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powerpc/ioda: Set "read" permission when "write" is set

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Quite often drivers set only "write" permission assuming that this
includes "read" permission as well and this works on plenty of
platforms. However IODA2 is strict about this and produces an EEH when
"read" permission is not set and reading happens.

This adds a workaround in the IODA code to always add the "read" bit
when the "write" bit is set.

Fixes: 10b35b2b7485 ("powerpc/powernv: Do not set "read" flag if direction==DMA_NONE")
Cc: stable@vger.kernel.org # 4.2+
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Douglas Miller <dougmill@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Alexey Kardashevskiy 2016-02-17 18:26:31 +11:00 committed by Michael Ellerman
parent c777e2a8b6
commit 6ecad912a0
1 changed files with 6 additions and 0 deletions
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6
arch/powerpc/platforms/powernv/pci.c
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@ -599,6 +599,9 @@ int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
u64 rpn = __pa(uaddr) >> tbl->it_page_shift;
long i;
if (proto_tce & TCE_PCI_WRITE)
proto_tce |= TCE_PCI_READ;
for (i = 0; i < npages; i++) {
unsigned long newtce = proto_tce |
((rpn + i) << tbl->it_page_shift);
@ -620,6 +623,9 @@ int pnv_tce_xchg(struct iommu_table *tbl, long index,
BUG_ON(*hpa & ~IOMMU_PAGE_MASK(tbl));
if (newtce & TCE_PCI_WRITE)
newtce |= TCE_PCI_READ;
oldtce = xchg(pnv_tce(tbl, idx), cpu_to_be64(newtce));
*hpa = be64_to_cpu(oldtce) & ~(TCE_PCI_READ | TCE_PCI_WRITE);
*direction = iommu_tce_direction(oldtce);