usb: dwc3: add tracepoints to aid debugging

When we're debugging hard-to-reproduce and time-sensitive
use cases, printk() poses too much overhead. That's when
the kernel's tracing infrastructure comes into play.

This patch implements a few initial tracepoints for the
dwc3 driver. More traces can be added as necessary in order
to ease the task of debugging dwc3.

Reviewed-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

9 files changed, 357 insertions, 53 deletions

diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index 10ac3e7..7793e6c 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -1,9 +1,12 @@
+# define_trace.h needs to know how to find our header
+CFLAGS_trace.o				:= -I$(src)
+
 ccflags-$(CONFIG_USB_DWC3_DEBUG)	:= -DDEBUG
 ccflags-$(CONFIG_USB_DWC3_VERBOSE)	+= -DVERBOSE_DEBUG
 
 obj-$(CONFIG_USB_DWC3)			+= dwc3.o
 
-dwc3-y					:= core.o
+dwc3-y					:= core.o debug.o trace.o
 
 ifneq ($(filter y,$(CONFIG_USB_DWC3_HOST) $(CONFIG_USB_DWC3_DUAL_ROLE)),)
 	dwc3-y				+= host.o
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index c123745..66f6256 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -33,6 +33,8 @@
 
 #include <linux/phy/phy.h>
 
+#define DWC3_MSG_MAX	500
+
 /* Global constants */
 #define DWC3_EP0_BOUNCE_SIZE	512
 #define DWC3_ENDPOINTS_NUM	32
diff --git a/drivers/usb/dwc3/debug.c b/drivers/usb/dwc3/debug.c
new file mode 100644
index 0000000..0be6885
--- /dev/null
+++ b/drivers/usb/dwc3/debug.c
@@ -0,0 +1,32 @@
+/**
+ * debug.c - DesignWare USB3 DRD Controller Debug/Trace Support
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: Felipe Balbi <balbi@ti.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "debug.h"
+
+void dwc3_trace(void (*trace)(struct va_format *), const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	trace(&vaf);
+
+	va_end(args);
+}
diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h
index 12ff4c9..07fbc2d 100644
--- a/drivers/usb/dwc3/debug.h
+++ b/drivers/usb/dwc3/debug.h
@@ -214,6 +214,8 @@ static inline const char *dwc3_gadget_event_type_string(u8 event)
 	}
 }
 
+void dwc3_trace(void (*trace)(struct va_format *), const char *fmt, ...);
+
 #ifdef CONFIG_DEBUG_FS
 extern int dwc3_debugfs_init(struct dwc3 *);
 extern void dwc3_debugfs_exit(struct dwc3 *);
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 994e1d8..b359387 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -66,7 +66,7 @@ static int dwc3_ep0_start_trans(struct dwc3 *dwc, u8 epnum, dma_addr_t buf_dma,
 
 	dep = dwc->eps[epnum];
 	if (dep->flags & DWC3_EP_BUSY) {
-		dev_vdbg(dwc->dev, "%s: still busy\n", dep->name);
+		dwc3_trace(trace_dwc3_ep0, "%s still busy", dep->name);
 		return 0;
 	}
 
@@ -89,7 +89,8 @@ static int dwc3_ep0_start_trans(struct dwc3 *dwc, u8 epnum, dma_addr_t buf_dma,
 	ret = dwc3_send_gadget_ep_cmd(dwc, dep->number,
 			DWC3_DEPCMD_STARTTRANSFER, &params);
 	if (ret < 0) {
-		dev_dbg(dwc->dev, "failed to send STARTTRANSFER command\n");
+		dwc3_trace(trace_dwc3_ep0, "%s STARTTRANSFER failed",
+				dep->name);
 		return ret;
 	}
 
@@ -154,7 +155,8 @@ static int __dwc3_gadget_ep0_queue(struct dwc3_ep *dep,
 		if (dwc->ep0state == EP0_STATUS_PHASE)
 			__dwc3_ep0_do_control_status(dwc, dwc->eps[direction]);
 		else
-			dev_dbg(dwc->dev, "too early for delayed status\n");
+			dwc3_trace(trace_dwc3_ep0,
+					"too early for delayed status");
 
 		return 0;
 	}
@@ -218,7 +220,8 @@ int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request,
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	if (!dep->endpoint.desc) {
-		dev_dbg(dwc->dev, "trying to queue request %p to disabled %s\n",
+		dwc3_trace(trace_dwc3_ep0,
+				"trying to queue request %p to disabled %s",
 				request, dep->name);
 		ret = -ESHUTDOWN;
 		goto out;
@@ -230,7 +233,8 @@ int dwc3_gadget_ep0_queue(struct usb_ep *ep, struct usb_request *request,
 		goto out;
 	}
 
