2 files changed, 72 insertions, 10 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index c20dfbfc49b4..e838e143baa7 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -33,6 +33,7 @@ struct class;
 struct subsys_private;
 struct bus_type;
 struct device_node;
+struct iommu_ops;
 
 struct bus_attribute {
         struct attribute        attr;
@@ -67,6 +68,9 @@ extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
  * @resume:     Called to bring a device on this bus out of sleep mode.
  * @pm:         Power management operations of this bus, callback the specific
  *              device driver's pm-ops.
+ * @iommu_ops   IOMMU specific operations for this bus, used to attach IOMMU
+ *              driver implementations to a bus and allow the driver to do
+ *              bus-specific setup
  * @p:          The private data of the driver core, only the driver core can
  *              touch this.
  *
@@ -96,6 +100,8 @@ struct bus_type {
 
         const struct dev_pm_ops *pm;
 
+        struct iommu_ops *iommu_ops;
+
         struct subsys_private *p;
 };
 
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 9940319d6f9d..432acc4c054d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -25,15 +25,29 @@
 #define IOMMU_WRITE     (2)
 #define IOMMU_CACHE     (4) /* DMA cache coherency */
 
+struct iommu_ops;
+struct bus_type;
 struct device;
+struct iommu_domain;
+
+/* iommu fault flags */
+#define IOMMU_FAULT_READ        0x0
+#define IOMMU_FAULT_WRITE       0x1
+
+typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
+                                struct device *, unsigned long, int);
 
 struct iommu_domain {
+        struct iommu_ops *ops;
         void *priv;
+        iommu_fault_handler_t handler;
 };
 
 #define IOMMU_CAP_CACHE_COHERENCY       0x1
 #define IOMMU_CAP_INTR_REMAP            0x2     /* isolates device intrs */
 
+#ifdef CONFIG_IOMMU_API
+
 struct iommu_ops {
         int (*domain_init)(struct iommu_domain *domain);
         void (*domain_destroy)(struct iommu_domain *domain);
@@ -49,11 +63,9 @@ struct iommu_ops {
                               unsigned long cap);
 };
 
-#ifdef CONFIG_IOMMU_API
-
-extern void register_iommu(struct iommu_ops *ops);
-extern bool iommu_found(void);
-extern struct iommu_domain *iommu_domain_alloc(void);
+extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
+extern bool iommu_present(struct bus_type *bus);
+extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
 extern void iommu_domain_free(struct iommu_domain *domain);
 extern int iommu_attach_device(struct iommu_domain *domain,
                                struct device *dev);
@@ -67,19 +79,58 @@ extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain,
                                       unsigned long iova);
 extern int iommu_domain_has_cap(struct iommu_domain *domain,
                                 unsigned long cap);
+extern void iommu_set_fault_handler(struct iommu_domain *domain,
+                                        iommu_fault_handler_t handler);
+
+/**
+ * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework
+ * @domain: the iommu domain where the fault has happened
+ * @dev: the device where the fault has happened
+ * @iova: the faulting address
+ * @flags: mmu fault flags (e.g. IOMMU_FAULT_READ/IOMMU_FAULT_WRITE/...)
+ *
+ * This function should be called by the low-level IOMMU implementations
+ * whenever IOMMU faults happen, to allow high-level users, that are
+ * interested in such events, to know about them.
+ *
+ * This event may be useful for several possible use cases:
+ * - mere logging of the event
+ * - dynamic TLB/PTE loading
+ * - if restarting of the faulting device is required
+ *
+ * Returns 0 on success and an appropriate error code otherwise (if dynamic
+ * PTE/TLB loading will one day be supported, implementations will be able
+ * to tell whether it succeeded or not according to this return value).
+ *
+ * Specifically, -ENOSYS is returned if a fault handler isn't installed
+ * (though fault handlers can also return -ENOSYS, in case they want to
+ * elicit the default behavior of the IOMMU drivers).
+ */
+static inline int report_iommu_fault(struct iommu_domain *domain,
+                struct device *dev, unsigned long iova, int flags)
+{
+        int ret = -ENOSYS;
 
-#else /* CONFIG_IOMMU_API */
+        /*
+         * if upper layers showed interest and installed a fault handler,
+         * invoke it.
+         */
+        if (domain->handler)
+                ret = domain->handler(domain, dev, iova, flags);
 
-static inline void register_iommu(struct iommu_ops *ops)
-{
+        return ret;
 }
 
-static inline bool iommu_found(void)
+#else /* CONFIG_IOMMU_API */
+
+struct iommu_ops {};
+
+static inline bool iommu_present(struct bus_type *bus)
 {
         return false;
 }
 
-static inline struct iommu_domain *iommu_domain_alloc(void)
+static inline struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
 {
         return NULL;
 }
@@ -123,6 +174,11 @@ static inline int domain_has_cap(struct iommu_domain *domain,
         return 0;
 }
 
+static inline void iommu_set_fault_handler(struct iommu_domain *domain,
+                                        iommu_fault_handler_t handler)
+{
+}
+
 #endif /* CONFIG_IOMMU_API */
 
 #endif /* __LINUX_IOMMU_H */