Commit bfb33f0b authored by Hans de Goede's avatar Hans de Goede

sunxi: mctl_mem_matches: Add missing memory barrier

We are running with the caches disabled when mctl_mem_matches gets called,
but the cpu's write buffer is still there and can still get in the way,
add a memory barrier to fix this.

This avoids mctl_mem_matches always returning false in some cases, which
was resulting in:

U-Boot SPL 2015.07 (Apr 14 2016 - 18:47:26)
DRAM: 1024 MiB

U-Boot 2015.07 (Apr 14 2016 - 18:47:26 +0200) Allwinner Technology

CPU:   Allwinner A23 (SUN8I)
DRAM:  512 MiB

Where 512 MiB is the right amount, but the DRAM controller would be
initialized for 1024 MiB.
Signed-off-by: default avatarHans de Goede <>
Acked-by: default avatarIan Campbell <>
parent e25b369c
......@@ -7,6 +7,7 @@
#include <common.h>
#include <asm/armv7.h>
#include <asm/io.h>
#include <asm/arch/dram.h>
......@@ -31,6 +32,7 @@ bool mctl_mem_matches(u32 offset)
/* Try to write different values to RAM at two addresses */
writel(0xaa55aa55, (ulong)CONFIG_SYS_SDRAM_BASE + offset);
/* Check if the same value is actually observed when reading back */
return readl(CONFIG_SYS_SDRAM_BASE) ==
readl((ulong)CONFIG_SYS_SDRAM_BASE + offset);
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