i2c: add tracepoints for I2C slave events

I2C slave events tracepoints can be enabled by:

	echo 1 > /sys/kernel/tracing/events/i2c_slave/enable

and logs in /sys/kernel/tracing/trace will look like:

	... i2c_slave: i2c-0 a=010 ret=0 WR_REQ []
	... i2c_slave: i2c-0 a=010 ret=0 WR_RCV [02]
	... i2c_slave: i2c-0 a=010 ret=0 WR_RCV [0c]
	... i2c_slave: i2c-0 a=010 ret=0   STOP []
	... i2c_slave: i2c-0 a=010 ret=0 RD_REQ [04]
	... i2c_slave: i2c-0 a=010 ret=0 RD_PRO [b4]
	... i2c_slave: i2c-0 a=010 ret=0  STOP []

formatted as:

	i2c-<adapter_nr>
	a=<addr>
	ret=<ret>	<- callback return value
	<event>
	[<data>]

trace printings can be selected by adding a filter like:

	echo adapter_nr==1 >/sys/kernel/tracing/events/i2c_slave/filter

Signed-off-by: Jae Hyun Yoo <quic_jaehyoo@quicinc.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/i2c-core-slave.c b/drivers/i2c/i2c-core-slave.c
index 1589179d5eb92af2b6dc5181b9a04b30efc05dfa..e3765e12f93bf61c75c0f57ac60b4072daa1505f 100644 (file)
--- a/drivers/i2c/i2c-core-slave.c
+++ b/drivers/i2c/i2c-core-slave.c
@@ -14,6 +14,9 @@
 
 #include "i2c-core.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/i2c_slave.h>
+
 int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
 {
        int ret;
@@ -79,6 +82,18 @@ int i2c_slave_unregister(struct i2c_client *client)
 }
 EXPORT_SYMBOL_GPL(i2c_slave_unregister);
 
+int i2c_slave_event(struct i2c_client *client,
+                   enum i2c_slave_event event, u8 *val)
+{
+       int ret = client->slave_cb(client, event, val);
+
+       if (trace_i2c_slave_enabled())
+               trace_i2c_slave(client, event, val, ret);
+
+       return ret;
+}
+EXPORT_SYMBOL_GPL(i2c_slave_event);
+
 /**
  * i2c_detect_slave_mode - detect operation mode
  * @dev: The device owning the bus

diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 7d4f52ceb7b547b8d485fa4e4de639df1acb579e..fbda5ada2afcaa6a8ca6f365476b04258595b1d7 100644 (file)
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -392,12 +392,8 @@ enum i2c_slave_event {
 int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb);
 int i2c_slave_unregister(struct i2c_client *client);
 bool i2c_detect_slave_mode(struct device *dev);
-
-static inline int i2c_slave_event(struct i2c_client *client,
-                                 enum i2c_slave_event event, u8 *val)
-{
-       return client->slave_cb(client, event, val);
-}
+int i2c_slave_event(struct i2c_client *client,
+                   enum i2c_slave_event event, u8 *val);
 #else
 static inline bool i2c_detect_slave_mode(struct device *dev) { return false; }
 #endif

diff --git a/include/trace/events/i2c_slave.h b/include/trace/events/i2c_slave.h
new file mode 100644 (file)
index 0000000..811166a
--- /dev/null
+++ b/include/trace/events/i2c_slave.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * I2C slave tracepoints
+ *
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM i2c_slave
+
+#if !defined(_TRACE_I2C_SLAVE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_I2C_SLAVE_H
+
+#include <linux/i2c.h>
+#include <linux/tracepoint.h>
+
+TRACE_DEFINE_ENUM(I2C_SLAVE_READ_REQUESTED);
+TRACE_DEFINE_ENUM(I2C_SLAVE_WRITE_REQUESTED);
+TRACE_DEFINE_ENUM(I2C_SLAVE_READ_PROCESSED);
+TRACE_DEFINE_ENUM(I2C_SLAVE_WRITE_RECEIVED);
+TRACE_DEFINE_ENUM(I2C_SLAVE_STOP);
+
+#define show_event_type(type)                                          \
+       __print_symbolic(type,                                          \
+               { I2C_SLAVE_READ_REQUESTED,     "RD_REQ" },             \
+               { I2C_SLAVE_WRITE_REQUESTED,    "WR_REQ" },             \
+               { I2C_SLAVE_READ_PROCESSED,     "RD_PRO" },             \
+               { I2C_SLAVE_WRITE_RECEIVED,     "WR_RCV" },             \
+               { I2C_SLAVE_STOP,               "  STOP" })
+
+TRACE_EVENT(i2c_slave,
+       TP_PROTO(const struct i2c_client *client, enum i2c_slave_event event,
+                __u8 *val, int cb_ret),
+       TP_ARGS(client, event, val, cb_ret),
+       TP_STRUCT__entry(
+               __field(int,                            adapter_nr      )
+               __field(int,                            ret             )
+               __field(__u16,                          addr            )
+               __field(__u16,                          len             )
+               __field(enum i2c_slave_event,           event           )
+               __array(__u8,                           buf,    1)      ),
+
+       TP_fast_assign(
+               __entry->adapter_nr = client->adapter->nr;
+               __entry->addr = client->addr;
+               __entry->event = event;
+               __entry->ret = cb_ret;
+               switch (event) {
+               case I2C_SLAVE_READ_REQUESTED:
+               case I2C_SLAVE_READ_PROCESSED:
+               case I2C_SLAVE_WRITE_RECEIVED:
+                       __entry->len = 1;
+                       memcpy(__entry->buf, val, __entry->len);
+                       break;
+               default:
+                       __entry->len = 0;
+                       break;
+               }
+               ),
+       TP_printk("i2c-%d a=%03x ret=%d %s [%*phD]",
+               __entry->adapter_nr, __entry->addr, __entry->ret,
+               show_event_type(__entry->event), __entry->len, __entry->buf
+               ));
+
+#endif /* _TRACE_I2C_SLAVE_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>