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Message-ID: <1a918f99-83b0-2f51-7634-126639a220de@arm.com>
Date: Wed, 26 Sep 2018 16:27:39 +0100
From: Robin Murphy <robin.murphy@....com>
To: Vivek Gautam <vivek.gautam@...eaurora.org>, joro@...tes.org,
robh+dt@...nel.org, will.deacon@....com,
iommu@...ts.linux-foundation.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: alex.williamson@...hat.com, mark.rutland@....com,
rjw@...ysocki.net, robdclark@...il.com, linux-pm@...r.kernel.org,
freedreno@...ts.freedesktop.org, sboyd@...nel.org,
tfiga@...omium.org, jcrouse@...eaurora.org,
sricharan@...eaurora.org, m.szyprowski@...sung.com,
architt@...eaurora.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v16 1/5] iommu/arm-smmu: Add pm_runtime/sleep ops
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).
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 = {
>
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