+ struct {
+ u32 dma_address0 :30;
+ u32 dma_0No_update : 1;
+ u32 dma_0start : 1;
+ } dma_0x0;
...
+
+ struct {
+ u32 dma_0start : 1;
+ u32 dma_0No_update : 1;
+ u32 dma_address0 :30;
+ } dma_0x0;
Oh dear. This is a good demonstration of the downside of trying to use
compiler bitfields to represent hardware registers. I have vague memories
of writing BFINS and BFEXT in 3c59x to stomp this problem.
I don't think there's any guarantee that the code you have there will work
on all architectures/compiler versions btw.
Also... The code appears to be assuming that BE architectures will
bit-reverse their bitfields. Is that right? I'd expect them to only
byte-reverse them?
Probably the code should use __BIG_ENDIAN_BITFIELD /
__LITTLE_ENDIAN_BITFIELD instead of __BIG_ENDIAN / __LITTLE_ENDIAN?
Anyway, the comment from the CVS commit suggests that it was tested.
I completely agree that this code is ugly as hell. It was the obvious, simple fix to make the driver work on PowerPC (and a few users happy), though. Rewriting the driver not to use bitfields seems to be quite a bit of work. Blame me for not paying enough attention when the initial flexcop driver was submitted ;-(