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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 4B6A5C6778C for ; Tue, 3 Jul 2018 16:02:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 100BE23EDE for ; Tue, 3 Jul 2018 16:02:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 100BE23EDE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933740AbeGCQB5 (ORCPT ); Tue, 3 Jul 2018 12:01:57 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:51810 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932531AbeGCQBz (ORCPT ); Tue, 3 Jul 2018 12:01:55 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 067EA7A9; Tue, 3 Jul 2018 09:01:55 -0700 (PDT) Received: from [10.1.210.23] (e110467-lin.cambridge.arm.com [10.1.210.23]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4A3843F5AD; Tue, 3 Jul 2018 09:01:51 -0700 (PDT) Subject: Re: [PATCH 4/7 v5] iommu: arm-smmu: Add support for the fsl-mc bus To: Nipun Gupta , will.deacon@arm.com, robh+dt@kernel.org, robh@kernel.org, mark.rutland@arm.com, catalin.marinas@arm.com, gregkh@linuxfoundation.org, laurentiu.tudor@nxp.com, bhelgaas@google.com Cc: hch@lst.de, joro@8bytes.org, m.szyprowski@samsung.com, shawnguo@kernel.org, frowand.list@gmail.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-pci@vger.kernel.org, bharat.bhushan@nxp.com, stuyoder@gmail.com, leoyang.li@nxp.com References: <1526824191-7000-1-git-send-email-nipun.gupta@nxp.com> <1526824191-7000-5-git-send-email-nipun.gupta@nxp.com> From: Robin Murphy Message-ID: <83174f21-50f3-2ed2-bf04-6136af591567@arm.com> Date: Tue, 3 Jul 2018 17:01:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <1526824191-7000-5-git-send-email-nipun.gupta@nxp.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/05/18 14:49, Nipun Gupta wrote: > Implement bus specific support for the fsl-mc bus including > registering arm_smmu_ops and bus specific device add operations. > > Signed-off-by: Nipun Gupta > --- > drivers/iommu/arm-smmu.c | 7 +++++++ > drivers/iommu/iommu.c | 21 +++++++++++++++++++++ > include/linux/fsl/mc.h | 8 ++++++++ > include/linux/iommu.h | 2 ++ > 4 files changed, 38 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 69e7c60..e1d5090 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -52,6 +52,7 @@ > #include > > #include > +#include > > #include "io-pgtable.h" > #include "arm-smmu-regs.h" > @@ -1459,6 +1460,8 @@ static struct iommu_group *arm_smmu_device_group(struct device *dev) > > if (dev_is_pci(dev)) > group = pci_device_group(dev); > + else if (dev_is_fsl_mc(dev)) > + group = fsl_mc_device_group(dev); > else > group = generic_device_group(dev); > > @@ -2037,6 +2040,10 @@ static void arm_smmu_bus_init(void) > bus_set_iommu(&pci_bus_type, &arm_smmu_ops); > } > #endif > +#ifdef CONFIG_FSL_MC_BUS > + if (!iommu_present(&fsl_mc_bus_type)) > + bus_set_iommu(&fsl_mc_bus_type, &arm_smmu_ops); > +#endif > } > > static int arm_smmu_device_probe(struct platform_device *pdev) > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index d2aa2320..6d4ce35 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -32,6 +32,7 @@ > #include > #include > #include > +#include > #include > > static struct kset *iommu_group_kset; > @@ -987,6 +988,26 @@ struct iommu_group *pci_device_group(struct device *dev) > return iommu_group_alloc(); > } > > +/* Get the IOMMU group for device on fsl-mc bus */ > +struct iommu_group *fsl_mc_device_group(struct device *dev) > +{ > + struct device *cont_dev = fsl_mc_cont_dev(dev); > + struct iommu_group *group; > + > + /* Container device is responsible for creating the iommu group */ > + if (fsl_mc_is_cont_dev(dev)) { Why duplicate what fsl_mc_cont_dev() has already figured out? AFAICS the overall operation here boils down to something like: cont_dev = fsl_mc_cont_dev(dev); group = iommu_group_get(cont_dev); if (!group) group = iommu_group_alloc(); return group; > + group = iommu_group_alloc(); > + if (IS_ERR(group)) > + return NULL; iommu_group_get_for_dev() expects a PTR_ERR, so I don't think munging the return here is the right thing to do. > + } else { > + get_device(cont_dev); If races are a concern, isn't this a bit late? Maybe in that case you want {get,put}_fsl_mc_cont_dev() routines instead of the simple macro below. But on the other hand if dev already has cont_dev as its parent, wouldn't the reference taken in device_add() be sufficient to prevent it from vanishing unexpectedly in this timescale? Robin. > + group = iommu_group_get(cont_dev); > + put_device(cont_dev); > + } > + > + return group; > +} > + > /** > * iommu_group_get_for_dev - Find or create the IOMMU group for a device > * @dev: target device > diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h > index f27cb14..dddaca1 100644 > --- a/include/linux/fsl/mc.h > +++ b/include/linux/fsl/mc.h > @@ -351,6 +351,14 @@ struct fsl_mc_io { > #define dev_is_fsl_mc(_dev) (0) > #endif > > +/* Macro to check if a device is a container device */ > +#define fsl_mc_is_cont_dev(_dev) (to_fsl_mc_device(_dev)->flags & \ > + FSL_MC_IS_DPRC) > + > +/* Macro to get the container device of a MC device */ > +#define fsl_mc_cont_dev(_dev) (fsl_mc_is_cont_dev(_dev) ? \ > + (_dev) : (_dev)->parent) > + > /* > * module_fsl_mc_driver() - Helper macro for drivers that don't do > * anything special in module init/exit. This eliminates a lot of > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 19938ee..2981200 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -389,6 +389,8 @@ static inline size_t iommu_map_sg(struct iommu_domain *domain, > extern struct iommu_group *pci_device_group(struct device *dev); > /* Generic device grouping function */ > extern struct iommu_group *generic_device_group(struct device *dev); > +/* FSL-MC device grouping function */ > +struct iommu_group *fsl_mc_device_group(struct device *dev); > > /** > * struct iommu_fwspec - per-device IOMMU instance data >