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authorThierry Reding <treding@nvidia.com>2014-08-26 17:33:53 +0200
committerSimon Glass <sjg@chromium.org>2014-10-22 16:56:41 -0600
commit56f42242f020254ea1c383694edb072e3a5ca6d6 (patch)
tree7a2b6410c681a09ce033217507b4c75d011fe85e
parent5094eb408a5de69cce8e6bc5564fda10eb79eba0 (diff)
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fdt: Add resource parsing functions
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> Acked-by: Simon Glass <sjg@chromium.org>
-rw-r--r--include/fdtdec.h52
-rw-r--r--lib/fdtdec.c57
2 files changed, 109 insertions, 0 deletions
diff --git a/include/fdtdec.h b/include/fdtdec.h
index 2590d30..8b24deb 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -40,6 +40,27 @@ struct fdt_memory {
fdt_addr_t end;
};
+/*
+ * Information about a resource. start is the first address of the resource
+ * and end is the last address (inclusive). The length of the resource will
+ * be equal to: end - start + 1.
+ */
+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
@@ -597,4 +618,35 @@ 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 prop_names name of the property containing the list of names
+ * @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 *prop_names, const char *name,
+ struct fdt_resource *res);
+
#endif
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 06d4542..b3c43be 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -708,4 +708,61 @@ int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
return 0;
}
+
+static u64 fdtdec_get_number(const fdt32_t *ptr, unsigned int cells)
+{
+ u64 number = 0;
+
+ while (cells--)
+ number = (number << 32) | fdt32_to_cpu(*ptr++);
+
+ return number;
+}
+
+int fdt_get_resource(const void *fdt, int node, const char *property,
+ unsigned int index, struct fdt_resource *res)
+{
+ const fdt32_t *ptr, *end;
+ int na, ns, len, parent;
+ unsigned int i = 0;
+
+ parent = fdt_parent_offset(fdt, node);
+ if (parent < 0)
+ return parent;
+
+ na = fdt_address_cells(fdt, parent);
+ ns = fdt_size_cells(fdt, parent);
+
+ ptr = fdt_getprop(fdt, node, property, &len);
+ if (!ptr)
+ return len;
+
+ end = ptr + len / sizeof(*ptr);
+
+ while (ptr + na + ns <= end) {
+ if (i == index) {
+ res->start = res->end = fdtdec_get_number(ptr, na);
+ res->end += fdtdec_get_number(&ptr[na], ns) - 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 *prop_names, const char *name,
+ struct fdt_resource *res)
+{
+ int index;
+
+ index = fdt_find_string(fdt, node, prop_names, name);
+ if (index < 0)
+ return index;
+
+ return fdt_get_resource(fdt, node, property, index, res);
+}
#endif