lkml.org 
[lkml]   [2016]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v5 6/7] iommu/exynos: Add runtime pm support
From
Date
Hi Sricharan


On 2016-10-22 07:50, Sricharan wrote:
>
>> This patch adds runtime pm implementation, which is based on previous
>> suspend/resume code. SYSMMU controller is now being enabled/disabled mainly
> > from the runtime pm callbacks. System sleep callbacks relies on generic
>> pm_runtime_force_suspend/pm_runtime_force_resume helpers. To ensure
>> internal state consistency, additional lock for runtime pm transitions
>> was introduced.
>>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> ---
>> drivers/iommu/exynos-iommu.c | 45 +++++++++++++++++++++++++++++++++++---------
>> 1 file changed, 36 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
>> index a959443e6f33..5e6d7bbf9b70 100644
>> --- a/drivers/iommu/exynos-iommu.c
>> +++ b/drivers/iommu/exynos-iommu.c
>> @@ -206,6 +206,7 @@ struct sysmmu_fault_info {
>> struct exynos_iommu_owner {
>> struct list_head controllers; /* list of sysmmu_drvdata.owner_node */
>> struct iommu_domain *domain; /* domain this device is attached */
>> + struct mutex rpm_lock; /* for runtime pm of all sysmmus */
>> };
>>
>> /*
>> @@ -594,40 +595,46 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>> return 0;
>> }
>>
>> -#ifdef CONFIG_PM_SLEEP
>> -static int exynos_sysmmu_suspend(struct device *dev)
>> +static int __maybe_unused exynos_sysmmu_suspend(struct device *dev)
>> {
>> struct sysmmu_drvdata *data = dev_get_drvdata(dev);
>> struct device *master = data->master;
>>
>> if (master) {
>> - pm_runtime_put(dev);
>> + struct exynos_iommu_owner *owner = master->archdata.iommu;
>> +
>> + mutex_lock(&owner->rpm_lock);
> More of a device link question,
> To understand, i see that with device link + runtime, the supplier
> callbacks are not called for irqsafe clients, even if supplier is irqsafe.
> Why so ?

Frankly I didn't care about irqsafe runtime pm, because there is no such
need
for Exynos platform and its drivers. Exynos power domain driver also doesn't
support irqsafe mode.

>
>> if (data->domain) {
>> dev_dbg(data->sysmmu, "saving state\n");
>> __sysmmu_disable(data);
>> }
>> + mutex_unlock(&owner->rpm_lock);
>> }
>> return 0;
>> }
>>
>> -static int exynos_sysmmu_resume(struct device *dev)
>> +static int __maybe_unused exynos_sysmmu_resume(struct device *dev)
>> {
>> struct sysmmu_drvdata *data = dev_get_drvdata(dev);
>> struct device *master = data->master;
>>
>> if (master) {
>> - pm_runtime_get_sync(dev);
>> + struct exynos_iommu_owner *owner = master->archdata.iommu;
>> +
>> + mutex_lock(&owner->rpm_lock);
>> if (data->domain) {
>> dev_dbg(data->sysmmu, "restoring state\n");
>> __sysmmu_enable(data);
>> }
>> + mutex_unlock(&owner->rpm_lock);
>> }
>> return 0;
>> }
>> -#endif
>>
>> static const struct dev_pm_ops sysmmu_pm_ops = {
>> - SET_LATE_SYSTEM_SLEEP_PM_OPS(exynos_sysmmu_suspend, exynos_sysmmu_resume)
>> + SET_RUNTIME_PM_OPS(exynos_sysmmu_suspend, exynos_sysmmu_resume, NULL)
>> + SET_LATE_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
>> + pm_runtime_force_resume)
>> };
> Is this needed to be LATE_SYSTEM_SLEEP_PM_OPS with device links to take care
> of the order ?

Hmmm. LASE_SYSTEM_SLEEP_PM_OPS is a left over from the previous versions
of the driver,
which doesn't use device links. You are right, that "normal"
SYSTEM_SLEEP_PM_OPS should
be enough assuming that device links will take care of the proper call
sequence between
consumer and supplier device.

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland

\
 
 \ /
  Last update: 2016-10-24 07:20    [W:0.946 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site