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JFFS2, unaligned accesses, Arm7Tdmi
I'm sending this to both uclinux-dev and jffs2-dev because I'm not sure
which is the correct forum... maybe both are!
I am currently using uClinux 2.4.19.uc1 on an Arm7Tdmi family
processor. I would like to get JFFS2 running on this platform.
On this uClinux CVS snapshot that I am using, I cannot enable MTD
because the arch/armnommu/config.in requires CONFIG_ALIGNMENT_TRAP to
access the mtd/config.in configuration items.
(CONFIG_ALIGNMENT_TRAP appears to be enable-able only for the EBSA1110
Some searches in Google state that MTD/JFFS2 require processor support
for unaligned accesses. However, the Arm7Tdmi does not support
unaligned access traps: The processor just clears the corresponding
addresses bits and forces address alignment. Thus, any attempt to
access data at an unaligned address will just result in
obtaining/writing the wrong data.
This suggests that MTD/JFFS2 would not work with this Arm7 processor?
Now, if I look in the current uClinux CVS, I see that the requirement
for CONFIG_ALIGNMENT_TRAP has been removed from arch/armnommu/config.in
and I could select MTD/JFFS2 without support for unaligned accesses in
Does anyone know what has changed? Why unaligned access support is no
longer required? Does anyone have any recommendations for JFFS2 support
on a processor without unaligned access traps?
Thanks in advance,
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