[v8,10/12] iommu/exynos: add bus notifier for registering System MMU

Commit Message

Cho KyongHo July 26, 2013, 11:30 a.m. UTC

When a device driver is registered, all constructs to handle System MMU
is prepared by bus notifier call.

Signed-off-by: Cho KyongHo <[e-mail]>
---
 drivers/iommu/exynos-iommu.c |  708 ++++++++++++++++++++++++++++++++---------
 1 files changed, 552 insertions(+), 156 deletions(-)

Comments

Rahul Sharma Aug. 2, 2013, 5:17 a.m. UTC | #1

Hi Cho,

On Fri, Jul 26, 2013 at 5:00 PM, Cho KyongHo <[e-mail]> wrote:
> When a device driver is registered, all constructs to handle System MMU
> is prepared by bus notifier call.
>
> Signed-off-by: Cho KyongHo <[e-mail]>
> ---
>  drivers/iommu/exynos-iommu.c |  708 ++++++++++++++++++++++++++++++++---------
>  1 files changed, 552 insertions(+), 156 deletions(-)
>
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index f9853fe..c62c244 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -27,6 +27,9 @@
>  #include <linux/memblock.h>
>  #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>
>  #include <asm/pgtable.h>
> @@ -80,7 +83,13 @@
>  #define CTRL_BLOCK     0x7
>  #define CTRL_DISABLE   0x0
>
> +#define CFG_LRU                0x1
> +#define CFG_QOS(n)     ((n & 0xF) << 7)
> +#define CFG_MASK       0x0150FFFF /* Selecting bit 0-15, 20, 22 and 24 */
> +#define CFG_ACGEN      (1 << 24) /* System MMU 3.3 only */
> +#define CFG_SYSSEL     (1 << 22) /* System MMU 3.2 only */
>  #define CFG_FLPDCACHE  (1 << 20) /* System MMU 3.2+ only */
> +#define CFG_SHAREABLE  (1 << 12) /* System MMU 3.x only */
>
>  #define REG_MMU_CTRL           0x000
>  #define REG_MMU_CFG            0x004
> @@ -154,6 +163,14 @@ static char *sysmmu_fault_name[SYSMMU_FAULTS_NUM] = {
>         "UNKNOWN FAULT"
>  };
>
> +struct exynos_iommu_client {
> +       struct list_head node;  /* entry of exynos_iommu_domain.clients */
> +       struct device *dev;
> +       spinlock_t lock;
> +       int num_sysmmu;
> +       struct device *sysmmu[0];

Shouldn't we keep limit on the max number of iommu's to a single client ? Even
this way, you will hit array overrun with multiple iommu's.

> +};
> +
>  struct exynos_iommu_domain {
>         struct list_head clients; /* list of sysmmu_drvdata.node */
>         unsigned long *pgtable; /* lv1 page table, 16KB */
> @@ -165,12 +182,14 @@ struct exynos_iommu_domain {
>  struct sysmmu_drvdata {
>         struct list_head node; /* entry of exynos_iommu_domain.clients */
>         struct device *sysmmu;  /* System MMU's device descriptor */
> -       struct device *dev;     /* Owner of system MMU */
> +       struct device *master;  /* Owner of system MMU */
>         int nsfrs;
>         struct clk *clk;
> +       struct clk *clk_master;
>         int activations;
>         rwlock_t lock;
>         struct iommu_domain *domain;
> +       bool runtime_active;
>         unsigned long pgtable;
>         void __iomem *sfrbases[0];
>  };
> @@ -245,7 +264,6 @@ static void __sysmmu_tlb_invalidate_entry(void __iomem *sfrbase,
>  static void __sysmmu_set_ptbase(void __iomem *sfrbase,
>                                        unsigned long pgd)
>  {
> -       __raw_writel(0x1, sfrbase + REG_MMU_CFG); /* 16KB LV1, LRU */
>         __raw_writel(pgd, sfrbase + REG_PT_BASE_ADDR);
>
>         __sysmmu_tlb_invalidate(sfrbase);
> @@ -273,6 +291,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
>         if (!is_sysmmu_active(data))
>                 goto finish;
>
> +       clk_enable(data->clk_master);
>         for (i = 0; i < data->nsfrs; i++) {
>                 if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
>                         if (!sysmmu_block(data->sfrbases[i]))
> @@ -298,6 +317,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
>                         sysmmu_unblock(data->sfrbases[i]);
>                 }
>         }
> +       clk_disable(data->clk_master);
>  finish:
>         read_unlock_irqrestore(&data->lock, flags);
>  }
> @@ -331,12 +351,13 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>  {
>         /* SYSMMU is in blocked when interrupt occurred. */
>         struct sysmmu_drvdata *data = dev_id;
> +       struct exynos_iommu_client *client = NULL;
>         enum exynos_sysmmu_inttype itype;
>         unsigned long addr = -1;
> -
>         int i, ret = -ENOSYS;
>
> -       read_lock(&data->lock);
> +       if (data->master)
> +               client = data->master->archdata.iommu;
>
>         WARN_ON(!is_sysmmu_active(data));
>
> @@ -348,6 +369,10 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>                         break;
>         }
>
> +       if (client)
> +               spin_lock(&client->lock);
> +       read_lock(&data->lock);
> +
>         if (i == data->nsfrs) {
>                 itype = SYSMMU_FAULT_UNKNOWN;
>         } else {
> @@ -361,7 +386,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>         }
>
>         if (data->domain)
> -               ret = report_iommu_fault(data->domain, data->dev,
> +               ret = report_iommu_fault(data->domain, data->master,
>                                 addr, itype);
>
>         if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
> @@ -378,177 +403,251 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>                 sysmmu_unblock(data->sfrbases[i]);
>
>         read_unlock(&data->lock);
> +       if (client)
> +               spin_unlock(&client->lock);
>
>         return IRQ_HANDLED;
>  }
>
> -static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
> +static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
>  {
> -       unsigned long flags;
> -       bool disabled = false;
>         int i;
>
> -       write_lock_irqsave(&data->lock, flags);
> +       clk_enable(data->clk_master);
> +       for (i = 0; i < data->nsfrs; i++) {
> +               __raw_writel(CTRL_DISABLE,
> +                               data->sfrbases[i] + REG_MMU_CTRL);
> +               __raw_writel(0, data->sfrbases[i] + REG_MMU_CFG);
> +       }
>
> -       if (!set_sysmmu_inactive(data))
> -               goto finish;
> +       clk_disable(data->clk);
> +       clk_disable(data->clk_master);
> +}
>
> -       for (i = 0; i < data->nsfrs; i++)
> -               __raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
> +static bool __sysmmu_disable(struct sysmmu_drvdata *data)
> +{
> +       bool disabled;
> +       unsigned long flags;
>
> -       if (data->clk)
> -               clk_disable(data->clk);
> +       write_lock_irqsave(&data->lock, flags);
>
> -       disabled = true;
> -       data->pgtable = 0;
> -       data->domain = NULL;
> -finish:
> -       write_unlock_irqrestore(&data->lock, flags);
> +       disabled = set_sysmmu_inactive(data);
> +
> +       if (disabled) {
> +               data->pgtable = 0;
> +               data->domain = NULL;
> +
> +               if (data->runtime_active)
> +                       __sysmmu_disable_nocount(data);
>
> -       if (disabled)
>                 dev_dbg(data->sysmmu, "Disabled\n");
> -       else
> -               dev_dbg(data->sysmmu, "%d times left to be disabled\n",
> +       } else  {
> +               dev_dbg(data->sysmmu, "%d times left to disable\n",
>                                         data->activations);
> +       }
> +
> +       write_unlock_irqrestore(&data->lock, flags);
>
>         return disabled;
>  }
>
> -/* __exynos_sysmmu_enable: Enables System MMU
> - *
> - * returns -error if an error occurred and System MMU is not enabled,
> - * 0 if the System MMU has been just enabled and 1 if System MMU was already
> - * enabled before.
> - */
> -static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> +
> +static void __sysmmu_init_config(struct sysmmu_drvdata *data, int idx)
> +{
> +       unsigned long cfg = CFG_LRU | CFG_QOS(15);
> +       int maj, min = 0;
> +
> +       maj = __sysmmu_version(data, idx, &min);
> +       if (maj == 3) {
> +               if (min > 1) {
> +                       cfg |= CFG_FLPDCACHE;
> +                       cfg |= (min == 2) ? CFG_SYSSEL : CFG_ACGEN;
> +               }
> +       }
> +
> +       __raw_writel(cfg, data->sfrbases[idx] + REG_MMU_CFG);
> +}
> +
> +static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
> +{
> +       int i;
> +
> +       clk_enable(data->clk_master);
> +       clk_enable(data->clk);
> +
> +       for (i = 0; i < data->nsfrs; i++) {
> +               __raw_writel(CTRL_BLOCK, data->sfrbases[i] + REG_MMU_CTRL);
> +
> +               __sysmmu_init_config(data, i);
> +
> +               __sysmmu_set_ptbase(data->sfrbases[i], data->pgtable);
> +
> +               __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> +       }
> +       clk_disable(data->clk_master);
> +}
> +
> +static int __sysmmu_enable(struct sysmmu_drvdata *data,
>                         unsigned long pgtable, struct iommu_domain *domain)
>  {
> -       int i, ret = 0;
> +       int ret = 0;
>         unsigned long flags;
>
>         write_lock_irqsave(&data->lock, flags);
> +       if (set_sysmmu_active(data)) {
> +               data->pgtable = pgtable;
> +               data->domain = domain;
>
> -       if (!set_sysmmu_active(data)) {
> -               if (WARN_ON(pgtable != data->pgtable)) {
> -                       ret = -EBUSY;
> -                       set_sysmmu_inactive(data);
> -               } else {
> -                       ret = 1;
> -               }
> +               if (data->runtime_active)
> +                       __sysmmu_enable_nocount(data);
>
> -               dev_dbg(data->sysmmu, "Already enabled\n");
> -               goto finish;
> +               dev_dbg(data->sysmmu, "Enabled\n");
> +       } else {
> +               ret = (pgtable == data->pgtable) ? 1 : -EBUSY;
> +
> +               dev_dbg(data->sysmmu, "already enabled\n");
>         }
>
> -       if (data->clk)
> -               clk_enable(data->clk);
> +       if (WARN_ON(ret < 0))
> +               set_sysmmu_inactive(data); /* decrement count */
>
> -       data->pgtable = pgtable;
> +       write_unlock_irqrestore(&data->lock, flags);
>
> -       for (i = 0; i < data->nsfrs; i++) {
> -               unsigned int min;
> +       return ret;
> +}
>
> -               __sysmmu_set_ptbase(data->sfrbases[i], pgtable);
> +/* __exynos_sysmmu_enable: Enables System MMU
> + *
> + * returns -error if an error occurred and System MMU is not enabled,
> + * 0 if the System MMU has been just enabled and 1 if System MMU was already
> + * enabled before.
> + */
> +static int __exynos_sysmmu_enable(struct device *dev, unsigned long pgtable,
> +                                 struct iommu_domain *domain)
> +{
> +       int ret = 0;
> +       unsigned long flags;
> +       struct exynos_iommu_client *client = dev->archdata.iommu;
> +       int i;
>
> -               if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
> -                       unsigned long cfg;
> -                       cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
> -                       __raw_writel(cfg | CFG_FLPDCACHE,
> -                                       data->sfrbases[i] + REG_MMU_CFG);
> -               }
> +       if (WARN_ON(!client))
> +               return -ENODEV;
>
> -               __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> -       }
> +       spin_lock_irqsave(&client->lock, flags);
>
> -       data->domain = domain;
> +       for (i = 0; i < client->num_sysmmu; i++) {
> +               struct sysmmu_drvdata *data =
> +                               dev_get_drvdata(client->sysmmu[i]);
> +               ret = __sysmmu_enable(data, pgtable, domain);
> +               if (ret < 0) {
> +                       int j;
> +                       for (j = 0; j < i; j++)
> +                               __sysmmu_disable(data);
> +                       break;
> +               } else {
> +                       data->master = dev;
> +               }
> +       }
>
> -       dev_dbg(data->sysmmu, "Enabled\n");
> -finish:
> -       write_unlock_irqrestore(&data->lock, flags);
> +       spin_unlock_irqrestore(&client->lock, flags);
>
>         return ret;
>  }
>
>  int exynos_sysmmu_enable(struct device *dev, unsigned long pgtable)
>  {
> -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>         int ret;
>
>         BUG_ON(!memblock_is_memory(pgtable));
>
> -       ret = pm_runtime_get_sync(data->sysmmu);
> -       if (ret < 0) {
> -               dev_dbg(data->sysmmu, "Failed to enable\n");
> -               return ret;
> -       }
> -
> -       ret = __exynos_sysmmu_enable(data, pgtable, NULL);
> -       if (WARN_ON(ret < 0)) {
> -               pm_runtime_put(data->sysmmu);
> -               dev_err(data->sysmmu,
> -                       "Already enabled with page table %#lx\n",
> -                       data->pgtable);
> -       } else {
> -               data->dev = dev;
> -       }
> +       ret = __exynos_sysmmu_enable(dev, pgtable, NULL);
>
>         return ret;
>  }
>
>  static bool exynos_sysmmu_disable(struct device *dev)
>  {
> -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> -       bool disabled;
> +       unsigned long flags;
> +       bool disabled = true;
> +       struct exynos_iommu_client *client = dev->archdata.iommu;
> +       int i;
>
> -       disabled = __exynos_sysmmu_disable(data);
> -       pm_runtime_put(data->sysmmu);
> +       if (WARN_ON(!client))
> +               return true;
> +
> +       spin_lock_irqsave(&client->lock, flags);
> +
> +       /* Every call to __sysmmu_disable() must return same result */
> +       for (i = 0; i < client->num_sysmmu; i++) {
> +               struct sysmmu_drvdata *data =
> +                               dev_get_drvdata(client->sysmmu[i]);
> +               disabled = __sysmmu_disable(data);
> +               if (disabled)
> +                       data->master = NULL;
> +       }
> +
> +       spin_unlock_irqrestore(&client->lock, flags);
>
>         return disabled;
>  }
>
>  static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
>  {
> -       unsigned long flags;
> -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> +       struct exynos_iommu_client *client = dev->archdata.iommu;
> +       int i;
>
> -       read_lock_irqsave(&data->lock, flags);
> +       for (i = 0; i < client->num_sysmmu; i++) {
> +               unsigned long flags;
> +               struct sysmmu_drvdata *data;
>
> -       if (is_sysmmu_active(data)) {
> -               int i;
> -               for (i = 0; i < data->nsfrs; i++) {
> -                       if (sysmmu_block(data->sfrbases[i])) {
> +               data = dev_get_drvdata(client->sysmmu[i]);
> +
> +               read_lock_irqsave(&data->lock, flags);
> +               if (is_sysmmu_active(data) && data->runtime_active) {
> +                       int i;
> +                       clk_enable(data->clk_master);
> +                       for (i = 0; i < data->nsfrs; i++)
>                                 __sysmmu_tlb_invalidate_entry(
>                                                 data->sfrbases[i], iova);
> -                               sysmmu_unblock(data->sfrbases[i]);
> -                       }
> +                       clk_disable(data->clk_master);
> +               } else {
> +                       dev_dbg(dev,
> +                               "disabled. Skipping TLB invalidation @ %#lx\n",
> +                               iova);
>                 }
> -       } else {
> -               dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> +               read_unlock_irqrestore(&data->lock, flags);
>         }
> -
> -       read_unlock_irqrestore(&data->lock, flags);
>  }
>
>  void exynos_sysmmu_tlb_invalidate(struct device *dev)
>  {
> -       unsigned long flags;
> -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> -
> -       read_lock_irqsave(&data->lock, flags);
> +       struct exynos_iommu_client *client = dev->archdata.iommu;
> +       int i;
>
> -       if (is_sysmmu_active(data)) {
> -               int i;
> -               for (i = 0; i < data->nsfrs; i++) {
> -                       if (sysmmu_block(data->sfrbases[i])) {
> -                               __sysmmu_tlb_invalidate(data->sfrbases[i]);
> -                               sysmmu_unblock(data->sfrbases[i]);
> +       for (i = 0; i < client->num_sysmmu; i++) {
> +               unsigned long flags;
> +               struct sysmmu_drvdata *data;
> +
> +               data = dev_get_drvdata(client->sysmmu[i]);
> +
> +               read_lock_irqsave(&data->lock, flags);
> +               if (is_sysmmu_active(data) &&
> +                               data->runtime_active) {
> +                       int i;
> +                       for (i = 0; i < data->nsfrs; i++) {
> +                               clk_enable(data->clk_master);
> +                               if (sysmmu_block(data->sfrbases[i])) {
> +                                       __sysmmu_tlb_invalidate(
> +                                                       data->sfrbases[i]);
> +                                       sysmmu_unblock(data->sfrbases[i]);
> +                               }
> +                               clk_disable(data->clk_master);
>                         }
> +               } else {
> +                       dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
>                 }
> -       } else {
> -               dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> +               read_unlock_irqrestore(&data->lock, flags);
>         }
> -
> -       read_unlock_irqrestore(&data->lock, flags);
>  }
>
>  static int __init exynos_sysmmu_probe(struct platform_device *pdev)
> @@ -610,12 +709,32 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>         pm_runtime_enable(dev);
>
>         data->sysmmu = dev;
> +
>         data->clk = devm_clk_get(dev, "sysmmu");
>         if (IS_ERR(data->clk)) {
>                 dev_info(dev, "No gate clock found!\n");
>                 data->clk = NULL;
>         }
>
> +       ret = clk_prepare(data->clk);
> +       if (ret) {
> +               dev_err(dev, "Failed to prepare clk\n");
> +               return ret;
> +       }
> +
> +       data->clk_master = devm_clk_get(dev, "master");
> +       if (IS_ERR(data->clk_master))
> +               data->clk_master = NULL;
> +
> +       ret = clk_prepare(data->clk_master);
> +       if (ret) {
> +               clk_unprepare(data->clk);
> +               dev_err(dev, "Failed to prepare master's clk\n");
> +               return ret;
> +       }
> +
> +       data->runtime_active = !pm_runtime_enabled(dev);
> +
>         rwlock_init(&data->lock);
>         INIT_LIST_HEAD(&data->node);
>
> @@ -625,6 +744,34 @@ 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", },
> @@ -637,6 +784,7 @@ 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),
>         }
>  };
> @@ -689,7 +837,7 @@ err_pgtable:
>  static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>  {
>         struct exynos_iommu_domain *priv = domain->priv;
> -       struct sysmmu_drvdata *data;
> +       struct exynos_iommu_client *client;
>         unsigned long flags;
>         int i;
>
> @@ -697,11 +845,14 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>
>         spin_lock_irqsave(&priv->lock, flags);
>
> -       list_for_each_entry(data, &priv->clients, node) {
> -               while (!exynos_sysmmu_disable(data->dev))
> +       list_for_each_entry(client, &priv->clients, node) {
> +               while (!exynos_sysmmu_disable(client->dev))
>                         ; /* until System MMU is actually disabled */
>         }
>
> +       while (!list_empty(&priv->clients))
> +               list_del_init(priv->clients.next);
> +
>         spin_unlock_irqrestore(&priv->lock, flags);
>
>         for (i = 0; i < NUM_LV1ENTRIES; i++)
> @@ -718,41 +869,26 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>  static int exynos_iommu_attach_device(struct iommu_domain *domain,
>                                    struct device *dev)
>  {
> -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> +       struct exynos_iommu_client *client = dev->archdata.iommu;
>         struct exynos_iommu_domain *priv = domain->priv;
>         unsigned long flags;
>         int ret;
>
> -       ret = pm_runtime_get_sync(data->sysmmu);
> -       if (ret < 0)
> -               return ret;
> -
> -       ret = 0;
> -
>         spin_lock_irqsave(&priv->lock, flags);
>
> -       ret = __exynos_sysmmu_enable(data, __pa(priv->pgtable), domain);
> -
> -       if (ret == 0) {
> -               /* 'data->node' must not be appeared in priv->clients */
> -               BUG_ON(!list_empty(&data->node));
> -               data->dev = dev;
> -               list_add_tail(&data->node, &priv->clients);
> -       }
> +       ret = __exynos_sysmmu_enable(dev, __pa(priv->pgtable), domain);
> +       if (ret == 0)
> +               list_add_tail(&client->node, &priv->clients);
>
>         spin_unlock_irqrestore(&priv->lock, flags);
>
> -       if (ret < 0) {
> +       if (ret < 0)
>                 dev_err(dev, "%s: Failed to attach IOMMU with pgtable %#lx\n",
>                                 __func__, __pa(priv->pgtable));
> -               pm_runtime_put(data->sysmmu);
> -       } else if (ret > 0) {
> -               dev_dbg(dev, "%s: IOMMU with pgtable 0x%lx already attached\n",
> -                                       __func__, __pa(priv->pgtable));
> -       } else {
> -               dev_dbg(dev, "%s: Attached new IOMMU with pgtable 0x%lx\n",
> -                                       __func__, __pa(priv->pgtable));
> -       }
> +       else
> +               dev_dbg(dev, "%s: Attached IOMMU with pgtable 0x%lx%s\n",
> +                                       __func__, __pa(priv->pgtable),
> +                                       (ret == 0) ? "" : ", again");
>
>         return ret;
>  }
> @@ -760,39 +896,27 @@ static int exynos_iommu_attach_device(struct iommu_domain *domain,
>  static void exynos_iommu_detach_device(struct iommu_domain *domain,
>                                     struct device *dev)
>  {
> -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> +       struct exynos_iommu_client *client = NULL;
>         struct exynos_iommu_domain *priv = domain->priv;
> -       struct list_head *pos;
>         unsigned long flags;
> -       bool found = false;
>
>         spin_lock_irqsave(&priv->lock, flags);
>
> -       list_for_each(pos, &priv->clients) {
> -               if (list_entry(pos, struct sysmmu_drvdata, node) == data) {
> -                       found = true;
> +       list_for_each_entry(client, &priv->clients, node) {
> +               if (client == dev->archdata.iommu) {
> +                       if (exynos_sysmmu_disable(dev))
> +                               list_del_init(&client->node);
>                         break;
>                 }
>         }
>
> -       if (!found)
> -               goto finish;
> +       spin_unlock_irqrestore(&priv->lock, flags);
>
> -       if (__exynos_sysmmu_disable(data)) {
> +       if (client == dev->archdata.iommu)
>                 dev_dbg(dev, "%s: Detached IOMMU with pgtable %#lx\n",
>                                         __func__, __pa(priv->pgtable));
> -               list_del_init(&data->node);
> -
> -       } else {
> -               dev_dbg(dev, "%s: Detaching IOMMU with pgtable %#lx delayed",
> -                                       __func__, __pa(priv->pgtable));
> -       }
> -
> -finish:
> -       spin_unlock_irqrestore(&priv->lock, flags);
> -
> -       if (found)
> -               pm_runtime_put(data->sysmmu);
> +       else
> +               dev_dbg(dev, "%s: No IOMMU is attached\n", __func__);
>  }
>
>  static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
> @@ -914,7 +1038,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
>                                                unsigned long iova, size_t size)
>  {
>         struct exynos_iommu_domain *priv = domain->priv;
> -       struct sysmmu_drvdata *data;
> +       struct exynos_iommu_client *client;
>         unsigned long flags;
>         unsigned long *ent;
>         size_t err_pgsize;
> @@ -975,8 +1099,8 @@ done:
>         spin_unlock_irqrestore(&priv->pgtablelock, flags);
>
>         spin_lock_irqsave(&priv->lock, flags);
> -       list_for_each_entry(data, &priv->clients, node)
> -               sysmmu_tlb_invalidate_entry(data->dev, iova);
> +       list_for_each_entry(client, &priv->clients, node)
> +               sysmmu_tlb_invalidate_entry(client->dev, iova);
>         spin_unlock_irqrestore(&priv->lock, flags);
>
>         return size;
> @@ -1055,3 +1179,275 @@ static int __init exynos_iommu_init(void)
>         return ret;
>  }
>  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)
> +{
> +       struct device *dev = p;
> +
> +       switch (val) {
> +       case BUS_NOTIFY_BIND_DRIVER:
> +       {
> +               int i = 0;
> +               int size = 0;

