On 19/01/18 11:43, Vivek Gautam wrote:
From: Sricharan R <sricha...@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 <sricha...@codeaurora.org>
Signed-off-by: Archit Taneja <arch...@codeaurora.org>
[vivek: Clock rework to request bulk of clocks]
Signed-off-by: Vivek Gautam <vivek.gau...@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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