-	dev_vdbg(dwc->dev, "queueing request %p to %s length %d, state '%s'\n",
+	dwc3_trace(trace_dwc3_ep0,
+			"queueing request %p to %s length %d state '%s'",
 			request, dep->name, request->length,
 			dwc3_ep0_state_string(dwc->ep0state));
 
@@ -486,12 +490,13 @@ static int dwc3_ep0_set_address(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 
 	addr = le16_to_cpu(ctrl->wValue);
 	if (addr > 127) {
-		dev_dbg(dwc->dev, "invalid device address %d\n", addr);
+		dwc3_trace(trace_dwc3_ep0, "invalid device address %d", addr);
 		return -EINVAL;
 	}
 
 	if (state == USB_STATE_CONFIGURED) {
-		dev_dbg(dwc->dev, "trying to set address when configured\n");
+		dwc3_trace(trace_dwc3_ep0,
+				"trying to set address when configured");
 		return -EINVAL;
 	}
 
@@ -557,7 +562,7 @@ static int dwc3_ep0_set_config(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 			dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 
 			dwc->resize_fifos = true;
-			dev_dbg(dwc->dev, "resize fifos flag SET\n");
+			dwc3_trace(trace_dwc3_ep0, "resize FIFOs flag SET");
 		}
 		break;
 
@@ -681,35 +686,35 @@ static int dwc3_ep0_std_request(struct dwc3 *dwc, struct usb_ctrlrequest *ctrl)
 
 	switch (ctrl->bRequest) {
 	case USB_REQ_GET_STATUS:
-		dev_vdbg(dwc->dev, "USB_REQ_GET_STATUS\n");
+		dwc3_trace(trace_dwc3_ep0, "USB_REQ_GET_STATUS\n");
 		ret = dwc3_ep0_handle_status(dwc, ctrl);
 		break;
 	case USB_REQ_CLEAR_FEATURE:
-		dev_vdbg(dwc->dev, "USB_REQ_CLEAR_FEATURE\n");
+		dwc3_trace(trace_dwc3_ep0, "USB_REQ_CLEAR_FEATURE\n");
 		ret = dwc3_ep0_handle_feature(dwc, ctrl, 0);
 		break;
 	case USB_REQ_SET_FEATURE:
-		dev_vdbg(dwc->dev, "USB_REQ_SET_FEATURE\n");
+		dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_FEATURE\n");
 		ret = dwc3_ep0_handle_feature(dwc, ctrl, 1);
 		break;
 	case USB_REQ_SET_ADDRESS:
-		dev_vdbg(dwc->dev, "USB_REQ_SET_ADDRESS\n");
+		dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_ADDRESS\n");
 		ret = dwc3_ep0_set_address(dwc, ctrl);
 		break;
 	case USB_REQ_SET_CONFIGURATION:
-		dev_vdbg(dwc->dev, "USB_REQ_SET_CONFIGURATION\n");
+		dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_CONFIGURATION\n");
 		ret = dwc3_ep0_set_config(dwc, ctrl);
 		break;
 	case USB_REQ_SET_SEL:
-		dev_vdbg(dwc->dev, "USB_REQ_SET_SEL\n");
+		dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_SEL\n");
 		ret = dwc3_ep0_set_sel(dwc, ctrl);
 		break;
 	case USB_REQ_SET_ISOCH_DELAY:
-		dev_vdbg(dwc->dev, "USB_REQ_SET_ISOCH_DELAY\n");
+		dwc3_trace(trace_dwc3_ep0, "USB_REQ_SET_ISOCH_DELAY\n");
 		ret = dwc3_ep0_set_isoch_delay(dwc, ctrl);
 		break;
 	default:
-		dev_vdbg(dwc->dev, "Forwarding to gadget driver\n");
+		dwc3_trace(trace_dwc3_ep0, "Forwarding to gadget driver\n");
 		ret = dwc3_ep0_delegate_req(dwc, ctrl);
 		break;
 	}
@@ -727,6 +732,8 @@ static void dwc3_ep0_inspect_setup(struct dwc3 *dwc,
 	if (!dwc->gadget_driver)
 		goto out;
 