You can drop the initialization here. They are getting initialised
before actual use.

> +               const __be32 *phandle;
> +               struct exynos_iommu_client *client;
> +
> +               phandle = of_get_property(dev->of_node, "iommu", &size);
> +               if (!phandle)
> +                       break;
> +
> +               size = size / sizeof(*phandle); /* number of elements */
> +
> +               client = devm_kzalloc(dev, sizeof(*client) * size, GFP_KERNEL);

You do not need to allocate memory of size "sizeof(*client) * size" ? It should
always be sizeof(*client).

> +               if (!client) {
> +                       dev_err(dev, "No Memory for exynos_iommu_client\n");
> +                       return -ENOMEM;
> +               }
> +
> +               client->num_sysmmu = size;
> +               client->dev = dev;
> +               INIT_LIST_HEAD(&client->node);
> +               spin_lock_init(&client->lock);
> +
> +               for (i = 0; i < size; i++) {
> +                       struct device_node *np;
> +                       struct platform_device *sysmmu;
> +
> +                       /* this always success: see above of_find_property() */
> +                       np = of_parse_phandle(dev->of_node, "iommu", i);
> +
> +                       sysmmu = of_find_device_by_node(np);
> +                       if (!sysmmu) {
> +                               dev_err(dev,
> +                                       "sysmmu node '%s' is not found\n",
> +                                       np->name);
> +                               break;
> +                       }
> +
> +                       client->sysmmu[i] = &sysmmu->dev;

Your array has space for single 'device *'. You should allocate memory to
client->sysmmu before accessing indexes above 0.

As if now, It is not corrupting other's memory since you have allocated a
much bigger chunk for your client pointer which is wrong IMO.

regards,
Rahul Sharma

> +               }
> +
> +               if (i < size) {
> +                       while (--i >= 0)
> +                               of_node_put(client->sysmmu[i]->of_node);
> +                       devm_kfree(dev, client);
> +                       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;
> +               }
> +               break;
> +       }
> +       } /* switch (val) */
> +
> +       return 0;
> +}
> +
> +static struct notifier_block sysmmu_notifier = {
> +       .notifier_call = &sysmmu_hook_driver_register,
> +};
> +
> +static int __init exynos_iommu_prepare(void)
> +{
> +       return bus_register_notifier(&platform_bus_type, &sysmmu_notifier);
> +}
> +arch_initcall(exynos_iommu_prepare);
> --
> 1.7.2.5
>
>
> _______________________________________________
> iommu mailing list
> [e-mail]
> https://lists.linuxfoundation.org/mailman/listinfo/iommu
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Cho KyongHo Aug. 2, 2013, 6:42 a.m. UTC | #2

> -----Original Message-----
> From: Rahul Sharma [mailto:[e-mail]]
> Sent: Friday, August 02, 2013 2:18 PM
> 
> Hi Cho,
> 
> On Fri, Jul 26, 2013 at 5:00 PM, Cho KyongHo <[e-mail]> wrote:
> > When a device driver is registered, all constructs to handle System MMU
> > is prepared by bus notifier call.
> >
> > Signed-off-by: Cho KyongHo <[e-mail]>
> > ---
> >  drivers/iommu/exynos-iommu.c |  708 ++++++++++++++++++++++++++++++++---------
> >  1 files changed, 552 insertions(+), 156 deletions(-)
> >
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index f9853fe..c62c244 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -27,6 +27,9 @@
> >  #include <linux/memblock.h>
> >  #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>
> >  #include <asm/pgtable.h>
> > @@ -80,7 +83,13 @@
> >  #define CTRL_BLOCK     0x7
> >  #define CTRL_DISABLE   0x0
> >
> > +#define CFG_LRU                0x1
> > +#define CFG_QOS(n)     ((n & 0xF) << 7)
> > +#define CFG_MASK       0x0150FFFF /* Selecting bit 0-15, 20, 22 and 24 */
> > +#define CFG_ACGEN      (1 << 24) /* System MMU 3.3 only */
> > +#define CFG_SYSSEL     (1 << 22) /* System MMU 3.2 only */
> >  #define CFG_FLPDCACHE  (1 << 20) /* System MMU 3.2+ only */
> > +#define CFG_SHAREABLE  (1 << 12) /* System MMU 3.x only */
> >
> >  #define REG_MMU_CTRL           0x000
> >  #define REG_MMU_CFG            0x004
> > @@ -154,6 +163,14 @@ static char *sysmmu_fault_name[SYSMMU_FAULTS_NUM] = {
> >         "UNKNOWN FAULT"
> >  };
> >
> > +struct exynos_iommu_client {
> > +       struct list_head node;  /* entry of exynos_iommu_domain.clients */
> > +       struct device *dev;
> > +       spinlock_t lock;
> > +       int num_sysmmu;
> > +       struct device *sysmmu[0];
> 
> Shouldn't we keep limit on the max number of iommu's to a single client ? Even
> this way, you will hit array overrun with multiple iommu's.
> 

I don't think it is needed to fix the size of the array because
we know the size of the array in booting time.
sysmmu[0] is just a placeholder of array.

> > +};
> > +
> >  struct exynos_iommu_domain {
> >         struct list_head clients; /* list of sysmmu_drvdata.node */
> >         unsigned long *pgtable; /* lv1 page table, 16KB */
> > @@ -165,12 +182,14 @@ struct exynos_iommu_domain {
> >  struct sysmmu_drvdata {
> >         struct list_head node; /* entry of exynos_iommu_domain.clients */
> >         struct device *sysmmu;  /* System MMU's device descriptor */
> > -       struct device *dev;     /* Owner of system MMU */
> > +       struct device *master;  /* Owner of system MMU */
> >         int nsfrs;
> >         struct clk *clk;
> > +       struct clk *clk_master;
> >         int activations;
> >         rwlock_t lock;
> >         struct iommu_domain *domain;
> > +       bool runtime_active;
> >         unsigned long pgtable;
> >         void __iomem *sfrbases[0];
> >  };
> > @@ -245,7 +264,6 @@ static void __sysmmu_tlb_invalidate_entry(void __iomem *sfrbase,
> >  static void __sysmmu_set_ptbase(void __iomem *sfrbase,
> >                                        unsigned long pgd)
> >  {
> > -       __raw_writel(0x1, sfrbase + REG_MMU_CFG); /* 16KB LV1, LRU */
> >         __raw_writel(pgd, sfrbase + REG_PT_BASE_ADDR);
> >
> >         __sysmmu_tlb_invalidate(sfrbase);
> > @@ -273,6 +291,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
> >         if (!is_sysmmu_active(data))
> >                 goto finish;
> >
> > +       clk_enable(data->clk_master);
> >         for (i = 0; i < data->nsfrs; i++) {
> >                 if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
> >                         if (!sysmmu_block(data->sfrbases[i]))
> > @@ -298,6 +317,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
> >                         sysmmu_unblock(data->sfrbases[i]);
> >                 }
> >         }
> > +       clk_disable(data->clk_master);
> >  finish:
> >         read_unlock_irqrestore(&data->lock, flags);
> >  }
> > @@ -331,12 +351,13 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >  {
> >         /* SYSMMU is in blocked when interrupt occurred. */
> >         struct sysmmu_drvdata *data = dev_id;
> > +       struct exynos_iommu_client *client = NULL;
> >         enum exynos_sysmmu_inttype itype;
> >         unsigned long addr = -1;
> > -
> >         int i, ret = -ENOSYS;
> >
> > -       read_lock(&data->lock);
> > +       if (data->master)
> > +               client = data->master->archdata.iommu;
> >
> >         WARN_ON(!is_sysmmu_active(data));
> >
> > @@ -348,6 +369,10 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >                         break;
> >         }
> >
> > +       if (client)
> > +               spin_lock(&client->lock);
> > +       read_lock(&data->lock);
> > +
> >         if (i == data->nsfrs) {
> >                 itype = SYSMMU_FAULT_UNKNOWN;
> >         } else {
> > @@ -361,7 +386,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >         }
> >
> >         if (data->domain)
> > -               ret = report_iommu_fault(data->domain, data->dev,
> > +               ret = report_iommu_fault(data->domain, data->master,
> >                                 addr, itype);
> >
> >         if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
> > @@ -378,177 +403,251 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >                 sysmmu_unblock(data->sfrbases[i]);
> >
> >         read_unlock(&data->lock);
> > +       if (client)
> > +               spin_unlock(&client->lock);
> >
> >         return IRQ_HANDLED;
> >  }
> >
> > -static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
> > +static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
> >  {
> > -       unsigned long flags;
> > -       bool disabled = false;
> >         int i;
> >
> > -       write_lock_irqsave(&data->lock, flags);
> > +       clk_enable(data->clk_master);
> > +       for (i = 0; i < data->nsfrs; i++) {
> > +               __raw_writel(CTRL_DISABLE,
> > +                               data->sfrbases[i] + REG_MMU_CTRL);
> > +               __raw_writel(0, data->sfrbases[i] + REG_MMU_CFG);
> > +       }
> >
> > -       if (!set_sysmmu_inactive(data))
> > -               goto finish;
> > +       clk_disable(data->clk);
> > +       clk_disable(data->clk_master);
> > +}
> >
> > -       for (i = 0; i < data->nsfrs; i++)
> > -               __raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > +static bool __sysmmu_disable(struct sysmmu_drvdata *data)
> > +{
> > +       bool disabled;
> > +       unsigned long flags;
> >
> > -       if (data->clk)
> > -               clk_disable(data->clk);
> > +       write_lock_irqsave(&data->lock, flags);
> >
> > -       disabled = true;
> > -       data->pgtable = 0;
> > -       data->domain = NULL;
> > -finish:
> > -       write_unlock_irqrestore(&data->lock, flags);
> > +       disabled = set_sysmmu_inactive(data);
> > +
> > +       if (disabled) {
> > +               data->pgtable = 0;
> > +               data->domain = NULL;
> > +
> > +               if (data->runtime_active)
> > +                       __sysmmu_disable_nocount(data);
> >
> > -       if (disabled)
> >                 dev_dbg(data->sysmmu, "Disabled\n");
> > -       else
> > -               dev_dbg(data->sysmmu, "%d times left to be disabled\n",
> > +       } else  {
> > +               dev_dbg(data->sysmmu, "%d times left to disable\n",
> >                                         data->activations);
> > +       }
> > +
> > +       write_unlock_irqrestore(&data->lock, flags);
> >
> >         return disabled;
> >  }
> >
> > -/* __exynos_sysmmu_enable: Enables System MMU
> > - *
> > - * returns -error if an error occurred and System MMU is not enabled,
> > - * 0 if the System MMU has been just enabled and 1 if System MMU was already
> > - * enabled before.
> > - */
> > -static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> > +
> > +static void __sysmmu_init_config(struct sysmmu_drvdata *data, int idx)
> > +{
> > +       unsigned long cfg = CFG_LRU | CFG_QOS(15);
> > +       int maj, min = 0;
> > +
> > +       maj = __sysmmu_version(data, idx, &min);
> > +       if (maj == 3) {
> > +               if (min > 1) {
> > +                       cfg |= CFG_FLPDCACHE;
> > +                       cfg |= (min == 2) ? CFG_SYSSEL : CFG_ACGEN;
> > +               }
> > +       }
> > +
> > +       __raw_writel(cfg, data->sfrbases[idx] + REG_MMU_CFG);
> > +}
> > +
> > +static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
> > +{
> > +       int i;
> > +
> > +       clk_enable(data->clk_master);
> > +       clk_enable(data->clk);
> > +
> > +       for (i = 0; i < data->nsfrs; i++) {
> > +               __raw_writel(CTRL_BLOCK, data->sfrbases[i] + REG_MMU_CTRL);
> > +
> > +               __sysmmu_init_config(data, i);
> > +
> > +               __sysmmu_set_ptbase(data->sfrbases[i], data->pgtable);
> > +
> > +               __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > +       }
> > +       clk_disable(data->clk_master);
> > +}
> > +
> > +static int __sysmmu_enable(struct sysmmu_drvdata *data,
> >                         unsigned long pgtable, struct iommu_domain *domain)
> >  {
> > -       int i, ret = 0;
> > +       int ret = 0;
> >         unsigned long flags;
> >
> >         write_lock_irqsave(&data->lock, flags);
> > +       if (set_sysmmu_active(data)) {
> > +               data->pgtable = pgtable;
> > +               data->domain = domain;
> >
> > -       if (!set_sysmmu_active(data)) {
> > -               if (WARN_ON(pgtable != data->pgtable)) {
> > -                       ret = -EBUSY;
> > -                       set_sysmmu_inactive(data);
> > -               } else {
> > -                       ret = 1;
> > -               }
> > +               if (data->runtime_active)
> > +                       __sysmmu_enable_nocount(data);
> >
> > -               dev_dbg(data->sysmmu, "Already enabled\n");
> > -               goto finish;
> > +               dev_dbg(data->sysmmu, "Enabled\n");
> > +       } else {
> > +               ret = (pgtable == data->pgtable) ? 1 : -EBUSY;
> > +
> > +               dev_dbg(data->sysmmu, "already enabled\n");
> >         }
> >
> > -       if (data->clk)
> > -               clk_enable(data->clk);
> > +       if (WARN_ON(ret < 0))
> > +               set_sysmmu_inactive(data); /* decrement count */
> >
> > -       data->pgtable = pgtable;
> > +       write_unlock_irqrestore(&data->lock, flags);
> >
> > -       for (i = 0; i < data->nsfrs; i++) {
> > -               unsigned int min;
> > +       return ret;
> > +}
> >
> > -               __sysmmu_set_ptbase(data->sfrbases[i], pgtable);
> > +/* __exynos_sysmmu_enable: Enables System MMU
> > + *
> > + * returns -error if an error occurred and System MMU is not enabled,
> > + * 0 if the System MMU has been just enabled and 1 if System MMU was already
> > + * enabled before.
> > + */
> > +static int __exynos_sysmmu_enable(struct device *dev, unsigned long pgtable,
> > +                                 struct iommu_domain *domain)
> > +{
> > +       int ret = 0;
> > +       unsigned long flags;
> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
> > +       int i;
> >
> > -               if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
> > -                       unsigned long cfg;
> > -                       cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
> > -                       __raw_writel(cfg | CFG_FLPDCACHE,
> > -                                       data->sfrbases[i] + REG_MMU_CFG);
> > -               }
> > +       if (WARN_ON(!client))
> > +               return -ENODEV;
> >
> > -               __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > -       }
> > +       spin_lock_irqsave(&client->lock, flags);
> >
> > -       data->domain = domain;
> > +       for (i = 0; i < client->num_sysmmu; i++) {
> > +               struct sysmmu_drvdata *data =
> > +                               dev_get_drvdata(client->sysmmu[i]);
> > +               ret = __sysmmu_enable(data, pgtable, domain);
> > +               if (ret < 0) {
> > +                       int j;
> > +                       for (j = 0; j < i; j++)
> > +                               __sysmmu_disable(data);
> > +                       break;
> > +               } else {
> > +                       data->master = dev;
> > +               }
> > +       }
> >
> > -       dev_dbg(data->sysmmu, "Enabled\n");
> > -finish:
> > -       write_unlock_irqrestore(&data->lock, flags);
> > +       spin_unlock_irqrestore(&client->lock, flags);
> >
> >         return ret;
> >  }
> >
> >  int exynos_sysmmu_enable(struct device *dev, unsigned long pgtable)
> >  {
> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> >         int ret;
> >
> >         BUG_ON(!memblock_is_memory(pgtable));
> >
> > -       ret = pm_runtime_get_sync(data->sysmmu);
> > -       if (ret < 0) {
> > -               dev_dbg(data->sysmmu, "Failed to enable\n");
> > -               return ret;
> > -       }
> > -
> > -       ret = __exynos_sysmmu_enable(data, pgtable, NULL);
> > -       if (WARN_ON(ret < 0)) {
> > -               pm_runtime_put(data->sysmmu);
> > -               dev_err(data->sysmmu,
> > -                       "Already enabled with page table %#lx\n",
> > -                       data->pgtable);
> > -       } else {
> > -               data->dev = dev;
> > -       }
> > +       ret = __exynos_sysmmu_enable(dev, pgtable, NULL);
> >
> >         return ret;
> >  }
> >
> >  static bool exynos_sysmmu_disable(struct device *dev)
> >  {
> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > -       bool disabled;
> > +       unsigned long flags;
> > +       bool disabled = true;
> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
> > +       int i;
> >
> > -       disabled = __exynos_sysmmu_disable(data);
> > -       pm_runtime_put(data->sysmmu);
> > +       if (WARN_ON(!client))
> > +               return true;
> > +
> > +       spin_lock_irqsave(&client->lock, flags);
> > +
> > +       /* Every call to __sysmmu_disable() must return same result */
> > +       for (i = 0; i < client->num_sysmmu; i++) {
> > +               struct sysmmu_drvdata *data =
> > +                               dev_get_drvdata(client->sysmmu[i]);
> > +               disabled = __sysmmu_disable(data);
> > +               if (disabled)
> > +                       data->master = NULL;
> > +       }
> > +
> > +       spin_unlock_irqrestore(&client->lock, flags);
> >
> >         return disabled;
> >  }
> >
> >  static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
> >  {
> > -       unsigned long flags;
> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
> > +       int i;
> >
> > -       read_lock_irqsave(&data->lock, flags);
> > +       for (i = 0; i < client->num_sysmmu; i++) {
> > +               unsigned long flags;
> > +               struct sysmmu_drvdata *data;
> >
> > -       if (is_sysmmu_active(data)) {
> > -               int i;
> > -               for (i = 0; i < data->nsfrs; i++) {
> > -                       if (sysmmu_block(data->sfrbases[i])) {
> > +               data = dev_get_drvdata(client->sysmmu[i]);
> > +
> > +               read_lock_irqsave(&data->lock, flags);
> > +               if (is_sysmmu_active(data) && data->runtime_active) {
> > +                       int i;
> > +                       clk_enable(data->clk_master);
> > +                       for (i = 0; i < data->nsfrs; i++)
> >                                 __sysmmu_tlb_invalidate_entry(
> >                                                 data->sfrbases[i], iova);
> > -                               sysmmu_unblock(data->sfrbases[i]);
> > -                       }
> > +                       clk_disable(data->clk_master);
> > +               } else {
> > +                       dev_dbg(dev,
> > +                               "disabled. Skipping TLB invalidation @ %#lx\n",
> > +                               iova);
> >                 }
> > -       } else {
> > -               dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> > +               read_unlock_irqrestore(&data->lock, flags);
> >         }
> > -
> > -       read_unlock_irqrestore(&data->lock, flags);
> >  }
> >
> >  void exynos_sysmmu_tlb_invalidate(struct device *dev)
> >  {
> > -       unsigned long flags;
> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > -
> > -       read_lock_irqsave(&data->lock, flags);
> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
> > +       int i;
> >
> > -       if (is_sysmmu_active(data)) {
> > -               int i;
> > -               for (i = 0; i < data->nsfrs; i++) {
> > -                       if (sysmmu_block(data->sfrbases[i])) {
> > -                               __sysmmu_tlb_invalidate(data->sfrbases[i]);
> > -                               sysmmu_unblock(data->sfrbases[i]);
> > +       for (i = 0; i < client->num_sysmmu; i++) {
> > +               unsigned long flags;
> > +               struct sysmmu_drvdata *data;
> > +
> > +               data = dev_get_drvdata(client->sysmmu[i]);
> > +
> > +               read_lock_irqsave(&data->lock, flags);
> > +               if (is_sysmmu_active(data) &&
> > +                               data->runtime_active) {
> > +                       int i;
> > +                       for (i = 0; i < data->nsfrs; i++) {
> > +                               clk_enable(data->clk_master);
> > +                               if (sysmmu_block(data->sfrbases[i])) {
> > +                                       __sysmmu_tlb_invalidate(
> > +                                                       data->sfrbases[i]);
> > +                                       sysmmu_unblock(data->sfrbases[i]);
> > +                               }
> > +                               clk_disable(data->clk_master);
> >                         }
> > +               } else {
> > +                       dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
> >                 }
> > -       } else {
> > -               dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> > +               read_unlock_irqrestore(&data->lock, flags);
> >         }
> > -
> > -       read_unlock_irqrestore(&data->lock, flags);
> >  }
> >
> >  static int __init exynos_sysmmu_probe(struct platform_device *pdev)
> > @@ -610,12 +709,32 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
> >         pm_runtime_enable(dev);
> >
> >         data->sysmmu = dev;
> > +
> >         data->clk = devm_clk_get(dev, "sysmmu");
> >         if (IS_ERR(data->clk)) {
> >                 dev_info(dev, "No gate clock found!\n");
> >                 data->clk = NULL;
> >         }
> >
> > +       ret = clk_prepare(data->clk);
> > +       if (ret) {
> > +               dev_err(dev, "Failed to prepare clk\n");
> > +               return ret;
> > +       }
> > +
> > +       data->clk_master = devm_clk_get(dev, "master");
> > +       if (IS_ERR(data->clk_master))
> > +               data->clk_master = NULL;
> > +
> > +       ret = clk_prepare(data->clk_master);
> > +       if (ret) {
> > +               clk_unprepare(data->clk);
> > +               dev_err(dev, "Failed to prepare master's clk\n");
> > +               return ret;
> > +       }
> > +
> > +       data->runtime_active = !pm_runtime_enabled(dev);
> > +
> >         rwlock_init(&data->lock);
> >         INIT_LIST_HEAD(&data->node);
> >
> > @@ -625,6 +744,34 @@ 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", },
> > @@ -637,6 +784,7 @@ 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),
> >         }
> >  };
> > @@ -689,7 +837,7 @@ err_pgtable:
> >  static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
> >  {
> >         struct exynos_iommu_domain *priv = domain->priv;
> > -       struct sysmmu_drvdata *data;
> > +       struct exynos_iommu_client *client;
> >         unsigned long flags;
> >         int i;
> >
> > @@ -697,11 +845,14 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
> >
> >         spin_lock_irqsave(&priv->lock, flags);
> >
> > -       list_for_each_entry(data, &priv->clients, node) {
> > -               while (!exynos_sysmmu_disable(data->dev))
> > +       list_for_each_entry(client, &priv->clients, node) {
> > +               while (!exynos_sysmmu_disable(client->dev))
> >                         ; /* until System MMU is actually disabled */
> >         }
> >
> > +       while (!list_empty(&priv->clients))
> > +               list_del_init(priv->clients.next);
> > +
> >         spin_unlock_irqrestore(&priv->lock, flags);
> >
> >         for (i = 0; i < NUM_LV1ENTRIES; i++)
> > @@ -718,41 +869,26 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
> >  static int exynos_iommu_attach_device(struct iommu_domain *domain,
> >                                    struct device *dev)
> >  {
> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
> >         struct exynos_iommu_domain *priv = domain->priv;
> >         unsigned long flags;
> >         int ret;
> >
> > -       ret = pm_runtime_get_sync(data->sysmmu);
> > -       if (ret < 0)
> > -               return ret;
> > -
> > -       ret = 0;
> > -
> >         spin_lock_irqsave(&priv->lock, flags);
> >
> > -       ret = __exynos_sysmmu_enable(data, __pa(priv->pgtable), domain);
> > -
> > -       if (ret == 0) {
> > -               /* 'data->node' must not be appeared in priv->clients */
> > -               BUG_ON(!list_empty(&data->node));
> > -               data->dev = dev;
> > -               list_add_tail(&data->node, &priv->clients);
> > -       }
> > +       ret = __exynos_sysmmu_enable(dev, __pa(priv->pgtable), domain);
> > +       if (ret == 0)
> > +               list_add_tail(&client->node, &priv->clients);
> >
> >         spin_unlock_irqrestore(&priv->lock, flags);
> >
> > -       if (ret < 0) {
> > +       if (ret < 0)
> >                 dev_err(dev, "%s: Failed to attach IOMMU with pgtable %#lx\n",
> >                                 __func__, __pa(priv->pgtable));
> > -               pm_runtime_put(data->sysmmu);
> > -       } else if (ret > 0) {
> > -               dev_dbg(dev, "%s: IOMMU with pgtable 0x%lx already attached\n",
> > -                                       __func__, __pa(priv->pgtable));
> > -       } else {
> > -               dev_dbg(dev, "%s: Attached new IOMMU with pgtable 0x%lx\n",
> > -                                       __func__, __pa(priv->pgtable));
> > -       }
> > +       else
> > +               dev_dbg(dev, "%s: Attached IOMMU with pgtable 0x%lx%s\n",
> > +                                       __func__, __pa(priv->pgtable),
> > +                                       (ret == 0) ? "" : ", again");
> >
> >         return ret;
> >  }
> > @@ -760,39 +896,27 @@ static int exynos_iommu_attach_device(struct iommu_domain *domain,
> >  static void exynos_iommu_detach_device(struct iommu_domain *domain,
> >                                     struct device *dev)
> >  {
> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > +       struct exynos_iommu_client *client = NULL;
> >         struct exynos_iommu_domain *priv = domain->priv;
> > -       struct list_head *pos;
> >         unsigned long flags;
> > -       bool found = false;
> >
> >         spin_lock_irqsave(&priv->lock, flags);
> >
> > -       list_for_each(pos, &priv->clients) {
> > -               if (list_entry(pos, struct sysmmu_drvdata, node) == data) {
> > -                       found = true;
> > +       list_for_each_entry(client, &priv->clients, node) {
> > +               if (client == dev->archdata.iommu) {
> > +                       if (exynos_sysmmu_disable(dev))
> > +                               list_del_init(&client->node);
> >                         break;
> >                 }
> >         }
> >
> > -       if (!found)
> > -               goto finish;
> > +       spin_unlock_irqrestore(&priv->lock, flags);
> >
> > -       if (__exynos_sysmmu_disable(data)) {
> > +       if (client == dev->archdata.iommu)
> >                 dev_dbg(dev, "%s: Detached IOMMU with pgtable %#lx\n",
> >                                         __func__, __pa(priv->pgtable));
> > -               list_del_init(&data->node);
> > -
> > -       } else {
> > -               dev_dbg(dev, "%s: Detaching IOMMU with pgtable %#lx delayed",
> > -                                       __func__, __pa(priv->pgtable));
> > -       }
> > -
> > -finish:
> > -       spin_unlock_irqrestore(&priv->lock, flags);
> > -
> > -       if (found)
> > -               pm_runtime_put(data->sysmmu);
> > +       else
> > +               dev_dbg(dev, "%s: No IOMMU is attached\n", __func__);
> >  }
> >
> >  static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
> > @@ -914,7 +1038,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
> >                                                unsigned long iova, size_t size)
> >  {
> >         struct exynos_iommu_domain *priv = domain->priv;
> > -       struct sysmmu_drvdata *data;
> > +       struct exynos_iommu_client *client;
> >         unsigned long flags;
> >         unsigned long *ent;
> >         size_t err_pgsize;
> > @@ -975,8 +1099,8 @@ done:
> >         spin_unlock_irqrestore(&priv->pgtablelock, flags);
> >
> >         spin_lock_irqsave(&priv->lock, flags);
> > -       list_for_each_entry(data, &priv->clients, node)
> > -               sysmmu_tlb_invalidate_entry(data->dev, iova);
> > +       list_for_each_entry(client, &priv->clients, node)
> > +               sysmmu_tlb_invalidate_entry(client->dev, iova);
> >         spin_unlock_irqrestore(&priv->lock, flags);
> >
> >         return size;
> > @@ -1055,3 +1179,275 @@ static int __init exynos_iommu_init(void)
> >         return ret;
> >  }
> >  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)
> > +{
> > +       struct device *dev = p;
> > +
> > +       switch (val) {
> > +       case BUS_NOTIFY_BIND_DRIVER:
> > +       {
> > +               int i = 0;
> > +               int size = 0;
> 
> You can drop the initialization here. They are getting initialised
> before actual use.

