thunderbolt: Add trace events support for the control channel

Sometimes it is useful to see the traffic happening inside the control
channel, especially when debugging a possible problem. This adds
tracepoints close to the hardware which can be enabled dynamically as
needed using the standard Linux trace events facility.
Signed-off-by: Gil Fine <gil.fine@linux.intel.com>
Co-developed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/thunderbolt/Makefile

 # SPDX-License-Identifier: GPL-2.0-only
+ccflags-y := -I$(src)
 obj-${CONFIG_USB4} := thunderbolt.o
 thunderbolt-objs := nhi.o nhi_ops.o ctl.o tb.o switch.o cap.o path.o tunnel.o eeprom.o
 thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o tmu.o usb4.o

drivers/thunderbolt/ctl.c

@@ -15,6 +15,8 @@
 
 #include "ctl.h"
 
+#define CREATE_TRACE_POINTS
+#include "trace.h"
 
 #define TB_CTL_RX_PKG_COUNT	10
 #define TB_CTL_RETRIES		4
@@ -32,6 +34,7 @@
  * @timeout_msec: Default timeout for non-raw control messages
  * @callback: Callback called when hotplug message is received
  * @callback_data: Data passed to @callback
+ * @index: Domain number. This will be output with the trace record.
  */
 struct tb_ctl {
 	struct tb_nhi *nhi;
@@ -47,6 +50,8 @@ struct tb_ctl {
 	int timeout_msec;
 	event_cb callback;
 	void *callback_data;
+
+	int index;
 };
 
 
@@ -369,6 +374,9 @@ static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
 	pkg->frame.size = len + 4;
 	pkg->frame.sof = type;
 	pkg->frame.eof = type;
+
+	trace_tb_tx(ctl->index, type, data, len);
+
 	cpu_to_be32_array(pkg->buffer, data, len / 4);
 	*(__be32 *) (pkg->buffer + len) = tb_crc(pkg->buffer, len);
 
@@ -384,6 +392,7 @@ static int tb_ctl_tx(struct tb_ctl *ctl, const void *data, size_t len,
 static bool tb_ctl_handle_event(struct tb_ctl *ctl, enum tb_cfg_pkg_type type,
 				struct ctl_pkg *pkg, size_t size)
 {
+	trace_tb_event(ctl->index, type, pkg->buffer, size);
 	return ctl->callback(ctl->callback_data, type, pkg->buffer, size);
 }
 
@@ -489,6 +498,9 @@ static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
 	 * triggered from messing with the active requests.
 	 */
 	req = tb_cfg_request_find(pkg->ctl, pkg);
+
+	trace_tb_rx(pkg->ctl->index, frame->eof, pkg->buffer, frame->size, !req);
+
 	if (req) {
 		if (req->copy(req, pkg))
 			schedule_work(&req->work);
@@ -614,6 +626,7 @@ struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
 /**
  * tb_ctl_alloc() - allocate a control channel
  * @nhi: Pointer to NHI
+ * @index: Domain number
  * @timeout_msec: Default timeout used with non-raw control messages
  * @cb: Callback called for plug events
  * @cb_data: Data passed to @cb
@@ -622,14 +635,16 @@ struct tb_cfg_result tb_cfg_request_sync(struct tb_ctl *ctl,
  *
  * Return: Returns a pointer on success or NULL on failure.
  */
-struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int timeout_msec, event_cb cb,
-			    void *cb_data)
+struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int index, int timeout_msec,
+			    event_cb cb, void *cb_data)
 {
 	int i;
 	struct tb_ctl *ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
 	if (!ctl)
 		return NULL;
+
 	ctl->nhi = nhi;
+	ctl->index = index;
 	ctl->timeout_msec = timeout_msec;
 	ctl->callback = cb;
 	ctl->callback_data = cb_data;

drivers/thunderbolt/ctl.h

@@ -21,8 +21,8 @@ struct tb_ctl;
 typedef bool (*event_cb)(void *data, enum tb_cfg_pkg_type type,
 			 const void *buf, size_t size);
 
-struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int timeout_msec, event_cb cb,
-			    void *cb_data);
+struct tb_ctl *tb_ctl_alloc(struct tb_nhi *nhi, int index, int timeout_msec,
+			    event_cb cb, void *cb_data);
 void tb_ctl_start(struct tb_ctl *ctl);
 void tb_ctl_stop(struct tb_ctl *ctl);
 void tb_ctl_free(struct tb_ctl *ctl);

drivers/thunderbolt/domain.c

@@ -397,7 +397,7 @@ struct tb *tb_domain_alloc(struct tb_nhi *nhi, int timeout_msec, size_t privsize
 	if (!tb->wq)
 		goto err_remove_ida;
 