+	trace_dwc3_ctrl_req(ctrl);
+
 	len = le16_to_cpu(ctrl->wLength);
 	if (!len) {
 		dwc->three_stage_setup = false;
@@ -775,7 +782,7 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
 
 	status = DWC3_TRB_SIZE_TRBSTS(trb->size);
 	if (status == DWC3_TRBSTS_SETUP_PENDING) {
-		dev_dbg(dwc->dev, "Setup Pending received\n");
+		dwc3_trace(trace_dwc3_ep0, "Setup Pending received");
 
 		if (r)
 			dwc3_gadget_giveback(ep0, r, -ECONNRESET);
@@ -835,7 +842,7 @@ static void dwc3_ep0_complete_status(struct dwc3 *dwc,
 
 		ret = dwc3_gadget_set_test_mode(dwc, dwc->test_mode_nr);
 		if (ret < 0) {
-			dev_dbg(dwc->dev, "Invalid Test #%d\n",
+			dwc3_trace(trace_dwc3_ep0, "Invalid Test #%d",
 					dwc->test_mode_nr);
 			dwc3_ep0_stall_and_restart(dwc);
 			return;
@@ -844,7 +851,7 @@ static void dwc3_ep0_complete_status(struct dwc3 *dwc,
 
 	status = DWC3_TRB_SIZE_TRBSTS(trb->size);
 	if (status == DWC3_TRBSTS_SETUP_PENDING)
-		dev_dbg(dwc->dev, "Setup Pending received\n");
+		dwc3_trace(trace_dwc3_ep0, "Setup Pending received\n");
 
 	dwc->ep0state = EP0_SETUP_PHASE;
 	dwc3_ep0_out_start(dwc);
@@ -861,17 +868,17 @@ static void dwc3_ep0_xfer_complete(struct dwc3 *dwc,
 
 	switch (dwc->ep0state) {
 	case EP0_SETUP_PHASE:
-		dev_vdbg(dwc->dev, "Inspecting Setup Bytes\n");
+		dwc3_trace(trace_dwc3_ep0, "Setup Phase");
 		dwc3_ep0_inspect_setup(dwc, event);
 		break;
 
 	case EP0_DATA_PHASE:
-		dev_vdbg(dwc->dev, "Data Phase\n");
+		dwc3_trace(trace_dwc3_ep0, "Data Phase");
 		dwc3_ep0_complete_data(dwc, event);
 		break;
 
 	case EP0_STATUS_PHASE:
-		dev_vdbg(dwc->dev, "Status Phase\n");
+		dwc3_trace(trace_dwc3_ep0, "Status Phase");
 		dwc3_ep0_complete_status(dwc, event);
 		break;
 	default:
@@ -947,7 +954,7 @@ static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
 static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep)
 {
 	if (dwc->resize_fifos) {
-		dev_dbg(dwc->dev, "starting to resize fifos\n");
+		dwc3_trace(trace_dwc3_ep0, "Resizing FIFOs");
 		dwc3_gadget_resize_tx_fifos(dwc);
 		dwc->resize_fifos = 0;
 	}
@@ -988,7 +995,7 @@ static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
 
 	switch (event->status) {
 	case DEPEVT_STATUS_CONTROL_DATA:
-		dev_vdbg(dwc->dev, "Control Data\n");
+		dwc3_trace(trace_dwc3_ep0, "Control Data");
 
 		/*
 		 * We already have a DATA transfer in the controller's cache,
@@ -1002,7 +1009,8 @@ static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
 		if (dwc->ep0_expect_in != event->endpoint_number) {
 			struct dwc3_ep	*dep = dwc->eps[dwc->ep0_expect_in];
 
-			dev_vdbg(dwc->dev, "Wrong direction for Data phase\n");
+			dwc3_trace(trace_dwc3_ep0,
+					"Wrong direction for Data phase");
 			dwc3_ep0_end_control_data(dwc, dep);
 			dwc3_ep0_stall_and_restart(dwc);
 			return;
@@ -1014,13 +1022,13 @@ static void dwc3_ep0_xfernotready(struct dwc3 *dwc,
 		if (dwc->ep0_next_event != DWC3_EP0_NRDY_STATUS)
 			return;
 
