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Subject: Re: [PATCH] of: use hash based search in of_find_node_by_phandle
To: Chintan Pandya <cpandya@codeaurora.org>, robh+dt@kernel.org,
        devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
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 <13846fcb-3aa2-a4fb-1bd8-e624855f105d@codeaurora.org>
From: Frank Rowand <frowand.list@gmail.com>
Message-ID: <2ac0d70d-074d-5eff-77e9-29d1a246a3ef@gmail.com>
Date: Fri, 26 Jan 2018 13:27:00 -0800
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On 01/26/18 00:22, Chintan Pandya wrote:
> 
> 
> 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) \
>         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