Re: [PATCH] Tracing events with GPIOs

From: Linus Walleij
Date: Thu Jan 02 2014 - 07:43:46 EST

On Thu, Dec 19, 2013 at 7:52 AM, Alexandre Courbot <gnurou@xxxxxxxxx> wrote:
> On Tue, Dec 17, 2013 at 9:22 AM, Jean-Jacques Hiblot
> <jjhiblot@xxxxxxxxxxxxxxx> wrote:
>> This patch implements a new tracing mechanism based on kprobes and using GPIO.
>> Debugging with GPIO is very common in the embedded world. At least for those of us
>> fortunate enough to have an oscilloscope or a logic analyzer on their bench...
>> This is especially true if the issue results of a hardware/sofware interaction.
>> Typical use cases are :
>> * mixed software/hardware debugging. For example when the software detects a
>> situation of interest (typically an error) it toggles a GPIO to trigger the
>> oscilloscope acquisition.
>> * direct latency/duration measurements.
>> examples:
>> To trig the oscilloscope whenever a mmc command error:
>> echo "p:my_mmc_blk_error mmc_blk_cmd_error gpiopulse@13" > /sys/kernel/debug/tracing/kprobe_events
>> echo 1 > /sys/kernel/debug/tracing/events/kprobes/my_mmc_blk_error/enable

I've never seen the whole patch.

Can you please repost this and include linux-gpio@xxxxxxxxxxxxxxx and also
me on the To: line?

Linus Walleij
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