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Date: Mon, 19 Aug 2013 11:13:27 +0100
From: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
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To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [RFC PATCH v2 3/4] powerpc: refactor of_get_cpu_node to support
 other architectures
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Cc: Jonas Bonn <jonas@southpole.se>,
 "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
 Michal Simek <monstr@monstr.eu>,
 "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
 Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 "rob.herring@calxeda.com" <rob.herring@calxeda.com>,
 "Rafael J. Wysocki" <rjw@sisk.pl>,
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On 16/08/13 23:13, Benjamin Herrenschmidt wrote:
> On Fri, 2013-08-16 at 18:39 +0100, Sudeep KarkadaNagesha wrote:
>> +static bool __of_find_n_match_cpu_property(struct device_node *cpun,
>> +                       const char *prop_name, int cpu, unsigned int
>> *thread)
>> +{
>> +       const __be32 *cell;
>> +       int ac, prop_len, tid;
>> +       u64 hwid;
>> +
>> +       ac =3D of_n_addr_cells(cpun);
>> +       cell =3D of_get_property(cpun, prop_name, &prop_len);
>> +       if (!cell)
>> +               return false;
>> +       prop_len /=3D sizeof(*cell);
>> +       for (tid =3D 0; tid < prop_len; tid++) {
>> +               hwid =3D of_read_number(cell, ac);
>> +               if (arch_match_cpu_phys_id(cpu, hwid)) {
>> +                       if (thread)
>> +                               *thread =3D tid;
>> +                       return true;
>> +               }
>> +               cell +=3D ac;
>> +       }
>> +       return false;
>> +}
>=20
> The only problem I can see here is if "ac" is not 1, that will not work
> for the ibm,ppc-interrupt-server#s case. IE. The latter is always 1 cell
> per entry, only "reg" depends on #address-cells.
>=20
> However that's only a theorical problem since on ppc #address-cells of
> /cpus is always 1...
>=20
Ok agreed, but I assume in future if thread ids need 2 ac, it would use
standard 'reg' instead of 'ibm,ppc-interrupt-server#' property.

So I assume the above function is generic and need not be modified to
handle non '1' ac case  with non standard 'ibm,ppc-interrupt-server#'.

Regards,
Sudeep