[Xen-devel] [PATCH v4 1/7] xen/arm: extend device_tree_for_each_node

[Stefano Stabellini <sstabellini@kernel.org>]

Add new parameters to device_tree_for_each_node: node, depth,
address_cells, size_cells.
Node is the parent node to start the search from;
depth is the min depth of the search (the depth of the parent node);
address_cells and size_cells are the respective parameters at the parent
node. Passing 0, 0, 0, 0 triggers the old behavior.

We need this change because in follow-up patches we want to be able to
use reuse device_tree_for_each_node to call a function for each children
nodes of a provided node.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
Changes in v4:
- add address_cells and size_cells parameters

Changes in v3:
- improve commit message
- improve in-code comments
- improve code style

Changes in v2:
- new
---
 xen/arch/arm/acpi/boot.c      |  2 +-
 xen/arch/arm/bootfdt.c        | 21 +++++++++++++++------
 xen/include/xen/device_tree.h |  6 ++++--
 3 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/xen/arch/arm/acpi/boot.c b/xen/arch/arm/acpi/boot.c
index 9b29769a10..d275f8c535 100644
--- a/xen/arch/arm/acpi/boot.c
+++ b/xen/arch/arm/acpi/boot.c
@@ -248,7 +248,7 @@ int __init acpi_boot_table_init(void)
      */
     if ( param_acpi_off || ( !param_acpi_force
                              && device_tree_for_each_node(device_tree_flattened,
-                                                   dt_scan_depth1_nodes, NULL)))
+                                 0, 0, 0, 0, dt_scan_depth1_nodes, NULL)))
         goto disable;
 
     /*
diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index 891b4b66ff..dfce8c2bfe 100644
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -77,6 +77,10 @@ static u32 __init device_tree_get_u32(const void *fdt, int node,
 /**
  * device_tree_for_each_node - iterate over all device tree nodes
  * @fdt: flat device tree.
+ * @node: parent node to start the search from
+ * @depth: depth of the parent node
+ * @address_cells: address_cells at the parent node
+ * @size_cells: size_cells at the parent node
  * @func: function to call for each node.
  * @data: data to pass to @func.
  *
@@ -86,17 +90,22 @@ static u32 __init device_tree_get_u32(const void *fdt, int node,
  * returns a value different from 0, that value is returned immediately.
  */
 int __init device_tree_for_each_node(const void *fdt,
+                                     int node, int depth,
+                                     u32 address_cells_p, u32 size_cells_p,
                                      device_tree_node_func func,
                                      void *data)
 {
-    int node;
-    int depth;
     u32 address_cells[DEVICE_TREE_MAX_DEPTH];
     u32 size_cells[DEVICE_TREE_MAX_DEPTH];
-    int ret;
+    int ret, min_depth = depth;
+
+    if ( depth > 0 )
+    {
+        address_cells[depth - 1] = address_cells_p;
+        size_cells[depth - 1] = size_cells_p;
+    }
 
-    for ( node = 0, depth = 0;
-          node >=0 && depth >= 0;
+    for ( ; node >= 0 && depth >= min_depth;
           node = fdt_next_node(fdt, node, &depth) )
     {
         const char *name = fdt_get_name(fdt, node, NULL);
@@ -357,7 +366,7 @@ size_t __init boot_fdt_info(const void *fdt, paddr_t paddr)
 
     add_boot_module(BOOTMOD_FDT, paddr, fdt_totalsize(fdt), false);
 
-    device_tree_for_each_node((void *)fdt, early_scan_node, NULL);
+    device_tree_for_each_node((void *)fdt, 0, 0, 0, 0, early_scan_node, NULL);
     early_print_info();
 
     return fdt_totalsize(fdt);
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index 83156297e2..358c67c912 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -159,8 +159,10 @@ typedef int (*device_tree_node_func)(const void *fdt,
 extern const void *device_tree_flattened;
 
 int device_tree_for_each_node(const void *fdt,
-                                     device_tree_node_func func,
-                                     void *data);
+                              int node, int depth,
+                              u32 address_cells, u32 size_cells,
+                              device_tree_node_func func,
+                              void *data);
 
 /**
  * dt_unflatten_host_device_tree - Unflatten the host device tree
-- 
2.17.1


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