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SubjectRe: [PATCH v7 2/6] iommu/arm-smmu: Add pm_runtime/sleep ops
Hi Vivek,

Thanks for the patch. Please see some comments inline.

On Wed, Feb 7, 2018 at 7:31 PM, Vivek Gautam
<vivek.gautam@codeaurora.org> 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 | 56 ++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 54 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 69e7c60792a8..9e2f917e16c2 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 *clocks;
> + int num_clks;

nit: Perhaps "num_clocks" to be consistent with "clocks"?

>
> 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;

nit: Perhaps s/clks/clocks/ here or s/clocks/clks/ in struct arm_smmu_device?

> };
>
> #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 +2006,7 @@ 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;
>
> parse_driver_options(smmu);
>
> @@ -2039,6 +2045,28 @@ static void arm_smmu_bus_init(void)
> #endif
> }
>
> +static int arm_smmu_init_clks(struct arm_smmu_device *smmu)
> +{
> + int i;
> + int num = smmu->num_clks;
> + const struct arm_smmu_match_data *data;
> +
> + if (num < 1)
> + return 0;
> +
> + smmu->clocks = devm_kcalloc(smmu->dev, num,
> + sizeof(*smmu->clocks), GFP_KERNEL);
> + if (!smmu->clocks)
> + return -ENOMEM;
> +
> + data = of_device_get_match_data(smmu->dev);
> +
> + for (i = 0; i < num; i++)
> + smmu->clocks[i].id = data->clks[i];

I'd argue that arm_smmu_device_dt_probe() is a better place for all
the code above, since this function is called regardless of whether
the device is probed from DT or not. Going further,
arm_smmu_device_acpi_probe() could fill smmu->num_clks and ->clocks
using ACPI-like way (as opposed to OF match data) if necessary.

Best regards,
Tomasz

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