[Xen-changelog] [xen staging] xen/arm: pass node to device_tree_for_each_node

[patchbot@xxxxxxx]

commit 40f2ea3df2e2980750ffa99bed3d877993c47254
Author:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
AuthorDate: Mon Aug 19 10:43:31 2019 -0700
Commit:     Julien Grall <julien.grall@xxxxxxx>
CommitDate: Tue Aug 20 13:39:36 2019 +0100

    xen/arm: pass node to device_tree_for_each_node
    
    Add a new parameter to device_tree_for_each_node: node, the node to
    start the search from.
    
    To avoid scanning device tree, and given that we only care about
    relative increments of depth compared to the depth of the initial node,
    we set the initial depth to 0. Then, we call func() for every node with
    depth > 0.
    
    Don't call func() on the parent node passed as an argument. Clarify the
    change in the comment on top of the function. The current callers pass
    the root node as argument: it is OK to skip the root node because no
    relevant properties are in it, only subnodes.
    
    Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
    [julien: Remove min_depth variable]
    Acked-by: Julien Grall <julien.grall@xxxxxxx>
---
 xen/arch/arm/acpi/boot.c      |  8 +++++---
 xen/arch/arm/bootfdt.c        | 37 +++++++++++++++++++++++--------------
 xen/include/xen/device_tree.h |  6 +++---
 3 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/xen/arch/arm/acpi/boot.c b/xen/arch/arm/acpi/boot.c
index 9b29769a10..bf9c78b02c 100644
--- a/xen/arch/arm/acpi/boot.c
+++ b/xen/arch/arm/acpi/boot.c
@@ -246,9 +246,11 @@ int __init acpi_boot_table_init(void)
      * - the device tree is not empty (it has more than just a /chosen node)
      *   and ACPI has not been force enabled (acpi=force)
      */
-    if ( param_acpi_off || ( !param_acpi_force
-                             && 
device_tree_for_each_node(device_tree_flattened,
-                                                   dt_scan_depth1_nodes, 
NULL)))
+    if ( param_acpi_off)
+        goto disable;
+    if ( !param_acpi_force &&
+         device_tree_for_each_node(device_tree_flattened, 0,
+                                   dt_scan_depth1_nodes, NULL) )
         goto disable;
 
     /*
diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index 891b4b66ff..7d298afc8b 100644
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -75,9 +75,10 @@ static u32 __init device_tree_get_u32(const void *fdt, int 
node,
 }
 
 /**
- * device_tree_for_each_node - iterate over all device tree nodes
+ * device_tree_for_each_node - iterate over all device tree sub-nodes
  * @fdt: flat device tree.
- * @func: function to call for each node.
+ * @node: parent node to start the search from
+ * @func: function to call for each sub-node.
  * @data: data to pass to @func.
  *
  * Any nodes nested at DEVICE_TREE_MAX_DEPTH or deeper are ignored.
@@ -85,20 +86,21 @@ static u32 __init device_tree_get_u32(const void *fdt, int 
node,
  * Returns 0 if all nodes were iterated over successfully.  If @func
  * returns a value different from 0, that value is returned immediately.
  */
-int __init device_tree_for_each_node(const void *fdt,
+int __init device_tree_for_each_node(const void *fdt, int node,
                                      device_tree_node_func func,
                                      void *data)
 {
-    int node;
-    int depth;
+    /*
+     * We only care about relative depth increments, assume depth of
+     * node is 0 for simplicity.
+     */
+    int depth = 0;
+    const int first_node = node;
     u32 address_cells[DEVICE_TREE_MAX_DEPTH];
     u32 size_cells[DEVICE_TREE_MAX_DEPTH];
     int ret;
 
-    for ( node = 0, depth = 0;
-          node >=0 && depth >= 0;
-          node = fdt_next_node(fdt, node, &depth) )
-    {
+    do {
         const char *name = fdt_get_name(fdt, node, NULL);
         u32 as, ss;
 
@@ -117,10 +119,17 @@ int __init device_tree_for_each_node(const void *fdt,
         size_cells[depth] = device_tree_get_u32(fdt, node,
                                                 "#size-cells", ss);
 
-        ret = func(fdt, node, name, depth, as, ss, data);
-        if ( ret != 0 )
-            return ret;
-    }
+        /* skip the first node */
+        if ( node != first_node )
+        {
+            ret = func(fdt, node, name, depth, as, ss, data);
+            if ( ret != 0 )
+                return ret;
+        }
+
+        node = fdt_next_node(fdt, node, &depth);
+    } while ( node >= 0 && depth > 0 );
+
     return 0;
 }
 
@@ -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, 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..9a7a8f2dab 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -158,9 +158,9 @@ 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 device_tree_for_each_node(const void *fdt, int node,
+                              device_tree_node_func func,
+                              void *data);
 
 /**
  * dt_unflatten_host_device_tree - Unflatten the host device tree
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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