From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH v12 3/4] iommu/arm-smmu: Add the device_link between masters and smmu Date: Wed, 11 Jul 2018 11:53:48 +0200 Message-ID: <5179668.PHK6S3sxLu@aspire.rjw.lan> References: <20180708173413.1965-1-vivek.gautam@codeaurora.org> <20180708173413.1965-4-vivek.gautam@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20180708173413.1965-4-vivek.gautam@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: Vivek Gautam Cc: joro@8bytes.org, robh+dt@kernel.org, mark.rutland@arm.com, robin.murphy@arm.com, will.deacon@arm.com, iommu@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, alex.williamson@redhat.com, robdclark@gmail.com, linux-pm@vger.kernel.org, freedreno@lists.freedesktop.org, sboyd@kernel.org, tfiga@chromium.org, sricharan@codeaurora.org, m.szyprowski@samsung.com, architt@codeaurora.org, linux-arm-msm@vger.kernel.org, jcrouse@codeaurora.org, Lukas Wunner List-Id: linux-arm-msm@vger.kernel.org On Sunday, July 8, 2018 7:34:12 PM CEST 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 > Cc: Rafael J. Wysocki > Cc: Lukas Wunner > --- > > - Change since v11 > * Replaced DL_FLAG_AUTOREMOVE flag with DL_FLAG_AUTOREMOVE_SUPPLIER. > > drivers/iommu/arm-smmu.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 09265e206e2d..916cde4954d2 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -1461,8 +1461,20 @@ static int arm_smmu_add_device(struct device *dev) > > iommu_device_link(&smmu->iommu, dev); > > + if (pm_runtime_enabled(smmu->dev) && Why does the creation of the link depend on whether or not runtime PM is enabled for the MMU device? What about system-wide PM and system shutdown? Are they always guaranteed to happen in the right order without the link? > + !device_link_add(dev, smmu->dev, > + DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER)) { > + dev_err(smmu->dev, "Unable to add link to the consumer %s\n", > + dev_name(dev)); > + ret = -ENODEV; > + goto out_unlink; > + } > + > return 0; > > +out_unlink: > + iommu_device_unlink(&smmu->iommu, dev); > + arm_smmu_master_free_smes(fwspec); > out_cfg_free: > kfree(cfg); > out_free: >