Mike,
I did the changes suggested by you and tested the build. The issue didn't come up. Then I reverted the code to the original (attributes retained and ehci directly de-referencing the pointers. The issue didn't come here too.
Today, I used armv7-linux-gcc (GCC) v4.6.2 So I suspect there has been some fix done in the GCC.
Now, even with the packed attributes, the word fields are accessed word-by-word in contrast to the earlier observed behavior (byte-by-byte). I could see ldr and str in the disassembly.
May be, we can discard this patch and keep drivers/usb/host/ehci.h intact.
not sure ... in general, device registers should be accessed with io.h helpers instead of dereferenced by volatile pointers. i can think of cases on Blackfin where the io.h helpers would be required, and even using volatile pointers could result in misbehavior.
If you guys agree, I can float the patch but how can we distribute the responsibility for testing on other architectures?
Thanks Amit Virdi