[PULL 14/23] docs/system/arm/aspeed: Support vbootrom for AST2700

["Cédric Le Goater" <clg@redhat.com>]

From: Jamin Lin <jamin_lin@aspeedtech.com>

Using the vbootrom image support and the boot ROM binary is
now passed via the -bios option, using the image located in
pc-bios/ast27x0_bootrom.bin.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Nabih Estefan <nabihestefan@google.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250424075135.3715128-7-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 docs/system/arm/aspeed.rst | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/docs/system/arm/aspeed.rst b/docs/system/arm/aspeed.rst
index 08a33b7008b7..014545f4440f 100644
--- a/docs/system/arm/aspeed.rst
+++ b/docs/system/arm/aspeed.rst
@@ -306,7 +306,14 @@ Images can be downloaded from the ASPEED Forked OpenBMC GitHub release repositor
 Booting the ast2700-evb machine
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Boot the AST2700 machine from the flash image, use an MTD drive :
+Boot the AST2700 machine from the flash image.
+
+There are two supported methods for booting the AST2700 machine with a flash image:
+
+Manual boot using ``-device loader``:
+
+It causes all 4 CPU cores to start execution from address ``0x430000000``, which
+corresponds to the BL31 image load address.
 
 .. code-block:: bash
 
@@ -326,6 +333,26 @@ Boot the AST2700 machine from the flash image, use an MTD drive :
        -drive file=${IMGDIR}/image-bmc,format=raw,if=mtd \
        -nographic
 
+Boot using a virtual boot ROM (``-bios``):
+
+If users do not specify the ``-bios option``, QEMU will attempt to load the
+default vbootrom image ``ast27x0_bootrom.bin`` from either the current working
+directory or the ``pc-bios`` directory within the QEMU source tree.
+
+.. code-block:: bash
+
+  $ qemu-system-aarch64 -M ast2700-evb \
+      -drive file=image-bmc,format=raw,if=mtd \
+      -nographic
+
+The ``-bios`` option allows users to specify a custom path for the vbootrom
+image to be loaded during boot. This will load the vbootrom image from the
+specified path in the ${HOME} directory.
+
+.. code-block:: bash
+
+  -bios ${HOME}/ast27x0_bootrom.bin
+
 Aspeed minibmc family boards (``ast1030-evb``)
 ==================================================================
 
-- 
2.49.0