[PATCH v9 08/16] iommu/exynos: gating clocks of master H/W

[Cho KyongHo <pullip.cho@samsung.com>]

This patch gates clocks of master H/W as well as clocks of System MMU
if master clocks are specified.

Some Exynos SoCs (i.e. GScalers in Exynos5250) have dependencies in
the gating clocks of master H/W and its System MMU. If a H/W is the
case, accessing control registers of System MMU is prohibited unless
both of the gating clocks of System MMU and its master H/W.

Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
---
 drivers/iommu/exynos-iommu.c |   38 ++++++++++++++++++++++++++++++++++----
 1 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 0ee73e8..005a7ed 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -173,6 +173,7 @@ struct sysmmu_drvdata {
 	struct device *dev;	/* Owner of system MMU */
 	int nsfrs;
 	struct clk *clk;
+	struct clk *clk_master;
 	int activations;
 	rwlock_t lock;
 	struct iommu_domain *domain;
@@ -263,6 +264,8 @@ 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]))
@@ -288,6 +291,8 @@ 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);
 }
@@ -358,6 +363,8 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 			break;
 	}
 
+	clk_enable(data->clk_master);
+
 	if (i == pdev->num_resources) {
 		itype = SYSMMU_FAULT_UNKNOWN;
 	} else {
@@ -391,6 +398,8 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
 	if (itype != SYSMMU_FAULT_UNKNOWN)
 		sysmmu_unblock(data->sfrbases[i]);
 
+	clk_disable(data->clk_master);
+
 	read_unlock(&data->lock);
 
 	return IRQ_HANDLED;
@@ -407,11 +416,14 @@ static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
 	if (!set_sysmmu_inactive(data))
 		goto finish;
 
+	clk_enable(data->clk_master);
+
 	for (i = 0; i < data->nsfrs; i++)
 		__raw_writel(CTRL_DISABLE, data->sfrbases[i] + REG_MMU_CTRL);
 
-	if (data->clk)
-		clk_disable(data->clk);
+	clk_disable(data->clk_master);
+
+	clk_disable(data->clk);
 
 	disabled = true;
 	data->pgtable = 0;
@@ -454,11 +466,12 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
 		goto finish;
 	}
 
-	if (data->clk)
-		clk_enable(data->clk);
+	clk_enable(data->clk);
 
 	data->pgtable = pgtable;
 
+	clk_enable(data->clk_master);
+
 	for (i = 0; i < data->nsfrs; i++) {
 		__sysmmu_set_ptbase(data->sfrbases[i], pgtable);
 
@@ -473,6 +486,8 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
 		__raw_writel(CTRL_ENABLE, data->sfrbases[i] + REG_MMU_CTRL);
 	}
 
+	clk_disable(data->clk_master);
+
 	data->domain = domain;
 
 	dev_dbg(data->sysmmu, "Enabled\n");
@@ -528,6 +543,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
 
 	if (is_sysmmu_active(data)) {
 		int i;
+		clk_enable(data->clk_master);
 		for (i = 0; i < data->nsfrs; i++) {
 			if (sysmmu_block(data->sfrbases[i])) {
 				__sysmmu_tlb_invalidate_entry(
@@ -535,6 +551,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
 				sysmmu_unblock(data->sfrbases[i]);
 			}
 		}
+		clk_disable(data->clk_master);
 	} else {
 		dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
 	}
@@ -551,12 +568,14 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
 
 	if (is_sysmmu_active(data)) {
 		int i;
+		clk_enable(data->clk_master);
 		for (i = 0; i < data->nsfrs; i++) {
 			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(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
 	}
@@ -637,6 +656,17 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 		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;
+	}
+
 	rwlock_init(&data->lock);
 	INIT_LIST_HEAD(&data->node);
 
-- 
1.7.2.5