[PATCH v9 14/16] iommu/exynos: add support for power management subsystems.

[PATCH v9 14/16] iommu/exynos: add support for power management subsystems.

[Cho KyongHo]

This adds support for Advance Power Management and Runtime Power
Management.

Since System MMU is located in the same local power domain of its
master H/W, System MMU must be initialized before it is working if
its power domain was ever turned off. TLB invalidation according to
unmapping on page tables must also be performed while power domain is
turned on.

This patch ensures that resume and runtime_resume(restore_state)
functions in this driver is called before the calls to resume and
runtime_resume callback functions in the drivers of master H/Ws.
Likewise, suspend and runtime_suspend(save_state) functions in this
driver is called after the calls to suspend and runtime_suspend in the
drivers of master H/Ws.

In order to get benefit of this support, the master H/W and its System
MMU must resides in the same power domain in terms of Linux kernel. If
a master H/W does not use generic I/O power domain, its driver must
call iommu_attach_device() after its local power domain is turned on,
iommu_detach_device before turned off.

Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
---
 drivers/iommu/exynos-iommu.c |  235 +++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 231 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 9e64483..56aead9 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -28,6 +28,7 @@
 #include <linux/export.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/pm_domain.h>
 #include <linux/notifier.h>
 
 #include <asm/cacheflush.h>
@@ -186,6 +187,7 @@ struct sysmmu_drvdata {
 	int activations;
 	rwlock_t lock;
 	struct iommu_domain *domain;
+	bool runtime_active;
 	unsigned long pgtable;
 	void __iomem *sfrbases[0];
 };
@@ -438,7 +440,8 @@ static bool __sysmmu_disable(struct sysmmu_drvdata *data)
 		data->pgtable = 0;
 		data->domain = NULL;
 
-		__sysmmu_disable_nocount(data);
+		if (data->runtime_active)
+			__sysmmu_disable_nocount(data);
 
 		dev_dbg(data->sysmmu, "Disabled\n");
 	} else  {
@@ -505,7 +508,8 @@ static int __sysmmu_enable(struct sysmmu_drvdata *data,
 		data->pgtable = pgtable;
 		data->domain = domain;
 
-		__sysmmu_enable_nocount(data);
+		if (data->runtime_active)
+			__sysmmu_enable_nocount(data);
 
 		dev_dbg(data->sysmmu, "Enabled\n");
 	} else {
@@ -609,7 +613,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
 		data = dev_get_drvdata(client->sysmmu[i]);
 
 		read_lock_irqsave(&data->lock, flags);
-		if (is_sysmmu_active(data)) {
+		if (is_sysmmu_active(data) && data->runtime_active) {
 			int i;
 			clk_enable(data->clk_master);
 			for (i = 0; i < data->nsfrs; i++)
@@ -637,7 +641,8 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
 		data = dev_get_drvdata(client->sysmmu[i]);
 
 		read_lock_irqsave(&data->lock, flags);
-		if (is_sysmmu_active(data)) {
+		if (is_sysmmu_active(data) &&
+				data->runtime_active) {
 			int i;
 			for (i = 0; i < data->nsfrs; i++) {
 				clk_enable(data->clk_master);
@@ -711,6 +716,8 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 		}
 	}
 
+	pm_runtime_enable(dev);
+
 	data->sysmmu = dev;
 
 	data->clk = devm_clk_get(dev, "sysmmu");
@@ -736,6 +743,8 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	data->runtime_active = !pm_runtime_enabled(dev);
+
 	rwlock_init(&data->lock);
 
 	platform_set_drvdata(pdev, data);
@@ -744,6 +753,34 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 	return ret;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int sysmmu_suspend(struct device *dev)
+{
+	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
+	unsigned long flags;
+	read_lock_irqsave(&data->lock, flags);
+	if (is_sysmmu_active(data) &&
+		(!pm_runtime_enabled(dev) || data->runtime_active))
+		__sysmmu_disable_nocount(data);
+	read_unlock_irqrestore(&data->lock, flags);
+	return 0;
+}
+
+static int sysmmu_resume(struct device *dev)
+{
+	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
+	unsigned long flags;
+	read_lock_irqsave(&data->lock, flags);
+	if (is_sysmmu_active(data) &&
+		(!pm_runtime_enabled(dev) || data->runtime_active))
+		__sysmmu_enable_nocount(data);
+	read_unlock_irqrestore(&data->lock, flags);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(sysmmu_pm_ops, sysmmu_suspend, sysmmu_resume);
+
 #ifdef CONFIG_OF
 static struct of_device_id sysmmu_of_match[] __initconst = {
 	{ .compatible	= "samsung,exynos4210-sysmmu", },
@@ -756,6 +793,7 @@ static struct platform_driver exynos_sysmmu_driver __refdata = {
 	.driver	= {
 		.owner		= THIS_MODULE,
 		.name		= "exynos-sysmmu",
+		.pm		= &sysmmu_pm_ops,
 		.of_match_table	= of_match_ptr(sysmmu_of_match),
 	}
 };
@@ -1141,6 +1179,163 @@ static int __init exynos_iommu_init(void)
 }
 subsys_initcall(exynos_iommu_init);
 
