[v2,10/10] iommu/exynos: Add proper runtime pm support

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 9d1a14f88891..80b7f1e7268c 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -233,8 +233,8 @@  struct sysmmu_drvdata {
 	struct clk *aclk;		/* SYSMMU's aclk clock */
 	struct clk *pclk;		/* SYSMMU's pclk clock */
 	struct clk *clk_master;		/* master's device clock */
-	int activations;		/* number of calls to sysmmu_enable */
 	spinlock_t lock;		/* lock for modyfying state */
+	int active;			/* current status */
 	struct exynos_iommu_domain *domain; /* domain we belong to */
 	struct list_head domain_node;	/* node for domain clients list */
 	struct list_head owner_node;	/* node for owner controllers list */
@@ -247,25 +247,6 @@  static struct exynos_iommu_domain *to_exynos_domain(struct iommu_domain *dom)
 	return container_of(dom, struct exynos_iommu_domain, domain);
 }
 
-static bool set_sysmmu_active(struct sysmmu_drvdata *data)
-{
-	/* return true if the System MMU was not active previously
-	   and it needs to be initialized */
-	return ++data->activations == 1;
-}
-
-static bool set_sysmmu_inactive(struct sysmmu_drvdata *data)
-{
-	/* return true if the System MMU is needed to be disabled */
-	BUG_ON(data->activations < 1);
-	return --data->activations == 0;
-}
-
-static bool is_sysmmu_active(struct sysmmu_drvdata *data)
-{
-	return data->activations > 0;
-}
-
 static void sysmmu_unblock(struct sysmmu_drvdata *data)
 {
 	writel(CTRL_ENABLE, data->sfrbase + REG_MMU_CTRL);
@@ -384,7 +365,7 @@  static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 	unsigned short reg_status, reg_clear;
 	int ret = -ENOSYS;
 
-	WARN_ON(!is_sysmmu_active(data));
+	WARN_ON(!data->active);
 
 	if (MMU_MAJ_VER(data->version) < 5) {
 		reg_status = REG_INT_STATUS;
@@ -430,7 +411,7 @@  static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
+static void __sysmmu_disable(struct sysmmu_drvdata *data)
 {
 	clk_enable(data->clk_master);
 
@@ -440,32 +421,6 @@  static void __sysmmu_disable_nocount(struct sysmmu_drvdata *data)
 	__sysmmu_disable_clocks(data);
 }
 
-static bool __sysmmu_disable(struct sysmmu_drvdata *data)
-{
-	bool disabled;
-	unsigned long flags;
-
-	spin_lock_irqsave(&data->lock, flags);
-
-	disabled = set_sysmmu_inactive(data);
-
-	if (disabled) {
-		data->pgtable = 0;
-		data->domain = NULL;
-
-		__sysmmu_disable_nocount(data);
-
-		dev_dbg(data->sysmmu, "Disabled\n");
-	} else  {
-		dev_dbg(data->sysmmu, "%d times left to disable\n",
-					data->activations);
-	}
-
-	spin_unlock_irqrestore(&data->lock, flags);
-
-	return disabled;
-}
-
 static void __sysmmu_init_config(struct sysmmu_drvdata *data)
 {
 	unsigned int cfg;
@@ -480,7 +435,7 @@  static void __sysmmu_init_config(struct sysmmu_drvdata *data)
 	writel(cfg, data->sfrbase + REG_MMU_CFG);
 }
 
-static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
+static void __sysmmu_enable(struct sysmmu_drvdata *data)
 {
 	__sysmmu_enable_clocks(data);
 
@@ -501,34 +456,6 @@  static void __sysmmu_enable_nocount(struct sysmmu_drvdata *data)
 	clk_disable(data->clk_master);
 }
 
