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Date: Thu, 27 Sep 2018 14:01:24 +0530
From: Vivek Gautam <vivek.gautam@...eaurora.org>
To: Robin Murphy <robin.murphy@....com>
Cc: Joerg Roedel <joro@...tes.org>, "robh+dt" <robh+dt@...nel.org>,
Will Deacon <will.deacon@....com>,
"list@....net:IOMMU DRIVERS <iommu@...ts.linux-foundation.org>, Joerg
Roedel <joro@...tes.org>," <iommu@...ts.linux-foundation.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>,
open list <linux-kernel@...r.kernel.org>,
Mark Rutland <mark.rutland@....com>,
Linux PM <linux-pm@...r.kernel.org>, sboyd@...nel.org,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
alex.williamson@...hat.com,
linux-arm-msm <linux-arm-msm@...r.kernel.org>,
freedreno <freedreno@...ts.freedesktop.org>
Subject: Re: [PATCH v16 1/5] iommu/arm-smmu: Add pm_runtime/sleep ops
On Wed, Sep 26, 2018 at 8:57 PM Robin Murphy <robin.murphy@....com> wrote:
>
> On 30/08/18 15:45, Vivek Gautam wrote:
> > From: Sricharan R <sricharan@...eaurora.org>
> >
> > The smmu needs to be functional only when the respective
> > master's using it are active. The device_link feature
> > helps to track such functional dependencies, so that the
> > iommu gets powered when the master device enables itself
> > using pm_runtime. So by adapting the smmu driver for
> > runtime pm, above said dependency can be addressed.
> >
> > This patch adds the pm runtime/sleep callbacks to the
> > driver and also the functions to parse the smmu clocks
> > from DT and enable them in resume/suspend.
> >
> > Also, while we enable the runtime pm add a pm sleep suspend
> > callback that pushes devices to low power state by turning
> > the clocks off in a system sleep.
> > Also add corresponding clock enable path in resume callback.
> >
> > Signed-off-by: Sricharan R <sricharan@...eaurora.org>
> > Signed-off-by: Archit Taneja <architt@...eaurora.org>
> > [vivek: rework for clock and pm ops]
> > Signed-off-by: Vivek Gautam <vivek.gautam@...eaurora.org>
> > Reviewed-by: Tomasz Figa <tfiga@...omium.org>
> > Tested-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
> > ---
> > drivers/iommu/arm-smmu.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++--
> > 1 file changed, 74 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index fd1b80ef9490..d900e007c3c9 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -48,6 +48,7 @@
> > #include <linux/of_iommu.h>
> > #include <linux/pci.h>
> > #include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > #include <linux/slab.h>
> > #include <linux/spinlock.h>
> >
> > @@ -205,6 +206,8 @@ struct arm_smmu_device {
> > u32 num_global_irqs;
> > u32 num_context_irqs;
> > unsigned int *irqs;
> > + struct clk_bulk_data *clks;
> > + int num_clks;
> >
> > u32 cavium_id_base; /* Specific to Cavium */
> >
> > @@ -1896,10 +1899,12 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
> > struct arm_smmu_match_data {
> > enum arm_smmu_arch_version version;
> > enum arm_smmu_implementation model;
> > + const char * const *clks;
> > + int num_clks;
> > };
> >
> > #define ARM_SMMU_MATCH_DATA(name, ver, imp) \
> > -static struct arm_smmu_match_data name = { .version = ver, .model = imp }
> > +static const struct arm_smmu_match_data name = { .version = ver, .model = imp }
> >
> > ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU);
> > ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU);
> > @@ -1918,6 +1923,23 @@ static const struct of_device_id arm_smmu_of_match[] = {
> > };
> > MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
> >
> > +static void arm_smmu_fill_clk_data(struct arm_smmu_device *smmu,
> > + const char * const *clks)
> > +{
> > + int i;
> > +
