From: Nishanth Aravamudan Date: Mon, 9 May 2011 12:58:03 +0000 (+0000) Subject: pseries/iommu: Restore iommu table pointer when restoring iommu ops X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=eb0dd411bd90dd5ad3f1936930d3e83d9ef95561;p=linux-edison.git 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 --- diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index 019009b10e6..48eec3b8702 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;