+#ifdef CONFIG_PM_SLEEP
+static int sysmmu_pm_genpd_suspend(struct device *dev)
+{
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < client->num_sysmmu; i++) {
+		ret = pm_generic_suspend(client->sysmmu[i]);
+		if (ret)
+			break;
+	}
+
+	if (!ret)
+		ret = pm_generic_suspend(dev);
+
+	if (ret) {
+		int j;
+
+		for (j = 0; j < i; j++)
+			pm_generic_resume(client->sysmmu[j]);
+	}
+
+	return ret;
+}
+
+static int sysmmu_pm_genpd_resume(struct device *dev)
+{
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < client->num_sysmmu; i++) {
+		ret = pm_generic_resume(client->sysmmu[i]);
+		if (ret)
+			break;
+	}
+
+	if (!ret)
+		ret = pm_generic_resume(dev);
+
+	if (ret) {
+		int j;
+
+		for (j = 0; j < i; j++)
+			pm_generic_suspend(client->sysmmu[j]);
+	}
+
+	return ret;
+}
+#endif
+
+#ifdef CONFIG_PM_RUNTIME
+static void sysmmu_restore_state(struct device *sysmmu)
+{
+	struct sysmmu_drvdata *data = dev_get_drvdata(sysmmu);
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->lock, flags);
+	data->runtime_active = true;
+	if (is_sysmmu_active(data))
+		__sysmmu_enable_nocount(data);
+	spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static void sysmmu_save_state(struct device *sysmmu)
+{
+	struct sysmmu_drvdata *data = dev_get_drvdata(sysmmu);
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->lock, flags);
+	if (is_sysmmu_active(data))
+		__sysmmu_disable_nocount(data);
+	data->runtime_active = false;
+	spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static int sysmmu_pm_genpd_save_state(struct device *dev)
+{
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int (*cb)(struct device *__dev);
+	int i;
+
+	if (dev->type && dev->type->pm)
+		cb = dev->type->pm->runtime_suspend;
+	else if (dev->class && dev->class->pm)
+		cb = dev->class->pm->runtime_suspend;
+	else if (dev->bus && dev->bus->pm)
+		cb = dev->bus->pm->runtime_suspend;
+	else
+		cb = NULL;
+
+	if (!cb && dev->driver && dev->driver->pm)
+		cb = dev->driver->pm->runtime_suspend;
+
+	if (cb) {
+		int ret;
+
+		ret = cb(dev);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < client->num_sysmmu; i++)
+		sysmmu_save_state(client->sysmmu[i]);
+
+	return 0;
+}
+
+static int sysmmu_pm_genpd_restore_state(struct device *dev)
+{
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int (*cb)(struct device *__dev);
+	int i;
+
+	if (dev->type && dev->type->pm)
+		cb = dev->type->pm->runtime_resume;
+	else if (dev->class && dev->class->pm)
+		cb = dev->class->pm->runtime_resume;
+	else if (dev->bus && dev->bus->pm)
+		cb = dev->bus->pm->runtime_resume;
+	else
+		cb = NULL;
+
+	if (!cb && dev->driver && dev->driver->pm)
+		cb = dev->driver->pm->runtime_resume;
+
+	for (i = 0; i < client->num_sysmmu; i++)
+		sysmmu_restore_state(client->sysmmu[i]);
+
+	if (cb) {
+		int ret;
+		ret = cb(dev);
+		if (ret) {
+			for (i = 0; i < client->num_sysmmu; i++)
+				sysmmu_save_state(client->sysmmu[i]);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS
+struct gpd_dev_ops sysmmu_devpm_ops = {
+#ifdef CONFIG_PM_RUNTIME
+	.save_state = &sysmmu_pm_genpd_save_state,
+	.restore_state = &sysmmu_pm_genpd_restore_state,
+#endif
+#ifdef CONFIG_PM_SLEEP
+	.suspend = &sysmmu_pm_genpd_suspend,
+	.resume = &sysmmu_pm_genpd_resume,
+#endif
+};
+#endif /* CONFIG_PM_GENERIC_DOMAINS */
+
 static int sysmmu_hook_driver_register(struct notifier_block *nb,
 					unsigned long val,
 					void *p)
@@ -1197,12 +1392,44 @@ static int sysmmu_hook_driver_register(struct notifier_block *nb,
 			return -ENODEV;
 		}
 
+		i = pm_genpd_add_callbacks(dev, &sysmmu_devpm_ops, NULL);
+		if (i && (i != -ENOSYS)) {
+			dev_err(dev,
+				"Failed to register 'dev_pm_ops' for iommu\n");
+			devm_kfree(dev, client);
+			return i;
+		}
+
 		dev->archdata.iommu = client;
 		break;
 	}
+	case BUS_NOTIFY_BOUND_DRIVER:
+	{
+		struct exynos_iommu_client *client = dev->archdata.iommu;
+		if (dev->archdata.iommu &&
+				(!pm_runtime_enabled(dev) ||
+					 IS_ERR(dev_to_genpd(dev)))) {
+			int i;
+			for (i = 0; i < client->num_sysmmu; i++) {
+				struct sysmmu_drvdata *data;
+				pm_runtime_disable(client->sysmmu[i]);
+				data = dev_get_drvdata(client->sysmmu[i]);
+				if (!data)
+					continue;
+				data->runtime_active =
+					!pm_runtime_enabled(data->sysmmu);
+				if (data->runtime_active &&
+						is_sysmmu_active(data))
+					__sysmmu_enable_nocount(data);
+			}
+		}
+		break;
+	}
 	case BUS_NOTIFY_UNBOUND_DRIVER:
 	{
 		if (dev->archdata.iommu) {
+			__pm_genpd_remove_callbacks(dev, false);
+
 			devm_kfree(dev, dev->archdata.iommu);
 			dev->archdata.iommu = NULL;
 		}
-- 
1.7.2.5

Re: [PATCH v9 14/16] iommu/exynos: add support for power management subsystems.

