Re: [PATCH] of: use hash based search in of_find_node_by_phandle

[Chintan Pandya]

On 1/26/2018 1:24 AM, Frank Rowand wrote:
> On 01/25/18 02:14, Chintan Pandya wrote:
> > of_find_node_by_phandle() takes a lot of time finding
> > right node when your intended device is too right-side
> > in the fdt. Reason is, we search each device serially
> > from the fdt, starting from left-most to right-most.
> Please give me a pointer to the code that is doing
> this search.
>
> -Frank
You can refer include/linux/of.h

#define for_each_of_allnodes_from(from, dn) \
ÂÂÂÂÂÂÂ for (dn = __of_find_all_nodes(from); dn; dn = 
__of_find_all_nodes(dn))
#define for_each_of_allnodes(dn) for_each_of_allnodes_from(NULL, dn)

where __of_find_all_nodes() does

struct device_node *__of_find_all_nodes(struct device_node *prev)
{
ÂÂÂÂÂÂÂ struct device_node *np;
ÂÂÂÂÂÂÂ if (!prev) {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ np = of_root;
ÂÂÂÂÂÂÂ } else if (prev->child) {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ np = prev->child;
ÂÂÂÂÂÂÂ } else {
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /* Walk back up looking for a sibling, or the end of 
the structure */
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ np = prev;
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ while (np->parent && !np->sibling)
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ np = np->parent;
ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ np = np->sibling; /* Might be null at the end of the 
tree */
ÂÂÂÂÂÂÂ }
ÂÂÂÂÂÂÂ return np;
}

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