Yes, it is basically right.
I just want to be convinced that the output argument to of_get_property()
is not referenced before initialization even though of_get_property()
does not reference to the argument, actually.

> 
> > +               const __be32 *phandle;
> > +               struct exynos_iommu_client *client;
> > +
> > +               phandle = of_get_property(dev->of_node, "iommu", &size);
> > +               if (!phandle)
> > +                       break;
> > +
> > +               size = size / sizeof(*phandle); /* number of elements */
> > +
> > +               client = devm_kzalloc(dev, sizeof(*client) * size, GFP_KERNEL);
> 
> You do not need to allocate memory of size "sizeof(*client) * size" ? It should
> always be sizeof(*client).

Oh. It is my fault.
It must be 'sizeof(*client) + size * sizeof(client->sysmmu[0])'.
It will be fixed.

> 
> > +               if (!client) {
> > +                       dev_err(dev, "No Memory for exynos_iommu_client\n");
> > +                       return -ENOMEM;
> > +               }
> > +
> > +               client->num_sysmmu = size;
> > +               client->dev = dev;
> > +               INIT_LIST_HEAD(&client->node);
> > +               spin_lock_init(&client->lock);
> > +
> > +               for (i = 0; i < size; i++) {
> > +                       struct device_node *np;
> > +                       struct platform_device *sysmmu;
> > +
> > +                       /* this always success: see above of_find_property() */
> > +                       np = of_parse_phandle(dev->of_node, "iommu", i);
> > +
> > +                       sysmmu = of_find_device_by_node(np);
> > +                       if (!sysmmu) {
> > +                               dev_err(dev,
> > +                                       "sysmmu node '%s' is not found\n",
> > +                                       np->name);
> > +                               break;
> > +                       }
> > +
> > +                       client->sysmmu[i] = &sysmmu->dev;
> 
> Your array has space for single 'device *'. You should allocate memory to
> client->sysmmu before accessing indexes above 0.

As I commented above, enough size is allocated.

> 
> As if now, It is not corrupting other's memory since you have allocated a
> much bigger chunk for your client pointer which is wrong IMO.

That is my fault :)
> 
> regards,
> Rahul Sharma

Thank you.

Cho KyongHo.

> 
> > +               }
> > +
> > +               if (i < size) {
> > +                       while (--i >= 0)
> > +                               of_node_put(client->sysmmu[i]->of_node);
> > +                       devm_kfree(dev, client);
> > +                       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;
> > +               }
> > +               break;
> > +       }
> > +       } /* switch (val) */
> > +
> > +       return 0;
> > +}
> > +
> > +static struct notifier_block sysmmu_notifier = {
> > +       .notifier_call = &sysmmu_hook_driver_register,
> > +};
> > +
> > +static int __init exynos_iommu_prepare(void)
> > +{
> > +       return bus_register_notifier(&platform_bus_type, &sysmmu_notifier);
> > +}
> > +arch_initcall(exynos_iommu_prepare);
> > --
> > 1.7.2.5
> >
> >
> > _______________________________________________
> > iommu mailing list
> > [e-mail]
> > https://lists.linuxfoundation.org/mailman/listinfo/iommu

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Rahul Sharma Aug. 2, 2013, 7:06 a.m. UTC | #3

