Strongly ordered memory is occasionally needed for some DMA
allocations for specialized use cases. Add the corresponding
DMA attribute.
Change-Id: Idd9e756c242ef57d6fa6700e51cc38d0863b760d
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
[ luis: adjuste context after commit
a9a62c938441 ("dma-mapping: introduce
the DMA_ATTR_NO_WARN attribute") has been applied to master ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
where allocation failures are not a problem, and shouldn't bother the logs.
NOTE: At the moment DMA_ATTR_NO_WARN is only implemented on PowerPC.
+
+DMA_ATTR_STRONGLY_ORDERED
+-------------------------
+
+DMA_ATTR_STRONGLY_ORDERED allocates memory with a very restrictive type
+of mapping (no unaligned accesses, no re-ordering, no write merging, no
+buffering, no pre-fetching). This has severe performance penalties and
+should not be used for general purpose DMA allocations. It should only
+be used if one of the restrictions on strongly ordered memory is required.
DMA_ATTR_SKIP_CPU_SYNC,
DMA_ATTR_FORCE_CONTIGUOUS,
DMA_ATTR_NO_WARN,
+ DMA_ATTR_STRONGLY_ORDERED,
DMA_ATTR_MAX,
};