On Thu, Jan 17, 2019 at 1:28 PM Sam Ravnborg <sam@xxxxxxxxxxxx> wrote:
>
> Hi Andrey.
>
> On Wed, Jan 16, 2019 at 10:38:37PM -0800, Andrey Smirnov wrote:
> > Both ARM and ARM64 have identical code for
> > dma_sync_single_for_cpu(). Move it to mmu-common.c so it can be shared.
> >
> > Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> > ---
> > arch/arm/cpu/mmu-common.c | 8 ++++++++
> > arch/arm/cpu/mmu.c | 7 -------
> > arch/arm/cpu/mmu_64.c | 7 -------
> > 3 files changed, 8 insertions(+), 14 deletions(-)
> >
> > diff --git a/arch/arm/cpu/mmu-common.c b/arch/arm/cpu/mmu-common.c
> > index 8c7d61447..a7d3b5b11 100644
> > --- a/arch/arm/cpu/mmu-common.c
> > +++ b/arch/arm/cpu/mmu-common.c
> > @@ -8,6 +8,14 @@
> >
> > #include "mmu.h"
> >
> > +
> > +void dma_sync_single_for_cpu(dma_addr_t address, size_t size,
> > + enum dma_data_direction dir)
> > +{
> > + if (dir != DMA_TO_DEVICE)
> > + dma_inv_range((void *)address, size);
> > +}
>
> I cannot see how this will work?!?
> We are on a v8 architecture for a 64bit variant.
> But in cache.c we have only:
>
> DEFINE_CPU_FNS(v4)
> DEFINE_CPU_FNS(v5)
> DEFINE_CPU_FNS(v6)
> DEFINE_CPU_FNS(v7)
>
Cache.c isn't going to be built on AArch64, so it doesn't really
matter what's in it. V8_* cache functions are defined in cache-armv8.S
and there's no analog of DEFINE_CPU_FNS() on AArch64.
> So I do not see how we call v8_inv_dcache_range() here.
> Do I miss something?
>
On AArch64 dma_inv_range() is defined as a wrapper around
v8_inv_dcache_range() in "ARM64: mmu: Invalidate memory before
remapping as DMA coherent" and exported to be available to other
compilation units in "ARM: mmu: Share code for dma_alloc_coherent()".
You can also see a pretty concise summary of it in this diff in this
bit:
diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c
index ed4aa00a8..2cb62370e 100644
--- a/arch/arm/cpu/mmu_64.c
+++ b/arch/arm/cpu/mmu_64.c
@@ -256,13 +256,6 @@ void dma_inv_range(void *ptr, size_t size)
v8_inv_dcache_range(start, end);
}
Hope this clarifies things.
Thanks,
Andrey Smirnov
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