-static int __sysmmu_enable(struct sysmmu_drvdata *data, phys_addr_t pgtable,
-			   struct exynos_iommu_domain *domain)
-{
-	int ret = 0;
-	unsigned long flags;
-
-	spin_lock_irqsave(&data->lock, flags);
-	if (set_sysmmu_active(data)) {
-		data->pgtable = pgtable;
-		data->domain = domain;
-
-		__sysmmu_enable_nocount(data);
-
-		dev_dbg(data->sysmmu, "Enabled\n");
-	} else {
-		ret = (pgtable == data->pgtable) ? 1 : -EBUSY;
-
-		dev_dbg(data->sysmmu, "already enabled\n");
-	}
-
-	if (WARN_ON(ret < 0))
-		set_sysmmu_inactive(data); /* decrement count */
-
-	spin_unlock_irqrestore(&data->lock, flags);
-
-	return ret;
-}
-
 static void sysmmu_tlb_invalidate_flpdcache(struct sysmmu_drvdata *data,
 					    sysmmu_iova_t iova)
 {
@@ -536,7 +463,7 @@  static void sysmmu_tlb_invalidate_flpdcache(struct sysmmu_drvdata *data,
 
 
 	spin_lock_irqsave(&data->lock, flags);
-	if (is_sysmmu_active(data) && data->version >= MAKE_MMU_VER(3, 3)) {
+	if (data->active && data->version >= MAKE_MMU_VER(3, 3)) {
 		clk_enable(data->clk_master);
 		__sysmmu_tlb_invalidate_entry(data, iova, 1);
 		clk_disable(data->clk_master);
@@ -551,7 +478,7 @@  static void sysmmu_tlb_invalidate_entry(struct sysmmu_drvdata *data,
 	unsigned long flags;
 
 	spin_lock_irqsave(&data->lock, flags);
-	if (is_sysmmu_active(data)) {
+	if (data->active) {
 		unsigned int num_inv = 1;
 
 		clk_enable(data->clk_master);
@@ -652,40 +579,78 @@  static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(dev);
-
 	of_iommu_set_ops(dev->of_node, &exynos_iommu_ops);
 
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
+static int exynos_sysmmu_runtime_suspend(struct device *dev)
+{
+	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->lock, flags);
+	if (data->master) {
+		dev_dbg(data->sysmmu, "runtime pm: saving state\n");
+		__sysmmu_disable(data);
+		data->active = false;
+	}
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+static int exynos_sysmmu_runtime_resume(struct device *dev)
+{
+	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&data->lock, flags);
+	if (data->master) {
+		dev_dbg(data->sysmmu, "runtime pm: restoring state\n");
+		__sysmmu_enable(data);
+		data->active = true;
+	}
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
 static int exynos_sysmmu_suspend(struct device *dev)
 {
 	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
+	unsigned long flags;
 
-	dev_dbg(dev, "suspend\n");
-	if (is_sysmmu_active(data)) {
-		__sysmmu_disable_nocount(data);
-		pm_runtime_put(dev);
+	spin_lock_irqsave(&data->lock, flags);
+	if (data->active) {
+		dev_dbg(data->sysmmu, "saving state\n");
+		__sysmmu_disable(data);
 	}
+	spin_unlock_irqrestore(&data->lock, flags);
+
 	return 0;
 }
 
 static int exynos_sysmmu_resume(struct device *dev)
 {
 	struct sysmmu_drvdata *data = dev_get_drvdata(dev);
+	unsigned long flags;
 
-	dev_dbg(dev, "resume\n");
-	if (is_sysmmu_active(data)) {
-		pm_runtime_get_sync(dev);
-		__sysmmu_enable_nocount(data);
+	spin_lock_irqsave(&data->lock, flags);
+	if (data->active) {
+		dev_dbg(data->sysmmu, "restoring state\n");
+		__sysmmu_enable(data);
 	}
+	spin_unlock_irqrestore(&data->lock, flags);
+
 	return 0;
 }
-#endif
 
 static const struct dev_pm_ops sysmmu_pm_ops = {
-	SET_LATE_SYSTEM_SLEEP_PM_OPS(exynos_sysmmu_suspend, exynos_sysmmu_resume)
+	SET_RUNTIME_PM_OPS(exynos_sysmmu_runtime_suspend,
+			   exynos_sysmmu_runtime_resume, NULL)
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(exynos_sysmmu_suspend,
+				     exynos_sysmmu_resume)
 };
 
 static const struct of_device_id sysmmu_of_match[] __initconst = {
@@ -789,9 +754,16 @@  static void exynos_iommu_domain_free(struct iommu_domain *iommu_domain)
 	spin_lock_irqsave(&domain->lock, flags);
 
