From 902d0f0953d0074b329a2780a4b637fae0d776da Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Wed, 27 Jul 2016 14:55:53 +0200 Subject: [PATCH] libfdt: Add a subnodes iterator macro The fdt_for_each_subnode() iterator macro provided by this patch can be used to iterate over a device tree node's subnodes. At each iteration a loop variable will be set to the next subnode. Signed-off-by: Thierry Reding Signed-off-by: Maxime Ripard Signed-off-by: David Gibson --- libfdt/libfdt.h | 28 ++++++++++++++++++++++++++++ tests/subnode_iterate.c | 8 ++------ 2 files changed, 30 insertions(+), 6 deletions(-) diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h index 36222fd..911e548 100644 --- a/libfdt/libfdt.h +++ b/libfdt/libfdt.h @@ -168,6 +168,34 @@ int fdt_first_subnode(const void *fdt, int offset); */ int fdt_next_subnode(const void *fdt, int offset); +/** + * fdt_for_each_subnode - iterate over all subnodes of a parent + * + * @node: child node (int, lvalue) + * @fdt: FDT blob (const void *) + * @parent: parent node (int) + * + * This is actually a wrapper around a for loop and would be used like so: + * + * fdt_for_each_subnode(node, fdt, parent) { + * Use node + * ... + * } + * + * if ((node < 0) && (node != -FDT_ERR_NOT_FOUND)) { + * Error handling + * } + * + * Note that this is implemented as a macro and @node is used as + * iterator in the loop. The parent variable be constant or even a + * literal. + * + */ +#define fdt_for_each_subnode(node, fdt, parent) \ + for (node = fdt_first_subnode(fdt, parent); \ + node >= 0; \ + node = fdt_next_subnode(fdt, node)) + /**********************************************************************/ /* General functions */ /**********************************************************************/ diff --git a/tests/subnode_iterate.c b/tests/subnode_iterate.c index b9f379d..0fb5c90 100644 --- a/tests/subnode_iterate.c +++ b/tests/subnode_iterate.c @@ -48,9 +48,7 @@ static void test_node(void *fdt, int parent_offset) subnodes = cpu_to_fdt32(*prop); count = 0; - for (offset = fdt_first_subnode(fdt, parent_offset); - offset >= 0; - offset = fdt_next_subnode(fdt, offset)) + fdt_for_each_subnode(offset, fdt, parent_offset) count++; if (count != subnodes) { @@ -65,9 +63,7 @@ static void check_fdt_next_subnode(void *fdt) int offset; int count = 0; - for (offset = fdt_first_subnode(fdt, 0); - offset >= 0; - offset = fdt_next_subnode(fdt, offset)) { + fdt_for_each_subnode(offset, fdt, 0) { test_node(fdt, offset); count++; }