arch/powerpc/platforms/pseries/of_helpers.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/string.h>
   3 #include <linux/err.h>
   4 #include <linux/slab.h>
   5 #include <linux/of.h>
   6 #include <asm/prom.h>
   7
   8 #include "of_helpers.h"
   9
  10 /**
  11  * pseries_of_derive_parent - basically like dirname(1)
  12  * @path:  the full_name of a node to be added to the tree
  13  *
  14  * Returns the node which should be the parent of the node
  15  * described by path.  E.g., for path = "/foo/bar", returns
  16  * the node with full_name = "/foo".
  17  */
  18 struct device_node *pseries_of_derive_parent(const char *path)
  19 {
  20         struct device_node *parent;
  21         char *parent_path = "/";
  22         const char *tail;
  23
  24         /* We do not want the trailing '/' character */
  25         tail = kbasename(path) - 1;
  26
  27         /* reject if path is "/" */
  28         if (!strcmp(path, "/"))
  29                 return ERR_PTR(-EINVAL);
  30
  31         if (tail > path) {
  32                 parent_path = kstrndup(path, tail - path, GFP_KERNEL);
  33                 if (!parent_path)
  34                         return ERR_PTR(-ENOMEM);
  35         }
  36         parent = of_find_node_by_path(parent_path);
  37         if (strcmp(parent_path, "/"))
  38                 kfree(parent_path);
  39         return parent ? parent : ERR_PTR(-EINVAL);
  40 }
  41
  42
  43 /* Helper Routines to convert between drc_index to cpu numbers */
  44
  45 int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
  46                         struct of_drc_info *data)
  47 {
  48         const char *p = (char *)(*curval);
  49         const __be32 *p2;
  50
  51         if (!data)
  52                 return -EINVAL;
  53
  54         /* Get drc-type:encode-string */
  55         data->drc_type = (char *)p;
  56         p = of_prop_next_string(*prop, p);
  57         if (!p)
  58                 return -EINVAL;
  59
  60         /* Get drc-name-prefix:encode-string */
  61         data->drc_name_prefix = (char *)p;
  62         p = of_prop_next_string(*prop, p);
  63         if (!p)
  64                 return -EINVAL;
  65
  66         /* Get drc-index-start:encode-int */
  67         p2 = (const __be32 *)p;
  68         data->drc_index_start = be32_to_cpu(*p2);
  69
  70         /* Get drc-name-suffix-start:encode-int */
  71         p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
  72         if (!p2)
  73                 return -EINVAL;
  74
  75         /* Get number-sequential-elements:encode-int */
  76         p2 = of_prop_next_u32(*prop, p2, &data->num_sequential_elems);
  77         if (!p2)
  78                 return -EINVAL;
  79
  80         /* Get sequential-increment:encode-int */
  81         p2 = of_prop_next_u32(*prop, p2, &data->sequential_inc);
  82         if (!p2)
  83                 return -EINVAL;
  84
  85         /* Get drc-power-domain:encode-int */
  86         p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
  87         if (!p2)
  88                 return -EINVAL;
  89
  90         /* Should now know end of current entry */
  91         (*curval) = (void *)(++p2);
  92         data->last_drc_index = data->drc_index_start +
  93                 ((data->num_sequential_elems - 1) * data->sequential_inc);
  94
  95         return 0;
  96 }
  97 EXPORT_SYMBOL(of_read_drc_info_cell);