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-rw-r--r--src/commonlib/include/commonlib/region.h23
-rw-r--r--src/commonlib/region.c53
2 files changed, 76 insertions, 0 deletions
diff --git a/src/commonlib/include/commonlib/region.h b/src/commonlib/include/commonlib/region.h
index d3e7ebdfff..fbc1790033 100644
--- a/src/commonlib/include/commonlib/region.h
+++ b/src/commonlib/include/commonlib/region.h
@@ -154,4 +154,27 @@ void mmap_helper_device_init(struct mmap_helper_region_device *mdev,
void *mmap_helper_rdev_mmap(const struct region_device *, size_t, size_t);
int mmap_helper_rdev_munmap(const struct region_device *, void *);
+/* A translated region device provides the ability to publish a region device
+ * in one address space and use an access mechansim within another address
+ * space. The sub region is the window within the 1st address space and
+ * the request is modified prior to accessing the second address space
+ * provided by access_dev. */
+struct xlate_region_device {
+ const struct region_device *access_dev;
+ struct region sub_region;
+ struct region_device rdev;
+};
+
+extern const struct region_device_ops xlate_rdev_ops;
+
+#define XLATE_REGION_INIT(access_dev_, sub_offset_, sub_size_, parent_sz_) \
+ { \
+ .access_dev = access_dev_, \
+ .sub_region = { \
+ .offset = (sub_offset_), \
+ .size = (sub_size_), \
+ }, \
+ .rdev = REGION_DEV_INIT(&xlate_rdev_ops, 0, (parent_sz_)),\
+ }
+
#endif /* _REGION_H_ */
diff --git a/src/commonlib/region.c b/src/commonlib/region.c
index 352f92e37f..49626005b9 100644
--- a/src/commonlib/region.c
+++ b/src/commonlib/region.c
@@ -194,3 +194,56 @@ int mmap_helper_rdev_munmap(const struct region_device *rd, void *mapping)
return 0;
}
+
+static void *xlate_mmap(const struct region_device *rd, size_t offset,
+ size_t size)
+{
+ const struct xlate_region_device *xldev;
+ struct region req = {
+ .offset = offset,
+ .size = size,
+ };
+
+ xldev = container_of(rd, typeof(*xldev), rdev);
+
+ if (!is_subregion(&xldev->sub_region, &req))
+ return NULL;
+
+ offset -= region_offset(&xldev->sub_region);
+
+ return rdev_mmap(xldev->access_dev, offset, size);
+}
+
+static int xlate_munmap(const struct region_device *rd, void *mapping)
+{
+ const struct xlate_region_device *xldev;
+
+ xldev = container_of(rd, typeof(*xldev), rdev);
+
+ return rdev_munmap(xldev->access_dev, mapping);
+}
+
+static ssize_t xlate_readat(const struct region_device *rd, void *b,
+ size_t offset, size_t size)
+{
+ struct region req = {
+ .offset = offset,
+ .size = size,
+ };
+ const struct xlate_region_device *xldev;
+
+ xldev = container_of(rd, typeof(*xldev), rdev);
+
+ if (!is_subregion(&xldev->sub_region, &req))
+ return -1;
+
+ offset -= region_offset(&xldev->sub_region);
+
+ return rdev_readat(xldev->access_dev, b, offset, size);
+}
+
+const struct region_device_ops xlate_rdev_ops = {
+ .mmap = xlate_mmap,
+ .munmap = xlate_munmap,
+ .readat = xlate_readat,
+};