> > + if (smmu->num_clks < 1)
> > + return;
> > +
> > + smmu->clks = devm_kcalloc(smmu->dev, smmu->num_clks,
> > + sizeof(*smmu->clks), GFP_KERNEL);
> > + if (!smmu->clks)
> > + return;
> > +
> > + for (i = 0; i < smmu->num_clks; i++)
> > + smmu->clks[i].id = clks[i];
> > +}
> > +
> > #ifdef CONFIG_ACPI
> > static int acpi_smmu_get_data(u32 model, struct arm_smmu_device *smmu)
> > {
> > @@ -2000,6 +2022,9 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
> > data = of_device_get_match_data(dev);
> > smmu->version = data->version;
> > smmu->model = data->model;
> > + smmu->num_clks = data->num_clks;
> > +
> > + arm_smmu_fill_clk_data(smmu, data->clks);
> >
> > parse_driver_options(smmu);
> >
> > @@ -2098,6 +2123,14 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> > smmu->irqs[i] = irq;
> > }
> >
> > + err = devm_clk_bulk_get(smmu->dev, smmu->num_clks, smmu->clks);
> > + if (err)
> > + return err;
> > +
> > + err = clk_bulk_prepare_enable(smmu->num_clks, smmu->clks);
> > + if (err)
> > + return err;
> > +
>
> Hmm, if we error out beyond here it looks like we should strictly
> balance that prepare/enable before devres does the clk_bulk_put(),
> however the probe error path is starting to look like it needs a bit of
> love in general, so I might just spin a cleanup patch on top (and even
> then only for the sake of not being a bad example; SMMU probe failure is
> never a realistic situation for the system to actually recover from).
Sure Robin. Thanks for the review on the series.
Let me know, I can spin a change for probe failure path cleanup.
Best regards
Vivek
>
> Otherwise,
>
> Reviewed-by: Robin Murphy <robin.murphy@....com>
>
> > err = arm_smmu_device_cfg_probe(smmu);
> > if (err)
> > return err;
> > @@ -2184,6 +2217,9 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
> >
> > /* Turn the thing off */
> > writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0);
> > +
> > + clk_bulk_disable_unprepare(smmu->num_clks, smmu->clks);
> > +
> > return 0;
> > }
> >
> > @@ -2192,15 +2228,50 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev)
> > arm_smmu_device_remove(pdev);
> > }
> >
> > -static int __maybe_unused arm_smmu_pm_resume(struct device *dev)
> > +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev)
> > {
> > struct arm_smmu_device *smmu = dev_get_drvdata(dev);
> > + int ret;
> > +
> > + ret = clk_bulk_enable(smmu->num_clks, smmu->clks);
> > + if (ret)
> > + return ret;
> >
> > arm_smmu_device_reset(smmu);
> > +
> > return 0;
> > }
> >
> > -static SIMPLE_DEV_PM_OPS(arm_smmu_pm_ops, NULL, arm_smmu_pm_resume);
> > +static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev)
> > +{
> > + struct arm_smmu_device *smmu = dev_get_drvdata(dev);
> > +
> > + clk_bulk_disable(smmu->num_clks, smmu->clks);
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused arm_smmu_pm_resume(struct device *dev)
> > +{
> > + if (pm_runtime_suspended(dev))
> > + return 0;
> > +
> > + return arm_smmu_runtime_resume(dev);
> > +}
> > +
> > +static int __maybe_unused arm_smmu_pm_suspend(struct device *dev)
> > +{
> > + if (pm_runtime_suspended(dev))
> > + return 0;
> > +
> > + return arm_smmu_runtime_suspend(dev);
> > +}
> > +
> > +static const struct dev_pm_ops arm_smmu_pm_ops = {
> > + SET_SYSTEM_SLEEP_PM_OPS(arm_smmu_pm_suspend, arm_smmu_pm_resume)
> > + SET_RUNTIME_PM_OPS(arm_smmu_runtime_suspend,
> > + arm_smmu_runtime_resume, NULL)
> > +};
> >
> > static struct platform_driver arm_smmu_driver = {
> > .driver = {
> >
> _______________________________________________
> iommu mailing list
> iommu@...ts.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu
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