The only functional differences (modulo a few missing fixes in the arch
code) is that architectures without coherent caches need a hook to
convert a virtual or dma address into a pfn, given that we don't have
the kernel linear mapping available for the otherwise easy virt_to_page
call. As a side effect we can support mmap of the per-device coherent
area even on architectures not providing the callback, and we make
previous dangerous default methods dma_common_mmap actually save for
non-coherent architectures by rejecting it without the right helper.
In addition to that we need a hook so that some architectures can
override the protection bits when mmaping a dma coherent allocations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
All the cache maintainance is already stubbed out when not enabled,
but merging the two allows us to nicely handle the case where
cache maintainance is required for some devices, but not others.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
Various architectures support both coherent and non-coherent dma on a
per-device basis. Move the dma_noncoherent flag from the mips archdata
field to struct device proper to prepare the infrastructure for reuse on
other architectures.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Burton <paul.burton@mips.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Converting an address between cached & uncached (typically addresses in
(c)kseg0 & (c)kseg1 or 2 xkphys regions) should not depend upon
PHYS_OFFSET in any way - we're converting from a virtual address in one
unmapped region to a virtual address in another unmapped region.
For some reason our CAC_ADDR() & UNCAC_ADDR() macros make use of
PAGE_OFFSET, which typically includes PHYS_OFFSET. This means that
platforms with a non-zero PHYS_OFFSET typically have to workaround
miscalculation by these 2 macros by also defining UNCAC_BASE to a value
that isn't really correct.
It appears that an attempt has previously been made to address this with
commit 3f4579252aa1 ("MIPS: make CAC_ADDR and UNCAC_ADDR account for
PHYS_OFFSET") which was later undone by commit ed3ce16c3d ("Revert
"MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET"") which
also introduced the ar7 workaround. That attempt at a fix was roughly
equivalent, but essentially caused the CAC_ADDR() & UNCAC_ADDR() macros
to cancel out PHYS_OFFSET by adding & then subtracting it again. In his
revert Leonid is correct that using PHYS_OFFSET makes no sense in the
context of these macros, but appears to have missed its inclusion via
PAGE_OFFSET which means PHYS_OFFSET actually had an effect after the
revert rather than before it.
Here we fix this by modifying CAC_ADDR() & UNCAC_ADDR() to stop using
PAGE_OFFSET (& thus PHYS_OFFSET), instead using __pa() & __va() along
with UNCAC_BASE.
For UNCAC_ADDR(), __pa() will convert a cached address to a physical
address which we can simply use as an offset from UNCAC_BASE to obtain
an address in the uncached region.
For CAC_ADDR() we can undo the effect of UNCAC_ADDR() by subtracting
UNCAC_BASE and using __va() on the result.
With this change made, remove definitions of UNCAC_BASE from the ar7 &
pic32 platforms which appear to have defined them only to workaround
this problem.
Signed-off-by: Paul Burton <paul.burton@mips.com>
References: 3f4579252aa1 ("MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET")
References: ed3ce16c3d ("Revert "MIPS: make CAC_ADDR and UNCAC_ADDR account for PHYS_OFFSET"")
Patchwork: https://patchwork.linux-mips.org/patch/20046/
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: Vladimir Kondratiev <vladimir.kondratiev@intel.com>
Convert everything not overriding dma-coherence.h to the generic
noncoherent ops. The new dma-noncoherent.c file duplicates a lot of
the code in dma-default.c, but that file will be gone by the end of
this series.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Patchwork: https://patchwork.linux-mips.org/patch/19544/
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Tom Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-mips@linux-mips.org
Platforms will now have to supply a function dma_device_is_coherent which
returns if a particular device participates in the coherence domain. For
most platforms this function will always return 0 or 1.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pass struct dev pointer to dma_cache_sync()
dma_cache_sync() is ill-designed in that it does not have a struct device
pointer argument which makes proper support for systems that consist of a
mix of coherent and non-coherent DMA devices hard. Change dma_cache_sync
to take a struct device pointer as first argument and fix all its callers
to pass it.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
dma_is_consistent() is ill-designed in that it does not have a struct
device pointer argument which makes proper support for systems that consist
of a mix of coherent and non-coherent DMA devices hard. Change
dma_is_consistent to take a struct device pointer as first argument and fix
the sole caller to pass it.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