 	list_for_each_entry_safe(data, next, &domain->clients, domain_node) {
-		if (__sysmmu_disable(data))
-			data->master = NULL;
+		spin_lock(&data->lock);
+		if (WARN_ON(data->active)) {
+			__sysmmu_disable(data);
+			data->active = false;
+		}
+		data->master = NULL;
+		data->pgtable = 0;
+		data->domain = NULL;
 		list_del_init(&data->domain_node);
+		spin_unlock(&data->lock);
 	}
 
 	spin_unlock_irqrestore(&domain->lock, flags);
@@ -832,18 +804,22 @@  static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
 
 	spin_lock_irqsave(&domain->lock, flags);
 	list_for_each_entry_safe(data, next, &domain->clients, domain_node) {
+		spin_lock(&data->lock);
 		if (data->master == dev) {
-			if (__sysmmu_disable(data)) {
-				data->master = NULL;
-				list_del_init(&data->domain_node);
-			}
-			pm_runtime_put(data->sysmmu);
 			found = true;
+			if (data->active) {
+				__sysmmu_disable(data);
+				data->active = false;
+			}
+			data->master = NULL;
+			data->pgtable = 0;
+			data->domain = NULL;
+			list_del_init(&data->domain_node);
 		}
+		spin_unlock(&data->lock);
 	}
-	spin_unlock_irqrestore(&domain->lock, flags);
-
 	owner->domain = NULL;
+	spin_unlock_irqrestore(&domain->lock, flags);
 
 	if (found)
 		dev_dbg(dev, "%s: Detached IOMMU with pgtable %pa\n",
@@ -860,7 +836,6 @@  static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
 	struct sysmmu_drvdata *data;
 	phys_addr_t pagetable = virt_to_phys(domain->pgtable);
 	unsigned long flags;
-	int ret = -ENODEV;
 
 	if (!has_sysmmu(dev))
 		return -ENODEV;
@@ -868,29 +843,26 @@  static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
 	if (owner->domain)
 		exynos_iommu_detach_device(owner->domain, dev);
 
+	spin_lock_irqsave(&domain->lock, flags);
 	list_for_each_entry(data, &owner->controllers, owner_node) {
-		pm_runtime_get_sync(data->sysmmu);
-		ret = __sysmmu_enable(data, pagetable, domain);
-		if (ret >= 0) {
-			data->master = dev;
-
-			spin_lock_irqsave(&domain->lock, flags);
-			list_add_tail(&data->domain_node, &domain->clients);
-			spin_unlock_irqrestore(&domain->lock, flags);
+		spin_lock(&data->lock);
+		data->master = dev;
+		data->pgtable = pagetable;
+		data->domain = domain;
+		list_add_tail(&data->domain_node, &domain->clients);
+		if (pm_runtime_active(data->sysmmu)) {
+			__sysmmu_enable(data);
+			data->active = true;
 		}
+		spin_unlock(&data->lock);
 	}
-
-	if (ret < 0) {
-		dev_err(dev, "%s: Failed to attach IOMMU with pgtable %pa\n",
-					__func__, &pagetable);
-		return ret;
-	}
-
 	owner->domain = iommu_domain;
-	dev_dbg(dev, "%s: Attached IOMMU with pgtable %pa %s\n",
-		__func__, &pagetable, (ret == 0) ? "" : ", again");
+	spin_unlock_irqrestore(&domain->lock, flags);
 
-	return ret;
+	dev_dbg(dev, "%s: Attached IOMMU with pgtable %pa\n",
+		__func__, &pagetable);
+
+	return 0;
 }
 
 static sysmmu_pte_t *alloc_lv2entry(struct exynos_iommu_domain *domain,
@@ -1265,6 +1237,14 @@  static int exynos_iommu_of_xlate(struct device *dev,
 	}
 
 	list_add_tail(&data->owner_node, &owner->controllers);
+
+	/*
+	 * SYSMMU will be runtime enabled via device link (dependency) to its
+	 * master device, so there are no direct calls to pm_runtime_get/put
+	 * in this driver
+	 */
+	device_link_add(dev, &sysmmu->dev, DEVICE_LINK_PERSISTENT |
+					   DEVICE_LINK_PM_RUNTIME);
 	return 0;
 }