Merge tag 'iommu-config-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

Pull ARM SoC/iommu configuration update from Arnd Bergmann:
 "The iomm-config branch contains work from Will Deacon, quoting his
  description:

    This series adds automatic IOMMU and DMA-mapping configuration for
    OF-based DMA masters described using the generic IOMMU devicetree
    bindings. Although there is plenty of future work around splitting up
    iommu_ops, adding default IOMMU domains and sorting out automatic IOMMU
    group creation for the platform_bus, this is already useful enough for
    people to port over their IOMMU drivers and start using the new probing
    infrastructure (indeed, Marek has patches queued for the Exynos IOMMU).

  The branch touches core ARM and IOMMU driver files, and the respective
  maintainers (Russell King and Joerg Roedel) agreed to have the
  contents merged through the arm-soc tree.

  The final version was ready just before the merge window, so we ended
  up delaying it a bit longer than the rest, but we don't expect to see
  regressions because this is just additional infrastructure that will
  get used in drivers starting in 3.20 but is unused so far"

* tag 'iommu-config-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  iommu: store DT-probed IOMMU data privately
  arm: dma-mapping: plumb our iommu mapping ops into arch_setup_dma_ops
  arm: call iommu_init before of_platform_populate
  dma-mapping: detect and configure IOMMU in of_dma_configure
  iommu: fix initialization without 'add_device' callback
  iommu: provide helper function to configure an IOMMU for an of master
  iommu: add new iommu_ops callback for adding an OF device
  dma-mapping: replace set_arch_dma_coherent_ops with arch_setup_dma_ops
  iommu: provide early initialisation hook for IOMMU drivers

3 files changed, 85 insertions, 14 deletions

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index e6e3446abdf6..b52101d37ec7 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -121,13 +121,12 @@ static inline unsigned long dma_max_pfn(struct device *dev)
 }
 #define dma_max_pfn(dev) dma_max_pfn(dev)
 
-static inline int set_arch_dma_coherent_ops(struct device *dev)
-{
-        dev->archdata.dma_coherent = true;
-        set_dma_ops(dev, &arm_coherent_dma_ops);
-        return 0;
-}
-#define set_arch_dma_coherent_ops(dev)  set_arch_dma_coherent_ops(dev)
+#define arch_setup_dma_ops arch_setup_dma_ops
+extern void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                               struct iommu_ops *iommu, bool coherent);
+
+#define arch_teardown_dma_ops arch_teardown_dma_ops
+extern void arch_teardown_dma_ops(struct device *dev);
 
 /* do not use this function in a driver */
 static inline bool is_device_dma_coherent(struct device *dev)
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 8361652b6dab..f9c863911038 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -18,6 +18,7 @@
 #include <linux/bootmem.h>
 #include <linux/seq_file.h>
 #include <linux/screen_info.h>
+#include <linux/of_iommu.h>
 #include <linux/of_platform.h>
 #include <linux/init.h>
 #include <linux/kexec.h>
@@ -806,6 +807,7 @@ static int __init customize_machine(void)
          * machine from the device tree, if no callback is provided,
          * otherwise we would always need an init_machine callback.
          */
+        of_iommu_init();
         if (machine_desc->init_machine)
                 machine_desc->init_machine();
 #ifdef CONFIG_OF
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index e8907117861e..7864797609b3 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1947,9 +1947,8 @@ EXPORT_SYMBOL_GPL(arm_iommu_release_mapping);
  *      arm_iommu_create_mapping)
  *
  * Attaches specified io address space mapping to the provided device,
- * this replaces the dma operations (dma_map_ops pointer) with the
- * IOMMU aware version. More than one client might be attached to
- * the same io address space mapping.
+ * More than one client might be attached to the same io address space
+ * mapping.
  */
 int arm_iommu_attach_device(struct device *dev,
                             struct dma_iommu_mapping *mapping)
@@ -1962,7 +1961,6 @@ int arm_iommu_attach_device(struct device *dev,
 
         kref_get(&mapping->kref);
         dev->archdata.mapping = mapping;
-        set_dma_ops(dev, &iommu_ops);
 
         pr_debug("Attached IOMMU controller to %s device.\n", dev_name(dev));
         return 0;
@@ -1974,7 +1972,6 @@ EXPORT_SYMBOL_GPL(arm_iommu_attach_device);
  * @dev: valid struct device pointer
  *
  * Detaches the provided device from a previously attached map.
- * This voids the dma operations (dma_map_ops pointer)
  */
 void arm_iommu_detach_device(struct device *dev)
 {
@@ -1989,10 +1986,83 @@ void arm_iommu_detach_device(struct device *dev)
         iommu_detach_device(mapping->domain, dev);
         kref_put(&mapping->kref, release_iommu_mapping);
         dev->archdata.mapping = NULL;
-        set_dma_ops(dev, NULL);
 
         pr_debug("Detached IOMMU controller from %s device.\n", dev_name(dev));
 }
 EXPORT_SYMBOL_GPL(arm_iommu_detach_device);
 
-#endif
+static struct dma_map_ops *arm_get_iommu_dma_map_ops(bool coherent)
+{
+        return coherent ? &iommu_coherent_ops : &iommu_ops;
+}
+
+static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                                    struct iommu_ops *iommu)
+{
+        struct dma_iommu_mapping *mapping;
+
+        if (!iommu)
+                return false;
+
+        mapping = arm_iommu_create_mapping(dev->bus, dma_base, size);
+        if (IS_ERR(mapping)) {
+                pr_warn("Failed to create %llu-byte IOMMU mapping for device %s\n",
+                                size, dev_name(dev));
+                return false;
+        }
+
+        if (arm_iommu_attach_device(dev, mapping)) {
+                pr_warn("Failed to attached device %s to IOMMU_mapping\n",
+                                dev_name(dev));
+                arm_iommu_release_mapping(mapping);
+                return false;
+        }
+
+        return true;
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev)
+{
+        struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+
+        arm_iommu_detach_device(dev);
+        arm_iommu_release_mapping(mapping);
+}
+
+#else
+
+static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                                    struct iommu_ops *iommu)
+{
+        return false;
+}
+
+static void arm_teardown_iommu_dma_ops(struct device *dev) { }
+
+#define arm_get_iommu_dma_map_ops arm_get_dma_map_ops
+
+#endif  /* CONFIG_ARM_DMA_USE_IOMMU */
+
+static struct dma_map_ops *arm_get_dma_map_ops(bool coherent)
+{
+        return coherent ? &arm_coherent_dma_ops : &arm_dma_ops;
+}
+
+void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
+                        struct iommu_ops *iommu, bool coherent)
+{
+        struct dma_map_ops *dma_ops;
+
+        dev->archdata.dma_coherent = coherent;
+        if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu))
+                dma_ops = arm_get_iommu_dma_map_ops(coherent);
+        else
+                dma_ops = arm_get_dma_map_ops(coherent);
+
+        set_dma_ops(dev, dma_ops);
+}
+
+void arch_teardown_dma_ops(struct device *dev)
+{
+        arm_teardown_iommu_dma_ops(dev);
+}