From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750948AbdGYJt2 (ORCPT ); Tue, 25 Jul 2017 05:49:28 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:43642 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750781AbdGYJt1 (ORCPT ); Tue, 25 Jul 2017 05:49:27 -0400 Cc: Sudeep Holla , mark.rutland@arm.com, peterz@infradead.org, will.deacon@arm.com, linux-kernel@vger.kernel.org, Rob Herring Subject: Re: [PATCH v2 2/6] of: Add helper for mapping device node to logical CPU number To: Suzuki K Poulose , linux-arm-kernel@lists.infradead.org References: <1500892161-17634-1-git-send-email-suzuki.poulose@arm.com> <1500892161-17634-3-git-send-email-suzuki.poulose@arm.com> <7ec47d12-3b6b-82c0-ba15-5664b5169974@arm.com> <18f06d4c-f063-30f7-70e8-aacd6e7a129b@arm.com> From: Sudeep Holla Organization: ARM Message-ID: Date: Tue, 25 Jul 2017 10:49:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <18f06d4c-f063-30f7-70e8-aacd6e7a129b@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 25/07/17 10:27, Suzuki K Poulose wrote: > On 24/07/17 17:42, Sudeep Holla wrote: >> >> >> On 24/07/17 11:29, Suzuki K Poulose wrote: >>> Add a helper to map a device node to a logical CPU number to avoid >>> duplication. Currently this is open coded in different places (e.g >>> gic-v3, coresight). The helper tries to map device node to a "possible" >>> logical CPU id, which may not be online yet. It is the responsibility >>> of the user to make sure that the CPU is online. The helper uses >>> of_get_cpu_node() which uses arch specific backends to match the >>> phyiscal >>> ids. >>> >>> Cc: Rob Herring >>> Cc: Mark Rutland >>> Signed-off-by: Suzuki K Poulose >>> --- >>> drivers/of/base.c | 26 ++++++++++++++++++++++++++ >>> include/linux/of_device.h | 7 +++++++ >>> 2 files changed, 33 insertions(+) >>> >>> diff --git a/drivers/of/base.c b/drivers/of/base.c >>> index 686628d..639af23 100644 >>> --- a/drivers/of/base.c >>> +++ b/drivers/of/base.c >>> @@ -420,6 +420,32 @@ struct device_node *of_get_cpu_node(int cpu, >>> unsigned int *thread) >>> EXPORT_SYMBOL(of_get_cpu_node); >>> >>> /** >>> + * of_device_node_get_cpu: Get the logical CPU number for a given >>> device_node >>> + * >>> + * @cpu_node: Pointer to the device_node for CPU. >>> + * >>> + * Returns the logical CPU number of the given CPU device_node. >>> + * Returns >= nr_cpu_ids if CPU is not found. >>> + */ >>> +int of_device_node_get_cpu(struct device_node *cpu_node) >>> +{ >>> + int cpu, thread; >>> + bool found = false; >>> + struct device_node *np; >>> + >>> + for_each_possible_cpu(cpu) { >>> + np = of_get_cpu_node(cpu, &thread); >> >> Ideally, we should be able to use of_cpu_device_node_get instead of >> of_get_cpu_node which parses the device tree. Not sure if that's the >> case here too. >> >> Sorry for following up on this so late. I had a patch in my tree >> for-a-while to address that. Just posted it[1] now seeing this patch now. >> >> You can move to of_cpu_device_node_get if all users of this function are >> called after CPU's are registered. Otherwise, you can keep it as is for >> now and it can be changed once [1] lands. > > As you mentioned offline, since GIC uses this, we need to stick to > of_get_cpu_node. Agreed. > In fact, I started off with the of_cpu_device_node_get() and switched > to the former. > Ah OK. > It would be really nice to have your patch, which streamlines the > interface and we could switch to that. > Yes, I will wait for that patch to land in the mainline, I can follow up and remove the use of of_get_cpu_node wherever required. -- Regards, Sudeep