1 files changed, 114 insertions, 1 deletions

diff --git a/drivers/staging/tidspbridge/core/ue_deh.c b/drivers/staging/tidspbridge/core/ue_deh.c
index e24ea0c73914..3430418190da 100644
--- a/drivers/staging/tidspbridge/core/ue_deh.c
+++ b/drivers/staging/tidspbridge/core/ue_deh.c
@@ -31,6 +31,57 @@
 #include <dspbridge/drv.h>
 #include <dspbridge/wdt.h>
 
+static u32 fault_addr;
+
+static void mmu_fault_dpc(unsigned long data)
+{
+	struct deh_mgr *deh = (void *)data;
+
+	if (!deh)
+		return;
+
+	bridge_deh_notify(deh, DSP_MMUFAULT, 0);
+}
+
+static irqreturn_t mmu_fault_isr(int irq, void *data)
+{
+	struct deh_mgr *deh = data;
+	struct cfg_hostres *resources;
+	u32 event;
+
+	if (!deh)
+		return IRQ_HANDLED;
+
+	resources = deh->hbridge_context->resources;
+	if (!resources) {
+		dev_dbg(bridge, "%s: Failed to get Host Resources\n",
+				__func__);
+		return IRQ_HANDLED;
+	}
+
+	hw_mmu_event_status(resources->dw_dmmu_base, &event);
+	if (event == HW_MMU_TRANSLATION_FAULT) {
+		hw_mmu_fault_addr_read(resources->dw_dmmu_base, &fault_addr);
+		dev_dbg(bridge, "%s: event=0x%x, fault_addr=0x%x\n", __func__,
+				event, fault_addr);
+		/*
+		 * Schedule a DPC directly. In the future, it may be
+		 * necessary to check if DSP MMU fault is intended for
+		 * Bridge.
+		 */
+		tasklet_schedule(&deh->dpc_tasklet);
+
+		/* Disable the MMU events, else once we clear it will
+		 * start to raise INTs again */
+		hw_mmu_event_disable(resources->dw_dmmu_base,
+				HW_MMU_TRANSLATION_FAULT);
+	} else {
+		hw_mmu_event_disable(resources->dw_dmmu_base,
+				HW_MMU_ALL_INTERRUPTS);
+	}
+	return IRQ_HANDLED;
+}
+
 int bridge_deh_create(struct deh_mgr **ret_deh,
 		struct dev_object *hdev_obj)
 {
@@ -58,9 +109,18 @@ int bridge_deh_create(struct deh_mgr **ret_deh,
 	}
 	ntfy_init(deh->ntfy_obj);
 
+	/* Create a MMUfault DPC */
+	tasklet_init(&deh->dpc_tasklet, mmu_fault_dpc, (u32) deh);
+
 	/* Fill in context structure */
 	deh->hbridge_context = hbridge_context;
 
+	/* Install ISR function for DSP MMU fault */
+	status = request_irq(INT_DSP_MMU_IRQ, mmu_fault_isr, 0,
+			"DspBridge\tiommu fault", deh);
+	if (status < 0)
+		goto err;
+
 	*ret_deh = deh;
 	return 0;
 
@@ -80,6 +140,11 @@ int bridge_deh_destroy(struct deh_mgr *deh)
 		ntfy_delete(deh->ntfy_obj);
 		kfree(deh->ntfy_obj);
 	}
+	/* Disable DSP MMU fault */
+	free_irq(INT_DSP_MMU_IRQ, deh);
+
+	/* Free DPC object */
+	tasklet_kill(&deh->dpc_tasklet);
 
 	/* Deallocate the DEH manager object */
 	kfree(deh);
@@ -101,6 +166,48 @@ int bridge_deh_register_notify(struct deh_mgr *deh, u32 event_mask,
 		return ntfy_unregister(deh->ntfy_obj, hnotification);
 }
 
+#ifdef CONFIG_TIDSPBRIDGE_BACKTRACE
+static void mmu_fault_print_stack(struct bridge_dev_context *dev_context)
+{
+	struct cfg_hostres *resources;
+	struct hw_mmu_map_attrs_t map_attrs = {
+		.endianism = HW_LITTLE_ENDIAN,
+		.element_size = HW_ELEM_SIZE16BIT,
+		.mixed_size = HW_MMU_CPUES,
+	};
+	void *dummy_va_addr;
+
+	resources = dev_context->resources;
+	dummy_va_addr = (void*)__get_free_page(GFP_ATOMIC);
+
+	/*
+	 * Before acking the MMU fault, let's make sure MMU can only
+	 * access entry #0. Then add a new entry so that the DSP OS
+	 * can continue in order to dump the stack.
+	 */
+	hw_mmu_twl_disable(resources->dw_dmmu_base);
+	hw_mmu_tlb_flush_all(resources->dw_dmmu_base);
+
+	hw_mmu_tlb_add(resources->dw_dmmu_base,
+			virt_to_phys(dummy_va_addr), fault_addr,
+			HW_PAGE_SIZE4KB, 1,
+			&map_attrs, HW_SET, HW_SET);
+
+	dsp_clk_enable(DSP_CLK_GPT8);
+
+	dsp_gpt_wait_overflow(DSP_CLK_GPT8, 0xfffffffe);
+
+	/* Clear MMU interrupt */
+	hw_mmu_event_ack(resources->dw_dmmu_base,
+			HW_MMU_TRANSLATION_FAULT);
+	dump_dsp_stack(dev_context);
+	dsp_clk_disable(DSP_CLK_GPT8);
+
+	hw_mmu_disable(resources->dw_dmmu_base);
+	free_page((unsigned long)dummy_va_addr);
+}
+#endif
+
 static inline const char *event_to_string(int event)
 {
 	switch (event) {
@@ -133,7 +240,13 @@ void bridge_deh_notify(struct deh_mgr *deh, int event, int info)
 #endif
 		break;
 	case DSP_MMUFAULT:
-		dev_err(bridge, "%s: %s, addr=0x%x", __func__, str, info);
+		dev_err(bridge, "%s: %s, addr=0x%x", __func__,
+				str, fault_addr);
+#ifdef CONFIG_TIDSPBRIDGE_BACKTRACE
+		print_dsp_trace_buffer(dev_context);
+		dump_dl_modules(dev_context);
+		mmu_fault_print_stack(dev_context);
+#endif
 		break;
 	default:
 		dev_err(bridge, "%s: %s", __func__, str);