[PATCH v9 14/16] iommu/exynos: add support for power management subsystems.
Tomasz Figa
tomasz.figa at gmail.com
Thu Aug 8 19:03:05 EDT 2013
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 at 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
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