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i2c: Add message transfer tracepoints for SMBUS [ver #2]
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The SMBUS tracepoints 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:

         ... smbus_read: i2c-0 a=051 f=0000 c=fa BYTE_DATA
         ... smbus_reply: i2c-0 a=051 f=0000 c=fa BYTE_DATA l=1 [39]
         ... smbus_result: i2c-0 a=051 f=0000 c=fa BYTE_DATA rd res=0

formatted as:

	i2c-<adapter-nr>
	a=<addr>
	f=<flags>
	c=<command>
	<protocol-name>
	<rd|wr>
	res=<result>
	l=<data-len>
	[<data-block>]

The adapters to be traced can be selected by something like:

	echo adapter_nr==1 >/sys/kernel/debug/tracing/events/i2c/filter

Note that this shares the same filter and enablement as i2c.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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@dhowells
dhowells authored and Wolfram Sang committed Mar 13, 2014
1 parent d9a83d6 commit 8a32599
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Showing 2 changed files with 243 additions and 4 deletions.
23 changes: 20 additions & 3 deletions drivers/i2c/i2c-core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2565,6 +2565,14 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
int try;
s32 res;

/* If enabled, the following two tracepoints are conditional on
* read_write and protocol.
*/
trace_smbus_write(adapter, addr, flags, read_write,
command, protocol, data);
trace_smbus_read(adapter, addr, flags, read_write,
command, protocol);

flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;

if (adapter->algo->smbus_xfer) {
Expand All @@ -2585,15 +2593,24 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
i2c_unlock_adapter(adapter);

if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
return res;
goto trace;
/*
* Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
* implement native support for the SMBus operation.
*/
}

return i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
command, protocol, data);
res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
command, protocol, data);

trace:
/* If enabled, the reply tracepoint is conditional on read_write. */
trace_smbus_reply(adapter, addr, flags, read_write,
command, protocol, data);
trace_smbus_result(adapter, addr, flags, read_write,
command, protocol, res);

return res;
}
EXPORT_SYMBOL(i2c_smbus_xfer);

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224 changes: 223 additions & 1 deletion include/trace/events/i2c.h
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
/* I2C message transfer tracepoints
/* I2C and SMBUS message transfer tracepoints
*
* Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
Expand Down Expand Up @@ -144,6 +144,228 @@ TRACE_EVENT_FN(i2c_result,
i2c_transfer_trace_reg,
i2c_transfer_trace_unreg);

/*
* i2c_smbus_xfer() write data or procedure call request
*/
TRACE_EVENT_CONDITION(smbus_write,
TP_PROTO(const struct i2c_adapter *adap,
u16 addr, unsigned short flags,
char read_write, u8 command, int protocol,
const union i2c_smbus_data *data),
TP_ARGS(adap, addr, flags, read_write, command, protocol, data),
TP_CONDITION(read_write == I2C_SMBUS_WRITE ||
protocol == I2C_SMBUS_PROC_CALL ||
protocol == I2C_SMBUS_BLOCK_PROC_CALL),
TP_STRUCT__entry(
__field(int, adapter_nr )
__field(__u16, addr )
__field(__u16, flags )
__field(__u8, command )
__field(__u8, len )
__field(__u32, protocol )
__array(__u8, buf, I2C_SMBUS_BLOCK_MAX + 2) ),
TP_fast_assign(
__entry->adapter_nr = adap->nr;
__entry->addr = addr;
__entry->flags = flags;
__entry->command = command;
__entry->protocol = protocol;

