cmd: bcb: fix bcb struct alignment issue

Without this patch the bcb struct could be located at an odd address
which resulted in data not being copied to the buffer.

Here was the repro steps (from Mattijs):
=> mmc dev 1
=> bcb load 1 misc
=> bcb dump command
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=> part start mmc 1 misc misc_start
=> mmc read ${loadaddr} ${misc_start} 4
=> bcb load 1 misc
=> bcb dump command
00000000: 62 6f 6f 74 6f 6e 63 65 2d 62 6f 6f 74 6c 6f 61
00000010: 64 65 72 00 00 00 00 00 00 00 00 00 00 00 00 00

This behavior was observed on an Amlogic A311D (ARM64) platform with a
recent GCC toolchain (11.2.0) but is most likely affecting other
platforms.

To avoid issues the structure is aligned on DMA minimum alignment value
as it is passed directly to the read function.

Signed-off-by: Gary Bisson <gary.bisson@boundarydevices.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@baylibre.com> # on khadas vim3

diff --git a/cmd/bcb.c b/cmd/bcb.c
index 6b6f1e9a2f10ca4f2ed6c10e203059f218c8aa43..92f4d27990df981e66d766dd4c4b4dd7c2f56a03 100644 (file)
--- a/cmd/bcb.c
+++ b/cmd/bcb.c
@@ -12,6 +12,7 @@
 #include <log.h>
 #include <part.h>
 #include <malloc.h>
+#include <memalign.h>
 
 enum bcb_cmd {
        BCB_CMD_LOAD,
@@ -24,7 +25,7 @@ enum bcb_cmd {
 
 static int bcb_dev = -1;
 static int bcb_part = -1;
-static struct bootloader_message bcb = { { 0 } };
+static struct bootloader_message bcb __aligned(ARCH_DMA_MINALIGN) = { { 0 } };
 
 static int bcb_cmd_get(char *cmd)
 {