[PATCH v3 04/13] MIPS: qemu-malta: generate swapped image as part of multi-image build

[Ahmad Fatoum]

Having to manually swap the words in the MIPS Malta image for QEMU
little endian emulation is annoying.

Have the multi-image build for Malta generate a second .swapped
image that can be readily used if needed.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
 Documentation/boards/mips/qemu-malta.rst | 16 ++++------------
 images/.gitignore                        |  1 +
 images/Makefile                          |  2 +-
 images/Makefile.malta                    | 10 +++++++++-
 4 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/Documentation/boards/mips/qemu-malta.rst b/Documentation/boards/mips/qemu-malta.rst
index e188ae8c642a..fd37d5edb229 100644
--- a/Documentation/boards/mips/qemu-malta.rst
+++ b/Documentation/boards/mips/qemu-malta.rst
@@ -10,31 +10,23 @@ QEMU run string:
 
   qemu-system-mips -nodefaults -M malta -m 256 \
       -device VGA -serial stdio -monitor null \
-      -bios barebox-flash-image
+      -bios ./images/barebox-qemu-malta.img
 
 
 Little-endian mode
 ------------------
 
-Running little-endian Malta is a bit tricky.
 In little-endian mode the 32bit words in the boot flash image are swapped,
 a neat trick which allows bi-endian firmware.
 
-You have to swap words of ``zbarebox.bin`` image, e.g.:
-
-.. code-block:: sh
-
-  echo arch/mips/pbl/zbarebox.bin \
-      | cpio --create \
-      | cpio --extract --swap --unconditional
-
-QEMU run string:
+The barebox build generates a second ``./images/barebox-qemu-malta.img.swapped``
+image that can be used in this case, e.g.:
 
 .. code-block:: sh
 
   qemu-system-mipsel -nodefaults -M malta -m 256 \
       -device VGA -serial stdio -monitor null \
-      -bios barebox-flash-image
+      -bios ./images/barebox-qemu-malta.img.swapped
 
 
 Using GXemul
diff --git a/images/.gitignore b/images/.gitignore
index eafdb44b5bdd..3a9a77dad16e 100644
--- a/images/.gitignore
+++ b/images/.gitignore
@@ -32,3 +32,4 @@ barebox.sum
 *.mvebu1img
 *.stm32
 *.nmon
+*.swapped
diff --git a/images/Makefile b/images/Makefile
index c185982c17ed..cc330d957597 100644
--- a/images/Makefile
+++ b/images/Makefile
@@ -218,5 +218,5 @@ $(flash-list): $(image-y-path)
 clean-files := *.pbl *.pblb *.map start_*.imximg *.img barebox.z start_*.kwbimg \
 	start_*.kwbuartimg *.socfpgaimg *.mlo *.t20img *.t20img.cfg *.t30img \
 	*.t30img.cfg *.t124img *.t124img.cfg *.mlospi *.mlo *.mxsbs *.mxssd \
-	start_*.simximg start_*.usimximg *.zynqimg *.image
+	start_*.simximg start_*.usimximg *.zynqimg *.image *.swapped
 clean-files += pbl.lds
diff --git a/images/Makefile.malta b/images/Makefile.malta
index 5739ec464092..96d7b86b1187 100644
--- a/images/Makefile.malta
+++ b/images/Makefile.malta
@@ -1,3 +1,11 @@
+quiet_cmd_bswap32_image = BSWAP4  $@
+      cmd_bswap32_image = cp $< $@ && \
+			  truncate -s %4 $@ && \
+			  objcopy -I binary --reverse-byte=4 $@
+
+$(obj)/%.img.swapped: $(obj)/%.img FORCE
+	$(call if_changed,bswap32_image)
+
 pblb-$(CONFIG_BOARD_QEMU_MALTA) += start_qemu_malta
 FILE_barebox-qemu-malta.img = start_qemu_malta.pblb
-image-$(CONFIG_BOARD_QEMU_MALTA) += barebox-qemu-malta.img
+image-$(CONFIG_BOARD_QEMU_MALTA) += barebox-qemu-malta.img barebox-qemu-malta.img.swapped
-- 
2.29.2