1 files changed, 121 insertions, 0 deletions
diff --git a/src/lib/region.c b/src/lib/region.c
new file mode 100644
index 0000000000..948addd2ca
--- /dev/null
+++ b/src/lib/region.c
@@ -0,0 +1,121 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc.
+ */
+
+#include <region.h>
+#include <string.h>
+
+static inline size_t region_offset(const struct region *r)
+{
+	return r->offset;
+}
+
+static inline size_t region_end(const struct region *r)
+{
+	return region_sz(r) + region_offset(r);
+}
+
+static int is_subregion(const struct region *p, const struct region *c)
+{
+	if (region_offset(c) < region_offset(p))
+		return 0;
+
+	if (region_sz(c) > region_sz(p))
+		return 0;
+
+	if (region_end(c) > region_end(p))
+		return 0;
+
+	return 1;
+}
+
+static int normalize_and_ok(const struct region *outer, struct region *inner)
+{
+	inner->offset += region_offset(outer);
+	return is_subregion(outer, inner);
+}
+
+static const struct region_device *rdev_root(const struct region_device *rdev)
+{
+	if (rdev->root == NULL)
+		return rdev;
+	return rdev->root;
+}
+
+void *rdev_mmap(const struct region_device *rd, size_t offset, size_t size)
+{
+	const struct region_device *rdev;
+	struct region req = {
+		.offset = offset,
+		.size = size,
+	};
+
+	if (!normalize_and_ok(&rd->region, &req))
+		return NULL;
+
+	rdev = rdev_root(rd);
+
+	return rdev->ops->mmap(rdev, req.offset, req.size);
+}
+
+int rdev_munmap(const struct region_device *rd, void *mapping)
+{
+	const struct region_device *rdev;
+
+	rdev = rdev_root(rd);
+
+	return rdev->ops->munmap(rdev, mapping);
+}
+
+ssize_t rdev_readat(const struct region_device *rd, void *b, size_t offset,
+			size_t size)
+{
+	const struct region_device *rdev;
+	struct region req = {
+		.offset = offset,
+		.size = size,
+	};
+
+	if (!normalize_and_ok(&rd->region, &req))
+		return -1;
+
+	rdev = rdev_root(rd);
+
+	return rdev->ops->readat(rdev, b, req.offset, req.size);
+}
+
+int rdev_chain(struct region_device *child, const struct region_device *parent,
+		size_t offset, size_t size)
+{
+	struct region req = {
+		.offset = offset,
+		.size = size,
+	};
+
+	if (!normalize_and_ok(&parent->region, &req))
+		return -1;
+
+	/* Keep track of root region device. Note the offsets are relative
+	 * to the root device. */
+	child->root = rdev_root(parent);
+	child->ops = NULL;
+	child->region.offset = req.offset;
+	child->region.size = req.size;
+
+	return 0;
+}