[Xen-devel] [PATCH 5/6] xen/device_tree: introduce find_compatible_node

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

Introduce a find_compatible_node function that can be used by device
drivers to find the node corresponding to their device in the device
tree.

Also add device_tree_node_compatible to device_tree.h, that is currently
missing.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 xen/arch/arm/setup.c          |    2 +-
 xen/common/device_tree.c      |   47 +++++++++++++++++++++++++++++++++++++++++
 xen/include/xen/device_tree.h |    3 ++
 3 files changed, 51 insertions(+), 1 deletions(-)

diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 5f4e318..d978938 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -187,7 +187,7 @@ void __init start_xen(unsigned long boot_phys_offset,
 
     smp_clear_cpu_maps();
 
-    fdt = (void *)BOOT_MISC_VIRT_START
+    device_tree_flattened = fdt = (void *)BOOT_MISC_VIRT_START
         + (atag_paddr & ((1 << SECOND_SHIFT) - 1));
     fdt_size = device_tree_early_init(fdt);
 
diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 8d5b6b0..ca0aba7 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -173,6 +173,53 @@ int device_tree_for_each_node(const void *fdt,
     return 0;
 }
 
+struct find_compat {
+    const char *compatible;
+    int found;
+    int node;
+    int depth;
+    u32 address_cells;
+    u32 size_cells;
+};
+
+static int _find_compatible_node(const void *fdt,
+                             int node, const char *name, int depth,
+                             u32 address_cells, u32 size_cells,
+                             void *data)
+{
+    struct find_compat *c = (struct find_compat *) data;
+    if ( device_tree_node_compatible(fdt, node, c->compatible) )
+    {
+        c->found = 1;
+        c->node = node;
+        c->depth = depth;
+        c->address_cells = address_cells;
+        c->size_cells = size_cells;
+    }
+    return 0;
+}
+ 
+int find_compatible_node(const char *compatible, int *node, int *depth,
+                u32 *address_cells, u32 *size_cells)
+{
+    int ret;
+    struct find_compat c;
+    c.compatible = compatible;
+    c.found = 0;
+
+    ret = device_tree_for_each_node(device_tree_flattened, 
_find_compatible_node, &c);
+    if ( !c.found )
+        return ret;
+    else
+    {
+        *node = c.node;
+        *depth = c.depth;
+        *address_cells = c.address_cells;
+        *size_cells = c.size_cells;
+        return 1;
+    }
+}
+
 /**
  * device_tree_bootargs - return the bootargs (the Xen command line)
  * @fdt flat device tree.
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index a0e3a97..5a75f0e 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -54,6 +54,9 @@ void device_tree_set_reg(u32 **cell, u32 address_cells, u32 
size_cells,
                          u64 start, u64 size);
 u32 device_tree_get_u32(const void *fdt, int node, const char *prop_name);
 bool_t device_tree_node_matches(const void *fdt, int node, const char *match);
+bool_t device_tree_node_compatible(const void *fdt, int node, const char 
*match);
+int find_compatible_node(const char *compatible, int *node, int *depth,
+                u32 *address_cells, u32 *size_cells);
 int device_tree_for_each_node(const void *fdt,
                               device_tree_node_func func, void *data);
 const char *device_tree_bootargs(const void *fdt);
-- 
1.7.2.5


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