-		dev_vdbg(dwc->dev, "Control Status\n");
+		dwc3_trace(trace_dwc3_ep0, "Control Status");
 
 		dwc->ep0state = EP0_STATUS_PHASE;
 
 		if (dwc->delayed_status) {
 			WARN_ON_ONCE(event->endpoint_number != 1);
-			dev_vdbg(dwc->dev, "Mass Storage delayed status\n");
+			dwc3_trace(trace_dwc3_ep0, "Delayed Status");
 			return;
 		}
 
@@ -1033,7 +1041,7 @@ void dwc3_ep0_interrupt(struct dwc3 *dwc,
 {
 	u8			epnum = event->endpoint_number;
 
-	dev_dbg(dwc->dev, "%s while ep%d%s in state '%s'\n",
+	dwc3_trace(trace_dwc3_ep0, "%s while ep%d%s in state '%s'",
 			dwc3_ep_event_string(event->endpoint_event),
 			epnum >> 1, (epnum & 1) ? "in" : "out",
 			dwc3_ep0_state_string(dwc->ep0state));
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 096b638..f2dbaca 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -267,6 +267,7 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct dwc3_request *req,
 	dev_dbg(dwc->dev, "request %p from %s completed %d/%d ===> %d\n",
 			req, dep->name, req->request.actual,
 			req->request.length, status);
+	trace_dwc3_gadget_giveback(req);
 
 	spin_unlock(&dwc->lock);
 	req->request.complete(&dep->endpoint, &req->request);
@@ -278,8 +279,7 @@ int dwc3_send_gadget_generic_command(struct dwc3 *dwc, unsigned cmd, u32 param)
 	u32		timeout = 500;
 	u32		reg;
 
-	dev_vdbg(dwc->dev, "generic cmd '%s' [%d] param %08x\n",
-			dwc3_gadget_generic_cmd_string(cmd), cmd, param);
+	trace_dwc3_gadget_generic_cmd(cmd, param);
 
 	dwc3_writel(dwc->regs, DWC3_DGCMDPAR, param);
 	dwc3_writel(dwc->regs, DWC3_DGCMD, cmd | DWC3_DGCMD_CMDACT);
@@ -310,10 +310,7 @@ int dwc3_send_gadget_ep_cmd(struct dwc3 *dwc, unsigned ep,
 	u32			timeout = 500;
 	u32			reg;
 
-	dev_vdbg(dwc->dev, "%s: cmd '%s' [%d] params %08x %08x %08x\n",
-			dep->name,
-			dwc3_gadget_ep_cmd_string(cmd), cmd, params->param0,
-			params->param1, params->param2);
+	trace_dwc3_gadget_ep_cmd(dep, cmd, params);
 
 	dwc3_writel(dwc->regs, DWC3_DEPCMDPAR0(ep), params->param0);
 	dwc3_writel(dwc->regs, DWC3_DEPCMDPAR1(ep), params->param1);
@@ -710,6 +707,8 @@ static struct usb_request *dwc3_gadget_ep_alloc_request(struct usb_ep *ep,
 	req->epnum	= dep->number;
 	req->dep	= dep;
 
+	trace_dwc3_alloc_request(req);
+
 	return &req->request;
 }
 
@@ -718,6 +717,7 @@ static void dwc3_gadget_ep_free_request(struct usb_ep *ep,
 {
 	struct dwc3_request		*req = to_dwc3_request(request);
 
+	trace_dwc3_free_request(req);
 	kfree(req);
 }
 
@@ -799,6 +799,8 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
 		trb->ctrl |= DWC3_TRB_CTRL_SID_SOFN(req->request.stream_id);
 
 	trb->ctrl |= DWC3_TRB_CTRL_HWO;
+
+	trace_dwc3_prepare_trb(dep, trb);
 }
 
 /*
@@ -1143,6 +1145,7 @@ static int dwc3_gadget_ep_queue(struct usb_ep *ep, struct usb_request *request,
 
 	dev_vdbg(dwc->dev, "queing request %p to %s length %d\n",
 			request, ep->name, request->length);
+	trace_dwc3_ep_queue(req);
 
 	spin_lock_irqsave(&dwc->lock, flags);
 	ret = __dwc3_gadget_ep_queue(dep, req);
@@ -1163,6 +1166,8 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
 	unsigned long			flags;
 	int				ret = 0;
 
