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    Subject[PATCH v13 1/4] iommu/arm-smmu: Add pm_runtime/sleep ops
    Date
    From: Sricharan R <sricharan@codeaurora.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@codeaurora.org>
    Signed-off-by: Archit Taneja <architt@codeaurora.org>
    [vivek: rework for clock and pm ops]
    Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
    Reviewed-by: Tomasz Figa <tfiga@chromium.org>
    ---

    Changes since v12:
    - Added pm sleep .suspend callback. This disables the clocks.
    - Added corresponding change to enable clocks in .resume
    pm sleep callback.

    drivers/iommu/arm-smmu.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++--
    1 file changed, 73 insertions(+), 2 deletions(-)

    diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
    index c73cfce1ccc0..9138a6fffe04 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 */

    @@ -1897,10 +1900,12 @@ 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);
    @@ -1919,6 +1924,23 @@ 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)
    {
    @@ -2001,6 +2023,9 @@ 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);

    @@ -2099,6 +2124,14 @@ 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(smmu->num_clks, smmu->clks);
    + if (err)
    + return err;
    +
    err = arm_smmu_device_cfg_probe(smmu);
    if (err)
    return err;
    @@ -2181,6 +2214,9 @@ 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_unprepare(smmu->num_clks, smmu->clks);
    +
    return 0;
    }

    @@ -2189,15 +2225,50 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev)
    arm_smmu_device_remove(pdev);
    }

    +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev)
    +{
    + struct arm_smmu_device *smmu = dev_get_drvdata(dev);
    +
    + return clk_bulk_enable(smmu->num_clks, smmu->clks);
    +}
    +
    +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)
    {
    struct arm_smmu_device *smmu = dev_get_drvdata(dev);
    + int ret;
    +
    + if (!pm_runtime_suspended(dev)) {
    + ret = arm_smmu_runtime_resume(dev);
    + 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_pm_suspend(struct device *dev)
    +{
    + if (!pm_runtime_suspended(dev))
    + return arm_smmu_runtime_suspend(dev);
    +
    + return 0;
    +}
    +
    +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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