On Fri, Aug 2, 2013 at 12:12 PM, Cho KyongHo <[e-mail]> wrote:
>> -----Original Message-----
>> From: Rahul Sharma [mailto:[e-mail]]
>> Sent: Friday, August 02, 2013 2:18 PM
>>
>> Hi Cho,
>>
>> On Fri, Jul 26, 2013 at 5:00 PM, Cho KyongHo <[e-mail]> wrote:
>> > When a device driver is registered, all constructs to handle System MMU
>> > is prepared by bus notifier call.
>> >
>> > Signed-off-by: Cho KyongHo <[e-mail]>
>> > ---
>> >  drivers/iommu/exynos-iommu.c |  708 ++++++++++++++++++++++++++++++++---------
>> >  1 files changed, 552 insertions(+), 156 deletions(-)
>> >
>> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
>> > index f9853fe..c62c244 100644
>> > --- a/drivers/iommu/exynos-iommu.c
>> > +++ b/drivers/iommu/exynos-iommu.c
>> > @@ -27,6 +27,9 @@
>> >  #include <linux/memblock.h>
>> >  #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>
>> >  #include <asm/pgtable.h>
>> > @@ -80,7 +83,13 @@
>> >  #define CTRL_BLOCK     0x7
>> >  #define CTRL_DISABLE   0x0
>> >
>> > +#define CFG_LRU                0x1
>> > +#define CFG_QOS(n)     ((n & 0xF) << 7)
>> > +#define CFG_MASK       0x0150FFFF /* Selecting bit 0-15, 20, 22 and 24 */
>> > +#define CFG_ACGEN      (1 << 24) /* System MMU 3.3 only */
>> > +#define CFG_SYSSEL     (1 << 22) /* System MMU 3.2 only */
>> >  #define CFG_FLPDCACHE  (1 << 20) /* System MMU 3.2+ only */
>> > +#define CFG_SHAREABLE  (1 << 12) /* System MMU 3.x only */
>> >
>> >  #define REG_MMU_CTRL           0x000
>> >  #define REG_MMU_CFG            0x004
>> > @@ -154,6 +163,14 @@ static char *sysmmu_fault_name[SYSMMU_FAULTS_NUM] = {
>> >         "UNKNOWN FAULT"
>> >  };
>> >
>> > +struct exynos_iommu_client {
>> > +       struct list_head node;  /* entry of exynos_iommu_domain.clients */
>> > +       struct device *dev;
>> > +       spinlock_t lock;
>> > +       int num_sysmmu;
>> > +       struct device *sysmmu[0];
>>
>> Shouldn't we keep limit on the max number of iommu's to a single client ? Even
>> this way, you will hit array overrun with multiple iommu's.
>>
>
> I don't think it is needed to fix the size of the array because
> we know the size of the array in booting time.
> sysmmu[0] is just a placeholder of array.
>
>> > +};
>> > +
>> >  struct exynos_iommu_domain {
>> >         struct list_head clients; /* list of sysmmu_drvdata.node */
>> >         unsigned long *pgtable; /* lv1 page table, 16KB */
>> > @@ -165,12 +182,14 @@ struct exynos_iommu_domain {
>> >  struct sysmmu_drvdata {
>> >         struct list_head node; /* entry of exynos_iommu_domain.clients */
>> >         struct device *sysmmu;  /* System MMU's device descriptor */
>> > -       struct device *dev;     /* Owner of system MMU */
>> > +       struct device *master;  /* Owner of system MMU */
>> >         int nsfrs;
>> >         struct clk *clk;
>> > +       struct clk *clk_master;
>> >         int activations;
>> >         rwlock_t lock;
>> >         struct iommu_domain *domain;
>> > +       bool runtime_active;
>> >         unsigned long pgtable;
>> >         void __iomem *sfrbases[0];
>> >  };
>> > @@ -245,7 +264,6 @@ static void __sysmmu_tlb_invalidate_entry(void __iomem *sfrbase,
>> >  static void __sysmmu_set_ptbase(void __iomem *sfrbase,
>> >                                        unsigned long pgd)
>> >  {
>> > -       __raw_writel(0x1, sfrbase + REG_MMU_CFG); /* 16KB LV1, LRU */
>> >         __raw_writel(pgd, sfrbase + REG_PT_BASE_ADDR);
>> >
>> >         __sysmmu_tlb_invalidate(sfrbase);
>> > @@ -273,6 +291,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
>> >         if (!is_sysmmu_active(data))
>> >                 goto finish;
>> >
>> > +       clk_enable(data->clk_master);
>> >         for (i = 0; i < data->nsfrs; i++) {
>> >                 if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
>> >                         if (!sysmmu_block(data->sfrbases[i]))
>> > @@ -298,6 +317,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
>> >                         sysmmu_unblock(data->sfrbases[i]);
>> >                 }
>> >         }
>> > +       clk_disable(data->clk_master);
>> >  finish:
>> >         read_unlock_irqrestore(&data->lock, flags);
>> >  }
>> > @@ -331,12 +351,13 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>> >  {
>> >         /* SYSMMU is in blocked when interrupt occurred. */
>> >         struct sysmmu_drvdata *data = dev_id;
>> > +       struct exynos_iommu_client *client = NULL;
>> >         enum exynos_sysmmu_inttype itype;
>> >         unsigned long addr = -1;
>> > -
>> >         int i, ret = -ENOSYS;
>> >
>> > -       read_lock(&data->lock);
>> > +       if (data->master)
>> > +               client = data->master->archdata.iommu;
>> >
>> >         WARN_ON(!is_sysmmu_active(data));
>> >
>> > @@ -348,6 +369,10 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>> >                         break;
>> >         }
>> >
>> > +       if (client)
>> > +               spin_lock(&client->lock);
>> > +       read_lock(&data->lock);
>> > +
>> >         if (i == data->nsfrs) {
>> >                 itype = SYSMMU_FAULT_UNKNOWN;
>> >         } else {
>> > @@ -361,7 +386,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>> >         }
>> >
>> >         if (data->domain)
>> > -               ret = report_iommu_fault(data->domain, data->dev,
>> > +               ret = report_iommu_fault(data->domain, data->master,
>> >                                 addr, itype);
>> >
>> >         if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
>> > @@ -378,177 +403,251 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>> >                 sysmmu_unblock(data->sfrbases[i]);
>> >
>> >         read_unlock(&data->lock);
>> > +       if (client)
>> > +               spin_unlock(&client->lock);
>> >
>> >         return IRQ_HANDLED;
>> >  }
>> >
>> > -static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
>> > +static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
>> >  {
>> > -       unsigned long flags;
>> > -       bool disabled = false;
>> >         int i;
>> >
>> > -       write_lock_irqsave(&data->lock, flags);
>> > +       clk_enable(data->clk_master);
>> > +       for (i = 0; i < data->nsfrs; i++) {
>> > +               __raw_writel(CTRL_DISABLE,
>> > +                               data->sfrbases[i] + REG_MMU_CTRL);
>> > +               __raw_writel(0, data->sfrbases[i] + REG_MMU_CFG);
>> > +       }
>> >
>> > -       if (!set_sysmmu_inactive(data))
>> > -               goto finish;
>> > +       clk_disable(data->clk);
>> > +       clk_disable(data->clk_master);
>> > +}
>> >
>> > -       for (i = 0; i < data->nsfrs; i++)
>> > -               __raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
>> > +static bool __sysmmu_disable(struct sysmmu_drvdata *data)
>> > +{
>> > +       bool disabled;
>> > +       unsigned long flags;
>> >
>> > -       if (data->clk)
>> > -               clk_disable(data->clk);
>> > +       write_lock_irqsave(&data->lock, flags);
>> >
>> > -       disabled = true;
>> > -       data->pgtable = 0;
>> > -       data->domain = NULL;
>> > -finish:
>> > -       write_unlock_irqrestore(&data->lock, flags);
>> > +       disabled = set_sysmmu_inactive(data);
>> > +
>> > +       if (disabled) {
>> > +               data->pgtable = 0;
>> > +               data->domain = NULL;
>> > +
>> > +               if (data->runtime_active)
>> > +                       __sysmmu_disable_nocount(data);
>> >
>> > -       if (disabled)
>> >                 dev_dbg(data->sysmmu, "Disabled\n");
>> > -       else
>> > -               dev_dbg(data->sysmmu, "%d times left to be disabled\n",
>> > +       } else  {
>> > +               dev_dbg(data->sysmmu, "%d times left to disable\n",
>> >                                         data->activations);
>> > +       }
>> > +
>> > +       write_unlock_irqrestore(&data->lock, flags);
>> >
>> >         return disabled;
>> >  }
>> >
>> > -/* __exynos_sysmmu_enable: Enables System MMU
>> > - *
>> > - * returns -error if an error occurred and System MMU is not enabled,
>> > - * 0 if the System MMU has been just enabled and 1 if System MMU was already
>> > - * enabled before.
>> > - */
>> > -static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
>> > +
>> > +static void __sysmmu_init_config(struct sysmmu_drvdata *data, int idx)
>> > +{
>> > +       unsigned long cfg = CFG_LRU | CFG_QOS(15);
>> > +       int maj, min = 0;
>> > +
>> > +       maj = __sysmmu_version(data, idx, &min);
>> > +       if (maj == 3) {
>> > +               if (min > 1) {
>> > +                       cfg |= CFG_FLPDCACHE;
>> > +                       cfg |= (min == 2) ? CFG_SYSSEL : CFG_ACGEN;
>> > +               }
>> > +       }
>> > +
>> > +       __raw_writel(cfg, data->sfrbases[idx] + REG_MMU_CFG);
>> > +}
>> > +
>> > +static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
>> > +{
>> > +       int i;
>> > +
>> > +       clk_enable(data->clk_master);
>> > +       clk_enable(data->clk);
>> > +
>> > +       for (i = 0; i < data->nsfrs; i++) {
>> > +               __raw_writel(CTRL_BLOCK, data->sfrbases[i] + REG_MMU_CTRL);
>> > +
>> > +               __sysmmu_init_config(data, i);
>> > +
>> > +               __sysmmu_set_ptbase(data->sfrbases[i], data->pgtable);
>> > +
>> > +               __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
>> > +       }
>> > +       clk_disable(data->clk_master);
>> > +}
>> > +
>> > +static int __sysmmu_enable(struct sysmmu_drvdata *data,
>> >                         unsigned long pgtable, struct iommu_domain *domain)
>> >  {
>> > -       int i, ret = 0;
>> > +       int ret = 0;
>> >         unsigned long flags;
>> >
>> >         write_lock_irqsave(&data->lock, flags);
>> > +       if (set_sysmmu_active(data)) {
>> > +               data->pgtable = pgtable;
>> > +               data->domain = domain;
>> >
>> > -       if (!set_sysmmu_active(data)) {
>> > -               if (WARN_ON(pgtable != data->pgtable)) {
>> > -                       ret = -EBUSY;
>> > -                       set_sysmmu_inactive(data);
>> > -               } else {
>> > -                       ret = 1;
>> > -               }
>> > +               if (data->runtime_active)
>> > +                       __sysmmu_enable_nocount(data);
>> >
>> > -               dev_dbg(data->sysmmu, "Already enabled\n");
>> > -               goto finish;
>> > +               dev_dbg(data->sysmmu, "Enabled\n");
>> > +       } else {
>> > +               ret = (pgtable == data->pgtable) ? 1 : -EBUSY;
>> > +
>> > +               dev_dbg(data->sysmmu, "already enabled\n");
>> >         }
>> >
>> > -       if (data->clk)
>> > -               clk_enable(data->clk);
>> > +       if (WARN_ON(ret < 0))
>> > +               set_sysmmu_inactive(data); /* decrement count */
>> >
>> > -       data->pgtable = pgtable;
>> > +       write_unlock_irqrestore(&data->lock, flags);
>> >
>> > -       for (i = 0; i < data->nsfrs; i++) {
>> > -               unsigned int min;
>> > +       return ret;
>> > +}
>> >
>> > -               __sysmmu_set_ptbase(data->sfrbases[i], pgtable);
>> > +/* __exynos_sysmmu_enable: Enables System MMU
>> > + *
>> > + * returns -error if an error occurred and System MMU is not enabled,
>> > + * 0 if the System MMU has been just enabled and 1 if System MMU was already
>> > + * enabled before.
>> > + */
>> > +static int __exynos_sysmmu_enable(struct device *dev, unsigned long pgtable,
>> > +                                 struct iommu_domain *domain)
>> > +{
>> > +       int ret = 0;
>> > +       unsigned long flags;
>> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
>> > +       int i;
>> >
>> > -               if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
>> > -                       unsigned long cfg;
>> > -                       cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
>> > -                       __raw_writel(cfg | CFG_FLPDCACHE,
>> > -                                       data->sfrbases[i] + REG_MMU_CFG);
>> > -               }
>> > +       if (WARN_ON(!client))
>> > +               return -ENODEV;
>> >
>> > -               __raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
>> > -       }
>> > +       spin_lock_irqsave(&client->lock, flags);
>> >
>> > -       data->domain = domain;
>> > +       for (i = 0; i < client->num_sysmmu; i++) {
>> > +               struct sysmmu_drvdata *data =
>> > +                               dev_get_drvdata(client->sysmmu[i]);
>> > +               ret = __sysmmu_enable(data, pgtable, domain);
>> > +               if (ret < 0) {
>> > +                       int j;
>> > +                       for (j = 0; j < i; j++)
>> > +                               __sysmmu_disable(data);
>> > +                       break;
>> > +               } else {
>> > +                       data->master = dev;
>> > +               }
>> > +       }
>> >
>> > -       dev_dbg(data->sysmmu, "Enabled\n");
>> > -finish:
>> > -       write_unlock_irqrestore(&data->lock, flags);
>> > +       spin_unlock_irqrestore(&client->lock, flags);
>> >
>> >         return ret;
>> >  }
>> >
>> >  int exynos_sysmmu_enable(struct device *dev, unsigned long pgtable)
>> >  {
>> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>> >         int ret;
>> >
>> >         BUG_ON(!memblock_is_memory(pgtable));
>> >
>> > -       ret = pm_runtime_get_sync(data->sysmmu);
>> > -       if (ret < 0) {
>> > -               dev_dbg(data->sysmmu, "Failed to enable\n");
>> > -               return ret;
>> > -       }
>> > -
>> > -       ret = __exynos_sysmmu_enable(data, pgtable, NULL);
>> > -       if (WARN_ON(ret < 0)) {
>> > -               pm_runtime_put(data->sysmmu);
>> > -               dev_err(data->sysmmu,
>> > -                       "Already enabled with page table %#lx\n",
>> > -                       data->pgtable);
>> > -       } else {
>> > -               data->dev = dev;
>> > -       }
>> > +       ret = __exynos_sysmmu_enable(dev, pgtable, NULL);
>> >
>> >         return ret;
>> >  }
>> >
>> >  static bool exynos_sysmmu_disable(struct device *dev)
>> >  {
>> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>> > -       bool disabled;
>> > +       unsigned long flags;
>> > +       bool disabled = true;
>> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
>> > +       int i;
>> >
>> > -       disabled = __exynos_sysmmu_disable(data);
>> > -       pm_runtime_put(data->sysmmu);
>> > +       if (WARN_ON(!client))
>> > +               return true;
>> > +
>> > +       spin_lock_irqsave(&client->lock, flags);
>> > +
>> > +       /* Every call to __sysmmu_disable() must return same result */
>> > +       for (i = 0; i < client->num_sysmmu; i++) {
>> > +               struct sysmmu_drvdata *data =
>> > +                               dev_get_drvdata(client->sysmmu[i]);
>> > +               disabled = __sysmmu_disable(data);
>> > +               if (disabled)
>> > +                       data->master = NULL;
>> > +       }
>> > +
>> > +       spin_unlock_irqrestore(&client->lock, flags);
>> >
>> >         return disabled;
>> >  }
>> >
>> >  static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
>> >  {
>> > -       unsigned long flags;
>> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
>> > +       int i;
>> >
>> > -       read_lock_irqsave(&data->lock, flags);
>> > +       for (i = 0; i < client->num_sysmmu; i++) {
>> > +               unsigned long flags;
>> > +               struct sysmmu_drvdata *data;
>> >
>> > -       if (is_sysmmu_active(data)) {
>> > -               int i;
>> > -               for (i = 0; i < data->nsfrs; i++) {
>> > -                       if (sysmmu_block(data->sfrbases[i])) {
>> > +               data = dev_get_drvdata(client->sysmmu[i]);
>> > +
>> > +               read_lock_irqsave(&data->lock, flags);
>> > +               if (is_sysmmu_active(data) && data->runtime_active) {
>> > +                       int i;
>> > +                       clk_enable(data->clk_master);
>> > +                       for (i = 0; i < data->nsfrs; i++)
>> >                                 __sysmmu_tlb_invalidate_entry(
>> >                                                 data->sfrbases[i], iova);
>> > -                               sysmmu_unblock(data->sfrbases[i]);
>> > -                       }
>> > +                       clk_disable(data->clk_master);
>> > +               } else {
>> > +                       dev_dbg(dev,
>> > +                               "disabled. Skipping TLB invalidation @ %#lx\n",
>> > +                               iova);
>> >                 }
>> > -       } else {
>> > -               dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
>> > +               read_unlock_irqrestore(&data->lock, flags);
>> >         }
>> > -
>> > -       read_unlock_irqrestore(&data->lock, flags);
>> >  }
>> >
>> >  void exynos_sysmmu_tlb_invalidate(struct device *dev)
>> >  {
>> > -       unsigned long flags;
>> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>> > -
>> > -       read_lock_irqsave(&data->lock, flags);
>> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
>> > +       int i;
>> >
>> > -       if (is_sysmmu_active(data)) {
>> > -               int i;
>> > -               for (i = 0; i < data->nsfrs; i++) {
>> > -                       if (sysmmu_block(data->sfrbases[i])) {
>> > -                               __sysmmu_tlb_invalidate(data->sfrbases[i]);
>> > -                               sysmmu_unblock(data->sfrbases[i]);
>> > +       for (i = 0; i < client->num_sysmmu; i++) {
>> > +               unsigned long flags;
>> > +               struct sysmmu_drvdata *data;
>> > +
>> > +               data = dev_get_drvdata(client->sysmmu[i]);
>> > +
>> > +               read_lock_irqsave(&data->lock, flags);
>> > +               if (is_sysmmu_active(data) &&
>> > +                               data->runtime_active) {
>> > +                       int i;
>> > +                       for (i = 0; i < data->nsfrs; i++) {
>> > +                               clk_enable(data->clk_master);
>> > +                               if (sysmmu_block(data->sfrbases[i])) {
>> > +                                       __sysmmu_tlb_invalidate(
>> > +                                                       data->sfrbases[i]);
>> > +                                       sysmmu_unblock(data->sfrbases[i]);
>> > +                               }
>> > +                               clk_disable(data->clk_master);
>> >                         }
>> > +               } else {
>> > +                       dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
>> >                 }
>> > -       } else {
>> > -               dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
>> > +               read_unlock_irqrestore(&data->lock, flags);
>> >         }
>> > -
>> > -       read_unlock_irqrestore(&data->lock, flags);
>> >  }
>> >
>> >  static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>> > @@ -610,12 +709,32 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>> >         pm_runtime_enable(dev);
>> >
>> >         data->sysmmu = dev;
>> > +
>> >         data->clk = devm_clk_get(dev, "sysmmu");
>> >         if (IS_ERR(data->clk)) {
>> >                 dev_info(dev, "No gate clock found!\n");
>> >                 data->clk = NULL;
>> >         }
>> >
>> > +       ret = clk_prepare(data->clk);
>> > +       if (ret) {
>> > +               dev_err(dev, "Failed to prepare clk\n");
>> > +               return ret;
>> > +       }
>> > +
>> > +       data->clk_master = devm_clk_get(dev, "master");
>> > +       if (IS_ERR(data->clk_master))
>> > +               data->clk_master = NULL;
>> > +
>> > +       ret = clk_prepare(data->clk_master);
>> > +       if (ret) {
>> > +               clk_unprepare(data->clk);
>> > +               dev_err(dev, "Failed to prepare master's clk\n");
>> > +               return ret;
>> > +       }
>> > +
>> > +       data->runtime_active = !pm_runtime_enabled(dev);
>> > +
>> >         rwlock_init(&data->lock);
>> >         INIT_LIST_HEAD(&data->node);
>> >
>> > @@ -625,6 +744,34 @@ 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", },
>> > @@ -637,6 +784,7 @@ 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),
>> >         }
>> >  };
>> > @@ -689,7 +837,7 @@ err_pgtable:
>> >  static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>> >  {
>> >         struct exynos_iommu_domain *priv = domain->priv;
>> > -       struct sysmmu_drvdata *data;
>> > +       struct exynos_iommu_client *client;
>> >         unsigned long flags;
>> >         int i;
>> >
>> > @@ -697,11 +845,14 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>> >
>> >         spin_lock_irqsave(&priv->lock, flags);
>> >
>> > -       list_for_each_entry(data, &priv->clients, node) {
>> > -               while (!exynos_sysmmu_disable(data->dev))
>> > +       list_for_each_entry(client, &priv->clients, node) {
>> > +               while (!exynos_sysmmu_disable(client->dev))
>> >                         ; /* until System MMU is actually disabled */
>> >         }
>> >
>> > +       while (!list_empty(&priv->clients))
>> > +               list_del_init(priv->clients.next);
>> > +
>> >         spin_unlock_irqrestore(&priv->lock, flags);
>> >
>> >         for (i = 0; i < NUM_LV1ENTRIES; i++)
>> > @@ -718,41 +869,26 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>> >  static int exynos_iommu_attach_device(struct iommu_domain *domain,
>> >                                    struct device *dev)
>> >  {
>> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>> > +       struct exynos_iommu_client *client = dev->archdata.iommu;
>> >         struct exynos_iommu_domain *priv = domain->priv;
>> >         unsigned long flags;
>> >         int ret;
>> >
>> > -       ret = pm_runtime_get_sync(data->sysmmu);
>> > -       if (ret < 0)
>> > -               return ret;
>> > -
>> > -       ret = 0;
>> > -
>> >         spin_lock_irqsave(&priv->lock, flags);
>> >
>> > -       ret = __exynos_sysmmu_enable(data, __pa(priv->pgtable), domain);
>> > -
>> > -       if (ret == 0) {
>> > -               /* 'data->node' must not be appeared in priv->clients */
>> > -               BUG_ON(!list_empty(&data->node));
>> > -               data->dev = dev;
>> > -               list_add_tail(&data->node, &priv->clients);
>> > -       }
>> > +       ret = __exynos_sysmmu_enable(dev, __pa(priv->pgtable), domain);
>> > +       if (ret == 0)
>> > +               list_add_tail(&client->node, &priv->clients);
>> >
>> >         spin_unlock_irqrestore(&priv->lock, flags);
>> >
>> > -       if (ret < 0) {
>> > +       if (ret < 0)
>> >                 dev_err(dev, "%s: Failed to attach IOMMU with pgtable %#lx\n",
>> >                                 __func__, __pa(priv->pgtable));
>> > -               pm_runtime_put(data->sysmmu);
>> > -       } else if (ret > 0) {
>> > -               dev_dbg(dev, "%s: IOMMU with pgtable 0x%lx already attached\n",
>> > -                                       __func__, __pa(priv->pgtable));
>> > -       } else {
>> > -               dev_dbg(dev, "%s: Attached new IOMMU with pgtable 0x%lx\n",
>> > -                                       __func__, __pa(priv->pgtable));
>> > -       }
>> > +       else
>> > +               dev_dbg(dev, "%s: Attached IOMMU with pgtable 0x%lx%s\n",
>> > +                                       __func__, __pa(priv->pgtable),
>> > +                                       (ret == 0) ? "" : ", again");
>> >
>> >         return ret;
>> >  }
>> > @@ -760,39 +896,27 @@ static int exynos_iommu_attach_device(struct iommu_domain *domain,
>> >  static void exynos_iommu_detach_device(struct iommu_domain *domain,
>> >                                     struct device *dev)
>> >  {
>> > -       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>> > +       struct exynos_iommu_client *client = NULL;
>> >         struct exynos_iommu_domain *priv = domain->priv;
>> > -       struct list_head *pos;
>> >         unsigned long flags;
>> > -       bool found = false;
>> >
>> >         spin_lock_irqsave(&priv->lock, flags);
>> >
>> > -       list_for_each(pos, &priv->clients) {
>> > -               if (list_entry(pos, struct sysmmu_drvdata, node) == data) {
>> > -                       found = true;
>> > +       list_for_each_entry(client, &priv->clients, node) {
>> > +               if (client == dev->archdata.iommu) {
>> > +                       if (exynos_sysmmu_disable(dev))
>> > +                               list_del_init(&client->node);
>> >                         break;
>> >                 }
>> >         }
>> >
>> > -       if (!found)
>> > -               goto finish;
>> > +       spin_unlock_irqrestore(&priv->lock, flags);
>> >
>> > -       if (__exynos_sysmmu_disable(data)) {
>> > +       if (client == dev->archdata.iommu)
>> >                 dev_dbg(dev, "%s: Detached IOMMU with pgtable %#lx\n",
>> >                                         __func__, __pa(priv->pgtable));
>> > -               list_del_init(&data->node);
>> > -
>> > -       } else {
>> > -               dev_dbg(dev, "%s: Detaching IOMMU with pgtable %#lx delayed",
>> > -                                       __func__, __pa(priv->pgtable));
>> > -       }
>> > -
>> > -finish:
>> > -       spin_unlock_irqrestore(&priv->lock, flags);
>> > -
>> > -       if (found)
>> > -               pm_runtime_put(data->sysmmu);
>> > +       else
>> > +               dev_dbg(dev, "%s: No IOMMU is attached\n", __func__);
>> >  }
>> >
>> >  static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
>> > @@ -914,7 +1038,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
>> >                                                unsigned long iova, size_t size)
>> >  {
>> >         struct exynos_iommu_domain *priv = domain->priv;
>> > -       struct sysmmu_drvdata *data;
>> > +       struct exynos_iommu_client *client;
>> >         unsigned long flags;
>> >         unsigned long *ent;
>> >         size_t err_pgsize;
>> > @@ -975,8 +1099,8 @@ done:
>> >         spin_unlock_irqrestore(&priv->pgtablelock, flags);
>> >
>> >         spin_lock_irqsave(&priv->lock, flags);
>> > -       list_for_each_entry(data, &priv->clients, node)
>> > -               sysmmu_tlb_invalidate_entry(data->dev, iova);
>> > +       list_for_each_entry(client, &priv->clients, node)
>> > +               sysmmu_tlb_invalidate_entry(client->dev, iova);
>> >         spin_unlock_irqrestore(&priv->lock, flags);
>> >
>> >         return size;
>> > @@ -1055,3 +1179,275 @@ static int __init exynos_iommu_init(void)
>> >         return ret;
>> >  }
>> >  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)
>> > +{
>> > +       struct device *dev = p;
>> > +
>> > +       switch (val) {
>> > +       case BUS_NOTIFY_BIND_DRIVER:
>> > +       {
>> > +               int i = 0;
>> > +               int size = 0;
>>
>> You can drop the initialization here. They are getting initialised
>> before actual use.
>
> Yes, it is basically right.
> I just want to be convinced that the output argument to of_get_property()
> is not referenced before initialization even though of_get_property()
> does not reference to the argument, actually.
>

This is not wrong but I found it optional since you are already checking
for phandle. No problem.

