Hi Tomasz,


Please find my response inline below.

On Tue, Feb 13, 2018 at 1:33 PM, Tomasz Figa [off-list ref] wrote:

Hi Vivek,

Thanks for the patch. Please see some comments inline.

On Wed, Feb 7, 2018 at 7:31 PM, Vivek Gautam
[off-list ref] wrote:

quoted

From: Sricharan R <redacted>

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 <redacted>
Signed-off-by: Archit Taneja <redacted>
[vivek: Clock rework to request bulk of clocks]
Signed-off-by: Vivek Gautam <redacted>
---
 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"?

quoted

        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?

Sure. Will change to s/clocks/clks/ in struct arm_smmu_device.

quoted

 };

 #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.

Right, it's valid to fill the data in arm_smmu_device_dt_probe().
Perhaps we can just keep the devm_clk_bulk_get() in arm_smmu_device_probe()
at the point where we are currently doing arm_smmu_init_clks().

Thanks & regards
Vivek

Best regards,
Tomasz
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