+	trace_dwc3_ep_dequeue(req);
+
 	spin_lock_irqsave(&dwc->lock, flags);
 
 	list_for_each_entry(r, &dep->request_list, list) {
@@ -1753,6 +1758,8 @@ static int __dwc3_cleanup_done_trbs(struct dwc3 *dwc, struct dwc3_ep *dep,
 	unsigned int		s_pkt = 0;
 	unsigned int		trb_status;
 
+	trace_dwc3_complete_trb(dep, trb);
+
 	if ((trb->ctrl & DWC3_TRB_CTRL_HWO) && status != -ESHUTDOWN)
 		/*
 		 * We continue despite the error. There is not much we
@@ -1927,9 +1934,6 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 	if (!(dep->flags & DWC3_EP_ENABLED))
 		return;
 
-	dev_vdbg(dwc->dev, "%s: %s\n", dep->name,
-			dwc3_ep_event_string(event->endpoint_event));
-
 	if (epnum == 0 || epnum == 1) {
 		dwc3_ep0_interrupt(dwc, event);
 		return;
@@ -2122,8 +2126,6 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc)
 {
 	int			reg;
 
-	dev_vdbg(dwc->dev, "%s\n", __func__);
-
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	reg &= ~DWC3_DCTL_INITU1ENA;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
@@ -2142,8 +2144,6 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
 {
 	u32			reg;
 
-	dev_vdbg(dwc->dev, "%s\n", __func__);
-
 	/*
 	 * WORKAROUND: DWC3 revisions <1.88a have an issue which
 	 * would cause a missing Disconnect Event if there's a
@@ -2228,8 +2228,6 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
 	u32			reg;
 	u8			speed;
 
-	dev_vdbg(dwc->dev, "%s\n", __func__);
-
 	reg = dwc3_readl(dwc->regs, DWC3_DSTS);
 	speed = reg & DWC3_DSTS_CONNECTSPD;
 	dwc->speed = speed;
@@ -2327,8 +2325,6 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
 
 static void dwc3_gadget_wakeup_interrupt(struct dwc3 *dwc)
 {
-	dev_vdbg(dwc->dev, "%s\n", __func__);
-
 	/*
 	 * TODO take core out of low power mode when that's
 	 * implemented.
@@ -2433,10 +2429,6 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
 		break;
 	}
 
-	dev_vdbg(dwc->dev, "link change: %s [%d] -> %s [%d]\n",
-			dwc3_gadget_link_string(dwc->link_state),
-			dwc->link_state, dwc3_gadget_link_string(next), next);
-
 	dwc->link_state = next;
 }
 
@@ -2513,6 +2505,8 @@ static void dwc3_gadget_interrupt(struct dwc3 *dwc,
 static void dwc3_process_event_entry(struct dwc3 *dwc,
 		const union dwc3_event *event)
 {
+	trace_dwc3_event(event->raw);
+
 	/* Endpoint IRQ, handle it and return early */
 	if (event->type.is_devspec == 0) {
 		/* depevt */
diff --git a/drivers/usb/dwc3/io.h b/drivers/usb/dwc3/io.h
index d94441c..6a79c8e 100644
--- a/drivers/usb/dwc3/io.h
+++ b/drivers/usb/dwc3/io.h
@@ -20,27 +20,51 @@
 #define __DRIVERS_USB_DWC3_IO_H
 
 #include <linux/io.h>
-
+#include "trace.h"
+#include "debug.h"
 #include "core.h"
 
 static inline u32 dwc3_readl(void __iomem *base, u32 offset)
 {
+	u32 offs = offset - DWC3_GLOBALS_REGS_START;
+	u32 value;
+
 	/*
 	 * We requested the mem region starting from the Globals address
 	 * space, see dwc3_probe in core.c.
 	 * However, the offsets are given starting from xHCI address space.
 	 */
-	return readl(base + (offset - DWC3_GLOBALS_REGS_START));
+	value = readl(base + offs);
+
+	/*
+	 * When tracing we want to make it easy to find the correct address on
+	 * documentation, so we revert it back to the proper addresses, the
+	 * same way they are described on SNPS documentation
+	 */
+	dwc3_trace(trace_dwc3_readl, "addr %p value %08x",
+			base - DWC3_GLOBALS_REGS_START + offset, value);
+
+	return value;
 }
 
 static inline void dwc3_writel(void __iomem *base, u32 offset, u32 value)
 {
+	u32 offs = offset - DWC3_GLOBALS_REGS_START;
+
 	/*
 	 * We requested the mem region starting from the Globals address
 	 * space, see dwc3_probe in core.c.
 	 * However, the offsets are given starting from xHCI address space.
 	 */
-	writel(value, base + (offset - DWC3_GLOBALS_REGS_START));
+	writel(value, base + offs);
+
+	/*
+	 * When tracing we want to make it easy to find the correct address on
+	 * documentation, so we revert it back to the proper addresses, the
+	 * same way they are described on SNPS documentation
+	 */
+	dwc3_trace(trace_dwc3_writel, "addr %p value %08x",
+			base - DWC3_GLOBALS_REGS_START + offset, value);
 }
 
