omap:iommu-notifier callback mechanism for mmu events

Implement notifier callback mechanism for IOMMU events
such as MMU fault and file close.
The Error handler that hooks to this registration would notify
the remote processor whenever a process closed the iommu. This is
to ensure that the Processes on Remote process stop accessing the
buffers mapped by the terminating Process

Signed-off-by: Hari Kanigeri <h-kanigeri2@ti.com>
Signed-off-by: Angela Stegmaier <angelabaker@ti.com>

2 files changed, 39 insertions, 1 deletions

diff --git a/arch/arm/plat-omap/include/plat/iommu.h b/arch/arm/plat-omap/include/plat/iommu.h
index 5c6a4821c5f..5fd42f6547c 100644
--- a/arch/arm/plat-omap/include/plat/iommu.h
+++ b/arch/arm/plat-omap/include/plat/iommu.h
@@ -48,7 +48,7 @@ struct iommu {
 	struct list_head	mmap;
 	struct mutex		mmap_lock; /* protect mmap */
 
-	int (*isr)(struct iommu *obj, u32 da, u32 iommu_errs, void *priv);
+	struct blocking_notifier_head	notifier;
 
 	void *ctx; /* iommu context: registres saved area */
 	u32 da_start;
@@ -110,6 +110,11 @@ struct iommu_functions {
 	ssize_t (*dump_ctx)(struct iommu *obj, char *buf, ssize_t len);
 };
 
+enum {
+	IOMMU_FAULT,
+	IOMMU_CLOSE,
+};
+
 struct iommu_platform_data {
 	const char *name;
 	const char *oh_name;
@@ -165,6 +170,12 @@ extern u32 iommu_arch_version(void);
 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 iommu_register_notifier(struct iommu *obj,
+						struct notifier_block *nb);
+extern int iommu_unregister_notifier(struct iommu *obj,
+						struct notifier_block *nb);
+extern int iommu_notify_event(struct iommu *obj, int event, void *data);
+
 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);
diff --git a/arch/arm/plat-omap/iommu.c b/arch/arm/plat-omap/iommu.c
index 9e728d34266..ec6e20c7643 100644
--- a/arch/arm/plat-omap/iommu.c
+++ b/arch/arm/plat-omap/iommu.c
@@ -746,6 +746,26 @@ void eventfd_notification(struct iommu *obj)
 		eventfd_signal(fd_reg->evt_ctx, 1);
 }
 
+int iommu_notify_event(struct iommu *obj, int event, void *data) {
+	return blocking_notifier_call_chain(&obj->notifier, event, data);
+}
+
+int iommu_register_notifier(struct iommu *obj, struct notifier_block *nb)
+{
+	if (!nb)
+		return -EINVAL;
+	return blocking_notifier_chain_register(&obj->notifier, nb);
+}
+EXPORT_SYMBOL_GPL(iommu_register_notifier);
+
+int iommu_unregister_notifier(struct iommu *obj, struct notifier_block *nb)
+{
+	if (!nb)
+		return -EINVAL;
+	return blocking_notifier_chain_unregister(&obj->notifier, nb);
+}
+EXPORT_SYMBOL_GPL(iommu_unregister_notifier);
+
 /*
  *	Device IOMMU generic operations
  */
@@ -759,6 +779,12 @@ static irqreturn_t iommu_fault_handler(int irq, void *data)
 		return IRQ_NONE;
 
 	eventfd_notification(obj);
+	/* Dynamic loading TLB or PTE */
+	errs = iommu_notify_event(obj, IOMMU_FAULT, data);
+
+	if (errs == NOTIFY_OK)
+		return IRQ_HANDLED;
+
 	errs = iommu_report_fault(obj, &da);
 	if (errs == 0)
 		return IRQ_HANDLED;
@@ -937,6 +963,7 @@ static int __devinit omap_iommu_probe(struct platform_device *pdev)
 	INIT_LIST_HEAD(&obj->event_list);
 
 	obj->regbase = pdata->io_base;
+	BLOCKING_INIT_NOTIFIER_HEAD(&obj->notifier);
 
 	err = request_irq(pdata->irq, iommu_fault_handler, IRQF_SHARED,
 			  dev_name(&pdev->dev), obj);