diff options
| -rw-r--r-- | drivers/i2c/i2c-core.c | 37 | ||||
| -rw-r--r-- | include/trace/events/i2c.h | 150 |
2 files changed, 187 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); diff --git a/include/trace/events/i2c.h b/include/trace/events/i2c.h new file mode 100644 index 000000000000..4800207269a2 --- /dev/null +++ b/include/trace/events/i2c.h @@ -0,0 +1,150 @@ +/* I2C message transfer tracepoints + * + * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM i2c + +#if !defined(_TRACE_I2C_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_I2C_H + +#include <linux/i2c.h> +#include <linux/tracepoint.h> + +/* + * drivers/i2c/i2c-core.c + */ +extern void i2c_transfer_trace_reg(void); +extern void i2c_transfer_trace_unreg(void); + +/* + * __i2c_transfer() write request + */ +TRACE_EVENT_FN(i2c_write, + TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg, + int num), + TP_ARGS(adap, msg, num), + TP_STRUCT__entry( + __field(int, adapter_nr ) + __field(__u16, msg_nr ) + __field(__u16, addr ) + __field(__u16, flags ) + __field(__u16, len ) + __dynamic_array(__u8, buf, msg->len) ), + TP_fast_assign( + __entry->adapter_nr = adap->nr; + __entry->msg_nr = num; + __entry->addr = msg->addr; + __entry->flags = msg->flags; + __entry->len = msg->len; + memcpy(__get_dynamic_array(buf), msg->buf, msg->len); + ), + TP_printk("i2c-%d #%u a=%03x f=%04x l=%u [%*phD]", + __entry->adapter_nr, + __entry->msg_nr, + __entry->addr, + __entry->flags, + __entry->len, + __entry->len, __get_dynamic_array(buf) + ), + i2c_transfer_trace_reg, + i2c_transfer_trace_unreg); + +/* + * __i2c_transfer() read request + */ +TRACE_EVENT_FN(i2c_read, + TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg, + int num), + TP_ARGS(adap, msg, num), + TP_STRUCT__entry( + __field(int, adapter_nr ) + __field(__u16, msg_nr ) + __field(__u16, addr ) + __field(__u16, flags ) + __field(__u16, len ) + ), + TP_fast_assign( + __entry->adapter_nr = adap->nr; + __entry->msg_nr = num; + __entry->addr = msg->addr; + __entry->flags = msg->flags; + __entry->len = msg->len; + ), + TP_printk("i2c-%d #%u a=%03x f=%04x l=%u", + __entry->adapter_nr, + __entry->msg_nr, + __entry->addr, + __entry->flags, + __entry->len + ), + i2c_transfer_trace_reg, + i2c_transfer_trace_unreg); + +/* + * __i2c_transfer() read reply + */ +TRACE_EVENT_FN(i2c_reply, + TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg, + int num), + TP_ARGS(adap, msg, num), + TP_STRUCT__entry( + __field(int, adapter_nr ) + __field(__u16, msg_nr ) + __field(__u16, addr ) + __field(__u16, flags ) + __field(__u16, len ) + __dynamic_array(__u8, buf, msg->len) ), + TP_fast_assign( + __entry->adapter_nr = adap->nr; + __entry->msg_nr = num; + __entry->addr = msg->addr; + __entry->flags = msg->flags; + __entry->len = msg->len; + memcpy(__get_dynamic_array(buf), msg->buf, msg->len); + ), + TP_printk("i2c-%d #%u a=%03x f=%04x l=%u [%*phD]", + __entry->adapter_nr, + __entry->msg_nr, + __entry->addr, + __entry->flags, + __entry->len, + __entry->len, __get_dynamic_array(buf) + ), + i2c_transfer_trace_reg, + i2c_transfer_trace_unreg); + +/* + * __i2c_transfer() result + */ +TRACE_EVENT_FN(i2c_result, + TP_PROTO(const struct i2c_adapter *adap, int num, int ret), + TP_ARGS(adap, num, ret), + TP_STRUCT__entry( + __field(int, adapter_nr ) + __field(__u16, nr_msgs ) + __field(__s16, ret ) + ), + TP_fast_assign( + __entry->adapter_nr = adap->nr; + __entry->nr_msgs = num; + __entry->ret = ret; + ), + TP_printk("i2c-%d n=%u ret=%d", + __entry->adapter_nr, + __entry->nr_msgs, + __entry->ret + ), + i2c_transfer_trace_reg, + i2c_transfer_trace_unreg); + +#endif /* _TRACE_I2C_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> |