[U-Boot] [PATCH 03/23] fdt: Add resource parsing functions

[Thierry Reding <thierry.reding@gmail.com>]

From: Thierry Reding <treding@nvidia.com>

Add the fdt_get_resource() and fdt_get_named_resource() functions which
can be used to parse resources (memory regions) from an FDT. A helper to
compute the size of a region is also provided.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 include/fdtdec.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 lib/fdtdec.c     | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+)

diff --git a/include/fdtdec.h b/include/fdtdec.h
index 856e6cf766de..e9091eee6bae 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -40,6 +40,23 @@ struct fdt_memory {
 	fdt_addr_t end;
 };
 
+/* information about a resource */
+struct fdt_resource {
+	fdt_addr_t start;
+	fdt_addr_t end;
+};
+
+/**
+ * Compute the size of a resource.
+ *
+ * @param res	the resource to operate on
+ * @return the size of the resource
+ */
+static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
+{
+	return res->end - res->start + 1;
+}
+
 /**
  * Compat types that we know about and for which we might have drivers.
  * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
@@ -583,4 +600,35 @@ struct fmap_entry {
  */
 int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
 			   struct fmap_entry *entry);
+
+/**
+ * Obtain an indexed resource from a device property.
+ *
+ * @param fdt		FDT blob
+ * @param node		node to examine
+ * @param property	name of the property to parse
+ * @param index		index of the resource to retrieve
+ * @param res		returns the resource
+ * @return 0 if ok, negative on error
+ */
+int fdt_get_resource(const void *fdt, int node, const char *property,
+		     unsigned int index, struct fdt_resource *res);
+
+/**
+ * Obtain a named resource from a device property.
+ *
+ * Look up the index of the name in a list of strings and return the resource
+ * at that index.
+ *
+ * @param fdt		FDT blob
+ * @param node		node to examine
+ * @param property	name of the property to parse
+ * @param names		name of the property to obtain the match the name to
+ * @param name		the name of the entry to look up
+ * @param res		returns the resource
+ */
+int fdt_get_named_resource(const void *fdt, int node, const char *property,
+			   const char *names, const char *name,
+			   struct fdt_resource *res);
+
 #endif
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index eb5aa20526fd..fbfae4a7cbaf 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -691,4 +691,47 @@ int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
 
 	return 0;
 }
+
+int fdt_get_resource(const void *fdt, int node, const char *property,
+		     unsigned int index, struct fdt_resource *res)
+{
+	const fdt32_t *ptr, *end;
+	unsigned int i = 0;
+	int na, ns, len;
+
+	na = fdt_n_addr_cells(fdt, node);
+	ns = fdt_n_size_cells(fdt, node);
+
+	ptr = fdt_getprop(fdt, node, property, &len);
+	if (!ptr)
+		return len;
+
+	end = ptr + len / 4;
+
+	while (ptr + na + ns <= end) {
+		if (i == index) {
+			res->start = fdt_addr_to_cpu(*ptr);
+			res->end = res->start + fdt_size_to_cpu(ptr[na]) - 1;
+			return 0;
+		}
+
+		ptr += na + ns;
+		i++;
+	}
+
+	return -FDT_ERR_NOTFOUND;
+}
+
+int fdt_get_named_resource(const void *fdt, int node, const char *property,
+			   const char *names, const char *name,
+			   struct fdt_resource *res)
+{
+	int index;
+
+	index = fdt_get_string_index(fdt, node, names, name);
+	if (index < 0)
+		return index;
+
+	return fdt_get_resource(fdt, node, property, index, res);
+}
 #endif
-- 
2.0.4