>>
>> > +               const __be32 *phandle;
>> > +               struct exynos_iommu_client *client;
>> > +
>> > +               phandle = of_get_property(dev->of_node, "iommu", &size);
>> > +               if (!phandle)
>> > +                       break;
>> > +
>> > +               size = size / sizeof(*phandle); /* number of elements */
>> > +
>> > +               client = devm_kzalloc(dev, sizeof(*client) * size, GFP_KERNEL);
>>
>> You do not need to allocate memory of size "sizeof(*client) * size" ? It should
>> always be sizeof(*client).
>
> Oh. It is my fault.
> It must be 'sizeof(*client) + size * sizeof(client->sysmmu[0])'.
> It will be fixed.
>

sure.

Regards,
Rahul Sharma.

>>
>> > +               if (!client) {
>> > +                       dev_err(dev, "No Memory for exynos_iommu_client\n");
>> > +                       return -ENOMEM;
>> > +               }
>> > +
>> > +               client->num_sysmmu = size;
>> > +               client->dev = dev;
>> > +               INIT_LIST_HEAD(&client->node);
>> > +               spin_lock_init(&client->lock);
>> > +
>> > +               for (i = 0; i < size; i++) {
>> > +                       struct device_node *np;
>> > +                       struct platform_device *sysmmu;
>> > +
>> > +                       /* this always success: see above of_find_property() */
>> > +                       np = of_parse_phandle(dev->of_node, "iommu", i);
>> > +
>> > +                       sysmmu = of_find_device_by_node(np);
>> > +                       if (!sysmmu) {
>> > +                               dev_err(dev,
>> > +                                       "sysmmu node '%s' is not found\n",
>> > +                                       np->name);
>> > +                               break;
>> > +                       }
>> > +
>> > +                       client->sysmmu[i] = &sysmmu->dev;
>>
>> Your array has space for single 'device *'. You should allocate memory to
>> client->sysmmu before accessing indexes above 0.
>
> As I commented above, enough size is allocated.
>
>>
>> As if now, It is not corrupting other's memory since you have allocated a
>> much bigger chunk for your client pointer which is wrong IMO.
>
> That is my fault :)
>>
>> regards,
>> Rahul Sharma
>
> Thank you.
>
> Cho KyongHo.
>
>>
>> > +               }
>> > +
>> > +               if (i < size) {
>> > +                       while (--i >= 0)
>> > +                               of_node_put(client->sysmmu[i]->of_node);
>> > +                       devm_kfree(dev, client);
>> > +                       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;
>> > +               }
>> > +               break;
>> > +       }
>> > +       } /* switch (val) */
>> > +
>> > +       return 0;
>> > +}
>> > +
>> > +static struct notifier_block sysmmu_notifier = {
>> > +       .notifier_call = &sysmmu_hook_driver_register,
>> > +};
>> > +
>> > +static int __init exynos_iommu_prepare(void)
>> > +{
>> > +       return bus_register_notifier(&platform_bus_type, &sysmmu_notifier);
>> > +}
>> > +arch_initcall(exynos_iommu_prepare);
>> > --
>> > 1.7.2.5
>> >
>> >
>> > _______________________________________________
>> > iommu mailing list
>> > [e-mail]
>> > https://lists.linuxfoundation.org/mailman/listinfo/iommu
>
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Bartlomiej Zolnierkiewicz Aug. 2, 2013, 5:32 p.m. UTC | #4

Hi,

On Friday, July 26, 2013 08:30:17 PM Cho KyongHo wrote:
> When a device driver is registered, all constructs to handle System MMU
> is prepared by bus notifier call.

Patch description could be improved greatly by documenting what the patch
is doing and it does a lot more than simply adding bus notifier.

The patch can be also split further (at least code adding support for
muplitple System MMUs per struct exynos_iommu_client instance could be
separate which would make review a lot easier as the code wouldn't be
moved around so much).

Could you also tell me how (on which SoC/board and with what drivers) are
you testing these changes? I've tried to test v7 with FIMC and MFC devices
(on EXYNOS4210 based Universal C210 board) but as soon as I added actual
IOMMU mappings (none of your patches in this series does it BTW) I've
encountered problems (namely lockup related to clocks usage, probably
related to "master" clock, I haven't had time to debug it further yet).

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> Signed-off-by: Cho KyongHo <[e-mail]>
> ---
>  drivers/iommu/exynos-iommu.c |  708 ++++++++++++++++++++++++++++++++---------
>  1 files changed, 552 insertions(+), 156 deletions(-)
> 
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index f9853fe..c62c244 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -27,6 +27,9 @@
>  #include <linux/memblock.h>
>  #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>
>  #include <asm/pgtable.h>
> @@ -80,7 +83,13 @@
>  #define CTRL_BLOCK	0x7
>  #define CTRL_DISABLE	0x0
>  
> +#define CFG_LRU		0x1
> +#define CFG_QOS(n)	((n & 0xF) << 7)
> +#define CFG_MASK	0x0150FFFF /* Selecting bit 0-15, 20, 22 and 24 */
> +#define CFG_ACGEN	(1 << 24) /* System MMU 3.3 only */
> +#define CFG_SYSSEL	(1 << 22) /* System MMU 3.2 only */
>  #define CFG_FLPDCACHE	(1 << 20) /* System MMU 3.2+ only */
> +#define CFG_SHAREABLE	(1 << 12) /* System MMU 3.x only */
>  
>  #define REG_MMU_CTRL		0x000
>  #define REG_MMU_CFG		0x004
> @@ -154,6 +163,14 @@ static char *sysmmu_fault_name[SYSMMU_FAULTS_NUM] = {
>  	"UNKNOWN FAULT"
>  };
>  
> +struct exynos_iommu_client {
> +	struct list_head node;	/* entry of exynos_iommu_domain.clients */
> +	struct device *dev;
> +	spinlock_t lock;
> +	int num_sysmmu;
> +	struct device *sysmmu[0];
> +};
> +
>  struct exynos_iommu_domain {
>  	struct list_head clients; /* list of sysmmu_drvdata.node */
>  	unsigned long *pgtable; /* lv1 page table, 16KB */
> @@ -165,12 +182,14 @@ struct exynos_iommu_domain {
>  struct sysmmu_drvdata {
>  	struct list_head node; /* entry of exynos_iommu_domain.clients */
>  	struct device *sysmmu;	/* System MMU's device descriptor */
> -	struct device *dev;	/* Owner of system MMU */
> +	struct device *master;	/* Owner of system MMU */
>  	int nsfrs;
>  	struct clk *clk;
> +	struct clk *clk_master;
>  	int activations;
>  	rwlock_t lock;
>  	struct iommu_domain *domain;
> +	bool runtime_active;
>  	unsigned long pgtable;
>  	void __iomem *sfrbases[0];
>  };
> @@ -245,7 +264,6 @@ static void __sysmmu_tlb_invalidate_entry(void __iomem *sfrbase,
>  static void __sysmmu_set_ptbase(void __iomem *sfrbase,
>  				       unsigned long pgd)
>  {
> -	__raw_writel(0x1, sfrbase + REG_MMU_CFG); /* 16KB LV1, LRU */
>  	__raw_writel(pgd, sfrbase + REG_PT_BASE_ADDR);
>  
>  	__sysmmu_tlb_invalidate(sfrbase);
> @@ -273,6 +291,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
>  	if (!is_sysmmu_active(data))
>  		goto finish;
>  
> +	clk_enable(data->clk_master);
>  	for (i = 0; i < data->nsfrs; i++) {
>  		if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
>  			if (!sysmmu_block(data->sfrbases[i]))
> @@ -298,6 +317,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
>  			sysmmu_unblock(data->sfrbases[i]);
>  		}
>  	}
> +	clk_disable(data->clk_master);
>  finish:
>  	read_unlock_irqrestore(&data->lock, flags);
>  }
> @@ -331,12 +351,13 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>  {
>  	/* SYSMMU is in blocked when interrupt occurred. */
>  	struct sysmmu_drvdata *data = dev_id;
> +	struct exynos_iommu_client *client = NULL;
>  	enum exynos_sysmmu_inttype itype;
>  	unsigned long addr = -1;
> -
>  	int i, ret = -ENOSYS;
>  
> -	read_lock(&data->lock);
> +	if (data->master)
> +		client = data->master->archdata.iommu;
>  
>  	WARN_ON(!is_sysmmu_active(data));
>  
> @@ -348,6 +369,10 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>  			break;
>  	}
>  
> +	if (client)
> +		spin_lock(&client->lock);
> +	read_lock(&data->lock);
> +
>  	if (i == data->nsfrs) {
>  		itype = SYSMMU_FAULT_UNKNOWN;
>  	} else {
> @@ -361,7 +386,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>  	}
>  
>  	if (data->domain)
> -		ret = report_iommu_fault(data->domain, data->dev,
> +		ret = report_iommu_fault(data->domain, data->master,
>  				addr, itype);
>  
>  	if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
> @@ -378,177 +403,251 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>  		sysmmu_unblock(data->sfrbases[i]);
>  
>  	read_unlock(&data->lock);
> +	if (client)
> +		spin_unlock(&client->lock);
>  
>  	return IRQ_HANDLED;
>  }
>  
> -static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
> +static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
>  {
> -	unsigned long flags;
> -	bool disabled = false;
>  	int i;
>  
> -	write_lock_irqsave(&data->lock, flags);
> +	clk_enable(data->clk_master);
> +	for (i = 0; i < data->nsfrs; i++) {
> +		__raw_writel(CTRL_DISABLE,
> +				data->sfrbases[i] + REG_MMU_CTRL);
> +		__raw_writel(0, data->sfrbases[i] + REG_MMU_CFG);
> +	}
>  
> -	if (!set_sysmmu_inactive(data))
> -		goto finish;
> +	clk_disable(data->clk);
> +	clk_disable(data->clk_master);
> +}
>  
> -	for (i = 0; i < data->nsfrs; i++)
> -		__raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
> +static bool __sysmmu_disable(struct sysmmu_drvdata *data)
> +{
> +	bool disabled;
> +	unsigned long flags;
>  
> -	if (data->clk)
> -		clk_disable(data->clk);
> +	write_lock_irqsave(&data->lock, flags);
>  
> -	disabled = true;
> -	data->pgtable = 0;
> -	data->domain = NULL;
> -finish:
> -	write_unlock_irqrestore(&data->lock, flags);
> +	disabled = set_sysmmu_inactive(data);
> +
> +	if (disabled) {
> +		data->pgtable = 0;
> +		data->domain = NULL;
> +
> +		if (data->runtime_active)
> +			__sysmmu_disable_nocount(data);
>  
> -	if (disabled)
>  		dev_dbg(data->sysmmu, "Disabled\n");
> -	else
> -		dev_dbg(data->sysmmu, "%d times left to be disabled\n",
> +	} else  {
> +		dev_dbg(data->sysmmu, "%d times left to disable\n",
>  					data->activations);
> +	}
> +
> +	write_unlock_irqrestore(&data->lock, flags);
>  
>  	return disabled;
>  }
>  
> -/* __exynos_sysmmu_enable: Enables System MMU
> - *
> - * returns -error if an error occurred and System MMU is not enabled,
> - * 0 if the System MMU has been just enabled and 1 if System MMU was already
> - * enabled before.
> - */
> -static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> +
> +static void __sysmmu_init_config(struct sysmmu_drvdata *data, int idx)
> +{
> +	unsigned long cfg = CFG_LRU | CFG_QOS(15);
> +	int maj, min = 0;
> +
> +	maj = __sysmmu_version(data, idx, &min);
> +	if (maj == 3) {
> +		if (min > 1) {
> +			cfg |= CFG_FLPDCACHE;
> +			cfg |= (min == 2) ? CFG_SYSSEL : CFG_ACGEN;
> +		}
> +	}
> +
> +	__raw_writel(cfg, data->sfrbases[idx] + REG_MMU_CFG);
> +}
> +
> +static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
> +{
> +	int i;
> +
> +	clk_enable(data->clk_master);
> +	clk_enable(data->clk);
> +
> +	for (i = 0; i < data->nsfrs; i++) {
> +		__raw_writel(CTRL_BLOCK, data->sfrbases[i] + REG_MMU_CTRL);
> +
> +		__sysmmu_init_config(data, i);
> +
> +		__sysmmu_set_ptbase(data->sfrbases[i], data->pgtable);
> +
> +		__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> +	}
> +	clk_disable(data->clk_master);
> +}
> +
> +static int __sysmmu_enable(struct sysmmu_drvdata *data,
>  			unsigned long pgtable, struct iommu_domain *domain)
>  {
> -	int i, ret = 0;
> +	int ret = 0;
>  	unsigned long flags;
>  
>  	write_lock_irqsave(&data->lock, flags);
> +	if (set_sysmmu_active(data)) {
> +		data->pgtable = pgtable;
> +		data->domain = domain;
>  
> -	if (!set_sysmmu_active(data)) {
> -		if (WARN_ON(pgtable != data->pgtable)) {
> -			ret = -EBUSY;
> -			set_sysmmu_inactive(data);
> -		} else {
> -			ret = 1;
> -		}
> +		if (data->runtime_active)
> +			__sysmmu_enable_nocount(data);
>  
> -		dev_dbg(data->sysmmu, "Already enabled\n");
> -		goto finish;
> +		dev_dbg(data->sysmmu, "Enabled\n");
> +	} else {
> +		ret = (pgtable == data->pgtable) ? 1 : -EBUSY;
> +
> +		dev_dbg(data->sysmmu, "already enabled\n");
>  	}
>  
> -	if (data->clk)
> -		clk_enable(data->clk);
> +	if (WARN_ON(ret < 0))
> +		set_sysmmu_inactive(data); /* decrement count */
>  
> -	data->pgtable = pgtable;
> +	write_unlock_irqrestore(&data->lock, flags);
>  
> -	for (i = 0; i < data->nsfrs; i++) {
> -		unsigned int min;
> +	return ret;
> +}
>  
> -		__sysmmu_set_ptbase(data->sfrbases[i], pgtable);
> +/* __exynos_sysmmu_enable: Enables System MMU
> + *
> + * returns -error if an error occurred and System MMU is not enabled,
> + * 0 if the System MMU has been just enabled and 1 if System MMU was already
> + * enabled before.
> + */
> +static int __exynos_sysmmu_enable(struct device *dev, unsigned long pgtable,
> +				  struct iommu_domain *domain)
> +{
> +	int ret = 0;
> +	unsigned long flags;
> +	struct exynos_iommu_client *client = dev->archdata.iommu;
> +	int i;
>  
> -		if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
> -			unsigned long cfg;
> -			cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
> -			__raw_writel(cfg | CFG_FLPDCACHE,
> -					data->sfrbases[i] + REG_MMU_CFG);
> -		}
> +	if (WARN_ON(!client))
> +		return -ENODEV;
>  
> -		__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> -	}
> +	spin_lock_irqsave(&client->lock, flags);
>  
> -	data->domain = domain;
> +	for (i = 0; i < client->num_sysmmu; i++) {
> +		struct sysmmu_drvdata *data =
> +				dev_get_drvdata(client->sysmmu[i]);
> +		ret = __sysmmu_enable(data, pgtable, domain);
> +		if (ret < 0) {
> +			int j;
> +			for (j = 0; j < i; j++)
> +				__sysmmu_disable(data);
> +			break;
> +		} else {
> +			data->master = dev;
> +		}
> +	}
>  
> -	dev_dbg(data->sysmmu, "Enabled\n");
> -finish:
> -	write_unlock_irqrestore(&data->lock, flags);
> +	spin_unlock_irqrestore(&client->lock, flags);
>  
>  	return ret;
>  }
>  
>  int exynos_sysmmu_enable(struct device *dev, unsigned long pgtable)
>  {
> -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
>  	int ret;
>  
>  	BUG_ON(!memblock_is_memory(pgtable));
>  
> -	ret = pm_runtime_get_sync(data->sysmmu);
> -	if (ret < 0) {
> -		dev_dbg(data->sysmmu, "Failed to enable\n");
> -		return ret;
> -	}
> -
> -	ret = __exynos_sysmmu_enable(data, pgtable, NULL);
> -	if (WARN_ON(ret < 0)) {
> -		pm_runtime_put(data->sysmmu);
> -		dev_err(data->sysmmu,
> -			"Already enabled with page table %#lx\n",
> -			data->pgtable);
> -	} else {
> -		data->dev = dev;
> -	}
> +	ret = __exynos_sysmmu_enable(dev, pgtable, NULL);
>  
>  	return ret;
>  }
>  
>  static bool exynos_sysmmu_disable(struct device *dev)
>  {
> -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> -	bool disabled;
> +	unsigned long flags;
> +	bool disabled = true;
> +	struct exynos_iommu_client *client = dev->archdata.iommu;
> +	int i;
>  
> -	disabled = __exynos_sysmmu_disable(data);
> -	pm_runtime_put(data->sysmmu);
> +	if (WARN_ON(!client))
> +		return true;
> +
> +	spin_lock_irqsave(&client->lock, flags);
> +
> +	/* Every call to __sysmmu_disable() must return same result */
> +	for (i = 0; i < client->num_sysmmu; i++) {
> +		struct sysmmu_drvdata *data =
> +				dev_get_drvdata(client->sysmmu[i]);
> +		disabled = __sysmmu_disable(data);
> +		if (disabled)
> +			data->master = NULL;
> +	}
> +
> +	spin_unlock_irqrestore(&client->lock, flags);
>  
>  	return disabled;
>  }
>  
>  static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
>  {
> -	unsigned long flags;
> -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> +	struct exynos_iommu_client *client = dev->archdata.iommu;
> +	int i;
>  
> -	read_lock_irqsave(&data->lock, flags);
> +	for (i = 0; i < client->num_sysmmu; i++) {
> +		unsigned long flags;
> +		struct sysmmu_drvdata *data;
>  
> -	if (is_sysmmu_active(data)) {
> -		int i;
> -		for (i = 0; i < data->nsfrs; i++) {
> -			if (sysmmu_block(data->sfrbases[i])) {
> +		data = dev_get_drvdata(client->sysmmu[i]);
> +
> +		read_lock_irqsave(&data->lock, flags);
> +		if (is_sysmmu_active(data) && data->runtime_active) {
> +			int i;
> +			clk_enable(data->clk_master);
> +			for (i = 0; i < data->nsfrs; i++)
>  				__sysmmu_tlb_invalidate_entry(
>  						data->sfrbases[i], iova);
> -				sysmmu_unblock(data->sfrbases[i]);
> -			}
> +			clk_disable(data->clk_master);
> +		} else {
> +			dev_dbg(dev,
> +				"disabled. Skipping TLB invalidation @ %#lx\n",
> +				iova);
>  		}
> -	} else {
> -		dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> +		read_unlock_irqrestore(&data->lock, flags);
>  	}
> -
> -	read_unlock_irqrestore(&data->lock, flags);
>  }
>  
>  void exynos_sysmmu_tlb_invalidate(struct device *dev)
>  {
> -	unsigned long flags;
> -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> -
> -	read_lock_irqsave(&data->lock, flags);
> +	struct exynos_iommu_client *client = dev->archdata.iommu;
> +	int i;
>  
> -	if (is_sysmmu_active(data)) {
> -		int i;
> -		for (i = 0; i < data->nsfrs; i++) {
> -			if (sysmmu_block(data->sfrbases[i])) {
> -				__sysmmu_tlb_invalidate(data->sfrbases[i]);
> -				sysmmu_unblock(data->sfrbases[i]);
> +	for (i = 0; i < client->num_sysmmu; i++) {
> +		unsigned long flags;
> +		struct sysmmu_drvdata *data;
> +
> +		data = dev_get_drvdata(client->sysmmu[i]);
> +
> +		read_lock_irqsave(&data->lock, flags);
> +		if (is_sysmmu_active(data) &&
> +				data->runtime_active) {
> +			int i;
> +			for (i = 0; i < data->nsfrs; i++) {
> +				clk_enable(data->clk_master);
> +				if (sysmmu_block(data->sfrbases[i])) {
> +					__sysmmu_tlb_invalidate(
> +							data->sfrbases[i]);
> +					sysmmu_unblock(data->sfrbases[i]);
> +				}
> +				clk_disable(data->clk_master);
>  			}
> +		} else {
> +			dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
>  		}
> -	} else {
> -		dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> +		read_unlock_irqrestore(&data->lock, flags);
>  	}
> -
> -	read_unlock_irqrestore(&data->lock, flags);
>  }
>  
>  static int __init exynos_sysmmu_probe(struct platform_device *pdev)
> @@ -610,12 +709,32 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>  	pm_runtime_enable(dev);
>  
>  	data->sysmmu = dev;
> +
>  	data->clk = devm_clk_get(dev, "sysmmu");
>  	if (IS_ERR(data->clk)) {
>  		dev_info(dev, "No gate clock found!\n");
>  		data->clk = NULL;
>  	}
>  
> +	ret = clk_prepare(data->clk);
> +	if (ret) {
> +		dev_err(dev, "Failed to prepare clk\n");
> +		return ret;
> +	}
> +
> +	data->clk_master = devm_clk_get(dev, "master");
> +	if (IS_ERR(data->clk_master))
> +		data->clk_master = NULL;
> +
> +	ret = clk_prepare(data->clk_master);
> +	if (ret) {
> +		clk_unprepare(data->clk);
> +		dev_err(dev, "Failed to prepare master's clk\n");
> +		return ret;
> +	}
> +
> +	data->runtime_active = !pm_runtime_enabled(dev);
> +
>  	rwlock_init(&data->lock);
>  	INIT_LIST_HEAD(&data->node);
>  
> @@ -625,6 +744,34 @@ 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", },
> @@ -637,6 +784,7 @@ 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),
>  	}
>  };
> @@ -689,7 +837,7 @@ err_pgtable:
>  static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>  {
>  	struct exynos_iommu_domain *priv = domain->priv;
> -	struct sysmmu_drvdata *data;
> +	struct exynos_iommu_client *client;
>  	unsigned long flags;
>  	int i;
>  
> @@ -697,11 +845,14 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>  
>  	spin_lock_irqsave(&priv->lock, flags);
>  
> -	list_for_each_entry(data, &priv->clients, node) {
> -		while (!exynos_sysmmu_disable(data->dev))
> +	list_for_each_entry(client, &priv->clients, node) {
> +		while (!exynos_sysmmu_disable(client->dev))
>  			; /* until System MMU is actually disabled */
>  	}
>  
> +	while (!list_empty(&priv->clients))
> +		list_del_init(priv->clients.next);
> +
>  	spin_unlock_irqrestore(&priv->lock, flags);
>  
>  	for (i = 0; i < NUM_LV1ENTRIES; i++)
> @@ -718,41 +869,26 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
>  static int exynos_iommu_attach_device(struct iommu_domain *domain,
>  				   struct device *dev)
>  {
> -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> +	struct exynos_iommu_client *client = dev->archdata.iommu;
>  	struct exynos_iommu_domain *priv = domain->priv;
>  	unsigned long flags;
>  	int ret;
>  
> -	ret = pm_runtime_get_sync(data->sysmmu);
> -	if (ret < 0)
> -		return ret;
> -
> -	ret = 0;
> -
>  	spin_lock_irqsave(&priv->lock, flags);
>  
> -	ret = __exynos_sysmmu_enable(data, __pa(priv->pgtable), domain);
> -
> -	if (ret == 0) {
> -		/* 'data->node' must not be appeared in priv->clients */
> -		BUG_ON(!list_empty(&data->node));
> -		data->dev = dev;
> -		list_add_tail(&data->node, &priv->clients);
> -	}
> +	ret = __exynos_sysmmu_enable(dev, __pa(priv->pgtable), domain);
> +	if (ret == 0)
> +		list_add_tail(&client->node, &priv->clients);
>  
>  	spin_unlock_irqrestore(&priv->lock, flags);
>  
> -	if (ret < 0) {
> +	if (ret < 0)
>  		dev_err(dev, "%s: Failed to attach IOMMU with pgtable %#lx\n",
>  				__func__, __pa(priv->pgtable));
> -		pm_runtime_put(data->sysmmu);
> -	} else if (ret > 0) {
> -		dev_dbg(dev, "%s: IOMMU with pgtable 0x%lx already attached\n",
> -					__func__, __pa(priv->pgtable));
> -	} else {
> -		dev_dbg(dev, "%s: Attached new IOMMU with pgtable 0x%lx\n",
> -					__func__, __pa(priv->pgtable));
> -	}
> +	else
> +		dev_dbg(dev, "%s: Attached IOMMU with pgtable 0x%lx%s\n",
> +					__func__, __pa(priv->pgtable),
> +					(ret == 0) ? "" : ", again");
>  
>  	return ret;
>  }
> @@ -760,39 +896,27 @@ static int exynos_iommu_attach_device(struct iommu_domain *domain,
>  static void exynos_iommu_detach_device(struct iommu_domain *domain,
>  				    struct device *dev)
>  {
> -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> +	struct exynos_iommu_client *client = NULL;
>  	struct exynos_iommu_domain *priv = domain->priv;
> -	struct list_head *pos;
>  	unsigned long flags;
> -	bool found = false;
>  
>  	spin_lock_irqsave(&priv->lock, flags);
>  
> -	list_for_each(pos, &priv->clients) {
> -		if (list_entry(pos, struct sysmmu_drvdata, node) == data) {
> -			found = true;
> +	list_for_each_entry(client, &priv->clients, node) {
> +		if (client == dev->archdata.iommu) {
> +			if (exynos_sysmmu_disable(dev))
> +				list_del_init(&client->node);
>  			break;
>  		}
>  	}
>  
> -	if (!found)
> -		goto finish;
> +	spin_unlock_irqrestore(&priv->lock, flags);
>  
> -	if (__exynos_sysmmu_disable(data)) {
> +	if (client == dev->archdata.iommu)
>  		dev_dbg(dev, "%s: Detached IOMMU with pgtable %#lx\n",
>  					__func__, __pa(priv->pgtable));
> -		list_del_init(&data->node);
> -
> -	} else {
> -		dev_dbg(dev, "%s: Detaching IOMMU with pgtable %#lx delayed",
> -					__func__, __pa(priv->pgtable));
> -	}
> -
> -finish:
> -	spin_unlock_irqrestore(&priv->lock, flags);
> -
> -	if (found)
> -		pm_runtime_put(data->sysmmu);
> +	else
> +		dev_dbg(dev, "%s: No IOMMU is attached\n", __func__);
>  }
>  
>  static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
> @@ -914,7 +1038,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
>  					       unsigned long iova, size_t size)
>  {
>  	struct exynos_iommu_domain *priv = domain->priv;
> -	struct sysmmu_drvdata *data;
> +	struct exynos_iommu_client *client;
>  	unsigned long flags;
>  	unsigned long *ent;
>  	size_t err_pgsize;
> @@ -975,8 +1099,8 @@ done:
>  	spin_unlock_irqrestore(&priv->pgtablelock, flags);
>  
>  	spin_lock_irqsave(&priv->lock, flags);
> -	list_for_each_entry(data, &priv->clients, node)
> -		sysmmu_tlb_invalidate_entry(data->dev, iova);
> +	list_for_each_entry(client, &priv->clients, node)
> +		sysmmu_tlb_invalidate_entry(client->dev, iova);
>  	spin_unlock_irqrestore(&priv->lock, flags);
>  
>  	return size;
> @@ -1055,3 +1179,275 @@ static int __init exynos_iommu_init(void)
>  	return ret;
>  }
>  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)
> +{
> +	struct device *dev = p;
> +
> +	switch (val) {
> +	case BUS_NOTIFY_BIND_DRIVER:
> +	{
> +		int i = 0;
> +		int size = 0;
> +		const __be32 *phandle;
> +		struct exynos_iommu_client *client;
> +
> +		phandle = of_get_property(dev->of_node, "iommu", &size);
> +		if (!phandle)
> +			break;
> +
> +		size = size / sizeof(*phandle); /* number of elements */
> +
> +		client = devm_kzalloc(dev, sizeof(*client) * size, GFP_KERNEL);
> +		if (!client) {
> +			dev_err(dev, "No Memory for exynos_iommu_client\n");
> +			return -ENOMEM;
> +		}
> +
> +		client->num_sysmmu = size;
> +		client->dev = dev;
> +		INIT_LIST_HEAD(&client->node);
> +		spin_lock_init(&client->lock);
> +
> +		for (i = 0; i < size; i++) {
> +			struct device_node *np;
> +			struct platform_device *sysmmu;
> +
> +			/* this always success: see above of_find_property() */
> +			np = of_parse_phandle(dev->of_node, "iommu", i);
> +
> +			sysmmu = of_find_device_by_node(np);
> +			if (!sysmmu) {
> +				dev_err(dev,
> +					"sysmmu node '%s' is not found\n",
> +					np->name);
> +				break;
> +			}
> +
> +			client->sysmmu[i] = &sysmmu->dev;
> +		}
> +
> +		if (i < size) {
> +			while (--i >= 0)
> +				of_node_put(client->sysmmu[i]->of_node);
> +			devm_kfree(dev, client);
> +			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;
> +		}
> +		break;
> +	}
> +	} /* switch (val) */
> +
> +	return 0;
> +}
> +
> +static struct notifier_block sysmmu_notifier = {
> +	.notifier_call = &sysmmu_hook_driver_register,
> +};
> +
> +static int __init exynos_iommu_prepare(void)
> +{
> +	return bus_register_notifier(&platform_bus_type, &sysmmu_notifier);
> +}
> +arch_initcall(exynos_iommu_prepare);

