Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756050Ab3GVOOK (ORCPT ); Mon, 22 Jul 2013 10:14:10 -0400 Received: from mail-qa0-f41.google.com ([209.85.216.41]:49020 "EHLO mail-qa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754420Ab3GVOOG (ORCPT ); Mon, 22 Jul 2013 10:14:06 -0400 Date: Mon, 22 Jul 2013 10:14:02 -0400 (EDT) From: Nicolas Pitre To: Sudeep KarkadaNagesha cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, Russell King , Shawn Guo , Gregory Clement , Greg Kroah-Hartman , Viresh Kumar , "Rafael J. Wysocki" , Grant Likely , Rob Herring , Lorenzo Pieralisi , Olof Johansson , Arnd Bergmann Subject: Re: [PATCH v3 01/16] of: add support for retrieving cpu node for a given logical cpu index In-Reply-To: <1374492747-13879-2-git-send-email-Sudeep.KarkadaNagesha@arm.com> Message-ID: References: <1374069984-20567-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1374492747-13879-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1374492747-13879-2-git-send-email-Sudeep.KarkadaNagesha@arm.com> User-Agent: Alpine 2.03 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3133 Lines: 83 On Mon, 22 Jul 2013, Sudeep KarkadaNagesha wrote: > From: Sudeep KarkadaNagesha > > Currently different drivers requiring to access cpu device node are > parsing the device tree themselves. Since the ordering in the DT need > not match the logical cpu ordering, the parsing logic needs to consider > that. However, this has resulted in lots of code duplication and in some > cases even incorrect logic. > > It's better to consolidate them by adding support for getting cpu > device node for a given logical cpu index in DT core library. However > logical to physical index mapping can be architecture specific. > > This patch adds of_get_cpu_node to retrieve a cpu device node for a > given logical cpu index. The default matching of the physical id to the > logical cpu index can be overridden by architecture specific code. > > It is recommended to use these helper function only in pre-SMP/early > initialisation stages to retrieve CPU device node pointers in logical > ordering. Once the cpu devices are registered, it can be retrieved easily > from cpu device of_node which avoids unnecessary parsing and matching. > > Acked-by: Rob Herring > Signed-off-by: Sudeep KarkadaNagesha Minor nits below. Otherwise... Acked-by: Nicolas Pitre > --- > drivers/of/base.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/of.h | 6 +++++ > 2 files changed, 78 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 5c54279..1e690bf 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -230,6 +230,78 @@ const void *of_get_property(const struct device_node *np, const char *name, > } > EXPORT_SYMBOL(of_get_property); > > +/* > + * arch_match_cpu_phys_id - Match the given logical CPU and physical id > + * > + * @cpu: logical index of a cpu > + * @phys_id: physical identifier of a cpu > + * > + * CPU logical to physical index mapping is architecture specific. > + * However this __weak function provides a default match of physical > + * id to logical cpu index. > + * > + * Returns true if the physical identifier and the logical index correspond > + * to the same cpu, false otherwise. > + */ > +bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id) Maybe a prototype declaration for this function should be added to include/linux/of.h to avoid mismatch with architecture provided versions. > +{ > + return (u32)phys_id == cpu; > +} > + > +/** > + * of_get_cpu_node - Get device node associated with the given logical CPU > + * > + * @cpu: CPU number(logical index) for which device node is required > + * > + * The main purpose of this function is to retrieve the device node for the > + * given logical CPU index. It should be used to intialize the of_node in s/intialize/initialize/ Nicolas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/