From eb0dd411bd90dd5ad3f1936930d3e83d9ef95561 Mon Sep 17 00:00:00 2001 From: Nishanth Aravamudan Date: Mon, 9 May 2011 12:58:03 +0000 Subject: [PATCH] pseries/iommu: Restore iommu table pointer when restoring iommu ops When we swtich to direct dma ops, we set the dma data union to have the dma offset. When we switch back to iommu table ops because of a later dma_set_mask, we need to restore the iommu table pointer. Without this change, crashes have been observed on kexec where (for reasons still being investigated) we fall back to a 32-bit dma mask on a particular device and then panic because the table pointer is not valid. The easiset way to find this value is to call pci_dma_dev_setup_pSeriesLP which will search up the pci tree until it finds the node with the table. Signed-off-by: Nishanth Aravamudan Cc: Milton Miller Cc: Paul Mackerras Cc: Anton Blanchard Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/iommu.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 019009b10e62..48eec3b87026 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -1029,10 +1029,10 @@ static int dma_set_mask_pSeriesLP(struct device *dev, u64 dma_mask) if (!dev->dma_mask || !dma_supported(dev, dma_mask)) return -EIO; + pdev = to_pci_dev(dev); + /* only attempt to use a new window if 64-bit DMA is requested */ if (!disable_ddw && dma_mask == DMA_BIT_MASK(64)) { - pdev = to_pci_dev(dev); - dn = pci_device_to_OF_node(pdev); dev_dbg(dev, "node is %s\n", dn->full_name); @@ -1063,6 +1063,7 @@ static int dma_set_mask_pSeriesLP(struct device *dev, u64 dma_mask) if (!ddw_enabled) { dev_info(dev, "Using 32-bit DMA via iommu\n"); set_dma_ops(dev, &dma_iommu_ops); + pci_dma_dev_setup_pSeriesLP(pdev); } *dev->dma_mask = dma_mask;