From: Marek Vasut [marek.vasut@gmail.com] Sent: Sunday, April 28, 2013 22:58 To: u-boot@lists.denx.de Cc: Gabbasov, Andrew; Albert ARIBAUD; Tom Rini Subject: Re: [U-Boot] [PATCH] ARM: cfi_flash: Avoid generation of unaligned accesses

Dear Andrew Gabbasov,

...

Packed structure cfi_qry contains unaligned 16- and 32-bits members, accessing which causes problems when cfi_flash driver is compiled with -munaligned-access option: flash initialization hangs, probably due to data error.

Since fixing the code to use some other way of accessing those fields seems quite expensive, just force the compiler to use -mno-unaligned-access.

Signed-off-by: Andrew Gabbasov andrew_gabbasov@mentor.com

drivers/mtd/Makefile | 3 +++ 1 file changed, 3 insertions(+)

diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile index 543c845..a120f0b 100644 --- a/drivers/mtd/Makefile +++ b/drivers/mtd/Makefile @@ -46,6 +46,9 @@ all: $(LIB) $(LIB): $(obj).depend $(OBJS) $(call cmd_link_o_target, $(OBJS))

+# SEE README.arm-unaligned-accesses +$(obj)cfi_flash.o: CFLAGS += $(PLATFORM_NO_UNALIGNED)

#########################################################################

# defines $(obj).depend target

I'd say rather fix the structure than use this workaround. See, using

u8[3] u16

will make unaligned access. The fix would be to split that u16 into two u8 and add a proper accessor. It'll be much larger effort, but it'd also be more correct.

Best regards, Marek Vasut

Hi Marek,

Thank you for your response.

I was thinking about this way of fixing, but it seemed too require too much effort. However, after some closer look it turned out to be not quite difficult, since there are quite a few accesses to such unaligned fields. So, I made another fix and sent to separately to the list with Subject: "[U-Boot][PATCH] ARM: cfi_flash: Fix unaligned accesses to cfi_qry structure". Please, look at it, if it is OK from your point of view.

Thanks.

Best regards, Andrew