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  1. /*
  2.  * Copyright (c) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <ofw_tree.h>
  30. #include <ofw.h>
  31. #include <types.h>
  32. #include <string.h>
  33. #include <balloc.h>
  34. #include <asm.h>
  35.  
  36. #define MAX_PATH_LEN    256
  37.  
  38. static ofw_tree_node_t *ofw_tree_node_alloc(void)
  39. {
  40.     return balloc(sizeof(ofw_tree_node_t), sizeof(ofw_tree_node_t));
  41. }
  42.  
  43. static ofw_tree_property_t *ofw_tree_properties_alloc(unsigned count)
  44. {
  45.     return balloc(count * sizeof(ofw_tree_property_t), sizeof(ofw_tree_property_t));
  46. }
  47.  
  48. static void * ofw_tree_space_alloc(size_t size)
  49. {
  50.     char *addr;
  51.  
  52.     /*
  53.      * What we do here is a nasty hack :-)
  54.      * Problem: string property values that are allocated via this
  55.      * function typically do not contain the trailing '\0'. This
  56.      * is very uncomfortable for kernel, which is supposed to deal
  57.      * with the properties.
  58.      * Solution: when allocating space via this function, we always
  59.      * allocate space for the extra '\0' character that we store
  60.      * behind the requested memory.
  61.      */
  62.     addr = balloc(size + 1, size);
  63.     if (addr)
  64.         addr[size] = '\0';
  65.     return addr;
  66. }
  67.  
  68. /** Transfer information from one OpenFirmware node into its memory representation.
  69.  *
  70.  * Transfer entire information from the OpenFirmware device tree 'current' node to
  71.  * its memory representation in 'current_node'. This function recursively processes
  72.  * all node's children. Node's peers are processed iteratively in order to prevent
  73.  * stack from overflowing.
  74.  *
  75.  * @param current_node  Pointer to uninitialized ofw_tree_node structure that will
  76.  *          become the memory represenation of 'current'.
  77.  * @param parent_node   Parent ofw_tree_node structure or NULL in case of root node.
  78.  * @param current   OpenFirmware phandle to the current device tree node.
  79.  */
  80. static void ofw_tree_node_process(ofw_tree_node_t *current_node,
  81.     ofw_tree_node_t *parent_node, phandle current)
  82. {
  83.     static char path[MAX_PATH_LEN+1];
  84.     static char name[OFW_TREE_PROPERTY_MAX_NAMELEN];
  85.     phandle peer;
  86.     phandle child;
  87.     size_t len;
  88.     int i;
  89.  
  90.     while (current_node) {
  91.         /*
  92.          * Initialize node.
  93.          */
  94.         current_node->parent = parent_node;
  95.         current_node->peer = NULL;
  96.         current_node->child = NULL;
  97.         current_node->node_handle = current;
  98.         current_node->properties = 0;
  99.         current_node->property = NULL;
  100.         current_node->device = NULL;
  101.    
  102.         /*
  103.          * Get the disambigued name.
  104.          */
  105.         len = ofw_package_to_path(current, path, MAX_PATH_LEN);
  106.         if (len == -1)
  107.             return;
  108.    
  109.         path[len] = '\0';
  110.         for (i = len - 1; i >= 0 && path[i] != '/'; i--)
  111.             ;
  112.         i++;    /* do not include '/' */
  113.    
  114.         len -= i;
  115.  
  116.         /* add space for trailing '\0' */
  117.         current_node->da_name = ofw_tree_space_alloc(len + 1);
  118.         if (!current_node->da_name)
  119.             return;
  120.    
  121.         memcpy(current_node->da_name, &path[i], len);
  122.         current_node->da_name[len] = '\0';
  123.    
  124.    
  125.         /*
  126.          * Recursively process the potential child node.
  127.          */
  128.         child = ofw_get_child_node(current);
  129.         if (child != 0 && child != -1) {
  130.             ofw_tree_node_t *child_node;
  131.        
