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.
map the whole ocm memory on boot so we can translate physical to
virtual addresses and back for uncached memory using KADDR() and
PADDR().
replace ualloc() with ucalloc() returning virtual address. physical
address can be acquired with PADDR() now.
as ocm is now always mapped, use KADDR() instead of tmpmap() for
mp bootstrap.
there are no kernels currently that do page coloring,
so the only use of cachectl[] is flushing the icache
(on arm and ppc).
on pc64, cachectl consumes 32 bytes in each page resulting
in over 200 megabytes of overhead for 32gb of ram with 4K
pages.
this change removes cachectl[] and adds txtflush ulong
that is set to ~0 by pio() to instruct putmmu() to flush
the icache.
we have to call tmpmap() with interrupts disabled as the map
is a per cpu and a interrupt can preempt us while we where
commited to use a entry but *before* we wrote it!
tmpunmap() already calls coherence() before flushpg() so it
is not needed after tmpunmap().
splhi() in l2free() isnt needed as l2free() is always called
with interrupts disabled from mmuswitch() and mmurelease().
fpsave needs to disable the fpu! otherwise we won't catch
the mathtrap() in the kernel or when context switching to
another process that will attempt to use it.