[Tomasz Figa]

Hi KyongHo,

nit: Please drop the trailing dot at the end of patch subject.

On Thursday 08 of August 2013 18:41:17 Cho KyongHo wrote:
> This adds support for Advance Power Management and Runtime Power
> Management.

This patch adds support for system-wide and runtime power management.

> Since System MMU is located in the same local power domain of its
> master H/W, System MMU must be initialized before it is working if
> its power domain was ever turned off. TLB invalidation according to
> unmapping on page tables must also be performed while power domain is
> turned on.
> 
> This patch ensures that resume and runtime_resume(restore_state)
> functions in this driver is called before the calls to resume and
> runtime_resume callback functions in the drivers of master H/Ws.
> Likewise, suspend and runtime_suspend(save_state) functions in this
> driver is called after the calls to suspend and runtime_suspend in the
> drivers of master H/Ws.
> 
> In order to get benefit of this support, the master H/W and its System
> MMU must resides in the same power domain in terms of Linux kernel. If
> a master H/W does not use generic I/O power domain, its driver must
> call iommu_attach_device() after its local power domain is turned on,
> iommu_detach_device before turned off.

I don't get the point of this last paragraph. What a power domain can be 
in other terms? Is there any other way to support power domains on Exynos 
than generic power domains?

> Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
> ---
>  drivers/iommu/exynos-iommu.c |  235
> +++++++++++++++++++++++++++++++++++++++++- 1 files changed, 231
> insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index 9e64483..56aead9 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -28,6 +28,7 @@
>  #include <linux/export.h>
>  #include <linux/of.h>
>  #include <linux/of_platform.h>
> +#include <linux/pm_domain.h>
>  #include <linux/notifier.h>
> 
>  #include <asm/cacheflush.h>
> @@ -186,6 +187,7 @@ struct sysmmu_drvdata {
>  	int activations;
>  	rwlock_t lock;
>  	struct iommu_domain *domain;
> +	bool runtime_active;
>  	unsigned long pgtable;
>  	void __iomem *sfrbases[0];
>  };
> @@ -438,7 +440,8 @@ static bool __sysmmu_disable(struct sysmmu_drvdata
> *data) data->pgtable = 0;
>  		data->domain = NULL;
> 
> -		__sysmmu_disable_nocount(data);
> +		if (data->runtime_active)
> +			__sysmmu_disable_nocount(data);
> 
>  		dev_dbg(data->sysmmu, "Disabled\n");
>  	} else  {
> @@ -505,7 +508,8 @@ static int __sysmmu_enable(struct sysmmu_drvdata
> *data, data->pgtable = pgtable;
>  		data->domain = domain;
> 
> -		__sysmmu_enable_nocount(data);
> +		if (data->runtime_active)
> +			__sysmmu_enable_nocount(data);
> 
>  		dev_dbg(data->sysmmu, "Enabled\n");
>  	} else {
> @@ -609,7 +613,7 @@ static void sysmmu_tlb_invalidate_entry(struct
> device *dev, unsigned long iova) data =
> dev_get_drvdata(client->sysmmu[i]);
> 
>  		read_lock_irqsave(&data->lock, flags);
> -		if (is_sysmmu_active(data)) {
> +		if (is_sysmmu_active(data) && data->runtime_active) {
>  			int i;
>  			clk_enable(data->clk_master);
>  			for (i = 0; i < data->nsfrs; i++)
> @@ -637,7 +641,8 @@ void exynos_sysmmu_tlb_invalidate(struct device
> *dev) data = dev_get_drvdata(client->sysmmu[i]);
> 
>  		read_lock_irqsave(&data->lock, flags);
> -		if (is_sysmmu_active(data)) {
> +		if (is_sysmmu_active(data) &&
> +				data->runtime_active) {

nit: The whole if condition fits into single line.

