Hi,
>On 21 October 2016 at 11:14, Sricharan R <sricharan@xxxxxxxxxxxxxx> wrote:
>> The smmu needs to be functional when the respective
>> master/s using it are active. As there is a device_link
>> between the master and smmu, the pm runtime ops for the smmu
>> gets invoked in sync with the master's runtime, thus the
>> smmu remains powered only when needed.
>>
>> There are couple of places in the driver during probe,
>> master attach, where the smmu needs to be clocked without
>> the context of the master. So doing a pm_runtime_get/put sync
>> in those places separately.
>>
>> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
>> ---
>> drivers/iommu/arm-smmu.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-
>> 1 file changed, 108 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
>> index 083489e4..45f2762 100644
>> --- a/drivers/iommu/arm-smmu.c
>> +++ b/drivers/iommu/arm-smmu.c
>> @@ -45,6 +45,7 @@
>> #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>
>>
>> @@ -373,6 +374,8 @@ struct arm_smmu_device {
>> u32 num_global_irqs;
>> u32 num_context_irqs;
>> unsigned int *irqs;
>> + int num_clocks;
>> + struct clk **clocks;
>>
>> u32 cavium_id_base; /* Specific to Cavium */
>> };
>> @@ -430,6 +433,31 @@ static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
>> return container_of(dom, struct arm_smmu_domain, domain);
>> }
>>
>> +static int arm_smmu_enable_clocks(struct arm_smmu_device *smmu)
>> +{
>> + int i, ret = 0;
>> +
>> + for (i = 0; i < smmu->num_clocks; ++i) {
>> + ret = clk_prepare_enable(smmu->clocks[i]);
>> + if (ret) {
>> + dev_err(smmu->dev, "Couldn't enable clock #%d\n", i);
>> + while (i--)
>> + clk_disable_unprepare(smmu->clocks[i]);
>> + break;
>> + }
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static void arm_smmu_disable_clocks(struct arm_smmu_device *smmu)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < smmu->num_clocks; ++i)
>> + clk_disable_unprepare(smmu->clocks[i]);
>> +}
>> +
>> static void parse_driver_options(struct arm_smmu_device *smmu)
>> {
>> int i = 0;
>> @@ -1187,11 +1215,13 @@ static void arm_smmu_master_free_smes(struct iommu_fwspec *fwspec)
>> int i, idx;
>>
>> mutex_lock(&smmu->stream_map_mutex);
>> + pm_runtime_get_sync(smmu->dev);
>
>Since this is generic code it is probably a good idea to check the
>return value, same for _put_sync() below.
Ok, i will do it for V2.
>
>> for_each_cfg_sme(fwspec, i, idx) {
>> if (arm_smmu_free_sme(smmu, idx))
>> arm_smmu_write_sme(smmu, idx);
>> cfg->smendx[i] = INVALID_SMENDX;
>> }
>> + pm_runtime_put_sync(smmu->dev);
>> mutex_unlock(&smmu->stream_map_mutex);
>> }
>>
>> @@ -1424,9 +1454,11 @@ static int arm_smmu_add_device(struct device *dev)
>> while (i--)
>> cfg->smendx[i] = INVALID_SMENDX;
>>
>> + pm_runtime_get_sync(smmu->dev);
>> ret = arm_smmu_master_alloc_smes(dev);
>> if (ret)
>> goto out_free;
>> + pm_runtime_put_sync(smmu->dev);
>>
>> return 0;
>>
>> @@ -1650,6 +1682,44 @@ static int arm_smmu_id_size_to_bits(int size)
>> }
>> }
>>
>> +static int arm_smmu_init_clocks(struct arm_smmu_device *smmu)
>> +{
>> + const char *cname;
>> + struct property *prop;
>> + int i;
>> + struct device *dev = smmu->dev;
>> +
>> + smmu->num_clocks =
>> + of_property_count_strings(dev->of_node, "clock-names");
>> +
>> + if (smmu->num_clocks < 1)
>> + return 0;
>> +
>> + smmu->clocks = devm_kzalloc(dev,
>> + sizeof(*smmu->clocks) * smmu->num_clocks,
>> + GFP_KERNEL);
>> +
>> + if (!smmu->clocks) {
>> + dev_err(dev, "Failed to allocate memory for clocks\n");
>> + return -ENODEV;
>> + }
>> +
>> + i = 0;
>
>Please do the initialisation above when you declare the variable.
ok, will change it.
Regards,
Sricharan
--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
