kernel/arch/powerpc/platforms/pseries/of_helpers.c
2024-07-22 17:22:30 +08:00

98 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/string.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <asm/prom.h>
#include "of_helpers.h"
/**
* pseries_of_derive_parent - basically like dirname(1)
* @path: the full_name of a node to be added to the tree
*
* Returns the node which should be the parent of the node
* described by path. E.g., for path = "/foo/bar", returns
* the node with full_name = "/foo".
*/
struct device_node *pseries_of_derive_parent(const char *path)
{
struct device_node *parent;
char *parent_path = "/";
const char *tail;
/* We do not want the trailing '/' character */
tail = kbasename(path) - 1;
/* reject if path is "/" */
if (!strcmp(path, "/"))
return ERR_PTR(-EINVAL);
if (tail > path) {
parent_path = kstrndup(path, tail - path, GFP_KERNEL);
if (!parent_path)
return ERR_PTR(-ENOMEM);
}
parent = of_find_node_by_path(parent_path);
if (strcmp(parent_path, "/"))
kfree(parent_path);
return parent ? parent : ERR_PTR(-EINVAL);
}
/* Helper Routines to convert between drc_index to cpu numbers */
int of_read_drc_info_cell(struct property **prop, const __be32 **curval,
struct of_drc_info *data)
{
const char *p = (char *)(*curval);
const __be32 *p2;
if (!data)
return -EINVAL;
/* Get drc-type:encode-string */
data->drc_type = (char *)p;
p = of_prop_next_string(*prop, p);
if (!p)
return -EINVAL;
/* Get drc-name-prefix:encode-string */
data->drc_name_prefix = (char *)p;
p = of_prop_next_string(*prop, p);
if (!p)
return -EINVAL;
/* Get drc-index-start:encode-int */
p2 = (const __be32 *)p;
data->drc_index_start = be32_to_cpu(*p2);
/* Get drc-name-suffix-start:encode-int */
p2 = of_prop_next_u32(*prop, p2, &data->drc_name_suffix_start);
if (!p2)
return -EINVAL;
/* Get number-sequential-elements:encode-int */
p2 = of_prop_next_u32(*prop, p2, &data->num_sequential_elems);
if (!p2)
return -EINVAL;
/* Get sequential-increment:encode-int */
p2 = of_prop_next_u32(*prop, p2, &data->sequential_inc);
if (!p2)
return -EINVAL;
/* Get drc-power-domain:encode-int */
p2 = of_prop_next_u32(*prop, p2, &data->drc_power_domain);
if (!p2)
return -EINVAL;
/* Should now know end of current entry */
(*curval) = (void *)(++p2);
data->last_drc_index = data->drc_index_start +
((data->num_sequential_elems - 1) * data->sequential_inc);
return 0;
}
EXPORT_SYMBOL(of_read_drc_info_cell);