[Xen-devel] [RFC 4/6] xen/passthrough/arm: Introduce iommu_fwspec

[Sameer Goel <sgoel@xxxxxxxxxxxxxx>]

Introduce a common structure to hold the fw (ACPI or DT) defined
configuration for SMMU hw. The current use case is for arm SMMUs. So,
making this architecture specific.

Based on Linux kernel commit 57f98d2f61e1: iommu: Introduce iommu_fwspec
Signed-off-by: Sameer Goel <sgoel@xxxxxxxxxxxxxx>
---
 xen/drivers/passthrough/arm/iommu.c | 57 +++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/device.h        |  1 +
 xen/include/xen/iommu.h             | 28 ++++++++++++++++++
 3 files changed, 86 insertions(+)

diff --git a/xen/drivers/passthrough/arm/iommu.c 
b/xen/drivers/passthrough/arm/iommu.c
index 95b1abb..edf70c2 100644
--- a/xen/drivers/passthrough/arm/iommu.c
+++ b/xen/drivers/passthrough/arm/iommu.c
@@ -73,3 +73,60 @@ int arch_iommu_populate_page_table(struct domain *d)
     /* The IOMMU shares the p2m with the CPU */
     return -ENOSYS;
 }
+
+int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
+        const struct iommu_ops *ops)
+{
+    struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+
+    if (fwspec)
+        return ops == fwspec->ops ? 0 : -EINVAL;
+
+    fwspec = xzalloc(struct iommu_fwspec);
+    if (!fwspec)
+        return -ENOMEM;
+
+    /* Ref counting for the dt device node is not needed */
+
+    /*of_node_get(to_of_node(iommu_fwnode));*/
+
+    fwspec->iommu_fwnode = iommu_fwnode;
+    fwspec->ops = ops;
+    dev->iommu_fwspec = fwspec;
+    return 0;
+}
+
+void iommu_fwspec_free(struct device *dev)
+{
+    struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+
+    if (fwspec) {
+        /*fwnode_handle_put(fwspec->iommu_fwnode);*/
+        xfree(fwspec);
+        dev->iommu_fwspec = NULL;
+    }
+}
+
+int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids)
+{
+    struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+    size_t size;
+    int i;
+
+    if (!fwspec)
+        return -EINVAL;
+
+    size = offsetof(struct iommu_fwspec, ids[fwspec->num_ids + num_ids]);
+    if (size > sizeof(*fwspec)) {
+        fwspec = _xrealloc(dev->iommu_fwspec, size, sizeof(void *));
+        if (!fwspec)
+            return -ENOMEM;
+    }
+
+    for (i = 0; i < num_ids; i++)
+        fwspec->ids[fwspec->num_ids + i] = ids[i];
+
+    fwspec->num_ids += num_ids;
+    dev->iommu_fwspec = fwspec;
+    return 0;
+}
diff --git a/xen/include/asm-arm/device.h b/xen/include/asm-arm/device.h
index 78c38fe..5027c87 100644
--- a/xen/include/asm-arm/device.h
+++ b/xen/include/asm-arm/device.h
@@ -21,6 +21,7 @@ struct device
     struct dt_device_node *of_node; /* Used by drivers imported from Linux */
 #endif
     struct fwnode_handle *fwnode; /*fw device node identifier */
+    struct iommu_fwspec *iommu_fwspec;
     struct dev_archdata archdata;
 };
 
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index 5803e3f..7ef9b93 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -224,4 +224,32 @@ DECLARE_PER_CPU(bool_t, iommu_dont_flush_iotlb);
 extern struct spinlock iommu_pt_cleanup_lock;
 extern struct page_list_head iommu_pt_cleanup_list;
 
+/**
+ * Following block was ported from Linux to help with the implementation of
+ * arm64 iommu devices. Hence the architecture specific compile
+ */
+
+#if defined(CONFIG_ARM_64) || defined(CONFIG_ARM)
+/**
+ * struct iommu_fwspec - per-device IOMMU instance data
+ * @ops: ops for this device's IOMMU
+ * @iommu_fwnode: firmware handle for this device's IOMMU
+ * @iommu_priv: IOMMU driver private data for this device
+ * @num_ids: number of associated device IDs
+ * @ids: IDs which this device may present to the IOMMU
+ */
+struct iommu_fwspec {
+       const struct iommu_ops  *ops;
+       struct fwnode_handle    *iommu_fwnode;
+       void                    *iommu_priv;
+       unsigned int            num_ids;
+       u32                     ids[1];
+};
+
+int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
+                     const struct iommu_ops *ops);
+void iommu_fwspec_free(struct device *dev);
+int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
+
+#endif
 #endif /* _IOMMU_H_ */
-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc. 
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux 
Foundation Collaborative Project.


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