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

On 01/26/18 13:27, Frank Rowand wrote:

On 01/26/18 00:22, Chintan Pandya wrote:

quoted

On 1/26/2018 1:24 AM, Frank Rowand wrote:

quoted

On 01/25/18 02:14, Chintan Pandya wrote:

quoted

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

Let me restate my question.

Can you point me to the driver code that is invoking
the search?

-Frank

And also the .dts devicetree source file that you are seeing
large overhead with.