drivers/of/of_pci.c

   1 #include <linux/kernel.h>
   2 #include <linux/of_pci.h>
   3 #include <asm/prom.h>
   4
   5 static inline int __of_pci_pci_compare(struct device_node *node,
   6                                        unsigned int devfn)
   7 {
   8         unsigned int size;
   9         const __be32 *reg = of_get_property(node, "reg", &size);
  10
  11         if (!reg || size < 5 * sizeof(__be32))
  12                 return 0;
  13         return ((be32_to_cpup(&reg[0]) >> 8) & 0xff) == devfn;
  14 }
  15
  16 struct device_node *of_pci_find_child_device(struct device_node *parent,
  17                                              unsigned int devfn)
  18 {
  19         struct device_node *node, *node2;
  20
  21         for_each_child_of_node(parent, node) {
  22                 if (__of_pci_pci_compare(node, devfn))
  23                         return node;
  24                 /*
  25                  * Some OFs create a parent node "multifunc-device" as
  26                  * a fake root for all functions of a multi-function
  27                  * device we go down them as well.
  28                  */
  29                 if (!strcmp(node->name, "multifunc-device")) {
  30                         for_each_child_of_node(node, node2) {
  31                                 if (__of_pci_pci_compare(node2, devfn)) {
  32                                         of_node_put(node);
  33                                         return node2;
  34                                 }
  35                         }
  36                 }
  37         }
  38         return NULL;
  39 }
  40 EXPORT_SYMBOL_GPL(of_pci_find_child_device);