d9a83d62b3
Add tracepoints into the I2C message transfer function to retrieve the message sent or received. The following config options must be turned on to make use of the facility: CONFIG_FTRACE CONFIG_ENABLE_DEFAULT_TRACERS The I2C tracepoint can be enabled thusly: echo 1 >/sys/kernel/debug/tracing/events/i2c/enable and will dump messages that can be viewed in /sys/kernel/debug/tracing/trace that look like: ... i2c_write: i2c-5 #0 a=044 f=0000 l=2 [02-14] ... i2c_read: i2c-5 #1 a=044 f=0001 l=4 ... i2c_reply: i2c-5 #1 a=044 f=0001 l=4 [33-00-00-00] ... i2c_result: i2c-5 n=2 ret=2 formatted as: i2c-<adapter-nr> #<message-array-index> a=<addr> f=<flags> l=<datalen> n=<message-array-size> ret=<result> [<data>] The operation is done between the i2c_write/i2c_read lines and the i2c_reply and i2c_result lines so that if the hardware hangs, the trace buffer can be consulted to determine the problematic operation. The adapters to be traced can be selected by something like: echo adapter_nr==1 >/sys/kernel/debug/tracing/events/i2c/filter These changes are based on code from Steven Rostedt. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> [wsa: adapted path for 'enable' in the commit msg] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
150 lines
4.2 KiB
C
150 lines
4.2 KiB
C
/* I2C message transfer tracepoints
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*
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* Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#undef TRACE_SYSTEM
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#define TRACE_SYSTEM i2c
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#if !defined(_TRACE_I2C_H) || defined(TRACE_HEADER_MULTI_READ)
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#define _TRACE_I2C_H
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#include <linux/i2c.h>
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#include <linux/tracepoint.h>
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/*
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* drivers/i2c/i2c-core.c
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*/
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extern void i2c_transfer_trace_reg(void);
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extern void i2c_transfer_trace_unreg(void);
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/*
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* __i2c_transfer() write request
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*/
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TRACE_EVENT_FN(i2c_write,
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TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
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int num),
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TP_ARGS(adap, msg, num),
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TP_STRUCT__entry(
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__field(int, adapter_nr )
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__field(__u16, msg_nr )
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__field(__u16, addr )
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__field(__u16, flags )
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__field(__u16, len )
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__dynamic_array(__u8, buf, msg->len) ),
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TP_fast_assign(
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__entry->adapter_nr = adap->nr;
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__entry->msg_nr = num;
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__entry->addr = msg->addr;
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__entry->flags = msg->flags;
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__entry->len = msg->len;
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memcpy(__get_dynamic_array(buf), msg->buf, msg->len);
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),
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TP_printk("i2c-%d #%u a=%03x f=%04x l=%u [%*phD]",
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__entry->adapter_nr,
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__entry->msg_nr,
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__entry->addr,
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__entry->flags,
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__entry->len,
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__entry->len, __get_dynamic_array(buf)
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),
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i2c_transfer_trace_reg,
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i2c_transfer_trace_unreg);
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/*
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* __i2c_transfer() read request
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*/
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TRACE_EVENT_FN(i2c_read,
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TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
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int num),
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TP_ARGS(adap, msg, num),
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TP_STRUCT__entry(
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__field(int, adapter_nr )
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__field(__u16, msg_nr )
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__field(__u16, addr )
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__field(__u16, flags )
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__field(__u16, len )
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),
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TP_fast_assign(
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__entry->adapter_nr = adap->nr;
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__entry->msg_nr = num;
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__entry->addr = msg->addr;
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__entry->flags = msg->flags;
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__entry->len = msg->len;
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),
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TP_printk("i2c-%d #%u a=%03x f=%04x l=%u",
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__entry->adapter_nr,
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__entry->msg_nr,
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__entry->addr,
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__entry->flags,
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__entry->len
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),
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i2c_transfer_trace_reg,
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i2c_transfer_trace_unreg);
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/*
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* __i2c_transfer() read reply
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*/
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TRACE_EVENT_FN(i2c_reply,
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TP_PROTO(const struct i2c_adapter *adap, const struct i2c_msg *msg,
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int num),
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TP_ARGS(adap, msg, num),
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TP_STRUCT__entry(
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__field(int, adapter_nr )
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__field(__u16, msg_nr )
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__field(__u16, addr )
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__field(__u16, flags )
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__field(__u16, len )
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__dynamic_array(__u8, buf, msg->len) ),
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TP_fast_assign(
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__entry->adapter_nr = adap->nr;
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__entry->msg_nr = num;
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__entry->addr = msg->addr;
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__entry->flags = msg->flags;
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__entry->len = msg->len;
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memcpy(__get_dynamic_array(buf), msg->buf, msg->len);
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),
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TP_printk("i2c-%d #%u a=%03x f=%04x l=%u [%*phD]",
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__entry->adapter_nr,
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__entry->msg_nr,
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__entry->addr,
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__entry->flags,
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__entry->len,
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__entry->len, __get_dynamic_array(buf)
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),
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i2c_transfer_trace_reg,
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i2c_transfer_trace_unreg);
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/*
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* __i2c_transfer() result
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*/
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TRACE_EVENT_FN(i2c_result,
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TP_PROTO(const struct i2c_adapter *adap, int num, int ret),
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TP_ARGS(adap, num, ret),
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TP_STRUCT__entry(
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__field(int, adapter_nr )
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__field(__u16, nr_msgs )
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__field(__s16, ret )
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),
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TP_fast_assign(
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__entry->adapter_nr = adap->nr;
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__entry->nr_msgs = num;
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__entry->ret = ret;
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),
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TP_printk("i2c-%d n=%u ret=%d",
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__entry->adapter_nr,
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__entry->nr_msgs,
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__entry->ret
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),
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i2c_transfer_trace_reg,
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i2c_transfer_trace_unreg);
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#endif /* _TRACE_I2C_H */
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/* This part must be outside protection */
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#include <trace/define_trace.h>
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