fdt: Add functions to access phandles, arrays and bools

Add a function to look up a property which is a phandle in a node, and
another to read a fixed-length integer array from an fdt property.
Also add a function to read boolean properties, although there is no
actual boolean type in U-Boot.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Gerald Van Baren <vanbaren@cideas.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

diff --git a/include/fdtdec.h b/include/fdtdec.h
index 5469c16abd077e1dbc2083828051730f8c93eb9c..a4467000b7f42ef9be2ab452820e0e23636fd0f8 100644 (file)
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -188,3 +188,42 @@ int fdtdec_find_aliases_for_id(const void *blob, const char *name,
  * @return compatible string for that id
  */
 const char *fdtdec_get_compatible(enum fdt_compat_id id);
+
+/* Look up a phandle and follow it to its node. Then return the offset
+ * of that node.
+ *
+ * @param blob         FDT blob
+ * @param node         node to examine
+ * @param prop_name    name of property to find
+ * @return node offset if found, -ve error code on error
+ */
+int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
+
+/**
+ * Look up a property in a node and return its contents in an integer
+ * array of given length. The property must have at least enough data for
+ * the array (4*count bytes). It may have more, but this will be ignored.
+ *
+ * @param blob         FDT blob
+ * @param node         node to examine
+ * @param prop_name    name of property to find
+ * @param array                array to fill with data
+ * @param count                number of array elements
+ * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
+ *             or -FDT_ERR_BADLAYOUT if not enough data
+ */
+int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
+               u32 *array, int count);
+
+/**
+ * Look up a boolean property in a node and return it.
+ *
+ * A boolean properly is true if present in the device tree and false if not
+ * present, regardless of its value.
+ *
+ * @param blob FDT blob
+ * @param node node to examine
+ * @param prop_name    name of property to find
+ * @return 1 if the properly is present; 0 if it isn't present
+ */
+int fdtdec_get_bool(const void *blob, int node, const char *prop_name);

diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index bf3171730c4db5b0e0cb03b780223a6736f18b6b..13bb47002e463e9e24af33b377b66380952088cf 100644 (file)
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -271,3 +271,70 @@ int fdtdec_check_fdt(void)
                        "binary or define CONFIG_OF_EMBED\n");
        return 0;
 }
+
+int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name)
+{
+       const u32 *phandle;
+       int lookup;
+
+       phandle = fdt_getprop(blob, node, prop_name, NULL);
+       if (!phandle)
+               return -FDT_ERR_NOTFOUND;
+
+       lookup = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*phandle));
+       return lookup;
+}
+
+/**
+ * Look up a property in a node and check that it has a minimum length.
+ *
+ * @param blob         FDT blob
+ * @param node         node to examine
+ * @param prop_name    name of property to find
+ * @param min_len      minimum property length in bytes
+ * @param err          0 if ok, or -FDT_ERR_NOTFOUND if the property is not
+                       found, or -FDT_ERR_BADLAYOUT if not enough data
+ * @return pointer to cell, which is only valid if err == 0
+ */
+static const void *get_prop_check_min_len(const void *blob, int node,
+               const char *prop_name, int min_len, int *err)
+{
+       const void *cell;
+       int len;
+
+       debug("%s: %s\n", __func__, prop_name);
+       cell = fdt_getprop(blob, node, prop_name, &len);
+       if (!cell)
+               *err = -FDT_ERR_NOTFOUND;
+       else if (len < min_len)
+               *err = -FDT_ERR_BADLAYOUT;
+       else
+               *err = 0;
+       return cell;
+}
+
+int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
+               u32 *array, int count)
+{
+       const u32 *cell;
+       int i, err = 0;
+
+       debug("%s: %s\n", __func__, prop_name);
+       cell = get_prop_check_min_len(blob, node, prop_name,
+                                     sizeof(u32) * count, &err);
+       if (!err) {
+               for (i = 0; i < count; i++)
+                       array[i] = fdt32_to_cpu(cell[i]);
+       }
+       return err;
+}
+
+int fdtdec_get_bool(const void *blob, int node, const char *prop_name)
+{
+       const s32 *cell;
+       int len;
+
+       debug("%s: %s\n", __func__, prop_name);
+       cell = fdt_getprop(blob, node, prop_name, &len);
+       return cell != NULL;
+}