From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S933948AbbI1OQs (ORCPT <rfc822;w@1wt.eu>);
	Mon, 28 Sep 2015 10:16:48 -0400
Received: from mailapp01.imgtec.com ([195.59.15.196]:2432 "EHLO
	mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1755837AbbI1OQr (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 28 Sep 2015 10:16:47 -0400
Subject: Re: [PATCH 2/3] irqchip: irq-mips-gic: Provide function to map GIC
 user section
To: Marc Zyngier <marc.zyngier@arm.com>,
        Markos Chandras <markos.chandras@imgtec.com>
References: <1443434629-14325-1-git-send-email-markos.chandras@imgtec.com>
 <1443435117-17144-1-git-send-email-markos.chandras@imgtec.com>
 <56091CA1.1030808@arm.com>
CC: <linux-mips@linux-mips.org>, <alex@alex-smith.me.uk>,
        Alex Smith <alex.smith@imgtec.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jason Cooper <jason@lakedaemon.net>, <linux-kernel@vger.kernel.org>
From: Qais Yousef <qais.yousef@imgtec.com>
Message-ID: <56094BCD.6000600@imgtec.com>
Date: Mon, 28 Sep 2015 15:16:45 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.2.0
MIME-Version: 1.0
In-Reply-To: <56091CA1.1030808@arm.com>
Content-Type: text/plain; charset="windows-1252"; format=flowed
Content-Transfer-Encoding: 7bit
X-Originating-IP: [192.168.154.94]
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 09/28/2015 11:55 AM, Marc Zyngier wrote:
> On 28/09/15 11:11, Markos Chandras wrote:
>
>> +
>> +	pfn = (gic_base_addr + USM_VISIBLE_SECTION_OFS) >> PAGE_SHIFT;
>> +	return io_remap_pfn_range(vma, base, pfn, size,
>> +				  pgprot_noncached(PAGE_READONLY));
>
> - Does this code have to be in the irqchip driver? It really feels out
> of place, and I'd rather see a function that returns the mappable range
> to the VDSO code, where the mapping would occur.
>


I don't think it's a good idea either for the VDSO code to know about 
gic_base_addr. Maybe this function could be split to return the pfn and 
let the caller do io_remap_pfn_range(). Though I think it's nice to have 
it all there. USM stands for USer Mode - GIC wants to make some stuff 
visible to user mode and it puts them in that special section. So it 
makes sense to do it all there IMO.

Qais