 #endif /* __DRIVERS_USB_DWC3_IO_H */
diff --git a/drivers/usb/dwc3/trace.c b/drivers/usb/dwc3/trace.c
new file mode 100644
index 0000000..6cd1664
--- /dev/null
+++ b/drivers/usb/dwc3/trace.c
@@ -0,0 +1,19 @@
+/**
+ * trace.c - DesignWare USB3 DRD Controller Trace Support
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: Felipe Balbi <balbi@ti.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
diff --git a/drivers/usb/dwc3/trace.h b/drivers/usb/dwc3/trace.h
new file mode 100644
index 0000000..78aff1d
--- /dev/null
+++ b/drivers/usb/dwc3/trace.h
@@ -0,0 +1,220 @@
+/**
+ * trace.h - DesignWare USB3 DRD Controller Trace Support
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: Felipe Balbi <balbi@ti.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2  of
+ * the License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM dwc3
+
+#if !defined(__DWC3_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define __DWC3_TRACE_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+#include <asm/byteorder.h>
+#include "core.h"
+#include "debug.h"
+
+DECLARE_EVENT_CLASS(dwc3_log_msg,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf),
+	TP_STRUCT__entry(__dynamic_array(char, msg, DWC3_MSG_MAX)),
+	TP_fast_assign(
+		vsnprintf(__get_str(msg), DWC3_MSG_MAX, vaf->fmt, *vaf->va);
+	),
+	TP_printk("%s", __get_str(msg))
+);
+
+DEFINE_EVENT(dwc3_log_msg, dwc3_readl,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+
+DEFINE_EVENT(dwc3_log_msg, dwc3_writel,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+
+DEFINE_EVENT(dwc3_log_msg, dwc3_ep0,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+
+DECLARE_EVENT_CLASS(dwc3_log_event,
+	TP_PROTO(u32 event),
+	TP_ARGS(event),
+	TP_STRUCT__entry(
+		__field(u32, event)
+	),
+	TP_fast_assign(
+		__entry->event = event;
+	),
+	TP_printk("event %08x\n", __entry->event)
+);
+
+DEFINE_EVENT(dwc3_log_event, dwc3_event,
+	TP_PROTO(u32 event),
+	TP_ARGS(event)
+);
+
+DECLARE_EVENT_CLASS(dwc3_log_ctrl,
+	TP_PROTO(struct usb_ctrlrequest *ctrl),
+	TP_ARGS(ctrl),
+	TP_STRUCT__entry(
+		__field(struct usb_ctrlrequest *, ctrl)
+	),
+	TP_fast_assign(
+		__entry->ctrl = ctrl;
+	),
+	TP_printk("bRequestType %02x bRequest %02x wValue %04x wIndex %04x wLength %d",
+		__entry->ctrl->bRequestType, __entry->ctrl->bRequest,
+		le16_to_cpu(__entry->ctrl->wValue), le16_to_cpu(__entry->ctrl->wIndex),
+		le16_to_cpu(__entry->ctrl->wLength)
+	)
+);
+
+DEFINE_EVENT(dwc3_log_ctrl, dwc3_ctrl_req,
+	TP_PROTO(struct usb_ctrlrequest *ctrl),
+	TP_ARGS(ctrl)
+);
+
+DECLARE_EVENT_CLASS(dwc3_log_request,
+	TP_PROTO(struct dwc3_request *req),
+	TP_ARGS(req),
+	TP_STRUCT__entry(
+		__field(struct dwc3_request *, req)
+	),
+	TP_fast_assign(
+		__entry->req = req;
+	),
+	TP_printk("%s: req %p length %u/%u ==> %d",
+		__entry->req->dep->name, __entry->req,
