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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),
  46.         sizeof(ofw_tree_property_t));
  47. }
  48.  
  49. static void *ofw_tree_space_alloc(size_t size)
  50. {
  51.     char *addr;
  52.  
  53.     /*
  54.      * What we do here is a nasty hack :-)
  55.      * Problem: string property values that are allocated via this
  56.      * function typically do not contain the trailing '\0'. This
  57.      * is very uncomfortable for kernel, which is supposed to deal
  58.      * with the properties.
  59.      * Solution: when allocating space via this function, we always
  60.      * allocate space for the extra '\0' character that we store
  61.      * behind the requested memory.
  62.      */
  63.     addr = balloc(size + 1, size);
  64.     if (addr)
  65.         addr[size] = '\0';
  66.     return addr;
  67. }
  68.  
  69. /** Transfer information from one OpenFirmware node into its memory
  70.  * representation.
  71.  *
  72.  * Transfer entire information from the OpenFirmware device tree 'current' node
  73.  * to its memory representation in 'current_node'. This function recursively
  74.  * processes all node's children. Node's peers are processed iteratively in
  75.  * order to prevent stack from overflowing.
  76.  *
  77.  * @param current_node  Pointer to uninitialized ofw_tree_node structure that
  78.  *          will become the memory represenation of 'current'.
  79.  * @param parent_node   Parent ofw_tree_node structure or NULL in case of root
  80.  *          node.
  81.  * @param current   OpenFirmware phandle to the current device tree node.
  82.  */
  83. static void ofw_tree_node_process(ofw_tree_node_t *current_node,
  84.     ofw_tree_node_t *parent_node, phandle current)
  85. {
  86.     static char path[MAX_PATH_LEN + 1];
  87.     static char name[OFW_TREE_PROPERTY_MAX_NAMELEN];
  88.     static char name2[OFW_TREE_PROPERTY_MAX_NAMELEN];
  89.     phandle peer;
  90.     phandle child;
  91.     size_t len;
  92.     int i;
  93.  
  94.     while (current_node) {
  95.         /*
  96.          * Initialize node.
  97.          */
  98.         current_node->parent = parent_node;
  99.         current_node->peer = NULL;
  100.         current_node->child = NULL;
  101.         current_node->node_handle = current;
  102.         current_node->properties = 0;
  103.         current_node->property = NULL;
  104.         current_node->device = NULL;
  105.    
  106.         /*
  107.          * Get the disambigued name.
  108.          */
  109.         len = ofw_package_to_path(current, path, MAX_PATH_LEN);
  110.         if (len == -1)
  111.             return;
  112.    
  113.         path[len] = '\0';
  114.         for (i = len - 1; i >= 0 && path[i] != '/'; i--)
  115.             ;
  116.         i++;    /* do not include '/' */
  117.    
  118.         len -= i;
  119.  
  120.         /* add space for trailing '\0' */
  121.         current_node->da_name = ofw_tree_space_alloc(len + 1);
  122.         if (!current_node->da_name)
  123.             return;
  124.    
  125.         memcpy(current_node->da_name, &path[i], len);
  126.         current_node->da_name[len] = '\0';
  127.    
  128.         /*
  129.          * Recursively process the potential child node.
  130.          */
  131.         child = ofw_get_child_node(current);
  132.         if (child != 0 && child != -1) {
  133.             ofw_tree_node_t *child_node;
  134.        
  135.             child_node = ofw_tree_node_alloc();
  136.             if (child_node) {
  137.                 ofw_tree_node_process(child_node, current_node,
  138.                     child);
  139.                 current_node->child = child_node;
  140.             }
  141.         }
  142.    
  143.         /*
  144.          * Count properties.
  145.          */
  146.         name[0] = '\0';
  147.         while (ofw_next_property(current, name, name2) == 1) {
  148.             current_node->properties++;
  149.             memcpy(name, name2, OFW_TREE_PROPERTY_MAX_NAMELEN);
  150.         }
  151.  
  152.         if (!current_node->properties)
  153.             return;
  154.    
  155.         /*
  156.          * Copy properties.
  157.          */
  158.         current_node->property =
  159.             ofw_tree_properties_alloc(current_node->properties);
  160.         if (!current_node->property)
  161.             return;
  162.        
  163.         name[0] = '\0';
  164.         for (i = 0; ofw_next_property(current, name, name2) == 1; i++) {
  165.             size_t size;
  166.        
  167.             if (i == current_node->properties)
  168.                 break;
  169.        
  170.             memcpy(name, name2, OFW_TREE_PROPERTY_MAX_NAMELEN);
  171.             memcpy(current_node->property[i].name, name,
  172.                 OFW_TREE_PROPERTY_MAX_NAMELEN);
  173.             current_node->property[i].name[
  174.                 OFW_TREE_PROPERTY_MAX_NAMELEN] = '\0';
  175.  
  176.             size = ofw_get_proplen(current, name);
  177.             current_node->property[i].size = size;
  178.             if (size) {
  179.                 void *buf;
  180.            
  181.                 buf = ofw_tree_space_alloc(size);
  182.                 if (current_node->property[i].value = buf) {
  183.                     /*
  184.                      * Copy property value to memory node.
  185.                      */
  186.                     (void) ofw_get_property(current, name,
  187.                         buf, size);
  188.                 }
  189.             } else {
  190.                 current_node->property[i].value = NULL;
  191.             }
  192.         }
  193.  
  194.         /* Just in case we ran out of memory. */
  195.         current_node->properties = i;
  196.  
  197.         /*
  198.          * Iteratively process the next peer node.
  199.          * Note that recursion is a bad idea here.
  200.          * Due to the topology of the OpenFirmware device tree,
  201.          * the nesting of peer nodes could be to wide and the
  202.          * risk of overflowing the stack is too real.
  203.          */
  204.         peer = ofw_get_peer_node(current);
  205.         if (peer != 0 && peer != -1) {
  206.             ofw_tree_node_t *peer_node;
  207.        
  208.             peer_node = ofw_tree_node_alloc();
  209.             if (peer_node) {
  210.                 current_node->peer = peer_node;
  211.                 current_node = peer_node;
  212.                 current = peer;
  213.                 /*
  214.                  * Process the peer in next iteration.
  215.                  */
  216.                 continue;
  217.             }
  218.         }
  219.         /*
  220.          * No more peers on this level.
  221.          */
  222.         break;
  223.     }
  224. }
  225.  
  226. /** Construct memory representation of OpenFirmware device tree.
  227.  *
  228.  * @return      NULL on failure or pointer to the root node.
  229.  */
  230. ofw_tree_node_t *ofw_tree_build(void)
  231. {
  232.     ofw_tree_node_t *root;
  233.     phandle ssm_node;
  234.     ofw_tree_node_t *ssm;
  235.    
  236.     root = ofw_tree_node_alloc();
  237.     if (root)
  238.         ofw_tree_node_process(root, NULL, ofw_root);
  239.  
  240.     /*
  241.      * The firmware client interface does not automatically include the
  242.      * "ssm" node in the list of children of "/". A nasty yet working
  243.      * solution is to explicitly stick "ssm" to the OFW tree.
  244.      */
  245.     ssm_node = ofw_find_device("/ssm@0,0");
  246.     if (ssm_node != -1) {
  247.         ssm = ofw_tree_node_alloc();
  248.         if (ssm) {
  249.             ofw_tree_node_process(ssm, root,
  250.                 ofw_find_device("/ssm@0,0"));
  251.             ssm->peer = root->child;
  252.             root->child = ssm;
  253.         }
  254.     }
  255.    
  256.     return root;
  257. }
  258.