tools: imx8m_image: align spl bin image size

The loader for the DDR firmware in drivers/ddr/imx/imx8m/helper.c uses a
4-byte-aligned address to load the firmware. In cases where OF is
enabled in SPL the dtb will be appended to the SPL binary and can result
in a binary that is not aligned correctly. If OF is not enabled in SPL,
`_end` is already aligned correctly, but this patch does not hurt.

To ensure the correct alignment we use dd to create a temporary file
u-boot-spl-pad.bin with the correct padding.

Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Peng Fan <peng.fan@nxp.com>

tools/imx8m_image.sh

@@ -35,8 +35,9 @@ if [ $post_process = 1 ]; then
 		objcopy -I binary -O binary --pad-to 0x8000 --gap-fill=0x0 $srctree/lpddr4_pmu_train_2d_imem.bin lpddr4_pmu_train_2d_imem_pad.bin
 		cat lpddr4_pmu_train_1d_imem_pad.bin lpddr4_pmu_train_1d_dmem_pad.bin > lpddr4_pmu_train_1d_fw.bin
 		cat lpddr4_pmu_train_2d_imem_pad.bin $srctree/lpddr4_pmu_train_2d_dmem.bin > lpddr4_pmu_train_2d_fw.bin
-		cat spl/u-boot-spl.bin lpddr4_pmu_train_1d_fw.bin lpddr4_pmu_train_2d_fw.bin > spl/u-boot-spl-ddr.bin
-		rm -f lpddr4_pmu_train_1d_fw.bin lpddr4_pmu_train_2d_fw.bin lpddr4_pmu_train_1d_imem_pad.bin lpddr4_pmu_train_1d_dmem_pad.bin lpddr4_pmu_train_2d_imem_pad.bin
+		dd if=spl/u-boot-spl.bin of=spl/u-boot-spl-pad.bin bs=4 conv=sync
+		cat spl/u-boot-spl-pad.bin lpddr4_pmu_train_1d_fw.bin lpddr4_pmu_train_2d_fw.bin > spl/u-boot-spl-ddr.bin
+		rm -f lpddr4_pmu_train_1d_fw.bin lpddr4_pmu_train_2d_fw.bin lpddr4_pmu_train_1d_imem_pad.bin lpddr4_pmu_train_1d_dmem_pad.bin lpddr4_pmu_train_2d_imem_pad.bin spl/u-boot-spl-pad.bin
 	fi
 fi