>  			int i;
>  			for (i = 0; i < data->nsfrs; i++) {
>  				clk_enable(data->clk_master);
> @@ -711,6 +716,8 @@ static int __init exynos_sysmmu_probe(struct
> platform_device *pdev) }
>  	}
> 
> +	pm_runtime_enable(dev);
> +
>  	data->sysmmu = dev;
> 
>  	data->clk = devm_clk_get(dev, "sysmmu");
> @@ -736,6 +743,8 @@ static int __init exynos_sysmmu_probe(struct
> platform_device *pdev) return ret;
>  	}
> 
> +	data->runtime_active = !pm_runtime_enabled(dev);
> +
>  	rwlock_init(&data->lock);
> 
>  	platform_set_drvdata(pdev, data);
> @@ -744,6 +753,34 @@ static int __init exynos_sysmmu_probe(struct
> platform_device *pdev) return ret;
>  }
> 
> +#ifdef CONFIG_PM_SLEEP
> +static int sysmmu_suspend(struct device *dev)
> +{
> +	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> +	unsigned long flags;
> +	read_lock_irqsave(&data->lock, flags);
> +	if (is_sysmmu_active(data) &&
> +		(!pm_runtime_enabled(dev) || data->runtime_active))
> +		__sysmmu_disable_nocount(data);
> +	read_unlock_irqrestore(&data->lock, flags);
> +	return 0;
> +}
> +
> +static int sysmmu_resume(struct device *dev)
> +{
> +	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> +	unsigned long flags;
> +	read_lock_irqsave(&data->lock, flags);
> +	if (is_sysmmu_active(data) &&
> +		(!pm_runtime_enabled(dev) || data->runtime_active))
> +		__sysmmu_enable_nocount(data);
> +	read_unlock_irqrestore(&data->lock, flags);
> +	return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(sysmmu_pm_ops, sysmmu_suspend, sysmmu_resume);
> +
>  #ifdef CONFIG_OF
>  static struct of_device_id sysmmu_of_match[] __initconst = {
>  	{ .compatible	= "samsung,exynos4210-sysmmu", },
> @@ -756,6 +793,7 @@ static struct platform_driver exynos_sysmmu_driver
> __refdata = { .driver	= {
>  		.owner		= THIS_MODULE,
>  		.name		= "exynos-sysmmu",
> +		.pm		= &sysmmu_pm_ops,
>  		.of_match_table	= of_match_ptr(sysmmu_of_match),
>  	}
>  };
> @@ -1141,6 +1179,163 @@ static int __init exynos_iommu_init(void)
>  }
>  subsys_initcall(exynos_iommu_init);
> 
> +#ifdef CONFIG_PM_SLEEP
> +static int sysmmu_pm_genpd_suspend(struct device *dev)
> +{
> +	struct exynos_iommu_client *client = dev->archdata.iommu;
> +	int ret = 0;
> +	int i;
> +
> +	for (i = 0; i < client->num_sysmmu; i++) {
> +		ret = pm_generic_suspend(client->sysmmu[i]);
> +		if (ret)
> +			break;
> +	}
> +
> +	if (!ret)
> +		ret = pm_generic_suspend(dev);
> +
> +	if (ret) {
> +		int j;
> +
> +		for (j = 0; j < i; j++)
> +			pm_generic_resume(client->sysmmu[j]);
> +	}
> +
> +	return ret;
> +}
> +
> +static int sysmmu_pm_genpd_resume(struct device *dev)
> +{
> +	struct exynos_iommu_client *client = dev->archdata.iommu;
> +	int ret = 0;
> +	int i;
> +
> +	for (i = 0; i < client->num_sysmmu; i++) {
> +		ret = pm_generic_resume(client->sysmmu[i]);
> +		if (ret)
> +			break;

Error handling here can be cleaned up a lot.

s/break/goto err_suspend/

> +	}
> +
> +	if (!ret)

Now you can drop this check.

> +		ret = pm_generic_resume(dev);

	ret = pm_generic_resume(dev);
	if (ret)
		goto err_suspend;

	return 0;

> +

err_suspend:
> +	if (ret) {

This check can be dropped here as well now.

> +		int j;
> +
> +		for (j = 0; j < i; j++)
> +			pm_generic_suspend(client->sysmmu[j]);
> +	}
> +
> +	return ret;
> +}
> +#endif

Best regards,
Tomasz

Re: [PATCH v9 14/16] iommu/exynos: add support for power management subsystems.

[Cho KyongHo]

On Fri, 09 Aug 2013 01:03:05 +0200, Tomasz Figa wrote:
> Hi KyongHo,
> 
> nit: Please drop the trailing dot at the end of patch subject.
> 

Oh. I didn't catch that.
Thank you.

> On Thursday 08 of August 2013 18:41:17 Cho KyongHo wrote:
> > This adds support for Advance Power Management and Runtime Power
> > Management.
> 
> This patch adds support for system-wide and runtime power management.
> 

Ok.

> > Since System MMU is located in the same local power domain of its
> > master H/W, System MMU must be initialized before it is working if
> > its power domain was ever turned off. TLB invalidation according to
> > unmapping on page tables must also be performed while power domain is
> > turned on.
> > 
> > This patch ensures that resume and runtime_resume(restore_state)
> > functions in this driver is called before the calls to resume and
> > runtime_resume callback functions in the drivers of master H/Ws.
> > Likewise, suspend and runtime_suspend(save_state) functions in this
> > driver is called after the calls to suspend and runtime_suspend in the
> > drivers of master H/Ws.
> > 
> > In order to get benefit of this support, the master H/W and its System
> > MMU must resides in the same power domain in terms of Linux kernel. If
> > a master H/W does not use generic I/O power domain, its driver must
> > call iommu_attach_device() after its local power domain is turned on,
> > iommu_detach_device before turned off.
> 
> I don't get the point of this last paragraph. What a power domain can be 
> in other terms? Is there any other way to support power domains on Exynos 
> than generic power domains?
> 

I just addressed the case a device driver turns off local power of its
device without the help of generic I/O powerdomain.

> > Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
> > ---
> >  drivers/iommu/exynos-iommu.c |  235
> > +++++++++++++++++++++++++++++++++++++++++- 1 files changed, 231
> > insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index 9e64483..56aead9 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -28,6 +28,7 @@
> >  #include <linux/export.h>
> >  #include <linux/of.h>
> >  #include <linux/of_platform.h>
> > +#include <linux/pm_domain.h>
> >  #include <linux/notifier.h>
> > 
> >  #include <asm/cacheflush.h>
> > @@ -186,6 +187,7 @@ struct sysmmu_drvdata {
> >  	int activations;
> >  	rwlock_t lock;
> >  	struct iommu_domain *domain;
> > +	bool runtime_active;
> >  	unsigned long pgtable;
> >  	void __iomem *sfrbases[0];
> >  };
> > @@ -438,7 +440,8 @@ static bool __sysmmu_disable(struct sysmmu_drvdata
> > *data) data->pgtable = 0;
> >  		data->domain = NULL;
> > 
> > -		__sysmmu_disable_nocount(data);
> > +		if (data->runtime_active)
> > +			__sysmmu_disable_nocount(data);
> > 
> >  		dev_dbg(data->sysmmu, "Disabled\n");
> >  	} else  {
> > @@ -505,7 +508,8 @@ static int __sysmmu_enable(struct sysmmu_drvdata
> > *data, data->pgtable = pgtable;
> >  		data->domain = domain;
> > 
> > -		__sysmmu_enable_nocount(data);
> > +		if (data->runtime_active)
> > +			__sysmmu_enable_nocount(data);
> > 
> >  		dev_dbg(data->sysmmu, "Enabled\n");
> >  	} else {
> > @@ -609,7 +613,7 @@ static void sysmmu_tlb_invalidate_entry(struct
> > device *dev, unsigned long iova) data =
> > dev_get_drvdata(client->sysmmu[i]);
> > 
> >  		read_lock_irqsave(&data->lock, flags);
> > -		if (is_sysmmu_active(data)) {
> > +		if (is_sysmmu_active(data) && data->runtime_active) {
> >  			int i;
> >  			clk_enable(data->clk_master);
> >  			for (i = 0; i < data->nsfrs; i++)
> > @@ -637,7 +641,8 @@ void exynos_sysmmu_tlb_invalidate(struct device
> > *dev) data = dev_get_drvdata(client->sysmmu[i]);
> > 
> >  		read_lock_irqsave(&data->lock, flags);
> > -		if (is_sysmmu_active(data)) {
> > +		if (is_sysmmu_active(data) &&
> > +				data->runtime_active) {
> 
> nit: The whole if condition fits into single line.

Ok.

> 
> >  			int i;
> >  			for (i = 0; i < data->nsfrs; i++) {
> >  				clk_enable(data->clk_master);
> > @@ -711,6 +716,8 @@ static int __init exynos_sysmmu_probe(struct
> > platform_device *pdev) }
> >  	}
> > 
> > +	pm_runtime_enable(dev);
> > +
> >  	data->sysmmu = dev;
> > 
> >  	data->clk = devm_clk_get(dev, "sysmmu");
> > @@ -736,6 +743,8 @@ static int __init exynos_sysmmu_probe(struct
> > platform_device *pdev) return ret;
> >  	}
> > 
> > +	data->runtime_active = !pm_runtime_enabled(dev);
> > +
> >  	rwlock_init(&data->lock);
> > 
> >  	platform_set_drvdata(pdev, data);
> > @@ -744,6 +753,34 @@ static int __init exynos_sysmmu_probe(struct
> > platform_device *pdev) return ret;
> >  }
> > 
> > +#ifdef CONFIG_PM_SLEEP
> > +static int sysmmu_suspend(struct device *dev)
> > +{
> > +	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> > +	unsigned long flags;
> > +	read_lock_irqsave(&data->lock, flags);
> > +	if (is_sysmmu_active(data) &&
> > +		(!pm_runtime_enabled(dev) || data->runtime_active))
> > +		__sysmmu_disable_nocount(data);
> > +	read_unlock_irqrestore(&data->lock, flags);
> > +	return 0;
> > +}
> > +
> > +static int sysmmu_resume(struct device *dev)
> > +{
> > +	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> > +	unsigned long flags;
> > +	read_lock_irqsave(&data->lock, flags);
> > +	if (is_sysmmu_active(data) &&
> > +		(!pm_runtime_enabled(dev) || data->runtime_active))
> > +		__sysmmu_enable_nocount(data);
> > +	read_unlock_irqrestore(&data->lock, flags);
> > +	return 0;
> > +}
> > +#endif
> > +
> > +static SIMPLE_DEV_PM_OPS(sysmmu_pm_ops, sysmmu_suspend, sysmmu_resume);
> > +
> >  #ifdef CONFIG_OF
> >  static struct of_device_id sysmmu_of_match[] __initconst = {
> >  	{ .compatible	= "samsung,exynos4210-sysmmu", },
> > @@ -756,6 +793,7 @@ static struct platform_driver exynos_sysmmu_driver
> > __refdata = { .driver	= {
> >  		.owner		= THIS_MODULE,
> >  		.name		= "exynos-sysmmu",
> > +		.pm		= &sysmmu_pm_ops,
> >  		.of_match_table	= of_match_ptr(sysmmu_of_match),
> >  	}
> >  };
> > @@ -1141,6 +1179,163 @@ static int __init exynos_iommu_init(void)
> >  }
> >  subsys_initcall(exynos_iommu_init);
> > 
> > +#ifdef CONFIG_PM_SLEEP
> > +static int sysmmu_pm_genpd_suspend(struct device *dev)
> > +{
> > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > +	int ret = 0;
> > +	int i;
> > +
> > +	for (i = 0; i < client->num_sysmmu; i++) {
> > +		ret = pm_generic_suspend(client->sysmmu[i]);
> > +		if (ret)
> > +			break;
> > +	}
> > +
> > +	if (!ret)
> > +		ret = pm_generic_suspend(dev);
> > +
> > +	if (ret) {
> > +		int j;
> > +
> > +		for (j = 0; j < i; j++)
> > +			pm_generic_resume(client->sysmmu[j]);
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static int sysmmu_pm_genpd_resume(struct device *dev)
> > +{
> > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > +	int ret = 0;
> > +	int i;
> > +
> > +	for (i = 0; i < client->num_sysmmu; i++) {
> > +		ret = pm_generic_resume(client->sysmmu[i]);
> > +		if (ret)
> > +			break;
> 
> Error handling here can be cleaned up a lot.
> 
> s/break/goto err_suspend/
> 
> > +	}
> > +
> > +	if (!ret)
> 
> Now you can drop this check.
> 
> > +		ret = pm_generic_resume(dev);
> 
> 	ret = pm_generic_resume(dev);
> 	if (ret)
> 		goto err_suspend;
> 
> 	return 0;
> 
> > +
> 
> err_suspend:
> > +	if (ret) {
> 
> This check can be dropped here as well now.
> 

