From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51B50C43444 for ; Thu, 3 Jan 2019 20:11:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2894021872 for ; Thu, 3 Jan 2019 20:11:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727778AbfACULi (ORCPT ); Thu, 3 Jan 2019 15:11:38 -0500 Received: from mga03.intel.com ([134.134.136.65]:54025 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726601AbfACULi (ORCPT ); Thu, 3 Jan 2019 15:11:38 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Jan 2019 12:11:37 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,436,1539673200"; d="scan'208";a="115263347" Received: from moneill-mobl2.ger.corp.intel.com (HELO mara.localdomain) ([10.252.30.114]) by orsmga003.jf.intel.com with ESMTP; 03 Jan 2019 12:11:33 -0800 Received: from sailus by mara.localdomain with local (Exim 4.89) (envelope-from ) id 1gf9Ky-0000Ik-Kw; Thu, 03 Jan 2019 22:11:29 +0200 Date: Thu, 3 Jan 2019 22:11:27 +0200 From: Sakari Ailus To: Laurent Pinchart Cc: Joerg Roedel , yong.zhi@intel.com, iommu@lists.linux-foundation.org, linux-media@vger.kernel.org, tfiga@chromium.org, rajmohan.mani@intel.com, hans.verkuil@cisco.com, mchehab@kernel.org, bingbu.cao@intel.com, tian.shu.qiu@intel.com Subject: Re: [PATCH 1/1] iova: Allow compiling the library without IOMMU support Message-ID: <20190103201126.zzqpn2eylm4m2zxn@mara.localdomain> References: <20190102211657.13192-1-sakari.ailus@linux.intel.com> <12009133.IFJkWA3Ofo@avalon> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12009133.IFJkWA3Ofo@avalon> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Laurent, On Thu, Jan 03, 2019 at 12:52:00AM +0200, Laurent Pinchart wrote: > Hi Sakari, > > Thank you for the patch. > > On Wednesday, 2 January 2019 23:16:57 EET Sakari Ailus wrote: > > Drivers such as the Intel IPU3 ImgU driver use the IOVA library to manage > > the device's own virtual address space while not implementing the IOMMU > > API. > > Why is that ? Could the IPU3 IOMMU be implemented as an IOMMU driver ? You could do that, but: - it's a single PCI device so there's no advantage in doing so and - doing that would render the device inoperable if an IOMMU is enabled in the system, as chaining IOMMUs is not supported in the IOMMU framework AFAIK. > > > Currently the IOVA library is only compiled if the IOMMU support is > > enabled, resulting into a failure during linking due to missing symbols. > > > > Fix this by defining IOVA library Kconfig bits independently of IOMMU > > support configuration, and descending to the iommu directory > > unconditionally during the build. > > > > Signed-off-by: Sakari Ailus > > --- > > drivers/Makefile | 2 +- > > drivers/iommu/Kconfig | 7 ++++--- > > 2 files changed, 5 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/Makefile b/drivers/Makefile > > index 578f469f72fb..d9c469983592 100644 > > --- a/drivers/Makefile > > +++ b/drivers/Makefile > > @@ -56,7 +56,7 @@ obj-y += tty/ > > obj-y += char/ > > > > # iommu/ comes before gpu as gpu are using iommu controllers > > -obj-$(CONFIG_IOMMU_SUPPORT) += iommu/ > > +obj-y += iommu/ > > > > # gpu/ comes after char for AGP vs DRM startup and after iommu > > obj-y += gpu/ > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > > index d9a25715650e..d2c83e62873d 100644 > > --- a/drivers/iommu/Kconfig > > +++ b/drivers/iommu/Kconfig > > @@ -1,3 +1,7 @@ > > +# The IOVA library may also be used by non-IOMMU_API users > > +config IOMMU_IOVA > > + tristate > > + > > # IOMMU_API always gets selected by whoever wants it. > > config IOMMU_API > > bool > > @@ -81,9 +85,6 @@ config IOMMU_DEFAULT_PASSTHROUGH > > > > If unsure, say N here. > > > > -config IOMMU_IOVA > > - tristate > > - > > config OF_IOMMU > > def_bool y > > depends on OF && IOMMU_API > > > -- > Regards, > > Laurent Pinchart > > > -- Sakari Ailus sakari.ailus@linux.intel.com