From: Mike Rapoport <[email protected]> Some powerpc platforms (e.g. 85xx) limit DMA-able memory way below 4G. If a system has more physical memory than this limit, the swiotlb buffer is not addressable because it is allocated from memblock using top-down mode.
Force memblock to bottom-up mode before calling swiotlb_init() to ensure that the swiotlb buffer is DMA-able. Link: https://lkml.kernel.org/r/[email protected] Reported-by: Christian Zigotzky <[email protected]> Signed-off-by: Mike Rapoport <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Darren Stevens <[email protected]> Cc: mad skateman <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Nicolas Saenz Julienne <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Robin Murphy <[email protected]> Cc: Rob Herring <[email protected]> --- arch/powerpc/mm/mem.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index be941d382c8d..14c2c53e3f9e 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -260,6 +260,14 @@ void __init mem_init(void) BUILD_BUG_ON(MMU_PAGE_COUNT > 16); #ifdef CONFIG_SWIOTLB + /* + * Some platforms (e.g. 85xx) limit DMA-able memory way below + * 4G. We force memblock to bottom-up mode to ensure that the + * memory allocated in swiotlb_init() is DMA-able. + * As it's the last memblock allocation, no need to reset it + * back to to-down. + */ + memblock_set_bottom_up(true); swiotlb_init(0); #endif -- 2.24.0 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