Ok.

Let me think about it :)

Thank you!

KyongHo.

> > +		int j;
> > +
> > +		for (j = 0; j < i; j++)
> > +			pm_generic_suspend(client->sysmmu[j]);
> > +	}
> > +
> > +	return ret;
> > +}
> > +#endif
> 
> Best regards,
> Tomasz
> 

Re: [PATCH v9 14/16] iommu/exynos: add support for power management subsystems.

[Tomasz Figa]

On Friday 09 of August 2013 16:49:43 Cho KyongHo wrote:
> On Fri, 09 Aug 2013 01:03:05 +0200, Tomasz Figa wrote:
> > Hi KyongHo,
> > 
> > nit: Please drop the trailing dot at the end of patch subject.
> 
> Oh. I didn't catch that.
> Thank you.
> 
> > On Thursday 08 of August 2013 18:41:17 Cho KyongHo wrote:
> > > This adds support for Advance Power Management and Runtime Power
> > > Management.
> > 
> > This patch adds support for system-wide and runtime power management.
> 
> Ok.
> 
> > > Since System MMU is located in the same local power domain of its
> > > master H/W, System MMU must be initialized before it is working if
> > > its power domain was ever turned off. TLB invalidation according to
> > > unmapping on page tables must also be performed while power domain
> > > is
> > > turned on.
> > > 
> > > This patch ensures that resume and runtime_resume(restore_state)
> > > functions in this driver is called before the calls to resume and
> > > runtime_resume callback functions in the drivers of master H/Ws.
> > > Likewise, suspend and runtime_suspend(save_state) functions in this
> > > driver is called after the calls to suspend and runtime_suspend in
> > > the
> > > drivers of master H/Ws.
> > > 
> > > In order to get benefit of this support, the master H/W and its
> > > System
> > > MMU must resides in the same power domain in terms of Linux kernel.
> > > If
> > > a master H/W does not use generic I/O power domain, its driver must
> > > call iommu_attach_device() after its local power domain is turned
> > > on,
> > > iommu_detach_device before turned off.
> > 
> > I don't get the point of this last paragraph. What a power domain can
> > be in other terms? Is there any other way to support power domains on
> > Exynos than generic power domains?
> 
> I just addressed the case a device driver turns off local power of its
> device without the help of generic I/O powerdomain.

Out of curiosity, do we have such cases for Exynos in mainline kernel? 
IMHO this is what the generic PM core is for and drivers shouldn't care 
about such low level PM details.

> > > Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
> > > ---
> > > 
> > >  drivers/iommu/exynos-iommu.c |  235
> > > 
> > > +++++++++++++++++++++++++++++++++++++++++- 1 files changed, 231
> > > insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/drivers/iommu/exynos-iommu.c
> > > b/drivers/iommu/exynos-iommu.c index 9e64483..56aead9 100644
> > > --- a/drivers/iommu/exynos-iommu.c
> > > +++ b/drivers/iommu/exynos-iommu.c
> > > @@ -28,6 +28,7 @@
> > > 
> > >  #include <linux/export.h>
> > >  #include <linux/of.h>
> > >  #include <linux/of_platform.h>
> > > 
> > > +#include <linux/pm_domain.h>
> > > 
> > >  #include <linux/notifier.h>
> > >  
> > >  #include <asm/cacheflush.h>
> > > 
> > > @@ -186,6 +187,7 @@ struct sysmmu_drvdata {
> > > 
> > >  	int activations;
> > >  	rwlock_t lock;
> > >  	struct iommu_domain *domain;
> > > 
> > > +	bool runtime_active;
> > > 
> > >  	unsigned long pgtable;
> > >  	void __iomem *sfrbases[0];
> > >  
> > >  };
> > > 
> > > @@ -438,7 +440,8 @@ static bool __sysmmu_disable(struct
> > > sysmmu_drvdata
> > > *data) data->pgtable = 0;
> > > 
> > >  		data->domain = NULL;
> > > 
> > > -		__sysmmu_disable_nocount(data);
> > > +		if (data->runtime_active)
> > > +			__sysmmu_disable_nocount(data);
> > > 
> > >  		dev_dbg(data->sysmmu, "Disabled\n");
> > >  	
> > >  	} else  {
> > > 
> > > @@ -505,7 +508,8 @@ static int __sysmmu_enable(struct sysmmu_drvdata
> > > *data, data->pgtable = pgtable;
> > > 
> > >  		data->domain = domain;
> > > 
> > > -		__sysmmu_enable_nocount(data);
> > > +		if (data->runtime_active)
> > > +			__sysmmu_enable_nocount(data);
> > > 
> > >  		dev_dbg(data->sysmmu, "Enabled\n");
> > >  	
> > >  	} else {
> > > 
> > > @@ -609,7 +613,7 @@ static void sysmmu_tlb_invalidate_entry(struct
> > > device *dev, unsigned long iova) data =
> > > dev_get_drvdata(client->sysmmu[i]);
> > > 
> > >  		read_lock_irqsave(&data->lock, flags);
> > > 
> > > -		if (is_sysmmu_active(data)) {
> > > +		if (is_sysmmu_active(data) && data->runtime_active) {
> > > 
> > >  			int i;
> > >  			clk_enable(data->clk_master);
> > >  			for (i = 0; i < data->nsfrs; i++)
> > > 
> > > @@ -637,7 +641,8 @@ void exynos_sysmmu_tlb_invalidate(struct device
> > > *dev) data = dev_get_drvdata(client->sysmmu[i]);
> > > 
> > >  		read_lock_irqsave(&data->lock, flags);
> > > 
> > > -		if (is_sysmmu_active(data)) {
> > > +		if (is_sysmmu_active(data) &&
> > > +				data->runtime_active) {
> > 
> > nit: The whole if condition fits into single line.
> 
> Ok.
> 
> > >  			int i;
> > >  			for (i = 0; i < data->nsfrs; i++) {
> > >  			
> > >  				clk_enable(data->clk_master);
> > > 
> > > @@ -711,6 +716,8 @@ static int __init exynos_sysmmu_probe(struct
> > > platform_device *pdev) }
> > > 
> > >  	}
> > > 
> > > +	pm_runtime_enable(dev);
> > > +
> > > 
> > >  	data->sysmmu = dev;
> > >  	
> > >  	data->clk = devm_clk_get(dev, "sysmmu");
> > > 
> > > @@ -736,6 +743,8 @@ static int __init exynos_sysmmu_probe(struct
> > > platform_device *pdev) return ret;
> > > 
> > >  	}
> > > 
> > > +	data->runtime_active = !pm_runtime_enabled(dev);
> > > +
> > > 
> > >  	rwlock_init(&data->lock);
> > >  	
> > >  	platform_set_drvdata(pdev, data);
> > > 
> > > @@ -744,6 +753,34 @@ static int __init exynos_sysmmu_probe(struct
> > > platform_device *pdev) return ret;
> > > 
> > >  }
> > > 
> > > +#ifdef CONFIG_PM_SLEEP
> > > +static int sysmmu_suspend(struct device *dev)
> > > +{
> > > +	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> > > +	unsigned long flags;
> > > +	read_lock_irqsave(&data->lock, flags);
> > > +	if (is_sysmmu_active(data) &&
> > > +		(!pm_runtime_enabled(dev) || data->runtime_active))
> > > +		__sysmmu_disable_nocount(data);
> > > +	read_unlock_irqrestore(&data->lock, flags);
> > > +	return 0;
> > > +}
> > > +
> > > +static int sysmmu_resume(struct device *dev)
> > > +{
> > > +	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> > > +	unsigned long flags;
> > > +	read_lock_irqsave(&data->lock, flags);
> > > +	if (is_sysmmu_active(data) &&
> > > +		(!pm_runtime_enabled(dev) || data->runtime_active))
> > > +		__sysmmu_enable_nocount(data);
> > > +	read_unlock_irqrestore(&data->lock, flags);
> > > +	return 0;
> > > +}
> > > +#endif
> > > +
> > > +static SIMPLE_DEV_PM_OPS(sysmmu_pm_ops, sysmmu_suspend,
> > > sysmmu_resume); +
> > > 
> > >  #ifdef CONFIG_OF
> > >  static struct of_device_id sysmmu_of_match[] __initconst = {
> > >  
> > >  	{ .compatible	= "samsung,exynos4210-sysmmu", },
> > > 
> > > @@ -756,6 +793,7 @@ static struct platform_driver
> > > exynos_sysmmu_driver
> > > __refdata = { .driver	= {
> > > 
> > >  		.owner		= THIS_MODULE,
> > >  		.name		= "exynos-sysmmu",
> > > 
> > > +		.pm		= &sysmmu_pm_ops,
> > > 
> > >  		.of_match_table	= of_match_ptr(sysmmu_of_match),
> > >  	
> > >  	}
> > >  
> > >  };
> > > 
> > > @@ -1141,6 +1179,163 @@ static int __init exynos_iommu_init(void)
> > > 
> > >  }
> > >  subsys_initcall(exynos_iommu_init);
> > > 
> > > +#ifdef CONFIG_PM_SLEEP
> > > +static int sysmmu_pm_genpd_suspend(struct device *dev)
> > > +{
> > > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > > +	int ret = 0;
> > > +	int i;
> > > +
> > > +	for (i = 0; i < client->num_sysmmu; i++) {
> > > +		ret = pm_generic_suspend(client->sysmmu[i]);
> > > +		if (ret)
> > > +			break;
> > > +	}
> > > +
> > > +	if (!ret)
> > > +		ret = pm_generic_suspend(dev);
> > > +
> > > +	if (ret) {
> > > +		int j;
> > > +
> > > +		for (j = 0; j < i; j++)
> > > +			pm_generic_resume(client->sysmmu[j]);
> > > +	}
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int sysmmu_pm_genpd_resume(struct device *dev)
> > > +{
> > > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > > +	int ret = 0;
> > > +	int i;
> > > +
> > > +	for (i = 0; i < client->num_sysmmu; i++) {
> > > +		ret = pm_generic_resume(client->sysmmu[i]);
> > > +		if (ret)
> > > +			break;
> > 
> > Error handling here can be cleaned up a lot.
> > 
> > s/break/goto err_suspend/
> > 
> > > +	}
> > > +
> > > +	if (!ret)
> > 
> > Now you can drop this check.
> > 
> > > +		ret = pm_generic_resume(dev);
> > 	
> > 	ret = pm_generic_resume(dev);
> > 	if (ret)
> > 	
> > 		goto err_suspend;
> > 	
> > 	return 0;
> > 	
> > > +
> > 
> > err_suspend:
> > > +	if (ret) {
> > 
> > This check can be dropped here as well now.
> 
> Ok.
> 
> Let me think about it :)

