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-rw-r--r--drivers/i2c/i2c-core.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 98a5fd950f16..bdedbee85c01 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -48,10 +48,13 @@
#include <linux/rwsem.h>
#include <linux/pm_runtime.h>
#include <linux/acpi.h>
+#include <linux/jump_label.h>
#include <asm/uaccess.h>
#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
@@ -62,6 +65,18 @@ static DEFINE_IDR(i2c_adapter_idr);
static struct device_type i2c_client_type;
static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
+static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
+
+void i2c_transfer_trace_reg(void)
+{
+ static_key_slow_inc(&i2c_trace_msg);
+}
+
+void i2c_transfer_trace_unreg(void)
+{
+ static_key_slow_dec(&i2c_trace_msg);
+}
+
/* ------------------------------------------------------------------------- */
static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
@@ -1686,6 +1701,7 @@ static void __exit i2c_exit(void)
class_compat_unregister(i2c_adapter_compat_class);
#endif
bus_unregister(&i2c_bus_type);
+ tracepoint_synchronize_unregister();
}
/* We must initialize early, because some subsystems register i2c drivers
@@ -1716,6 +1732,19 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
unsigned long orig_jiffies;
int ret, try;
+ /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
+ * enabled. This is an efficient way of keeping the for-loop from
+ * being executed when not needed.
+ */
+ if (static_key_false(&i2c_trace_msg)) {
+ int i;
+ for (i = 0; i < num; i++)
+ if (msgs[i].flags & I2C_M_RD)
+ trace_i2c_read(adap, &msgs[i], i);
+ else
+ trace_i2c_write(adap, &msgs[i], i);
+ }
+
/* Retry automatically on arbitration loss */
orig_jiffies = jiffies;
for (ret = 0, try = 0; try <= adap->retries; try++) {
@@ -1726,6 +1755,14 @@ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
break;
}
+ if (static_key_false(&i2c_trace_msg)) {
+ int i;
+ for (i = 0; i < ret; i++)
+ if (msgs[i].flags & I2C_M_RD)
+ trace_i2c_reply(adap, &msgs[i], i);
+ trace_i2c_result(adap, i, ret);
+ }
+
return ret;
}
EXPORT_SYMBOL(__i2c_transfer);