of: create of_phandle_args to simplify return of phandle parsing data
of_parse_phandle_with_args() needs to return quite a bit of data. Rather
than making each datum a separate **out_ argument, this patch creates
struct of_phandle_args to contain all the returned data and reworks the
user of the function. This patch also enables of_parse_phandle_with_args()
to return the device node pointer for the phandle node.
This patch also ends up being fairly major surgery to
of_parse_handle_with_args(). The existing structure didn't work well
when extending to use of_phandle_args, and I discovered bugs during testing.
I also took the opportunity to rename the function to be like the
existing of_parse_phandle().
v2: - moved declaration of of_phandle_args to fix compile on non-DT builds
- fixed incorrect index in example usage
- fixed incorrect return code handling for empty entries
Reviewed-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 9b6588e..c6db9ab 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -824,17 +824,19 @@
EXPORT_SYMBOL(of_parse_phandle);
/**
- * of_parse_phandles_with_args - Find a node pointed by phandle in a list
+ * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
* @np: pointer to a device tree node containing a list
* @list_name: property name that contains a list
* @cells_name: property name that specifies phandles' arguments count
* @index: index of a phandle to parse out
- * @out_node: optional pointer to device_node struct pointer (will be filled)
- * @out_args: optional pointer to arguments pointer (will be filled)
+ * @out_args: optional pointer to output arguments structure (will be filled)
*
* This function is useful to parse lists of phandles and their arguments.
- * Returns 0 on success and fills out_node and out_args, on error returns
- * appropriate errno value.
+ * Returns 0 on success and fills out_args, on error returns appropriate
+ * errno value.
+ *
+ * Caller is responsible to call of_node_put() on the returned out_args->node
+ * pointer.
*
* Example:
*
@@ -851,94 +853,96 @@
* }
*
* To get a device_node of the `node2' node you may call this:
- * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);
+ * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
*/
-int of_parse_phandles_with_args(struct device_node *np, const char *list_name,
+int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
const char *cells_name, int index,
- struct device_node **out_node,
- const void **out_args)
+ struct of_phandle_args *out_args)
{
- int ret = -EINVAL;
- const __be32 *list;
- const __be32 *list_end;
- int size;
- int cur_index = 0;
+ const __be32 *list, *list_end;
+ int size, cur_index = 0;
+ uint32_t count = 0;
struct device_node *node = NULL;
- const void *args = NULL;
+ phandle phandle;
+ /* Retrieve the phandle list property */
list = of_get_property(np, list_name, &size);
- if (!list) {
- ret = -ENOENT;
- goto err0;
- }
+ if (!list)
+ return -EINVAL;
list_end = list + size / sizeof(*list);
+ /* Loop over the phandles until all the requested entry is found */
while (list < list_end) {
- const __be32 *cells;
- phandle phandle;
+ count = 0;
+ /*
+ * If phandle is 0, then it is an empty entry with no
+ * arguments. Skip forward to the next entry.
+ */
phandle = be32_to_cpup(list++);
- args = list;
+ if (phandle) {
+ /*
+ * Find the provider node and parse the #*-cells
+ * property to determine the argument length
+ */
+ node = of_find_node_by_phandle(phandle);
+ if (!node) {
+ pr_err("%s: could not find phandle\n",
+ np->full_name);
+ break;
+ }
+ if (of_property_read_u32(node, cells_name, &count)) {
+ pr_err("%s: could not get %s for %s\n",
+ np->full_name, cells_name,
+ node->full_name);
+ break;
+ }
- /* one cell hole in the list = <>; */
- if (!phandle)
- goto next;
-
- node = of_find_node_by_phandle(phandle);
- if (!node) {
- pr_debug("%s: could not find phandle\n",
- np->full_name);
- goto err0;
+ /*
+ * Make sure that the arguments actually fit in the
+ * remaining property data length
+ */
+ if (list + count > list_end) {
+ pr_err("%s: arguments longer than property\n",
+ np->full_name);
+ break;
+ }
}
- cells = of_get_property(node, cells_name, &size);
- if (!cells || size != sizeof(*cells)) {
- pr_debug("%s: could not get %s for %s\n",
- np->full_name, cells_name, node->full_name);
- goto err1;
- }
+ /*
+ * All of the error cases above bail out of the loop, so at
+ * this point, the parsing is successful. If the requested
+ * index matches, then fill the out_args structure and return,
+ * or return -ENOENT for an empty entry.
+ */
+ if (cur_index == index) {
+ if (!phandle)
+ return -ENOENT;
- list += be32_to_cpup(cells);
- if (list > list_end) {
- pr_debug("%s: insufficient arguments length\n",
- np->full_name);
- goto err1;
+ if (out_args) {
+ int i;
+ if (WARN_ON(count > MAX_PHANDLE_ARGS))
+ count = MAX_PHANDLE_ARGS;
+ out_args->np = node;
+ out_args->args_count = count;
+ for (i = 0; i < count; i++)
+ out_args->args[i] = be32_to_cpup(list++);
+ }
+ return 0;
}
-next:
- if (cur_index == index)
- break;
of_node_put(node);
node = NULL;
- args = NULL;
+ list += count;
cur_index++;
}
- if (!node) {
- /*
- * args w/o node indicates that the loop above has stopped at
- * the 'hole' cell. Report this differently.
- */
- if (args)
- ret = -EEXIST;
- else
- ret = -ENOENT;
- goto err0;
- }
-
- if (out_node)
- *out_node = node;
- if (out_args)
- *out_args = args;
-
- return 0;
-err1:
- of_node_put(node);
-err0:
- pr_debug("%s failed with status %d\n", __func__, ret);
- return ret;
+ /* Loop exited without finding a valid entry; return an error */
+ if (node)
+ of_node_put(node);
+ return -EINVAL;
}
-EXPORT_SYMBOL(of_parse_phandles_with_args);
+EXPORT_SYMBOL(of_parse_phandle_with_args);
/**
* prom_add_property - Add a property to a node