On Tue, Nov 08, 2016 at 02:29:24PM +0100, Marek Szyprowski wrote:
> This patch uses recently introduced device dependency links to track the
> runtime pm state of the master's device. The goal is to let SYSMMU
> controller device's runtime PM to follow the runtime PM state of the
> respective master's device. This way each SYSMMU controller is active
> only when its master's device is active and can properly restore or save
> its state instead on runtime PM transition of master's device.
> This approach replaces old behavior, when SYSMMU controller was set to
> runtime active once after attaching to the master device. In the new
> approach SYSMMU controllers no longer prevents respective power domains
> to be turned off when master's device is not being used.
>
> The dependency links also enforces proper order of suspending/restoring
> devices during system sleep transition, so there is no more need to use
> LATE_SYSTEM_SLEEP_PM_OPS-based workaround for ensuring that SYSMMUs are
> suspended after their master devices.
Patches 1-6 seems reasonable to me, however in so far as this patch is
concerned I'd appreaciate if you and Rafael can reply to Lukas Wunner's
questions.
Luis
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> ---
> drivers/iommu/exynos-iommu.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index 5e6d7bb..4b05a15 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -633,8 +633,8 @@ static int __maybe_unused exynos_sysmmu_resume(struct device *dev)
>
> static const struct dev_pm_ops sysmmu_pm_ops = {
> 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)
> + SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> + pm_runtime_force_resume)
> };
>
> static const struct of_device_id sysmmu_of_match[] __initconst = {
> @@ -781,10 +781,6 @@ static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
> if (!has_sysmmu(dev) || owner->domain != iommu_domain)
> return;
>
> - list_for_each_entry(data, &owner->controllers, owner_node) {
> - pm_runtime_put_sync(data->sysmmu);
> - }
> -
> mutex_lock(&owner->rpm_lock);
>
> list_for_each_entry(data, &owner->controllers, owner_node) {
> @@ -848,10 +844,6 @@ static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
>
> mutex_unlock(&owner->rpm_lock);
>
> - list_for_each_entry(data, &owner->controllers, owner_node) {
> - pm_runtime_get_sync(data->sysmmu);
> - }
> -
> dev_dbg(dev, "%s: Attached IOMMU with pgtable %pa\n", __func__,
> &pagetable);
>
> @@ -1232,6 +1224,14 @@ static int exynos_iommu_of_xlate(struct device *dev,
>
> list_add_tail(&data->owner_node, &owner->controllers);
> data->master = dev;
> +
> + /*
> + * SYSMMU will be runtime activated via device link (dependency) to its
> + * master device, so there are no direct calls to pm_runtime_get/put
> + * in this driver.
> + */
> + device_link_add(dev, data->sysmmu, DL_FLAG_PM_RUNTIME);
> +
> return 0;
> }
>
> --
> 1.9.1
>
>
--
Luis Rodriguez, SUSE LINUX GmbH
Maxfeldstrasse 5; D-90409 Nuernberg
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