pegasos2 -serial stdio \
+                    -kernel vmlinuz-chrp.initrd -append "---" \
+                    -cdrom debian-8.11.0-powerpc-netinst.iso
+
+aCube Sam460ex (``sam460ex``)
+=============================
+
+The ``sam460ex`` machine emulates the Sam460ex board by aCube which is
+based on the AMCC PowerPC 460EX SoC (that despite its name has a
+PPC440 CPU core).
+
+Firmware
+--------
+
+The board has a firmware based on an older U-Boot version with
+modifications to support booting AmigaOS 4. The firmware ROM is
+included with QEMU.
+
+Emulated devices
+----------------
+
+ * PowerPC 460EX SoC
+ * M41T80 serial RTC chip
+ * Silicon Motion SM501 display parts (identical to SM502 on real board)
+ * Silicon Image SiI3112 2 port SATA controller
+ * USB keyboard and mouse
+
+Running Linux
+-------------
+
+The only Linux distro that supported Sam460ex out of box was CruxPPC
+2.x. It can be booted by running:
+
+.. code-block:: bash
+
+  $ qemu-system-ppc -machine sam460ex -serial stdio \
+                    -drive if=none,id=cd,format=raw,file=crux-ppc-2.7a.iso \
+                    -device ide-cd,drive=cd,bus=ide.1
+
+There are some other kernels and instructions for booting other
+distros on aCube's product page at
+https://www.acube-systems.biz/index.php?page=hardware&pid=5
+but those are untested.

docs/system/target-ppc.rst

@@ -17,6 +17,7 @@ help``.
 .. toctree::
    :maxdepth: 1
 
+   ppc/amigang
    ppc/embedded
    ppc/powermac
    ppc/powernv