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Cho KyongHo Aug. 5, 2013, 1:17 p.m. UTC | #5

> -----Original Message-----
> From: Bartlomiej Zolnierkiewicz [mailto:[e-mail]]
> Sent: Saturday, August 03, 2013 2:32 AM
> 
> Hi,
> 
> On Friday, July 26, 2013 08:30:17 PM Cho KyongHo wrote:
> > When a device driver is registered, all constructs to handle System MMU
> > is prepared by bus notifier call.
> 
> Patch description could be improved greatly by documenting what the patch
> is doing and it does a lot more than simply adding bus notifier.
> 
> The patch can be also split further (at least code adding support for
> muplitple System MMUs per struct exynos_iommu_client instance could be
> separate which would make review a lot easier as the code wouldn't be
> moved around so much).
> 
> Could you also tell me how (on which SoC/board and with what drivers) are
> you testing these changes? I've tried to test v7 with FIMC and MFC devices
> (on EXYNOS4210 based Universal C210 board) but as soon as I added actual
> IOMMU mappings (none of your patches in this series does it BTW) I've
> encountered problems (namely lockup related to clocks usage, probably
> related to "master" clock, I haven't had time to debug it further yet).
> 

I am just testing if each System MMU is correctly enabled and disabled or page
tables are consistently managed. I does not run MFC nor FIMC with System MMU.

Please let me know if you found the problem.

> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
> 
> > Signed-off-by: Cho KyongHo <[e-mail]>
> > ---
> >  drivers/iommu/exynos-iommu.c |  708 ++++++++++++++++++++++++++++++++---------
> >  1 files changed, 552 insertions(+), 156 deletions(-)
> >
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index f9853fe..c62c244 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -27,6 +27,9 @@
> >  #include <linux/memblock.h>
> >  #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>
> >  #include <asm/pgtable.h>
> > @@ -80,7 +83,13 @@
> >  #define CTRL_BLOCK	0x7
> >  #define CTRL_DISABLE	0x0
> >
> > +#define CFG_LRU		0x1
> > +#define CFG_QOS(n)	((n & 0xF) << 7)
> > +#define CFG_MASK	0x0150FFFF /* Selecting bit 0-15, 20, 22 and 24 */
> > +#define CFG_ACGEN	(1 << 24) /* System MMU 3.3 only */
> > +#define CFG_SYSSEL	(1 << 22) /* System MMU 3.2 only */
> >  #define CFG_FLPDCACHE	(1 << 20) /* System MMU 3.2+ only */
> > +#define CFG_SHAREABLE	(1 << 12) /* System MMU 3.x only */
> >
> >  #define REG_MMU_CTRL		0x000
> >  #define REG_MMU_CFG		0x004
> > @@ -154,6 +163,14 @@ static char *sysmmu_fault_name[SYSMMU_FAULTS_NUM] = {
> >  	"UNKNOWN FAULT"
> >  };
> >
> > +struct exynos_iommu_client {
> > +	struct list_head node;	/* entry of exynos_iommu_domain.clients */
> > +	struct device *dev;
> > +	spinlock_t lock;
> > +	int num_sysmmu;
> > +	struct device *sysmmu[0];
> > +};
> > +
> >  struct exynos_iommu_domain {
> >  	struct list_head clients; /* list of sysmmu_drvdata.node */
> >  	unsigned long *pgtable; /* lv1 page table, 16KB */
> > @@ -165,12 +182,14 @@ struct exynos_iommu_domain {
> >  struct sysmmu_drvdata {
> >  	struct list_head node; /* entry of exynos_iommu_domain.clients */
> >  	struct device *sysmmu;	/* System MMU's device descriptor */
> > -	struct device *dev;	/* Owner of system MMU */
> > +	struct device *master;	/* Owner of system MMU */
> >  	int nsfrs;
> >  	struct clk *clk;
> > +	struct clk *clk_master;
> >  	int activations;
> >  	rwlock_t lock;
> >  	struct iommu_domain *domain;
> > +	bool runtime_active;
> >  	unsigned long pgtable;
> >  	void __iomem *sfrbases[0];
> >  };
> > @@ -245,7 +264,6 @@ static void __sysmmu_tlb_invalidate_entry(void __iomem *sfrbase,
> >  static void __sysmmu_set_ptbase(void __iomem *sfrbase,
> >  				       unsigned long pgd)
> >  {
> > -	__raw_writel(0x1, sfrbase + REG_MMU_CFG); /* 16KB LV1, LRU */
> >  	__raw_writel(pgd, sfrbase + REG_PT_BASE_ADDR);
> >
> >  	__sysmmu_tlb_invalidate(sfrbase);
> > @@ -273,6 +291,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
> >  	if (!is_sysmmu_active(data))
> >  		goto finish;
> >
> > +	clk_enable(data->clk_master);
> >  	for (i = 0; i < data->nsfrs; i++) {
> >  		if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
> >  			if (!sysmmu_block(data->sfrbases[i]))
> > @@ -298,6 +317,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
> >  			sysmmu_unblock(data->sfrbases[i]);
> >  		}
> >  	}
> > +	clk_disable(data->clk_master);
> >  finish:
> >  	read_unlock_irqrestore(&data->lock, flags);
> >  }
> > @@ -331,12 +351,13 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >  {
> >  	/* SYSMMU is in blocked when interrupt occurred. */
> >  	struct sysmmu_drvdata *data = dev_id;
> > +	struct exynos_iommu_client *client = NULL;
> >  	enum exynos_sysmmu_inttype itype;
> >  	unsigned long addr = -1;
> > -
> >  	int i, ret = -ENOSYS;
> >
> > -	read_lock(&data->lock);
> > +	if (data->master)
> > +		client = data->master->archdata.iommu;
> >
> >  	WARN_ON(!is_sysmmu_active(data));
> >
> > @@ -348,6 +369,10 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >  			break;
> >  	}
> >
> > +	if (client)
> > +		spin_lock(&client->lock);
> > +	read_lock(&data->lock);
> > +
> >  	if (i == data->nsfrs) {
> >  		itype = SYSMMU_FAULT_UNKNOWN;
> >  	} else {
> > @@ -361,7 +386,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >  	}
> >
> >  	if (data->domain)
> > -		ret = report_iommu_fault(data->domain, data->dev,
> > +		ret = report_iommu_fault(data->domain, data->master,
> >  				addr, itype);
> >
> >  	if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
> > @@ -378,177 +403,251 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >  		sysmmu_unblock(data->sfrbases[i]);
> >
> >  	read_unlock(&data->lock);
> > +	if (client)
> > +		spin_unlock(&client->lock);
> >
> >  	return IRQ_HANDLED;
> >  }
> >
> > -static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
> > +static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
> >  {
> > -	unsigned long flags;
> > -	bool disabled = false;
> >  	int i;
> >
> > -	write_lock_irqsave(&data->lock, flags);
> > +	clk_enable(data->clk_master);
> > +	for (i = 0; i < data->nsfrs; i++) {
> > +		__raw_writel(CTRL_DISABLE,
> > +				data->sfrbases[i] + REG_MMU_CTRL);
> > +		__raw_writel(0, data->sfrbases[i] + REG_MMU_CFG);
> > +	}
> >
> > -	if (!set_sysmmu_inactive(data))
> > -		goto finish;
> > +	clk_disable(data->clk);
> > +	clk_disable(data->clk_master);
> > +}
> >
> > -	for (i = 0; i < data->nsfrs; i++)
> > -		__raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > +static bool __sysmmu_disable(struct sysmmu_drvdata *data)
> > +{
> > +	bool disabled;
> > +	unsigned long flags;
> >
> > -	if (data->clk)
> > -		clk_disable(data->clk);
> > +	write_lock_irqsave(&data->lock, flags);
> >
> > -	disabled = true;
> > -	data->pgtable = 0;
> > -	data->domain = NULL;
> > -finish:
> > -	write_unlock_irqrestore(&data->lock, flags);
> > +	disabled = set_sysmmu_inactive(data);
> > +
> > +	if (disabled) {
> > +		data->pgtable = 0;
> > +		data->domain = NULL;
> > +
> > +		if (data->runtime_active)
> > +			__sysmmu_disable_nocount(data);
> >
> > -	if (disabled)
> >  		dev_dbg(data->sysmmu, "Disabled\n");
> > -	else
> > -		dev_dbg(data->sysmmu, "%d times left to be disabled\n",
> > +	} else  {
> > +		dev_dbg(data->sysmmu, "%d times left to disable\n",
> >  					data->activations);
> > +	}
> > +
> > +	write_unlock_irqrestore(&data->lock, flags);
> >
> >  	return disabled;
> >  }
> >
> > -/* __exynos_sysmmu_enable: Enables System MMU
> > - *
> > - * returns -error if an error occurred and System MMU is not enabled,
> > - * 0 if the System MMU has been just enabled and 1 if System MMU was already
> > - * enabled before.
> > - */
> > -static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> > +
> > +static void __sysmmu_init_config(struct sysmmu_drvdata *data, int idx)
> > +{
> > +	unsigned long cfg = CFG_LRU | CFG_QOS(15);
> > +	int maj, min = 0;
> > +
> > +	maj = __sysmmu_version(data, idx, &min);
> > +	if (maj == 3) {
> > +		if (min > 1) {
> > +			cfg |= CFG_FLPDCACHE;
> > +			cfg |= (min == 2) ? CFG_SYSSEL : CFG_ACGEN;
> > +		}
> > +	}
> > +
> > +	__raw_writel(cfg, data->sfrbases[idx] + REG_MMU_CFG);
> > +}
> > +
> > +static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
> > +{
> > +	int i;
> > +
> > +	clk_enable(data->clk_master);
> > +	clk_enable(data->clk);
> > +
> > +	for (i = 0; i < data->nsfrs; i++) {
> > +		__raw_writel(CTRL_BLOCK, data->sfrbases[i] + REG_MMU_CTRL);
> > +
> > +		__sysmmu_init_config(data, i);
> > +
> > +		__sysmmu_set_ptbase(data->sfrbases[i], data->pgtable);
> > +
> > +		__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > +	}
> > +	clk_disable(data->clk_master);
> > +}
> > +
> > +static int __sysmmu_enable(struct sysmmu_drvdata *data,
> >  			unsigned long pgtable, struct iommu_domain *domain)
> >  {
> > -	int i, ret = 0;
> > +	int ret = 0;
> >  	unsigned long flags;
> >
> >  	write_lock_irqsave(&data->lock, flags);
> > +	if (set_sysmmu_active(data)) {
> > +		data->pgtable = pgtable;
> > +		data->domain = domain;
> >
> > -	if (!set_sysmmu_active(data)) {
> > -		if (WARN_ON(pgtable != data->pgtable)) {
> > -			ret = -EBUSY;
> > -			set_sysmmu_inactive(data);
> > -		} else {
> > -			ret = 1;
> > -		}
> > +		if (data->runtime_active)
> > +			__sysmmu_enable_nocount(data);
> >
> > -		dev_dbg(data->sysmmu, "Already enabled\n");
> > -		goto finish;
> > +		dev_dbg(data->sysmmu, "Enabled\n");
> > +	} else {
> > +		ret = (pgtable == data->pgtable) ? 1 : -EBUSY;
> > +
> > +		dev_dbg(data->sysmmu, "already enabled\n");
> >  	}
> >
> > -	if (data->clk)
> > -		clk_enable(data->clk);
> > +	if (WARN_ON(ret < 0))
> > +		set_sysmmu_inactive(data); /* decrement count */
> >
> > -	data->pgtable = pgtable;
> > +	write_unlock_irqrestore(&data->lock, flags);
> >
> > -	for (i = 0; i < data->nsfrs; i++) {
> > -		unsigned int min;
> > +	return ret;
> > +}
> >
> > -		__sysmmu_set_ptbase(data->sfrbases[i], pgtable);
> > +/* __exynos_sysmmu_enable: Enables System MMU
> > + *
> > + * returns -error if an error occurred and System MMU is not enabled,
> > + * 0 if the System MMU has been just enabled and 1 if System MMU was already
> > + * enabled before.
> > + */
> > +static int __exynos_sysmmu_enable(struct device *dev, unsigned long pgtable,
> > +				  struct iommu_domain *domain)
> > +{
> > +	int ret = 0;
> > +	unsigned long flags;
> > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > +	int i;
> >
> > -		if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
> > -			unsigned long cfg;
> > -			cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
> > -			__raw_writel(cfg | CFG_FLPDCACHE,
> > -					data->sfrbases[i] + REG_MMU_CFG);
> > -		}
> > +	if (WARN_ON(!client))
> > +		return -ENODEV;
> >
> > -		__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
> > -	}
> > +	spin_lock_irqsave(&client->lock, flags);
> >
> > -	data->domain = domain;
> > +	for (i = 0; i < client->num_sysmmu; i++) {
> > +		struct sysmmu_drvdata *data =
> > +				dev_get_drvdata(client->sysmmu[i]);
> > +		ret = __sysmmu_enable(data, pgtable, domain);
> > +		if (ret < 0) {
> > +			int j;
> > +			for (j = 0; j < i; j++)
> > +				__sysmmu_disable(data);
> > +			break;
> > +		} else {
> > +			data->master = dev;
> > +		}
> > +	}
> >
> > -	dev_dbg(data->sysmmu, "Enabled\n");
> > -finish:
> > -	write_unlock_irqrestore(&data->lock, flags);
> > +	spin_unlock_irqrestore(&client->lock, flags);
> >
> >  	return ret;
> >  }
> >
> >  int exynos_sysmmu_enable(struct device *dev, unsigned long pgtable)
> >  {
> > -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> >  	int ret;
> >
> >  	BUG_ON(!memblock_is_memory(pgtable));
> >
> > -	ret = pm_runtime_get_sync(data->sysmmu);
> > -	if (ret < 0) {
> > -		dev_dbg(data->sysmmu, "Failed to enable\n");
> > -		return ret;
> > -	}
> > -
> > -	ret = __exynos_sysmmu_enable(data, pgtable, NULL);
> > -	if (WARN_ON(ret < 0)) {
> > -		pm_runtime_put(data->sysmmu);
> > -		dev_err(data->sysmmu,
> > -			"Already enabled with page table %#lx\n",
> > -			data->pgtable);
> > -	} else {
> > -		data->dev = dev;
> > -	}
> > +	ret = __exynos_sysmmu_enable(dev, pgtable, NULL);
> >
> >  	return ret;
> >  }
> >
> >  static bool exynos_sysmmu_disable(struct device *dev)
> >  {
> > -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > -	bool disabled;
> > +	unsigned long flags;
> > +	bool disabled = true;
> > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > +	int i;
> >
> > -	disabled = __exynos_sysmmu_disable(data);
> > -	pm_runtime_put(data->sysmmu);
> > +	if (WARN_ON(!client))
> > +		return true;
> > +
> > +	spin_lock_irqsave(&client->lock, flags);
> > +
> > +	/* Every call to __sysmmu_disable() must return same result */
> > +	for (i = 0; i < client->num_sysmmu; i++) {
> > +		struct sysmmu_drvdata *data =
> > +				dev_get_drvdata(client->sysmmu[i]);
> > +		disabled = __sysmmu_disable(data);
> > +		if (disabled)
> > +			data->master = NULL;
> > +	}
> > +
> > +	spin_unlock_irqrestore(&client->lock, flags);
> >
> >  	return disabled;
> >  }
> >
> >  static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
> >  {
> > -	unsigned long flags;
> > -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > +	int i;
> >
> > -	read_lock_irqsave(&data->lock, flags);
> > +	for (i = 0; i < client->num_sysmmu; i++) {
> > +		unsigned long flags;
> > +		struct sysmmu_drvdata *data;
> >
> > -	if (is_sysmmu_active(data)) {
> > -		int i;
> > -		for (i = 0; i < data->nsfrs; i++) {
> > -			if (sysmmu_block(data->sfrbases[i])) {
> > +		data = dev_get_drvdata(client->sysmmu[i]);
> > +
> > +		read_lock_irqsave(&data->lock, flags);
> > +		if (is_sysmmu_active(data) && data->runtime_active) {
> > +			int i;
> > +			clk_enable(data->clk_master);
> > +			for (i = 0; i < data->nsfrs; i++)
> >  				__sysmmu_tlb_invalidate_entry(
> >  						data->sfrbases[i], iova);
> > -				sysmmu_unblock(data->sfrbases[i]);
> > -			}
> > +			clk_disable(data->clk_master);
> > +		} else {
> > +			dev_dbg(dev,
> > +				"disabled. Skipping TLB invalidation @ %#lx\n",
> > +				iova);
> >  		}
> > -	} else {
> > -		dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> > +		read_unlock_irqrestore(&data->lock, flags);
> >  	}
> > -
> > -	read_unlock_irqrestore(&data->lock, flags);
> >  }
> >
> >  void exynos_sysmmu_tlb_invalidate(struct device *dev)
> >  {
> > -	unsigned long flags;
> > -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > -
> > -	read_lock_irqsave(&data->lock, flags);
> > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> > +	int i;
> >
> > -	if (is_sysmmu_active(data)) {
> > -		int i;
> > -		for (i = 0; i < data->nsfrs; i++) {
> > -			if (sysmmu_block(data->sfrbases[i])) {
> > -				__sysmmu_tlb_invalidate(data->sfrbases[i]);
> > -				sysmmu_unblock(data->sfrbases[i]);
> > +	for (i = 0; i < client->num_sysmmu; i++) {
> > +		unsigned long flags;
> > +		struct sysmmu_drvdata *data;
> > +
> > +		data = dev_get_drvdata(client->sysmmu[i]);
> > +
> > +		read_lock_irqsave(&data->lock, flags);
> > +		if (is_sysmmu_active(data) &&
> > +				data->runtime_active) {
> > +			int i;
> > +			for (i = 0; i < data->nsfrs; i++) {
> > +				clk_enable(data->clk_master);
> > +				if (sysmmu_block(data->sfrbases[i])) {
> > +					__sysmmu_tlb_invalidate(
> > +							data->sfrbases[i]);
> > +					sysmmu_unblock(data->sfrbases[i]);
> > +				}
> > +				clk_disable(data->clk_master);
> >  			}
> > +		} else {
> > +			dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
> >  		}
> > -	} else {
> > -		dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
> > +		read_unlock_irqrestore(&data->lock, flags);
> >  	}
> > -
> > -	read_unlock_irqrestore(&data->lock, flags);
> >  }
> >
> >  static int __init exynos_sysmmu_probe(struct platform_device *pdev)
> > @@ -610,12 +709,32 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
> >  	pm_runtime_enable(dev);
> >
> >  	data->sysmmu = dev;
> > +
> >  	data->clk = devm_clk_get(dev, "sysmmu");
> >  	if (IS_ERR(data->clk)) {
> >  		dev_info(dev, "No gate clock found!\n");
> >  		data->clk = NULL;
> >  	}
> >
> > +	ret = clk_prepare(data->clk);
> > +	if (ret) {
> > +		dev_err(dev, "Failed to prepare clk\n");
> > +		return ret;
> > +	}
> > +
> > +	data->clk_master = devm_clk_get(dev, "master");
> > +	if (IS_ERR(data->clk_master))
> > +		data->clk_master = NULL;
> > +
> > +	ret = clk_prepare(data->clk_master);
> > +	if (ret) {
> > +		clk_unprepare(data->clk);
> > +		dev_err(dev, "Failed to prepare master's clk\n");
> > +		return ret;
> > +	}
> > +
> > +	data->runtime_active = !pm_runtime_enabled(dev);
> > +
> >  	rwlock_init(&data->lock);
> >  	INIT_LIST_HEAD(&data->node);
> >
> > @@ -625,6 +744,34 @@ 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", },
> > @@ -637,6 +784,7 @@ 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),
> >  	}
> >  };
> > @@ -689,7 +837,7 @@ err_pgtable:
> >  static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
> >  {
> >  	struct exynos_iommu_domain *priv = domain->priv;
> > -	struct sysmmu_drvdata *data;
> > +	struct exynos_iommu_client *client;
> >  	unsigned long flags;
> >  	int i;
> >
> > @@ -697,11 +845,14 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
> >
> >  	spin_lock_irqsave(&priv->lock, flags);
> >
> > -	list_for_each_entry(data, &priv->clients, node) {
> > -		while (!exynos_sysmmu_disable(data->dev))
> > +	list_for_each_entry(client, &priv->clients, node) {
> > +		while (!exynos_sysmmu_disable(client->dev))
> >  			; /* until System MMU is actually disabled */
> >  	}
> >
> > +	while (!list_empty(&priv->clients))
> > +		list_del_init(priv->clients.next);
> > +
> >  	spin_unlock_irqrestore(&priv->lock, flags);
> >
> >  	for (i = 0; i < NUM_LV1ENTRIES; i++)
> > @@ -718,41 +869,26 @@ static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
> >  static int exynos_iommu_attach_device(struct iommu_domain *domain,
> >  				   struct device *dev)
> >  {
> > -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > +	struct exynos_iommu_client *client = dev->archdata.iommu;
> >  	struct exynos_iommu_domain *priv = domain->priv;
> >  	unsigned long flags;
> >  	int ret;
> >
> > -	ret = pm_runtime_get_sync(data->sysmmu);
> > -	if (ret < 0)
> > -		return ret;
> > -
> > -	ret = 0;
> > -
> >  	spin_lock_irqsave(&priv->lock, flags);
> >
> > -	ret = __exynos_sysmmu_enable(data, __pa(priv->pgtable), domain);
> > -
> > -	if (ret == 0) {
> > -		/* 'data->node' must not be appeared in priv->clients */
> > -		BUG_ON(!list_empty(&data->node));
> > -		data->dev = dev;
> > -		list_add_tail(&data->node, &priv->clients);
> > -	}
> > +	ret = __exynos_sysmmu_enable(dev, __pa(priv->pgtable), domain);
> > +	if (ret == 0)
> > +		list_add_tail(&client->node, &priv->clients);
> >
> >  	spin_unlock_irqrestore(&priv->lock, flags);
> >
> > -	if (ret < 0) {
> > +	if (ret < 0)
> >  		dev_err(dev, "%s: Failed to attach IOMMU with pgtable %#lx\n",
> >  				__func__, __pa(priv->pgtable));
> > -		pm_runtime_put(data->sysmmu);
> > -	} else if (ret > 0) {
> > -		dev_dbg(dev, "%s: IOMMU with pgtable 0x%lx already attached\n",
> > -					__func__, __pa(priv->pgtable));
> > -	} else {
> > -		dev_dbg(dev, "%s: Attached new IOMMU with pgtable 0x%lx\n",
> > -					__func__, __pa(priv->pgtable));
> > -	}
> > +	else
> > +		dev_dbg(dev, "%s: Attached IOMMU with pgtable 0x%lx%s\n",
> > +					__func__, __pa(priv->pgtable),
> > +					(ret == 0) ? "" : ", again");
> >
> >  	return ret;
> >  }
> > @@ -760,39 +896,27 @@ static int exynos_iommu_attach_device(struct iommu_domain *domain,
> >  static void exynos_iommu_detach_device(struct iommu_domain *domain,
> >  				    struct device *dev)
> >  {
> > -	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
> > +	struct exynos_iommu_client *client = NULL;
> >  	struct exynos_iommu_domain *priv = domain->priv;
> > -	struct list_head *pos;
> >  	unsigned long flags;
> > -	bool found = false;
> >
> >  	spin_lock_irqsave(&priv->lock, flags);
> >
> > -	list_for_each(pos, &priv->clients) {
> > -		if (list_entry(pos, struct sysmmu_drvdata, node) == data) {
> > -			found = true;
> > +	list_for_each_entry(client, &priv->clients, node) {
> > +		if (client == dev->archdata.iommu) {
> > +			if (exynos_sysmmu_disable(dev))
> > +				list_del_init(&client->node);
> >  			break;
> >  		}
> >  	}
> >
> > -	if (!found)
> > -		goto finish;
> > +	spin_unlock_irqrestore(&priv->lock, flags);
> >
> > -	if (__exynos_sysmmu_disable(data)) {
> > +	if (client == dev->archdata.iommu)
> >  		dev_dbg(dev, "%s: Detached IOMMU with pgtable %#lx\n",
> >  					__func__, __pa(priv->pgtable));
> > -		list_del_init(&data->node);
> > -
> > -	} else {
> > -		dev_dbg(dev, "%s: Detaching IOMMU with pgtable %#lx delayed",
> > -					__func__, __pa(priv->pgtable));
> > -	}
> > -
> > -finish:
> > -	spin_unlock_irqrestore(&priv->lock, flags);
> > -
> > -	if (found)
> > -		pm_runtime_put(data->sysmmu);
> > +	else
> > +		dev_dbg(dev, "%s: No IOMMU is attached\n", __func__);
> >  }
> >
> >  static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
> > @@ -914,7 +1038,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
> >  					       unsigned long iova, size_t size)
> >  {
> >  	struct exynos_iommu_domain *priv = domain->priv;
> > -	struct sysmmu_drvdata *data;
> > +	struct exynos_iommu_client *client;
> >  	unsigned long flags;
> >  	unsigned long *ent;
> >  	size_t err_pgsize;
> > @@ -975,8 +1099,8 @@ done:
> >  	spin_unlock_irqrestore(&priv->pgtablelock, flags);
> >
> >  	spin_lock_irqsave(&priv->lock, flags);
> > -	list_for_each_entry(data, &priv->clients, node)
> > -		sysmmu_tlb_invalidate_entry(data->dev, iova);
> > +	list_for_each_entry(client, &priv->clients, node)
> > +		sysmmu_tlb_invalidate_entry(client->dev, iova);
> >  	spin_unlock_irqrestore(&priv->lock, flags);
> >
> >  	return size;
> > @@ -1055,3 +1179,275 @@ static int __init exynos_iommu_init(void)
> >  	return ret;
> >  }
> >  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)
> > +{
> > +	struct device *dev = p;
> > +
> > +	switch (val) {
> > +	case BUS_NOTIFY_BIND_DRIVER:
> > +	{
> > +		int i = 0;
> > +		int size = 0;
> > +		const __be32 *phandle;
> > +		struct exynos_iommu_client *client;
> > +
> > +		phandle = of_get_property(dev->of_node, "iommu", &size);
> > +		if (!phandle)
> > +			break;
> > +
> > +		size = size / sizeof(*phandle); /* number of elements */
> > +
> > +		client = devm_kzalloc(dev, sizeof(*client) * size, GFP_KERNEL);
> > +		if (!client) {
> > +			dev_err(dev, "No Memory for exynos_iommu_client\n");
> > +			return -ENOMEM;
> > +		}
> > +
> > +		client->num_sysmmu = size;
> > +		client->dev = dev;
> > +		INIT_LIST_HEAD(&client->node);
> > +		spin_lock_init(&client->lock);
> > +
> > +		for (i = 0; i < size; i++) {
> > +			struct device_node *np;
> > +			struct platform_device *sysmmu;
> > +
> > +			/* this always success: see above of_find_property() */
> > +			np = of_parse_phandle(dev->of_node, "iommu", i);
> > +
> > +			sysmmu = of_find_device_by_node(np);
> > +			if (!sysmmu) {
> > +				dev_err(dev,
> > +					"sysmmu node '%s' is not found\n",
> > +					np->name);
> > +				break;
> > +			}
> > +
> > +			client->sysmmu[i] = &sysmmu->dev;
> > +		}
> > +
> > +		if (i < size) {
> > +			while (--i >= 0)
> > +				of_node_put(client->sysmmu[i]->of_node);
> > +			devm_kfree(dev, client);
> > +			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;
> > +		}
> > +		break;
> > +	}
> > +	} /* switch (val) */
> > +
> > +	return 0;
> > +}
> > +
> > +static struct notifier_block sysmmu_notifier = {
> > +	.notifier_call = &sysmmu_hook_driver_register,
> > +};
> > +
> > +static int __init exynos_iommu_prepare(void)
> > +{
> > +	return bus_register_notifier(&platform_bus_type, &sysmmu_notifier);
> > +}
> > +arch_initcall(exynos_iommu_prepare);

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Patch

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index f9853fe..c62c244 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -27,6 +27,9 @@ 
 #include <linux/memblock.h>
 #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>
 #include <asm/pgtable.h>
@@ -80,7 +83,13 @@ 
 #define CTRL_BLOCK	0x7
 #define CTRL_DISABLE	0x0
 
+#define CFG_LRU		0x1
+#define CFG_QOS(n)	((n & 0xF) << 7)
+#define CFG_MASK	0x0150FFFF /* Selecting bit 0-15, 20, 22 and 24 */
+#define CFG_ACGEN	(1 << 24) /* System MMU 3.3 only */
+#define CFG_SYSSEL	(1 << 22) /* System MMU 3.2 only */
 #define CFG_FLPDCACHE	(1 << 20) /* System MMU 3.2+ only */
+#define CFG_SHAREABLE	(1 << 12) /* System MMU 3.x only */
 
 #define REG_MMU_CTRL		0x000
 #define REG_MMU_CFG		0x004
@@ -154,6 +163,14 @@  static char *sysmmu_fault_name[SYSMMU_FAULTS_NUM] = {
 	"UNKNOWN FAULT"
 };
 
+struct exynos_iommu_client {
+	struct list_head node;	/* entry of exynos_iommu_domain.clients */
+	struct device *dev;
+	spinlock_t lock;
+	int num_sysmmu;
+	struct device *sysmmu[0];
+};
+
 struct exynos_iommu_domain {
 	struct list_head clients; /* list of sysmmu_drvdata.node */
 	unsigned long *pgtable; /* lv1 page table, 16KB */
@@ -165,12 +182,14 @@  struct exynos_iommu_domain {
 struct sysmmu_drvdata {
 	struct list_head node; /* entry of exynos_iommu_domain.clients */
 	struct device *sysmmu;	/* System MMU's device descriptor */
-	struct device *dev;	/* Owner of system MMU */
+	struct device *master;	/* Owner of system MMU */
 	int nsfrs;
 	struct clk *clk;
+	struct clk *clk_master;
 	int activations;
 	rwlock_t lock;
 	struct iommu_domain *domain;
+	bool runtime_active;
 	unsigned long pgtable;
 	void __iomem *sfrbases[0];
 };
@@ -245,7 +264,6 @@  static void __sysmmu_tlb_invalidate_entry(void __iomem *sfrbase,
 static void __sysmmu_set_ptbase(void __iomem *sfrbase,
 				       unsigned long pgd)
 {
-	__raw_writel(0x1, sfrbase + REG_MMU_CFG); /* 16KB LV1, LRU */
 	__raw_writel(pgd, sfrbase + REG_PT_BASE_ADDR);
 
 	__sysmmu_tlb_invalidate(sfrbase);
@@ -273,6 +291,7 @@  void exynos_sysmmu_set_prefbuf(struct device *dev,
 	if (!is_sysmmu_active(data))
 		goto finish;
 