switch (protocol) {
case I2C_SMBUS_BYTE_DATA:
__entry->len = 1;
goto copy;
case I2C_SMBUS_WORD_DATA:
case I2C_SMBUS_PROC_CALL:
__entry->len = 2;
goto copy;
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_BLOCK_PROC_CALL:
case I2C_SMBUS_I2C_BLOCK_DATA:
__entry->len = data->block[0] + 1;
copy:
memcpy(__entry->buf, data->block, __entry->len);
break;
case I2C_SMBUS_QUICK:
case I2C_SMBUS_BYTE:
case I2C_SMBUS_I2C_BLOCK_BROKEN:
default:
__entry->len = 0;
}
),
TP_printk("i2c-%d a=%03x f=%04x c=%x %s l=%u [%*phD]",
__entry->adapter_nr,
__entry->addr,
__entry->flags,
__entry->command,
__print_symbolic(__entry->protocol,
{ I2C_SMBUS_QUICK, "QUICK" },
{ I2C_SMBUS_BYTE, "BYTE" },
{ I2C_SMBUS_BYTE_DATA, "BYTE_DATA" },
{ I2C_SMBUS_WORD_DATA, "WORD_DATA" },
{ I2C_SMBUS_PROC_CALL, "PROC_CALL" },
{ I2C_SMBUS_BLOCK_DATA, "BLOCK_DATA" },
{ I2C_SMBUS_I2C_BLOCK_BROKEN, "I2C_BLOCK_BROKEN" },
{ I2C_SMBUS_BLOCK_PROC_CALL, "BLOCK_PROC_CALL" },
{ I2C_SMBUS_I2C_BLOCK_DATA, "I2C_BLOCK_DATA" }),
__entry->len,
__entry->len, __entry->buf
));

/*
* i2c_smbus_xfer() read data request
*/
TRACE_EVENT_CONDITION(smbus_read,
TP_PROTO(const struct i2c_adapter *adap,
u16 addr, unsigned short flags,
char read_write, u8 command, int protocol),
TP_ARGS(adap, addr, flags, read_write, command, protocol),
TP_CONDITION(!(read_write == I2C_SMBUS_WRITE ||
protocol == I2C_SMBUS_PROC_CALL ||
protocol == I2C_SMBUS_BLOCK_PROC_CALL)),
TP_STRUCT__entry(
__field(int, adapter_nr )
__field(__u16, flags )
__field(__u16, addr )
__field(__u8, command )
__field(__u32, protocol )
__array(__u8, buf, I2C_SMBUS_BLOCK_MAX + 2) ),
TP_fast_assign(
__entry->adapter_nr = adap->nr;
__entry->addr = addr;
__entry->flags = flags;
__entry->command = command;
__entry->protocol = protocol;
),
TP_printk("i2c-%d a=%03x f=%04x c=%x %s",
__entry->adapter_nr,
__entry->addr,
__entry->flags,
__entry->command,
__print_symbolic(__entry->protocol,
{ I2C_SMBUS_QUICK, "QUICK" },
{ I2C_SMBUS_BYTE, "BYTE" },
{ I2C_SMBUS_BYTE_DATA, "BYTE_DATA" },
{ I2C_SMBUS_WORD_DATA, "WORD_DATA" },
{ I2C_SMBUS_PROC_CALL, "PROC_CALL" },
{ I2C_SMBUS_BLOCK_DATA, "BLOCK_DATA" },
{ I2C_SMBUS_I2C_BLOCK_BROKEN, "I2C_BLOCK_BROKEN" },
{ I2C_SMBUS_BLOCK_PROC_CALL, "BLOCK_PROC_CALL" },
{ I2C_SMBUS_I2C_BLOCK_DATA, "I2C_BLOCK_DATA" })
));

/*
* i2c_smbus_xfer() read data or procedure call reply
*/
TRACE_EVENT_CONDITION(smbus_reply,
TP_PROTO(const struct i2c_adapter *adap,
u16 addr, unsigned short flags,
char read_write, u8 command, int protocol,
const union i2c_smbus_data *data),
TP_ARGS(adap, addr, flags, read_write, command, protocol, data),
TP_CONDITION(read_write == I2C_SMBUS_READ),
TP_STRUCT__entry(
__field(int, adapter_nr )
__field(__u16, addr )
__field(__u16, flags )
__field(__u8, command )
__field(__u8, len )
__field(__u32, protocol )
__array(__u8, buf, I2C_SMBUS_BLOCK_MAX + 2) ),
TP_fast_assign(
__entry->adapter_nr = adap->nr;
__entry->addr = addr;
__entry->flags = flags;
__entry->command = command;
__entry->protocol = protocol;

