On some MIPS systems, a subset of devices may have DMA coherent with CPU
caches. For example in systems including a MIPS I/O Coherence Unit
(IOCU), some devices may be connected to that IOCU whilst others are
not.
Prior to this patch, we have a plat_device_is_coherent() function but no
implementation which does anything besides return a global true or
false, optionally chosen at runtime. For devices such as those described
above this is insufficient.
Fix this by tracking DMA coherence on a per-device basis with a
dma_coherent field in struct dev_archdata. Setting this from
arch_setup_dma_ops() takes care of devices which set the dma-coherent
property via device tree, and any PCI devices beneath a bridge described
in DT, automatically.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14349/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit 20d330645cfb8cfecfb82b369e4d3084e429e68a)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
The coherentio variable has previously been used as a boolean value,
indicating whether the user specified that coherent I/O should be
enabled or disabled. It failed to take into account the case where the
user does not specify any preference, in which case it makes sense that
we should default to coherent I/O if the hardware supports it
(hw_coherentio is non-zero).
Introduce an enum to clarify the 3 different values of coherentio & use
it throughout the code, modifying plat_device_is_coherent() &
r4k_cache_init() to take into account the default case.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Paul Burton <paul.burton@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/14347/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
(cherry picked from commit f23020230e682a43cc4706cabb041bba469df2d6)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Instead of having platforms to copy the entirety of
mach-generic/dma-coherence.h, check whether these platforms have already
defined a plat_post_dma_flush hook, and if not, provide an inline stub.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: cernekee@gmail.com
Cc: jogo@openwrt.org
Patchwork: https://patchwork.linux-mips.org/patch/9725/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Only one MIPS development board actually supports enabling/disabling DMA
coherency at runtime, so it's not a good idea to push the overhead of
checking that configuration setting onto every other supported target as
well.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/5912/
The semantics stay the same - on Cavium Octeon the functions were dead
code (it overrides the MIPS DMA ops) - on other platforms they contained
no code at all.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5720/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Provide a default implementation of phys_to_dma and dma_to_phys in
mach-generic/dma_coherence.h.
If CONFIG_NEED_SG_DMA_LENGTH is defined, the dma_length field in
struct scatterlist is used. Set this up in mips_dma_map_sg so that
the default mips DMA ops can be used when SWIOTLB is enabled.
Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5409/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Some MIPS controllers have hardware I/O coherency. This patch
detects those and turns off software coherency. A new kernel
command line option also allows the user to manually turn
software coherency on or off.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
We add a dev parameter to plat_unmap_dma_mem(), and hooks for
plat_dma_supported() and plat_extra_sync_for_device() which should be
nop changes for all existing targets.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
