Driver core: Add iommu_ops to bus_type

This is the starting point to make the iommu_ops used for
the iommu-api a per-bus-type structure. It is required to
easily implement bus-specific setup in the iommu-layer.
The first user will be the iommu-group attribute in sysfs.

Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 30b06449748636bc8b4da767570b8daa65d60844..3343264f5105a33729e2ac0bd85e5786ba925e81 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -34,6 +34,37 @@ void register_iommu(struct iommu_ops *ops)
        iommu_ops = ops;
 }
 
+static void iommu_bus_init(struct bus_type *bus, struct iommu_ops *ops)
+{
+}
+
+/**
+ * bus_set_iommu - set iommu-callbacks for the bus
+ * @bus: bus.
+ * @ops: the callbacks provided by the iommu-driver
+ *
+ * This function is called by an iommu driver to set the iommu methods
+ * used for a particular bus. Drivers for devices on that bus can use
+ * the iommu-api after these ops are registered.
+ * This special function is needed because IOMMUs are usually devices on
+ * the bus itself, so the iommu drivers are not initialized when the bus
+ * is set up. With this function the iommu-driver can set the iommu-ops
+ * afterwards.
+ */
+int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops)
+{
+       if (bus->iommu_ops != NULL)
+               return -EBUSY;
+
+       bus->iommu_ops = ops;
+
+       /* Do IOMMU specific setup for this bus-type */
+       iommu_bus_init(bus, ops);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(bus_set_iommu);
+
 bool iommu_found(void)
 {
        return iommu_ops != NULL;

diff --git a/include/linux/device.h b/include/linux/device.h
index c20dfbfc49b425b39794011ab0fed4d226c4ad50..e838e143baa7ed85d8fcc20896922d12f2376a10 100644 (file)
--- 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 6470cd87b4ea2e5d4929fe9b821a0d572c2707ab..dca83d3405b1b3a723dd8cbaf3c89b2989c35760 100644 (file)
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -25,6 +25,7 @@
 #define IOMMU_WRITE    (2)
 #define IOMMU_CACHE    (4) /* DMA cache coherency */
 
+struct bus_type;
 struct device;
 
 struct iommu_domain {
@@ -52,6 +53,7 @@ struct iommu_ops {
 };
 
 extern void register_iommu(struct iommu_ops *ops);
+extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
 extern bool iommu_found(void);
 extern struct iommu_domain *iommu_domain_alloc(void);
 extern void iommu_domain_free(struct iommu_domain *domain);