From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751660AbeCNRvC (ORCPT ); Wed, 14 Mar 2018 13:51:02 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:57586 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414AbeCNRur (ORCPT ); Wed, 14 Mar 2018 13:50:47 -0400 Subject: Re: [PATCH v9 4/5] iommu/arm-smmu: Add the device_link between masters and smmu To: Vivek Gautam , joro@8bytes.org, robh+dt@kernel.org, iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: mark.rutland@arm.com, will.deacon@arm.com, robdclark@gmail.com, tfiga@chromium.org, sricharan@codeaurora.org, m.szyprowski@samsung.com, architt@codeaurora.org, linux-arm-msm@vger.kernel.org References: <20180313085534.11650-1-vivek.gautam@codeaurora.org> <20180313085534.11650-5-vivek.gautam@codeaurora.org> From: Robin Murphy Message-ID: <8b427ea2-5c13-4712-13d1-e4c1aed0779e@arm.com> Date: Wed, 14 Mar 2018 17:50:42 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180313085534.11650-5-vivek.gautam@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/03/18 08:55, Vivek Gautam wrote: > From: Sricharan R > > Finally add the device link between the master device and > smmu, so that the smmu gets runtime enabled/disabled only when the > master needs it. This is done from add_device callback which gets > called once when the master is added to the smmu. > > Signed-off-by: Sricharan R > Signed-off-by: Vivek Gautam > Reviewed-by: Tomasz Figa > --- > drivers/iommu/arm-smmu.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 56a04ae80bf3..64953ff2281f 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1460,10 +1460,31 @@ static int arm_smmu_add_device(struct device *dev) > > iommu_device_link(&smmu->iommu, dev); > > + if (pm_runtime_enabled(smmu->dev)) { > + struct device_link *link; > + > + /* > + * Establish the link between smmu and master, so that the > + * smmu gets runtime enabled/disabled as per the master's > + * needs. > + */ > + link = device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME); > + if (!link) { FWIW, given that we don't really care about link itself, I'd be quite happy to simplify that lot down to: if (pm_runtime_enabled(smmu_dev) && !device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME)) { > + dev_warn(smmu->dev, > + "Unable to add link to the consumer %s\n", > + dev_name(dev)); (side note: since device_link_add() already prints a message on success, maybe it could print its own failure message too?) Robin. > + ret = -ENODEV; > + goto out_unlink; > + } > + } > + > arm_smmu_rpm_put(smmu); > > return 0; > > +out_unlink: > + iommu_device_unlink(&smmu->iommu, dev); > + arm_smmu_master_free_smes(fwspec); > out_rpm_put: > arm_smmu_rpm_put(smmu); > out_cfg_free: > @@ -1486,6 +1507,14 @@ static void arm_smmu_remove_device(struct device *dev) > cfg = fwspec->iommu_priv; > smmu = cfg->smmu; > > + if (pm_runtime_enabled(smmu->dev)) { > + struct device_link *link; > + > + link = device_link_find(dev, smmu->dev); > + if (link) > + device_link_del(link); > + } > + > ret = arm_smmu_rpm_get(smmu); > if (ret < 0) > return; >