-	tb->ctl = tb_ctl_alloc(nhi, timeout_msec, tb_domain_event_cb, tb);
+	tb->ctl = tb_ctl_alloc(nhi, tb->index, timeout_msec, tb_domain_event_cb, tb);
 	if (!tb->ctl)
 		goto err_destroy_wq;
 

drivers/thunderbolt/trace.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Thunderbolt tracing support
+ *
+ * Copyright (C) 2024, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ *	   Gil Fine <gil.fine@intel.com>
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM thunderbolt
+
+#if !defined(TB_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
+#define TB_TRACE_H_
+
+#include <linux/trace_seq.h>
+#include <linux/tracepoint.h>
+
+#include "tb_msgs.h"
+
+#define tb_cfg_type_name(type)		{ type, #type }
+#define show_type_name(val)					\
+	__print_symbolic(val,					\
+		tb_cfg_type_name(TB_CFG_PKG_READ),		\
+		tb_cfg_type_name(TB_CFG_PKG_WRITE),		\
+		tb_cfg_type_name(TB_CFG_PKG_ERROR),		\
+		tb_cfg_type_name(TB_CFG_PKG_NOTIFY_ACK),	\
+		tb_cfg_type_name(TB_CFG_PKG_EVENT),		\
+		tb_cfg_type_name(TB_CFG_PKG_XDOMAIN_REQ),	\
+		tb_cfg_type_name(TB_CFG_PKG_XDOMAIN_RESP),	\
+		tb_cfg_type_name(TB_CFG_PKG_OVERRIDE),		\
+		tb_cfg_type_name(TB_CFG_PKG_RESET),		\
+		tb_cfg_type_name(TB_CFG_PKG_ICM_EVENT),		\
+		tb_cfg_type_name(TB_CFG_PKG_ICM_CMD),		\
+		tb_cfg_type_name(TB_CFG_PKG_ICM_RESP))
+
+#ifndef TB_TRACE_HELPERS
+#define TB_TRACE_HELPERS
+static inline const char *show_data_read_write(struct trace_seq *p,
+					       const u32 *data)
+{
+	const struct cfg_read_pkg *msg = (const struct cfg_read_pkg *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "offset=%#x, len=%u, port=%d, config=%#x, seq=%d, ",
+			 msg->addr.offset, msg->addr.length, msg->addr.port,
+			 msg->addr.space, msg->addr.seq);
+
+	return ret;
+}
+
+static inline const char *show_data_error(struct trace_seq *p, const u32 *data)
+{
+	const struct cfg_error_pkg *msg = (const struct cfg_error_pkg *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "error=%#x, port=%d, plug=%#x, ", msg->error,
+			 msg->port, msg->pg);
+
+	return ret;
+}
+
+static inline const char *show_data_event(struct trace_seq *p, const u32 *data)
+{
+	const struct cfg_event_pkg *msg = (const struct cfg_event_pkg *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "port=%d, unplug=%#x, ", msg->port, msg->unplug);
+
+	return ret;
+}
+
+static inline const char *show_route(struct trace_seq *p, const u32 *data)
+{
+	const struct tb_cfg_header *header = (const struct tb_cfg_header *)data;
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	trace_seq_printf(p, "route=%llx, ", tb_cfg_get_route(header));
+
+	return ret;
+}
+
+static inline const char *show_data(struct trace_seq *p, u8 type,
+				    const u32 *data, u32 length)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+	const char *prefix = "";
+	int i;
+
+	show_route(p, data);
+
+	switch (type) {
+	case TB_CFG_PKG_READ:
+	case TB_CFG_PKG_WRITE:
+		show_data_read_write(p, data);
+		break;
+
+	case TB_CFG_PKG_ERROR:
+		show_data_error(p, data);
+		break;
+
+	case TB_CFG_PKG_EVENT:
+		show_data_event(p, data);
+		break;
+
+	default:
+		break;
+	}
+
+	trace_seq_printf(p, "data=[");
+	for (i = 0; i < length; i++) {
+		trace_seq_printf(p, "%s0x%08x", prefix, data[i]);
+		prefix = ", ";
+	}
+	trace_seq_printf(p, "]");
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+#endif
+
+DECLARE_EVENT_CLASS(tb_raw,
+	TP_PROTO(int index, u8 type, const void *data, size_t size),
+	TP_ARGS(index, type, data, size),
+	TP_STRUCT__entry(
+		__field(int, index)
+		__field(u8, type)
+		__field(size_t, size)
+		__dynamic_array(u32, data, size / 4)
+	),
+	TP_fast_assign(
+		__entry->index = index;
+		__entry->type = type;
+		__entry->size = size / 4;
+		memcpy(__get_dynamic_array(data), data, size);
+	),
+	TP_printk("type=%s, size=%zd, domain=%d, %s",
+		  show_type_name(__entry->type), __entry->size, __entry->index,
+		  show_data(p, __entry->type, __get_dynamic_array(data),
+			    __entry->size)
+	)
+);
+
+DEFINE_EVENT(tb_raw, tb_tx,
+	TP_PROTO(int index, u8 type, const void *data, size_t size),
+	TP_ARGS(index, type, data, size)
+);
+
+DEFINE_EVENT(tb_raw, tb_event,
+	TP_PROTO(int index, u8 type, const void *data, size_t size),
+	TP_ARGS(index, type, data, size)
+);
+
+TRACE_EVENT(tb_rx,
+	TP_PROTO(int index, u8 type, const void *data, size_t size, bool dropped),
+	TP_ARGS(index, type, data, size, dropped),
+	TP_STRUCT__entry(
+		__field(int, index)
+		__field(u8, type)
+		__field(size_t, size)
+		__dynamic_array(u32, data, size / 4)
+		__field(bool, dropped)
+	),
+	TP_fast_assign(
+		__entry->index = index;
+		__entry->type = type;
+		__entry->size = size / 4;
+		memcpy(__get_dynamic_array(data), data, size);
+		__entry->dropped = dropped;
+	),
+	TP_printk("type=%s, dropped=%u, size=%zd, domain=%d, %s",
+		  show_type_name(__entry->type), __entry->dropped,
+		  __entry->size, __entry->index,
+		  show_data(p, __entry->type, __get_dynamic_array(data),
+			    __entry->size)
+	)
+);
+
+#endif /* TB_TRACE_H_ */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>