  132.             child_node = ofw_tree_node_alloc();
  133.             if (child_node) {
  134.                 ofw_tree_node_process(child_node, current_node, child);
  135.                 current_node->child = child_node;
  136.             }
  137.         }
  138.    
  139.         /*
  140.          * Count properties.
  141.          */
  142.         name[0] = '\0';
  143.         while (ofw_next_property(current, name, name) == 1)
  144.             current_node->properties++;
  145.    
  146.         if (!current_node->properties)
  147.             return;
  148.    
  149.         /*
  150.          * Copy properties.
  151.          */
  152.         current_node->property = ofw_tree_properties_alloc(current_node->properties);
  153.         if (!current_node->property)
  154.             return;
  155.        
  156.         name[0] = '\0';
  157.         for (i = 0; ofw_next_property(current, name, name) == 1; i++) {
  158.             size_t size;
  159.        
  160.             if (i == current_node->properties)
  161.                 break;
  162.        
  163.             memcpy(current_node->property[i].name, name,
  164.                 OFW_TREE_PROPERTY_MAX_NAMELEN);
  165.             current_node->property[i].name[OFW_TREE_PROPERTY_MAX_NAMELEN] = '\0';
  166.  
  167.             size = ofw_get_proplen(current, name);
  168.             current_node->property[i].size = size;
  169.             if (size) {
  170.                 void *buf;
  171.            
  172.                 buf = ofw_tree_space_alloc(size);
  173.                 if (current_node->property[i].value = buf) {
  174.                     /*
  175.                      * Copy property value to memory node.
  176.                      */
  177.                     (void) ofw_get_property(current, name, buf, size);
  178.                 }
  179.             } else {
  180.                 current_node->property[i].value = NULL;
  181.             }
  182.         }
  183.  
  184.         current_node->properties = i;   /* Just in case we ran out of memory. */
  185.  
  186.         /*
  187.          * Iteratively process the next peer node.
  188.          * Note that recursion is a bad idea here.
  189.          * Due to the topology of the OpenFirmware device tree,
  190.          * the nesting of peer nodes could be to wide and the
  191.          * risk of overflowing the stack is too real.
  192.          */
  193.         peer = ofw_get_peer_node(current);
  194.         if (peer != 0 && peer != -1) {
  195.             ofw_tree_node_t *peer_node;
  196.        
  197.             peer_node = ofw_tree_node_alloc();
  198.             if (peer_node) {
  199.                 current_node->peer = peer_node;
  200.                 current_node = peer_node;
  201.                 current = peer;
  202.                 /*
  203.                  * Process the peer in next iteration.
  204.                  */
  205.                 continue;
  206.             }
  207.         }
  208.         /*
  209.          * No more peers on this level.
  210.          */
  211.         break;
  212.     }
  213. }
  214.  
  215. /** Construct memory representation of OpenFirmware device tree.
  216.  *
  217.  * @return NULL on failure or pointer to the root node.
  218.  */
  219. ofw_tree_node_t *ofw_tree_build(void)
  220. {
  221.     ofw_tree_node_t *root;
  222.     phandle ssm_node;
  223.     ofw_tree_node_t *ssm;
  224.    
  225.     root = ofw_tree_node_alloc();
  226.     if (root)
  227.         ofw_tree_node_process(root, NULL, ofw_root);
  228.  
  229.     /*
  230.      * The firmware client interface does not automatically include the
  231.      * "ssm" node in the list of children of "/". A nasty yet working
  232.      * solution is to explicitly stick "ssm" to the OFW tree.
  233.      */
  234.     ssm_node = ofw_find_device("/ssm@0,0");
  235.     if (ssm_node != -1) {
  236.         ssm = ofw_tree_node_alloc();
  237.         if (ssm) {
  238.             ofw_tree_node_process(ssm, root, ofw_find_device("/ssm@0,0"));
  239.             ssm->peer = root->child;
  240.             root->child = ssm;
  241.         }
  242.     }
  243.    
  244.     return root;
  245. }
  246.