switch (protocol) {
case I2C_SMBUS_BYTE:
case I2C_SMBUS_BYTE_DATA:
__entry->len = 1;
goto copy;
case I2C_SMBUS_WORD_DATA:
case I2C_SMBUS_PROC_CALL:
__entry->len = 2;
goto copy;
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_BLOCK_PROC_CALL:
case I2C_SMBUS_I2C_BLOCK_DATA:
__entry->len = data->block[0] + 1;
copy:
memcpy(__entry->buf, data->block, __entry->len);
break;
case I2C_SMBUS_QUICK:
case I2C_SMBUS_I2C_BLOCK_BROKEN:
default:
__entry->len = 0;
}
),
TP_printk("i2c-%d a=%03x f=%04x c=%x %s l=%u [%*phD]",
__entry->adapter_nr,
__entry->addr,
__entry->flags,
__entry->command,
__print_symbolic(__entry->protocol,
{ I2C_SMBUS_QUICK, "QUICK" },
{ I2C_SMBUS_BYTE, "BYTE" },
{ I2C_SMBUS_BYTE_DATA, "BYTE_DATA" },
{ I2C_SMBUS_WORD_DATA, "WORD_DATA" },
{ I2C_SMBUS_PROC_CALL, "PROC_CALL" },
{ I2C_SMBUS_BLOCK_DATA, "BLOCK_DATA" },
{ I2C_SMBUS_I2C_BLOCK_BROKEN, "I2C_BLOCK_BROKEN" },
{ I2C_SMBUS_BLOCK_PROC_CALL, "BLOCK_PROC_CALL" },
{ I2C_SMBUS_I2C_BLOCK_DATA, "I2C_BLOCK_DATA" }),
__entry->len,
__entry->len, __entry->buf
));

/*
* i2c_smbus_xfer() result
*/
TRACE_EVENT(smbus_result,
TP_PROTO(const struct i2c_adapter *adap,
u16 addr, unsigned short flags,
char read_write, u8 command, int protocol,
int res),
TP_ARGS(adap, addr, flags, read_write, command, protocol, res),
TP_STRUCT__entry(
__field(int, adapter_nr )
__field(__u16, addr )
__field(__u16, flags )
__field(__u8, read_write )
__field(__u8, command )
__field(__s16, res )
__field(__u32, protocol )
),
TP_fast_assign(
__entry->adapter_nr = adap->nr;
__entry->addr = addr;
__entry->flags = flags;
__entry->read_write = read_write;
__entry->command = command;
__entry->protocol = protocol;
__entry->res = res;
),
TP_printk("i2c-%d a=%03x f=%04x c=%x %s %s res=%d",
__entry->adapter_nr,
__entry->addr,
__entry->flags,
__entry->command,
__print_symbolic(__entry->protocol,
{ I2C_SMBUS_QUICK, "QUICK" },
{ I2C_SMBUS_BYTE, "BYTE" },
{ I2C_SMBUS_BYTE_DATA, "BYTE_DATA" },
{ I2C_SMBUS_WORD_DATA, "WORD_DATA" },
{ I2C_SMBUS_PROC_CALL, "PROC_CALL" },
{ I2C_SMBUS_BLOCK_DATA, "BLOCK_DATA" },
{ I2C_SMBUS_I2C_BLOCK_BROKEN, "I2C_BLOCK_BROKEN" },
{ I2C_SMBUS_BLOCK_PROC_CALL, "BLOCK_PROC_CALL" },
{ I2C_SMBUS_I2C_BLOCK_DATA, "I2C_BLOCK_DATA" }),
__entry->read_write == I2C_SMBUS_WRITE ? "wr" : "rd",
__entry->res
));

#endif /* _TRACE_I2C_H */

/* This part must be outside protection */
Expand Down

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