On PowerPC processors with non-coherent cache architectures the DMA
subsystem calls invalidate_dcache_range() before performing a DMA read
operation. If the address and length of the DMA buffer are not aligned
to a cache-line boundary this can result in memory outside of the DMA
buffer being invalidated in the cache. If this memory has an
uncommitted store then the data will be lost and a subsequent read of
that address will result in an old value being returned from main memory.
Only when the DMA buffer starts on a cache-line boundary and is an exact
mutiple of the cache-line size can invalidate_dcache_range() be called,
otherwise flush_dcache_range() must be called. flush_dcache_range()
will first flush uncommitted writes, and then invalidate the cache.
Signed-off-by: Andrew Lewis <andrew-lewis at netspace.net.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
For 32-bit systems, powerpc still relies on the 4level-fixup.h hack,
to pretend that the generic pagetable handling stuff is 3-levels
rather than 4. This patch removes this, instead using the newer
pgtable-nopmd.h to handle the elision of both the pud and pmd
pagetable levels (ppc32 pagetables are actually 2 levels).
This removes a little extraneous code, and makes it more easily
compared to the 64-bit pagetable code.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Including support for non-coherent cache, some mm-related things +
relevant field in Kconfig and Makefiles. Also included rheap.o compilation
if 8xx is defined.
Non-coherent mapping were refined and renamed according to Cristoph
Hellwig. Orphaned functions were cleaned up.
[Also removed arch/ppc/kernel/dma-mapping.c, because otherwise
compiling with ARCH=ppc for a non DMA-cache-coherent platform ends up
with two copies of __dma_alloc_coherent etc.
-- paulus.]
Signed-off-by: Vitaly Bordug <vbordug@ru.mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