Thanks.

Best regards,
Tomasz

Re: [PATCH v9 14/16] iommu/exynos: add support for power management subsystems.

[Cho KyongHo]

On Fri, 09 Aug 2013 10:32:40 +0200, Tomasz Figa wrote:
> On Friday 09 of August 2013 16:49:43 Cho KyongHo wrote:
> > On Fri, 09 Aug 2013 01:03:05 +0200, Tomasz Figa wrote:
> > > Hi KyongHo,
> > > 
> > > nit: Please drop the trailing dot at the end of patch subject.
> > 
> > Oh. I didn't catch that.
> > Thank you.
> > 
> > > On Thursday 08 of August 2013 18:41:17 Cho KyongHo wrote:
> > > > This adds support for Advance Power Management and Runtime Power
> > > > Management.
> > > 
> > > This patch adds support for system-wide and runtime power management.
> > 
> > Ok.
> > 
> > > > Since System MMU is located in the same local power domain of its
> > > > master H/W, System MMU must be initialized before it is working if
> > > > its power domain was ever turned off. TLB invalidation according to
> > > > unmapping on page tables must also be performed while power domain
> > > > is
> > > > turned on.
> > > > 
> > > > This patch ensures that resume and runtime_resume(restore_state)
> > > > functions in this driver is called before the calls to resume and
> > > > runtime_resume callback functions in the drivers of master H/Ws.
> > > > Likewise, suspend and runtime_suspend(save_state) functions in this
> > > > driver is called after the calls to suspend and runtime_suspend in
> > > > the
> > > > drivers of master H/Ws.
> > > > 
> > > > In order to get benefit of this support, the master H/W and its
> > > > System
> > > > MMU must resides in the same power domain in terms of Linux kernel.
> > > > If
> > > > a master H/W does not use generic I/O power domain, its driver must
> > > > call iommu_attach_device() after its local power domain is turned
> > > > on,
> > > > iommu_detach_device before turned off.
> > > 
> > > I don't get the point of this last paragraph. What a power domain can
> > > be in other terms? Is there any other way to support power domains on
> > > Exynos than generic power domains?
> > 
> > I just addressed the case a device driver turns off local power of its
> > device without the help of generic I/O powerdomain.
> 
> Out of curiosity, do we have such cases for Exynos in mainline kernel? 
> IMHO this is what the generic PM core is for and drivers shouldn't care 
> about such low level PM details.

I don't know if there is the case and I also agree with you.

I hope that there is no case that I addressed.
I just mentioned an exceptional case.
The best way is that all device drivers of master H/W of System MMU register
their defvice in a generic i/o powerdomain.

Thank you.

KyongHo.