From 4cfc40799ab998056103c15ffe3bb9fc777c26f8 Mon Sep 17 00:00:00 2001 From: Oleksandr Tyshchenko Date: Tue, 21 May 2019 20:37:33 +0300 Subject: [PATCH] xen/device-tree: Add dt_count_phandle_with_args helper 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 Acked-by: Julien Grall --- 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 8fc401d91c..65862b58bb 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 7408a6c48c..83156297e2 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) -- 2.30.2