4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Alexey Kardashevskiy <[email protected]> commit 6ecad912a0073c768db1491c27ca55ad2d0ee68f upstream. 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: Benjamin Herrenschmidt <[email protected]> Signed-off-by: Alexey Kardashevskiy <[email protected]> Tested-by: Douglas Miller <[email protected]> Signed-off-by: Michael Ellerman <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/powerpc/platforms/powernv/pci.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/arch/powerpc/platforms/powernv/pci.c +++ b/arch/powerpc/platforms/powernv/pci.c @@ -601,6 +601,9 @@ int pnv_tce_build(struct iommu_table *tb 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); @@ -622,6 +625,9 @@ int pnv_tce_xchg(struct iommu_table *tbl 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);