+	clk_enable(data->clk_master);
 	for (i = 0; i < data->nsfrs; i++) {
 		if ((readl(data->sfrbases[i] + REG_MMU_VERSION) >> 28) == 3) {
 			if (!sysmmu_block(data->sfrbases[i]))
@@ -298,6 +317,7 @@  void exynos_sysmmu_set_prefbuf(struct device *dev,
 			sysmmu_unblock(data->sfrbases[i]);
 		}
 	}
+	clk_disable(data->clk_master);
 finish:
 	read_unlock_irqrestore(&data->lock, flags);
 }
@@ -331,12 +351,13 @@  static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 {
 	/* SYSMMU is in blocked when interrupt occurred. */
 	struct sysmmu_drvdata *data = dev_id;
+	struct exynos_iommu_client *client = NULL;
 	enum exynos_sysmmu_inttype itype;
 	unsigned long addr = -1;
-
 	int i, ret = -ENOSYS;
 
-	read_lock(&data->lock);
+	if (data->master)
+		client = data->master->archdata.iommu;
 
 	WARN_ON(!is_sysmmu_active(data));
 
@@ -348,6 +369,10 @@  static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 			break;
 	}
 
+	if (client)
+		spin_lock(&client->lock);
+	read_lock(&data->lock);
+
 	if (i == data->nsfrs) {
 		itype = SYSMMU_FAULT_UNKNOWN;
 	} else {
@@ -361,7 +386,7 @@  static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 	}
 
 	if (data->domain)
-		ret = report_iommu_fault(data->domain, data->dev,
+		ret = report_iommu_fault(data->domain, data->master,
 				addr, itype);
 
 	if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
@@ -378,177 +403,251 @@  static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 		sysmmu_unblock(data->sfrbases[i]);
 
 	read_unlock(&data->lock);
+	if (client)
+		spin_unlock(&client->lock);
 
 	return IRQ_HANDLED;
 }
 
-static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
+static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
 {
-	unsigned long flags;
-	bool disabled = false;
 	int i;
 
-	write_lock_irqsave(&data->lock, flags);
+	clk_enable(data->clk_master);
+	for (i = 0; i < data->nsfrs; i++) {
+		__raw_writel(CTRL_DISABLE,
+				data->sfrbases[i] + REG_MMU_CTRL);
+		__raw_writel(0, data->sfrbases[i] + REG_MMU_CFG);
+	}
 
-	if (!set_sysmmu_inactive(data))
-		goto finish;
+	clk_disable(data->clk);
+	clk_disable(data->clk_master);
+}
 
-	for (i = 0; i < data->nsfrs; i++)
-		__raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
+static bool __sysmmu_disable(struct sysmmu_drvdata *data)
+{
+	bool disabled;
+	unsigned long flags;
 
-	if (data->clk)
-		clk_disable(data->clk);
+	write_lock_irqsave(&data->lock, flags);
 
-	disabled = true;
-	data->pgtable = 0;
-	data->domain = NULL;
-finish:
-	write_unlock_irqrestore(&data->lock, flags);
+	disabled = set_sysmmu_inactive(data);
+
+	if (disabled) {
+		data->pgtable = 0;
+		data->domain = NULL;
+
+		if (data->runtime_active)
+			__sysmmu_disable_nocount(data);
 
-	if (disabled)
 		dev_dbg(data->sysmmu, "Disabled\n");
-	else
-		dev_dbg(data->sysmmu, "%d times left to be disabled\n",
+	} else  {
+		dev_dbg(data->sysmmu, "%d times left to disable\n",
 					data->activations);
+	}
+
+	write_unlock_irqrestore(&data->lock, flags);
 
 	return disabled;
 }
 
-/* __exynos_sysmmu_enable: Enables System MMU
- *
- * returns -error if an error occurred and System MMU is not enabled,
- * 0 if the System MMU has been just enabled and 1 if System MMU was already
- * enabled before.
- */
-static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
+
+static void __sysmmu_init_config(struct sysmmu_drvdata *data, int idx)
+{
+	unsigned long cfg = CFG_LRU | CFG_QOS(15);
+	int maj, min = 0;
+
+	maj = __sysmmu_version(data, idx, &min);
+	if (maj == 3) {
+		if (min > 1) {
+			cfg |= CFG_FLPDCACHE;
+			cfg |= (min == 2) ? CFG_SYSSEL : CFG_ACGEN;
+		}
+	}
+
+	__raw_writel(cfg, data->sfrbases[idx] + REG_MMU_CFG);
+}
+
+static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
+{
+	int i;
+
+	clk_enable(data->clk_master);
+	clk_enable(data->clk);
+
+	for (i = 0; i < data->nsfrs; i++) {
+		__raw_writel(CTRL_BLOCK, data->sfrbases[i] + REG_MMU_CTRL);
+
+		__sysmmu_init_config(data, i);
+
+		__sysmmu_set_ptbase(data->sfrbases[i], data->pgtable);
+
+		__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
+	}
+	clk_disable(data->clk_master);
+}
+
+static int __sysmmu_enable(struct sysmmu_drvdata *data,
 			unsigned long pgtable, struct iommu_domain *domain)
 {
-	int i, ret = 0;
+	int ret = 0;
 	unsigned long flags;
 
 	write_lock_irqsave(&data->lock, flags);
+	if (set_sysmmu_active(data)) {
+		data->pgtable = pgtable;
+		data->domain = domain;
 
-	if (!set_sysmmu_active(data)) {
-		if (WARN_ON(pgtable != data->pgtable)) {
-			ret = -EBUSY;
-			set_sysmmu_inactive(data);
-		} else {
-			ret = 1;
-		}
+		if (data->runtime_active)
+			__sysmmu_enable_nocount(data);
 
-		dev_dbg(data->sysmmu, "Already enabled\n");
-		goto finish;
+		dev_dbg(data->sysmmu, "Enabled\n");
+	} else {
+		ret = (pgtable == data->pgtable) ? 1 : -EBUSY;
+
+		dev_dbg(data->sysmmu, "already enabled\n");
 	}
 
-	if (data->clk)
-		clk_enable(data->clk);
+	if (WARN_ON(ret < 0))
+		set_sysmmu_inactive(data); /* decrement count */
 
-	data->pgtable = pgtable;
+	write_unlock_irqrestore(&data->lock, flags);
 
-	for (i = 0; i < data->nsfrs; i++) {
-		unsigned int min;
+	return ret;
+}
 
-		__sysmmu_set_ptbase(data->sfrbases[i], pgtable);
+/* __exynos_sysmmu_enable: Enables System MMU
+ *
+ * returns -error if an error occurred and System MMU is not enabled,
+ * 0 if the System MMU has been just enabled and 1 if System MMU was already
+ * enabled before.
+ */
+static int __exynos_sysmmu_enable(struct device *dev, unsigned long pgtable,
+				  struct iommu_domain *domain)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int i;
 
-		if ((__sysmmu_version(data, i, &min) == 3) && (min > 1)) {
-			unsigned long cfg;
-			cfg = __raw_readl(data->sfrbases[i] + REG_MMU_CFG);
-			__raw_writel(cfg | CFG_FLPDCACHE,
-					data->sfrbases[i] + REG_MMU_CFG);
-		}
+	if (WARN_ON(!client))
+		return -ENODEV;
 
-		__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
-	}
+	spin_lock_irqsave(&client->lock, flags);
 
-	data->domain = domain;
+	for (i = 0; i < client->num_sysmmu; i++) {
+		struct sysmmu_drvdata *data =
+				dev_get_drvdata(client->sysmmu[i]);
+		ret = __sysmmu_enable(data, pgtable, domain);
+		if (ret < 0) {
+			int j;
+			for (j = 0; j < i; j++)
+				__sysmmu_disable(data);
+			break;
+		} else {
+			data->master = dev;
+		}
+	}
 
-	dev_dbg(data->sysmmu, "Enabled\n");
-finish:
-	write_unlock_irqrestore(&data->lock, flags);
+	spin_unlock_irqrestore(&client->lock, flags);
 
 	return ret;
 }
 
 int exynos_sysmmu_enable(struct device *dev, unsigned long pgtable)
 {
-	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
 	int ret;
 
 	BUG_ON(!memblock_is_memory(pgtable));
 
-	ret = pm_runtime_get_sync(data->sysmmu);
-	if (ret < 0) {
-		dev_dbg(data->sysmmu, "Failed to enable\n");
-		return ret;
-	}
-
-	ret = __exynos_sysmmu_enable(data, pgtable, NULL);
-	if (WARN_ON(ret < 0)) {
-		pm_runtime_put(data->sysmmu);
-		dev_err(data->sysmmu,
-			"Already enabled with page table %#lx\n",
-			data->pgtable);
-	} else {
-		data->dev = dev;
-	}
+	ret = __exynos_sysmmu_enable(dev, pgtable, NULL);
 
 	return ret;
 }
 
 static bool exynos_sysmmu_disable(struct device *dev)
 {
-	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
-	bool disabled;
+	unsigned long flags;
+	bool disabled = true;
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int i;
 
-	disabled = __exynos_sysmmu_disable(data);
-	pm_runtime_put(data->sysmmu);
+	if (WARN_ON(!client))
+		return true;
+
+	spin_lock_irqsave(&client->lock, flags);
+
+	/* Every call to __sysmmu_disable() must return same result */
+	for (i = 0; i < client->num_sysmmu; i++) {
+		struct sysmmu_drvdata *data =
+				dev_get_drvdata(client->sysmmu[i]);
+		disabled = __sysmmu_disable(data);
+		if (disabled)
+			data->master = NULL;
+	}
+
+	spin_unlock_irqrestore(&client->lock, flags);
 
 	return disabled;
 }
 
 static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
 {
-	unsigned long flags;
-	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int i;
 
-	read_lock_irqsave(&data->lock, flags);
+	for (i = 0; i < client->num_sysmmu; i++) {
+		unsigned long flags;
+		struct sysmmu_drvdata *data;
 
-	if (is_sysmmu_active(data)) {
-		int i;
-		for (i = 0; i < data->nsfrs; i++) {
-			if (sysmmu_block(data->sfrbases[i])) {
+		data = dev_get_drvdata(client->sysmmu[i]);
+
+		read_lock_irqsave(&data->lock, flags);
+		if (is_sysmmu_active(data) && data->runtime_active) {
+			int i;
+			clk_enable(data->clk_master);
+			for (i = 0; i < data->nsfrs; i++)
 				__sysmmu_tlb_invalidate_entry(
 						data->sfrbases[i], iova);
-				sysmmu_unblock(data->sfrbases[i]);
-			}
+			clk_disable(data->clk_master);
+		} else {
+			dev_dbg(dev,
+				"disabled. Skipping TLB invalidation @ %#lx\n",
+				iova);
 		}
-	} else {
-		dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
+		read_unlock_irqrestore(&data->lock, flags);
 	}
-
-	read_unlock_irqrestore(&data->lock, flags);
 }
 
 void exynos_sysmmu_tlb_invalidate(struct device *dev)
 {
-	unsigned long flags;
-	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
-
-	read_lock_irqsave(&data->lock, flags);
+	struct exynos_iommu_client *client = dev->archdata.iommu;
+	int i;
 
-	if (is_sysmmu_active(data)) {
-		int i;
-		for (i = 0; i < data->nsfrs; i++) {
-			if (sysmmu_block(data->sfrbases[i])) {
-				__sysmmu_tlb_invalidate(data->sfrbases[i]);
-				sysmmu_unblock(data->sfrbases[i]);
+	for (i = 0; i < client->num_sysmmu; i++) {
+		unsigned long flags;
+		struct sysmmu_drvdata *data;
+
+		data = dev_get_drvdata(client->sysmmu[i]);
+
+		read_lock_irqsave(&data->lock, flags);
+		if (is_sysmmu_active(data) &&
+				data->runtime_active) {
+			int i;
+			for (i = 0; i < data->nsfrs; i++) {
+				clk_enable(data->clk_master);
+				if (sysmmu_block(data->sfrbases[i])) {
+					__sysmmu_tlb_invalidate(
+							data->sfrbases[i]);
+					sysmmu_unblock(data->sfrbases[i]);
+				}
+				clk_disable(data->clk_master);
 			}
+		} else {
+			dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
 		}
-	} else {
-		dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
+		read_unlock_irqrestore(&data->lock, flags);
 	}
-
-	read_unlock_irqrestore(&data->lock, flags);
 }
 
 static int __init exynos_sysmmu_probe(struct platform_device *pdev)
@@ -610,12 +709,32 @@  static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 	pm_runtime_enable(dev);
 
 	data->sysmmu = dev;
+
 	data->clk = devm_clk_get(dev, "sysmmu");
 	if (IS_ERR(data->clk)) {
 		dev_info(dev, "No gate clock found!\n");
 		data->clk = NULL;
 	}
 
+	ret = clk_prepare(data->clk);
+	if (ret) {
+		dev_err(dev, "Failed to prepare clk\n");
+		return ret;
+	}
+
+	data->clk_master = devm_clk_get(dev, "master");
+	if (IS_ERR(data->clk_master))
+		data->clk_master = NULL;
+
+	ret = clk_prepare(data->clk_master);
+	if (ret) {
+		clk_unprepare(data->clk);
+		dev_err(dev, "Failed to prepare master's clk\n");
+		return ret;
+	}
+
+	data->runtime_active = !pm_runtime_enabled(dev);
+
 	rwlock_init(&data->lock);
 	INIT_LIST_HEAD(&data->node);
 
@@ -625,6 +744,34 @@  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", },
@@ -637,6 +784,7 @@  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),
 	}
 };
@@ -689,7 +837,7 @@  err_pgtable:
 static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
 {
 	struct exynos_iommu_domain *priv = domain->priv;
-	struct sysmmu_drvdata *data;
+	struct exynos_iommu_client *client;
 	unsigned long flags;
 	int i;
 
@@ -697,11 +845,14 @@  static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	list_for_each_entry(data, &priv->clients, node) {
-		while (!exynos_sysmmu_disable(data->dev))
+	list_for_each_entry(client, &priv->clients, node) {
+		while (!exynos_sysmmu_disable(client->dev))
 			; /* until System MMU is actually disabled */
 	}
 
+	while (!list_empty(&priv->clients))
+		list_del_init(priv->clients.next);
+
 	spin_unlock_irqrestore(&priv->lock, flags);
 
 	for (i = 0; i < NUM_LV1ENTRIES; i++)
@@ -718,41 +869,26 @@  static void exynos_iommu_domain_destroy(struct iommu_domain *domain)
 static int exynos_iommu_attach_device(struct iommu_domain *domain,
 				   struct device *dev)
 {
-	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
+	struct exynos_iommu_client *client = dev->archdata.iommu;
 	struct exynos_iommu_domain *priv = domain->priv;
 	unsigned long flags;
 	int ret;
 
-	ret = pm_runtime_get_sync(data->sysmmu);
-	if (ret < 0)
-		return ret;
-
-	ret = 0;
-
 	spin_lock_irqsave(&priv->lock, flags);
 
-	ret = __exynos_sysmmu_enable(data, __pa(priv->pgtable), domain);
-
-	if (ret == 0) {
-		/* 'data->node' must not be appeared in priv->clients */
-		BUG_ON(!list_empty(&data->node));
-		data->dev = dev;
-		list_add_tail(&data->node, &priv->clients);
-	}
+	ret = __exynos_sysmmu_enable(dev, __pa(priv->pgtable), domain);
+	if (ret == 0)
+		list_add_tail(&client->node, &priv->clients);
 
 	spin_unlock_irqrestore(&priv->lock, flags);
 
-	if (ret < 0) {
+	if (ret < 0)
 		dev_err(dev, "%s: Failed to attach IOMMU with pgtable %#lx\n",
 				__func__, __pa(priv->pgtable));
-		pm_runtime_put(data->sysmmu);
-	} else if (ret > 0) {
-		dev_dbg(dev, "%s: IOMMU with pgtable 0x%lx already attached\n",
-					__func__, __pa(priv->pgtable));
-	} else {
-		dev_dbg(dev, "%s: Attached new IOMMU with pgtable 0x%lx\n",
-					__func__, __pa(priv->pgtable));
-	}
+	else
+		dev_dbg(dev, "%s: Attached IOMMU with pgtable 0x%lx%s\n",
+					__func__, __pa(priv->pgtable),
+					(ret == 0) ? "" : ", again");
 
 	return ret;
 }
@@ -760,39 +896,27 @@  static int exynos_iommu_attach_device(struct iommu_domain *domain,
 static void exynos_iommu_detach_device(struct iommu_domain *domain,
 				    struct device *dev)
 {
-	struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
+	struct exynos_iommu_client *client = NULL;
 	struct exynos_iommu_domain *priv = domain->priv;
-	struct list_head *pos;
 	unsigned long flags;
-	bool found = false;
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	list_for_each(pos, &priv->clients) {
-		if (list_entry(pos, struct sysmmu_drvdata, node) == data) {
-			found = true;
+	list_for_each_entry(client, &priv->clients, node) {
+		if (client == dev->archdata.iommu) {
+			if (exynos_sysmmu_disable(dev))
+				list_del_init(&client->node);
 			break;
 		}
 	}
 
-	if (!found)
-		goto finish;
+	spin_unlock_irqrestore(&priv->lock, flags);
 
-	if (__exynos_sysmmu_disable(data)) {
+	if (client == dev->archdata.iommu)
 		dev_dbg(dev, "%s: Detached IOMMU with pgtable %#lx\n",
 					__func__, __pa(priv->pgtable));
-		list_del_init(&data->node);
-
-	} else {
-		dev_dbg(dev, "%s: Detaching IOMMU with pgtable %#lx delayed",
-					__func__, __pa(priv->pgtable));
-	}
-
-finish:
-	spin_unlock_irqrestore(&priv->lock, flags);
-
-	if (found)
-		pm_runtime_put(data->sysmmu);
+	else
+		dev_dbg(dev, "%s: No IOMMU is attached\n", __func__);
 }
 
 static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
@@ -914,7 +1038,7 @@  static size_t exynos_iommu_unmap(struct iommu_domain *domain,
 					       unsigned long iova, size_t size)
 {
 	struct exynos_iommu_domain *priv = domain->priv;
-	struct sysmmu_drvdata *data;
+	struct exynos_iommu_client *client;
 	unsigned long flags;
 	unsigned long *ent;
 	size_t err_pgsize;
@@ -975,8 +1099,8 @@  done:
 	spin_unlock_irqrestore(&priv->pgtablelock, flags);
 
 	spin_lock_irqsave(&priv->lock, flags);
-	list_for_each_entry(data, &priv->clients, node)
-		sysmmu_tlb_invalidate_entry(data->dev, iova);
+	list_for_each_entry(client, &priv->clients, node)
+		sysmmu_tlb_invalidate_entry(client->dev, iova);
 	spin_unlock_irqrestore(&priv->lock, flags);
 
 	return size;
@@ -1055,3 +1179,275 @@  static int __init exynos_iommu_init(void)
 	return ret;
 }
 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)
+{
+	struct device *dev = p;
+
+	switch (val) {
+	case BUS_NOTIFY_BIND_DRIVER:
+	{
+		int i = 0;
+		int size = 0;
+		const __be32 *phandle;
+		struct exynos_iommu_client *client;
+
+		phandle = of_get_property(dev->of_node, "iommu", &size);
+		if (!phandle)
+			break;
+
+		size = size / sizeof(*phandle); /* number of elements */
+
+		client = devm_kzalloc(dev, sizeof(*client) * size, GFP_KERNEL);
+		if (!client) {
+			dev_err(dev, "No Memory for exynos_iommu_client\n");
+			return -ENOMEM;
+		}
+
+		client->num_sysmmu = size;
+		client->dev = dev;
+		INIT_LIST_HEAD(&client->node);
+		spin_lock_init(&client->lock);
+
+		for (i = 0; i < size; i++) {
+			struct device_node *np;
+			struct platform_device *sysmmu;
+
+			/* this always success: see above of_find_property() */
+			np = of_parse_phandle(dev->of_node, "iommu", i);
+
+			sysmmu = of_find_device_by_node(np);
+			if (!sysmmu) {
+				dev_err(dev,
+					"sysmmu node '%s' is not found\n",
+					np->name);
+				break;
+			}
+
+			client->sysmmu[i] = &sysmmu->dev;
+		}
+
+		if (i < size) {
+			while (--i >= 0)
+				of_node_put(client->sysmmu[i]->of_node);
+			devm_kfree(dev, client);
+			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;
+		}
+		break;
+	}
+	} /* switch (val) */
+
+	return 0;
+}
+
+static struct notifier_block sysmmu_notifier = {
+	.notifier_call = &sysmmu_hook_driver_register,
+};
+
+static int __init exynos_iommu_prepare(void)
+{
+	return bus_register_notifier(&platform_bus_type, &sysmmu_notifier);
+}
+arch_initcall(exynos_iommu_prepare);