This patch is adding trace events for each request that is being
enqueued into the hw and will be completed. This way it is possible
to track the fill status of the gadget hardware and find potential
issues.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>

---
v1 -> v5: - new patch
---
 drivers/usb/gadget/function/Makefile    |  5 +++
 drivers/usb/gadget/function/uvc_trace.c | 11 ++++++
 drivers/usb/gadget/function/uvc_trace.h | 60 +++++++++++++++++++++++++++++++++
 drivers/usb/gadget/function/uvc_video.c |  5 +++
 4 files changed, 81 insertions(+)

diff --git a/drivers/usb/gadget/function/Makefile b/drivers/usb/gadget/function/Makefile
index 87917a7d4a9be..99b2bab4cc32f 100644
--- a/drivers/usb/gadget/function/Makefile
+++ b/drivers/usb/gadget/function/Makefile
@@ -42,6 +42,11 @@ usb_f_uac2-y			:= f_uac2.o
 obj-$(CONFIG_USB_F_UAC2)	+= usb_f_uac2.o
 usb_f_uvc-y			:= f_uvc.o uvc_queue.o uvc_v4l2.o uvc_video.o uvc_configfs.o
 obj-$(CONFIG_USB_F_UVC)		+= usb_f_uvc.o
+ifeq ($(CONFIG_USB_F_UVC),y)
+  ifneq ($(CONFIG_TRACING),)
+    obj-$(CONFIG_USB_F_UVC)	+= uvc_trace.o
+  endif
+endif
 usb_f_midi-y			:= f_midi.o
 obj-$(CONFIG_USB_F_MIDI)	+= usb_f_midi.o
 usb_f_midi2-y			:= f_midi2.o
diff --git a/drivers/usb/gadget/function/uvc_trace.c b/drivers/usb/gadget/function/uvc_trace.c
new file mode 100644
index 0000000000000..d384f6d8221a5
--- /dev/null
+++ b/drivers/usb/gadget/function/uvc_trace.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace.c - USB UVC Gadget Trace Support
+ *
+ * Copyright (C) 2024 Pengutronix e.K.
+ *
+ * Author: Michael Grzeschik <m.grzeschik@pengutronix.de>
+ */
+
+#define CREATE_TRACE_POINTS
+#include "uvc_trace.h"
diff --git a/drivers/usb/gadget/function/uvc_trace.h b/drivers/usb/gadget/function/uvc_trace.h
new file mode 100644
index 0000000000000..43b9544d56550
--- /dev/null
+++ b/drivers/usb/gadget/function/uvc_trace.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * trace.h - USB UVC Gadget Trace Support
+ *
+ * Copyright (C) 2024 Pengutronix e.K.
+ *
+ * Author: Michael Grzeschik <m.grzeschik@pengutronix.de>
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM uvcg
+
+#if !defined(__UVCG_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define __UVCG_TRACE_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+#include <asm/byteorder.h>
+#include <linux/usb/gadget.h>
+
+DECLARE_EVENT_CLASS(uvcg_video_req,
+	TP_PROTO(struct usb_request *req, u32 queued),
+	TP_ARGS(req, queued),
+	TP_STRUCT__entry(
+		__field(struct usb_request *, req)
+		__field(u32, length)
+		__field(u32, queued)
+	),
+	TP_fast_assign(
+		__entry->req = req;
+		__entry->length = req->length;
+		__entry->queued = queued;
+	),
+	TP_printk("req %p length %u queued %u",
+		__entry->req,
+		__entry->length,
+		__entry->queued)
+);
+
+DEFINE_EVENT(uvcg_video_req, uvcg_video_complete,
+	TP_PROTO(struct usb_request *req, u32 queued),
+	TP_ARGS(req, queued)
+);
+
+DEFINE_EVENT(uvcg_video_req, uvcg_video_queue,
+	TP_PROTO(struct usb_request *req, u32 queued),
+	TP_ARGS(req, queued)
+);
+
+#endif /* __UVCG_TRACE_H */
+
+/* this part has to be here */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE uvc_trace
+
+#include <trace/define_trace.h>
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 0287a56fa50ad..115524b79ebd7 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -19,6 +19,7 @@
 #include "uvc.h"
 #include "uvc_queue.h"
 #include "uvc_video.h"
+#include "uvc_trace.h"
 
 /* --------------------------------------------------------------------------
  * Video codecs
@@ -271,6 +272,8 @@ static int uvcg_video_ep_queue(struct uvc_video *video, struct usb_request *req)
 
 	atomic_inc(&video->queued);
 
+	trace_uvcg_video_queue(req, atomic_read(&video->queued));
+
 	return ret;
 }
 
@@ -408,6 +411,8 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
 	 */
 	queue_work(video->async_wq, &video->pump);
 
+	trace_uvcg_video_complete(req, atomic_read(&video->queued));
+
 	spin_unlock_irqrestore(&video->req_lock, flags);
 
 	kthread_queue_work(video->kworker, &video->hw_submit);

-- 
2.39.5

Hi Michael,

kernel test robot noticed the following build errors:

[auto build test ERROR on 68d4209158f43a558c5553ea95ab0c8975eab18c]

url:    https://github.com/intel-lab-lkp/linux/commits/Michael-Grzeschik/usb-gadget-uvc-wake-pump-everytime-we-update-the-free-list/20240927-074027
base:   68d4209158f43a558c5553ea95ab0c8975eab18c
patch link:    https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v5-8-2de78794365c%40pengutronix.de
patch subject: [PATCH v5 8/9] usb: gadget: uvc: add trace of enqueued and completed requests
config: arm-defconfig (https://download.01.org/0day-ci/archive/20240928/202409281004.YHy0SVaY-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240928/202409281004.YHy0SVaY-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409281004.YHy0SVaY-lkp@intel.com/

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "__tracepoint_uvcg_video_complete" [drivers/usb/gadget/function/usb_f_uvc.ko] undefined!
>> ERROR: modpost: "__traceiter_uvcg_video_complete" [drivers/usb/gadget/function/usb_f_uvc.ko] undefined!
>> ERROR: modpost: "__tracepoint_uvcg_video_queue" [drivers/usb/gadget/function/usb_f_uvc.ko] undefined!
>> ERROR: modpost: "__traceiter_uvcg_video_queue" [drivers/usb/gadget/function/usb_f_uvc.ko] undefined!

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki