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SubjectRe: [PATCH v6 2/6] iommu/arm-smmu: Add pm_runtime/sleep ops
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On 19/01/18 11:43, Vivek Gautam wrote:
> 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.
>
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> Signed-off-by: Archit Taneja <architt@codeaurora.org>
> [vivek: Clock rework to request bulk of clocks]
> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> ---
> drivers/iommu/arm-smmu.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 53 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 78d4c6b8f1ba..21acffe91a1c 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 +206,9 @@ struct arm_smmu_device {
> u32 num_global_irqs;
> u32 num_context_irqs;
> unsigned int *irqs;
> + struct clk_bulk_data *clocks;
> + int num_clks;
> + const char * const *clk_names;

This seems unnecessary, as we use it a grand total of of once, during
initialisation when we have the source data directly to hand. Just pass
data->clks into arm_smmu_init_clks() as an additional argument.

Otherwise, I think this looks reasonable; it's about as unobtrusive as
it's going to get.

Robin.

> u32 cavium_id_base; /* Specific to Cavium */
>
> @@ -1685,6 +1689,25 @@ static int arm_smmu_id_size_to_bits(int size)
> }
> }
>
> +static int arm_smmu_init_clocks(struct arm_smmu_device *smmu)
> +{
> + int i;
> + int num = smmu->num_clks;
> +
> + if (num < 1)
> + return 0;
> +
> + smmu->clocks = devm_kcalloc(smmu->dev, num,
> + sizeof(*smmu->clocks), GFP_KERNEL);
> + if (!smmu->clocks)
> + return -ENOMEM;
> +
> + for (i = 0; i < num; i++)
> + smmu->clocks[i].id = smmu->clk_names[i];
> +
> + return devm_clk_bulk_get(smmu->dev, num, smmu->clocks);
> +}
> +
> static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
> {
> unsigned long size;
> @@ -1897,10 +1920,12 @@ 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);
> @@ -2001,6 +2026,8 @@ 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->clk_names = data->clks;
> + smmu->num_clks = data->num_clks;
>
> parse_driver_options(smmu);
>
> @@ -2099,6 +2126,10 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> smmu->irqs[i] = irq;
> }
>
> + err = arm_smmu_init_clocks(smmu);
> + if (err)
> + return err;
> +
> err = arm_smmu_device_cfg_probe(smmu);
> if (err)
> return err;
> @@ -2197,7 +2228,27 @@ static int __maybe_unused arm_smmu_pm_resume(struct device *dev)
> return 0;
> }
>
> -static SIMPLE_DEV_PM_OPS(arm_smmu_pm_ops, NULL, arm_smmu_pm_resume);
> +static int __maybe_unused arm_smmu_runtime_resume(struct device *dev)
> +{
> + struct arm_smmu_device *smmu = dev_get_drvdata(dev);
> +
> + return clk_bulk_prepare_enable(smmu->num_clks, smmu->clocks);
> +}
> +
> +static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev)
> +{
> + struct arm_smmu_device *smmu = dev_get_drvdata(dev);
> +
> + clk_bulk_disable_unprepare(smmu->num_clks, smmu->clocks);
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops arm_smmu_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(NULL, 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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