Re: [Freedreno] [PATCH v6 2/6] iommu/arm-smmu: Add pm_runtime/sleep ops

Wed, 31 Jan 2018 22:14:30 -0800 


On 1/31/2018 5:53 PM, Robin Murphy wrote:

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.


Sure, will do that.



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


Thanks for reviewing.

regards
Vivek



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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