+		__entry->req->request.actual, __entry->req->request.length,
+		__entry->req->request.status
+	)
+);
+
+DEFINE_EVENT(dwc3_log_request, dwc3_alloc_request,
+	TP_PROTO(struct dwc3_request *req),
+	TP_ARGS(req)
+);
+
+DEFINE_EVENT(dwc3_log_request, dwc3_free_request,
+	TP_PROTO(struct dwc3_request *req),
+	TP_ARGS(req)
+);
+
+DEFINE_EVENT(dwc3_log_request, dwc3_ep_queue,
+	TP_PROTO(struct dwc3_request *req),
+	TP_ARGS(req)
+);
+
+DEFINE_EVENT(dwc3_log_request, dwc3_ep_dequeue,
+	TP_PROTO(struct dwc3_request *req),
+	TP_ARGS(req)
+);
+
+DEFINE_EVENT(dwc3_log_request, dwc3_gadget_giveback,
+	TP_PROTO(struct dwc3_request *req),
+	TP_ARGS(req)
+);
+
+DECLARE_EVENT_CLASS(dwc3_log_generic_cmd,
+	TP_PROTO(unsigned int cmd, u32 param),
+	TP_ARGS(cmd, param),
+	TP_STRUCT__entry(
+		__field(unsigned int, cmd)
+		__field(u32, param)
+	),
+	TP_fast_assign(
+		__entry->cmd = cmd;
+		__entry->param = param;
+	),
+	TP_printk("cmd '%s' [%d] param %08x\n",
+		dwc3_gadget_generic_cmd_string(__entry->cmd),
+		__entry->cmd, __entry->param
+	)
+);
+
+DEFINE_EVENT(dwc3_log_generic_cmd, dwc3_gadget_generic_cmd,
+	TP_PROTO(unsigned int cmd, u32 param),
+	TP_ARGS(cmd, param)
+);
+
+DECLARE_EVENT_CLASS(dwc3_log_gadget_ep_cmd,
+	TP_PROTO(struct dwc3_ep *dep, unsigned int cmd,
+		struct dwc3_gadget_ep_cmd_params *params),
+	TP_ARGS(dep, cmd, params),
+	TP_STRUCT__entry(
+		__field(struct dwc3_ep *, dep)
+		__field(unsigned int, cmd)
+		__field(struct dwc3_gadget_ep_cmd_params *, params)
+	),
+	TP_fast_assign(
+		__entry->dep = dep;
+		__entry->cmd = cmd;
+		__entry->params = params;
+	),
+	TP_printk("%s: cmd '%s' [%d] params %08x %08x %08x\n",
+		__entry->dep->name, dwc3_gadget_ep_cmd_string(__entry->cmd),
+		__entry->cmd, __entry->params->param0,
+		__entry->params->param1, __entry->params->param2
+	)
+);
+
+DEFINE_EVENT(dwc3_log_gadget_ep_cmd, dwc3_gadget_ep_cmd,
+	TP_PROTO(struct dwc3_ep *dep, unsigned int cmd,
+		struct dwc3_gadget_ep_cmd_params *params),
+	TP_ARGS(dep, cmd, params)
+);
+
+DECLARE_EVENT_CLASS(dwc3_log_trb,
+	TP_PROTO(struct dwc3_ep *dep, struct dwc3_trb *trb),
+	TP_ARGS(dep, trb),
+	TP_STRUCT__entry(
+		__field(struct dwc3_ep *, dep)
+		__field(struct dwc3_trb *, trb)
+	),
+	TP_fast_assign(
+		__entry->dep = dep;
+		__entry->trb = trb;
+	),
+	TP_printk("%s: trb %p bph %08x bpl %08x size %08x ctrl %08x\n",
+		__entry->dep->name, __entry->trb, __entry->trb->bph,
+		__entry->trb->bpl, __entry->trb->size, __entry->trb->ctrl
+	)
+);
+
+DEFINE_EVENT(dwc3_log_trb, dwc3_prepare_trb,
+	TP_PROTO(struct dwc3_ep *dep, struct dwc3_trb *trb),
+	TP_ARGS(dep, trb)
+);
+
+DEFINE_EVENT(dwc3_log_trb, dwc3_complete_trb,
+	TP_PROTO(struct dwc3_ep *dep, struct dwc3_trb *trb),
+	TP_ARGS(dep, trb)
+);
+
+#endif /* __DWC3_TRACE_H */
+
+/* this part has to be here */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>