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.

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 <sricha...@codeaurora.org>
Signed-off-by: Archit Taneja <arch...@codeaurora.org>
[vivek: rework for clock and pm ops]
Signed-off-by: Vivek Gautam <vivek.gau...@codeaurora.org>
Reviewed-by: Tomasz Figa <tf...@chromium.org>
Tested-by: Srinivas Kandagatla <srinivas.kandaga...@linaro.org>
---

Changes since v14:
 - none.

 drivers/iommu/arm-smmu.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 74 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index fd1b80ef9490..a81224bc6637 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 */
 
@@ -1896,10 +1899,12 @@ 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);
@@ -1918,6 +1923,23 @@ 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)
 {
@@ -2000,6 +2022,9 @@ 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);
 
@@ -2098,6 +2123,14 @@ 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;
@@ -2184,6 +2217,9 @@ 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;
 }
 
@@ -2192,15 +2228,50 @@ static void arm_smmu_device_shutdown(struct 
platform_device *pdev)
        arm_smmu_device_remove(pdev);
 }
 
-static int __maybe_unused arm_smmu_pm_resume(struct device *dev)
+static int __maybe_unused arm_smmu_runtime_resume(struct device *dev)
 {
        struct arm_smmu_device *smmu = dev_get_drvdata(dev);
+       int ret;
+
+       ret = clk_bulk_enable(smmu->num_clks, smmu->clks);
+       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_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)
+{
+       if (pm_runtime_suspended(dev))
+               return 0;
+
+       return arm_smmu_runtime_resume(dev);
+}
+
+static int __maybe_unused arm_smmu_pm_suspend(struct device *dev)
+{
+       if (pm_runtime_suspended(dev))
+               return 0;
+
+       return arm_smmu_runtime_suspend(dev);
+}
+
+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 = {
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

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