Hi Oleksandr,
On 21/05/2019 18:37, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
Port Linux helper of_count_phandle_with_args for counting
number of phandles in a property.
Please note, this helper is ported from Linux v4.6.
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
Acked-by: Julien Grall <julien.gr...@arm.com>
Cheers,
---
Changes RFC -> V1:
- Add Linux version which is used as the base.
---
xen/common/device_tree.c | 7 +++++++
xen/include/xen/device_tree.h | 19 +++++++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 8fc401d..65862b5 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -1663,6 +1663,13 @@ int dt_parse_phandle_with_args(const struct
dt_device_node *np,
index, out_args);
}
+int dt_count_phandle_with_args(const struct dt_device_node *np,
+ const char *list_name,
+ const char *cells_name)
+{
+ return __dt_parse_phandle_with_args(np, list_name, cells_name, 0, -1,
NULL);
+}
+
/**
* unflatten_dt_node - Alloc and populate a device_node from the flat tree
* @fdt: The parent device tree blob
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 7408a6c..8315629 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -738,6 +738,25 @@ int dt_parse_phandle_with_args(const struct dt_device_node
*np,
const char *cells_name, int index,
struct dt_phandle_args *out_args);
+/**
+ * dt_count_phandle_with_args() - Find the number of phandles references in a
property
+ * @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
+ *
+ * Returns the number of phandle + argument tuples within a property. It
+ * is a typical pattern to encode a list of phandle and variable
+ * arguments into a single property. The number of arguments is encoded
+ * by a property in the phandle-target node. For example, a gpios
+ * property would contain a list of GPIO specifies consisting of a
+ * phandle and 1 or more arguments. The number of arguments are
+ * determined by the #gpio-cells property in the node pointed to by the
+ * phandle.
+ */
+int dt_count_phandle_with_args(const struct dt_device_node *np,
+ const char *list_name,
+ const char *cells_name);
+
#ifdef CONFIG_DEVICE_TREE_DEBUG
#define dt_dprintk(fmt, args...) \
printk(XENLOG_DEBUG fmt, ## args)
--
Julien Grall
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