Add basic trace events for i2c_transfer() and i2c_smbus_xfer() so we
can observe the I2C/SMBus activity without filling up the dmesg ring buffer.
Signed-off-by: Dimitris Papastamos <dp@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/i2c-core.c | 8 ++++-
include/trace/events/i2c.h | 70 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 77 insertions(+), 1 deletions(-)
create mode 100644 include/trace/events/i2c.h
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index f0bd5bc..848f0fc 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -42,6 +42,8 @@
#include "i2c-core.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/i2c.h>
/* core_lock protects i2c_adapter_idr, and guarantees
that device detection, deletion of detected devices, and attach_adapter
@@ -1289,7 +1291,7 @@ module_exit(i2c_exit);
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
unsigned long orig_jiffies;
- int ret, try;
+ int ret, try, i;
/* REVISIT the fault reporting model here is weak:
*
@@ -1330,6 +1332,8 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
/* Retry automatically on arbitration loss */
orig_jiffies = jiffies;
for (ret = 0, try = 0; try <= adap->retries; try++) {
+ for (i = 0; i < num; i++)
+ trace_i2c_transfer(adap->name, &msgs[i]);
ret = adap->algo->master_xfer(adap, msgs, num);
if (ret != -EAGAIN)
break;
@@ -2089,6 +2093,8 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
/* Retry automatically on arbitration loss */
orig_jiffies = jiffies;
for (res = 0, try = 0; try <= adapter->retries; try++) {
+ trace_i2c_smbus_xfer(adapter->name, addr, flags,
+ read_write, command, protocol);
res = adapter->algo->smbus_xfer(adapter, addr, flags,
read_write, command,
protocol, data);
diff --git a/include/trace/events/i2c.h b/include/trace/events/i2c.h
new file mode 100644
index 0000000..2c1fb9b
--- /dev/null
+++ b/include/trace/events/i2c.h
@@ -0,0 +1,70 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM i2c
+
+#if !defined(_TRACE_I2C_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_I2C_H
+
+#include <linux/ktime.h>
+#include <linux/tracepoint.h>
+
+struct i2c_msg;
+
+TRACE_EVENT(i2c_transfer,
+
+ TP_PROTO(const char *name, struct i2c_msg *msg),
+
+ TP_ARGS(name, msg),
+
+ TP_STRUCT__entry(
+ __string( name, name )
+ __field( u16, addr )
+ __field( u16, len )
+ __field( u16, flags )
+ ),
+
+ TP_fast_assign(
+ __assign_str(name, name);
+ __entry->addr = msg->addr;
+ __entry->len = msg->len;
+ __entry->flags = msg->flags;
+ ),
+
+ TP_printk("name=%s addr=%#x len=%#x flags=%#x", __get_str(name),
+ (u16)__entry->addr, (u16)__entry->len, (u16)__entry->flags)
+);
+
+TRACE_EVENT(i2c_smbus_xfer,
+
+ TP_PROTO(const char *name, u16 addr, unsigned short flags,
+ char read_write, u8 command, int protocol),
+
+ TP_ARGS(name, addr, flags, read_write, command, protocol),
+
+ TP_STRUCT__entry(
+ __string( name, name )
+ __field( u16, addr )
+ __field( unsigned short, flags )
+ __field( char, read_write )
+ __field( u8, command )
+ __field( int, protocol )
+ ),
+
+ TP_fast_assign(
+ __assign_str(name, name);
+ __entry->addr = addr;
+ __entry->flags = flags;
+ __entry->read_write = read_write;
+ __entry->command = command;
+ __entry->protocol = protocol;
+ ),
+
+ TP_printk("name=%s addr=%#x flags=%#x read_write=%#x command=%#x protocol=%#x",
+ __get_str(name), (u16)__entry->addr,
+ (unsigned short)__entry->flags, (char)__entry->read_write,
+ (u8)__entry->command, (int)__entry->protocol)
+);
+
+#endif /* _TRACE_I2C_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
1.7.3.5
--
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