the following hooks have been added to the ehci Ctlr
structore to handle cache coherency (on arm):
void* (*tdalloc)(ulong,int,ulong);
void* (*dmaalloc)(ulong);
void (*dmafree)(void*);
void (*dmaflush)(int,void*,ulong);
tdalloc() is used to allocate descriptors and the periodic
frame schedule array. on arm, this needs to return uncached
memory. tdalloc()ed memory is never freed.
dmaalloc()/dmafree() is used for io buffers. this can return
cached memory when when hardware maintains cache coherency (pc)
or dmaflush() is provided to flush/invalidate the cache (zynq),
otherwise needs to return uncached memory.
dmaflush() is used to flush/invalidate the cache. the first
argument tells us if we need to flush (non zero) or
invalidate (zero).
uncached.h is gone now. this change makes the handling explicit.
the rule that was used to copy header files from ../pc
accidently overwrote dat.h when ../pc/dat.h was updated
because it matched on all *.h files that was also found
in ../pc directory. change to exact match on $PCHEADERS
to prevent this.
