pasemi_mac: enable iommu support

pasemi_mac: enable iommu support

Enable IOMMU support for pasemi_mac, but avoid using it on non-partitioned
systems for performance reasons.

The user can override this by selecting the PPC_PASEMI_IOMMU_DMA_FORCE
configuration option.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 20 insertions, 5 deletions

diff --git a/arch/powerpc/platforms/pasemi/Kconfig b/arch/powerpc/platforms/pasemi/Kconfig
index 95cd90fd81c7..e95261ef6f98 100644
--- a/arch/powerpc/platforms/pasemi/Kconfig
+++ b/arch/powerpc/platforms/pasemi/Kconfig
@@ -18,6 +18,16 @@ config PPC_PASEMI_IOMMU
         help
           IOMMU support for PA6T-1682M
 
+config PPC_PASEMI_IOMMU_DMA_FORCE
+        bool "Force DMA engine to use IOMMU"
+        depends on PPC_PASEMI_IOMMU
+        help
+          This option forces the use of the IOMMU also for the
+          DMA engine. Otherwise the kernel will use it only when
+          running under a hypervisor.
+
+          If in doubt, say "N".
+
 config PPC_PASEMI_MDIO
         depends on PHYLIB
         tristate "MDIO support via GPIO"
diff --git a/arch/powerpc/platforms/pasemi/iommu.c b/arch/powerpc/platforms/pasemi/iommu.c
index 9014d55c717b..a1111b5c6cb4 100644
--- a/arch/powerpc/platforms/pasemi/iommu.c
+++ b/arch/powerpc/platforms/pasemi/iommu.c
@@ -25,6 +25,7 @@
 #include <asm/iommu.h>
 #include <asm/machdep.h>
 #include <asm/abs_addr.h>
+#include <asm/firmware.h>
 
 
 #define IOBMAP_PAGE_SHIFT       12
@@ -175,13 +176,17 @@ static void pci_dma_dev_setup_pasemi(struct pci_dev *dev)
 {
         pr_debug("pci_dma_dev_setup, dev %p (%s)\n", dev, pci_name(dev));
 
-        /* DMA device is untranslated, but all other PCI-e goes through
-         * the IOMMU
+#if !defined(CONFIG_PPC_PASEMI_IOMMU_DMA_FORCE)
+        /* For non-LPAR environment, don't translate anything for the DMA
+         * engine. The exception to this is if the user has enabled
+         * CONFIG_PPC_PASEMI_IOMMU_DMA_FORCE at build time.
          */
-        if (dev->vendor == 0x1959 && dev->device == 0xa007)
+        if (dev->vendor == 0x1959 && dev->device == 0xa007 &&
+            !firmware_has_feature(FW_FEATURE_LPAR))
                 dev->dev.archdata.dma_ops = &dma_direct_ops;
-        else
-                dev->dev.archdata.dma_data = &iommu_table_iobmap;
+#endif
+
+        dev->dev.archdata.dma_data = &iommu_table_iobmap;
 }
 
 static void pci_dma_bus_setup_null(struct pci_bus *b) { }