3 files changed, 46 insertions, 5 deletions

diff --git a/arch/arm/mach-omap2/iommu2.c b/arch/arm/mach-omap2/iommu2.c
index ebbdae262f78..edf7cd4b6553 100644
--- a/arch/arm/mach-omap2/iommu2.c
+++ b/arch/arm/mach-omap2/iommu2.c
@@ -65,6 +65,26 @@
          ((pgsz) == MMU_CAM_PGSZ_64K) ? 0xffff0000 :    \
          ((pgsz) == MMU_CAM_PGSZ_4K)  ? 0xfffff000 : 0)
 
+
+static void __iommu_set_twl(struct iommu *obj, bool on)
+{
+        u32 l = iommu_read_reg(obj, MMU_CNTL);
+
+        if (on)
+                iommu_write_reg(obj, MMU_IRQ_TWL_MASK, MMU_IRQENABLE);
+        else
+                iommu_write_reg(obj, MMU_IRQ_TLB_MISS_MASK, MMU_IRQENABLE);
+
+        l &= ~MMU_CNTL_MASK;
+        if (on)
+                l |= (MMU_CNTL_MMU_EN | MMU_CNTL_TWL_EN);
+        else
+                l |= (MMU_CNTL_MMU_EN);
+
+        iommu_write_reg(obj, l, MMU_CNTL);
+}
+
+
 static int omap2_iommu_enable(struct iommu *obj)
 {
         u32 l, pa;
@@ -100,13 +120,9 @@ static int omap2_iommu_enable(struct iommu *obj)
         l |= (MMU_SYS_IDLE_SMART | MMU_SYS_AUTOIDLE);
         iommu_write_reg(obj, l, MMU_SYSCONFIG);
 
-        iommu_write_reg(obj, MMU_IRQ_TWL_MASK, MMU_IRQENABLE);
         iommu_write_reg(obj, pa, MMU_TTB);
 
-        l = iommu_read_reg(obj, MMU_CNTL);
-        l &= ~MMU_CNTL_MASK;
-        l |= (MMU_CNTL_MMU_EN | MMU_CNTL_TWL_EN);
-        iommu_write_reg(obj, l, MMU_CNTL);
+        __iommu_set_twl(obj, true);
 
         return 0;
 }
@@ -122,6 +138,11 @@ static void omap2_iommu_disable(struct iommu *obj)
         dev_dbg(obj->dev, "%s is shutting down\n", obj->name);
 }
 
+static void omap2_iommu_set_twl(struct iommu *obj, bool on)
+{
+        __iommu_set_twl(obj, false);
+}
+
 static u32 omap2_iommu_fault_isr(struct iommu *obj, u32 *ra)
 {
         int i;
@@ -304,6 +325,7 @@ static const struct iommu_functions omap2_iommu_ops = {
 
         .enable         = omap2_iommu_enable,
         .disable        = omap2_iommu_disable,
+        .set_twl        = omap2_iommu_set_twl,
         .fault_isr      = omap2_iommu_fault_isr,
 
         .tlb_read_cr    = omap2_tlb_read_cr,
diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
index 0752af9d099e..33c7d41cb6a5 100644
--- a/arch/arm/plat-omap/include/plat/iommu.h
+++ b/arch/arm/plat-omap/include/plat/iommu.h
@@ -80,6 +80,7 @@ struct iommu_functions {
 
         int (*enable)(struct iommu *obj);
         void (*disable)(struct iommu *obj);
+        void (*set_twl)(struct iommu *obj, bool on);
         u32 (*fault_isr)(struct iommu *obj, u32 *ra);
 
         void (*tlb_read_cr)(struct iommu *obj, struct cr_regs *cr);
@@ -143,6 +144,7 @@ extern void iotlb_cr_to_e(struct cr_regs *cr, struct iotlb_entry *e);
 extern u32 iotlb_cr_to_virt(struct cr_regs *cr);
 
 extern int load_iotlb_entry(struct iommu *obj, struct iotlb_entry *e);
+extern void iommu_set_twl(struct iommu *obj, bool on);
 extern void flush_iotlb_page(struct iommu *obj, u32 da);
 extern void flush_iotlb_range(struct iommu *obj, u32 start, u32 end);
 extern void flush_iotlb_all(struct iommu *obj);
diff --git a/arch/arm/plat-omap/iommu.c b/arch/arm/plat-omap/iommu.c
index 341c48179ee0..688ae66bb8fc 100644
--- a/arch/arm/plat-omap/iommu.c
+++ b/arch/arm/plat-omap/iommu.c
@@ -370,6 +370,23 @@ void flush_iotlb_all(struct iommu *obj)
 }
 EXPORT_SYMBOL_GPL(flush_iotlb_all);
 
+/**
+ * iommu_set_twl - enable/disable table walking logic
+ * @obj:        target iommu
+ * @on:         enable/disable
+ *
+ * Function used to enable/disable TWL. If one wants to work
+ * exclusively with locked TLB entries and receive notifications
+ * for TLB miss then call this function to disable TWL.
+ */
+void iommu_set_twl(struct iommu *obj, bool on)
+{
+        clk_enable(obj->clk);
+        arch_iommu->set_twl(obj, on);
+        clk_disable(obj->clk);
+}
+EXPORT_SYMBOL_GPL(iommu_set_twl);
+
 #if defined(CONFIG_OMAP_IOMMU_DEBUG_MODULE)
 
 ssize_t iommu_dump_ctx(struct iommu *obj, char *buf, ssize_t bytes)