From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753780AbaELHw1 (ORCPT ); Mon, 12 May 2014 03:52:27 -0400 Received: from mout.kundenserver.de ([212.227.17.24]:57117 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752112AbaELHw0 (ORCPT ); Mon, 12 May 2014 03:52:26 -0400 From: Arnd Bergmann To: linux-arm-kernel@lists.infradead.org Cc: Richard Lee , linux@arm.linux.org.uk, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Richard Lee Subject: Re: [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support. Date: Mon, 12 May 2014 09:51:41 +0200 Message-ID: <5146762.jba3IJe7xt@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.11.0-18-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1399861195-21087-3-git-send-email-superlibj8301@gmail.com> References: <1399861195-21087-1-git-send-email-superlibj8301@gmail.com> <1399861195-21087-3-git-send-email-superlibj8301@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V02:K0:wflw0bXlYxVGEkyTMNcu5/3f+7TMSrx/HxY/T6ficzZ DKuiHttfUgVJcnWFxkfm7H11O7FyAZq5OwlMa2Ey0qpiXZZ7v6 f8yHQ4a32m8ejwu6CjHrdtFrMYFlsjj7ry9p0FgmnWgB1IyRll T750VVoj4JVIbh6mT4ekCkXPCBHBHUCo1PRFBBt+Lfpvv+scRY yGdvHsl/8IsigeG7JZnzmGddkNjCVhEtjKNVIeXyFEhflaxX0d LDC8cB2WiRxpGJQ6jluGC5yp3ccMyTBjVSVJFncAz+Tg/NLHK4 pLIx1blboeVhVU+FaaUUKzwc9jvmgcX8jiyEbD1pjbi7hAi/vf vZnW/qGZL1fdEwHNkMec= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 12 May 2014 10:19:55 Richard Lee wrote: > For the IO mapping, for the same physical address space maybe > mapped more than one time, for example, in some SoCs: > 0x20000000 ~ 0x20001000: are global control IO physical map, > and this range space will be used by many drivers. > And then if each driver will do the same ioremap operation, we > will waste to much malloc virtual spaces. > > This patch add IO mapping space reused support. > > Signed-off-by: Richard Lee What happens if the first driver then unmaps the area? Arnd