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pseries/iommu: Restore iommu table pointer when restoring iommu ops

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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 <nacc@us.ibm.com>
Cc: Milton Miller <miltonm@bga.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Nishanth Aravamudan 2011-05-09 12:58:03 +00:00 committed by Benjamin Herrenschmidt
parent 40f1ce7fb7
commit eb0dd411bd
1 changed files with 3 additions and 2 deletions
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5
arch/powerpc/platforms/pseries/iommu.c
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@ -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;