QEMU currently generates a devicetree for use with U-Boot. Explain how to
obtain it.
Signed-off-by: Simon Glass <sjg@chromium.org>
---
doc/board/emulation/qemu-arm.rst | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/doc/board/emulation/qemu-arm.rst b/doc/board/emulation/qemu-arm.rst
index 97b6ec64905..b458a398c69 100644
--- a/doc/board/emulation/qemu-arm.rst
+++ b/doc/board/emulation/qemu-arm.rst
@@ -91,3 +91,15 @@ The debug UART on the ARM virt board uses these settings::
CONFIG_DEBUG_UART_PL010=y
CONFIG_DEBUG_UART_BASE=0x9000000
CONFIG_DEBUG_UART_CLOCK=0
+
+Obtaining the QEMU devicetree
+-----------------------------
+
+QEMU generates its own devicetree to pass to U-Boot and does this by default.
+You can use `-dtb u-boot.dtb` to force QEMU to use U-Boot's in-tree version.
this is for either Qemu experts or u-boot for Qemu maintainers. Not for the kernel développer as it is recipe for problems: could you add this warning ?
+
+To obtain the devicetree that qemu generates, add `-machine dumpdtb=dtb.dtb`,
+e.g.::
+
+ qemu-system-aarch64 -machine virt -nographic -cpu cortex-a57 \
+ -bios u-boot.bin -machine dumpdtb=dtb.dtb
--
2.33.0.882.g93a45727a2-goog