Messages in this thread | | | From | Alexander Shishkin <> | Subject | Re: [RFC PATCH v3 1/4] STM trace event: Adding generic buffer interface driver | Date | Wed, 08 Jul 2015 13:23:21 +0300 |
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Chunyan Zhang <zhang.chunyan@linaro.org> writes:
> From: Mathieu Poirier <mathieu.poirier@linaro.org> > > This patch adds a driver that models itself as an stm_source and > who's sole purpose is to export an interface to the rest of the > kernel. Once the stm and stm_source have been linked via sysfs, > everything that is passed to the interface will endup in the STM > trace engine. > > Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> > Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> > --- > drivers/stm/Kconfig | 11 +++++++++++ > drivers/stm/Makefile | 2 ++ > drivers/stm/stm_trace_event.c | 46 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 59 insertions(+) > create mode 100644 drivers/stm/stm_trace_event.c > > diff --git a/drivers/stm/Kconfig b/drivers/stm/Kconfig > index 6f2db70..8ead418 100644 > --- a/drivers/stm/Kconfig > +++ b/drivers/stm/Kconfig > @@ -25,3 +25,14 @@ config STM_SOURCE_CONSOLE > > If you want to send kernel console messages over STM devices, > say Y. > + > +config STM_TRACE_EVENT > + tristate "Redirect/copy the output from kernel trace event to STM engine" > + depends on STM > + help > + This option can be used to redirect or copy the output from kernel trace > + event to STM engine. Enabling this option will introduce a slight > + timing effect. > + > + If you want to send kernel trace event messages over STM devices, > + say Y. > diff --git a/drivers/stm/Makefile b/drivers/stm/Makefile > index 74baf59..55b152c 100644 > --- a/drivers/stm/Makefile > +++ b/drivers/stm/Makefile > @@ -5,3 +5,5 @@ stm_core-y := core.o policy.o > obj-$(CONFIG_STM_DUMMY) += dummy_stm.o > > obj-$(CONFIG_STM_SOURCE_CONSOLE) += console.o > + > +obj-$(CONFIG_STM_TRACE_EVENT) += stm_trace_event.o > diff --git a/drivers/stm/stm_trace_event.c b/drivers/stm/stm_trace_event.c > new file mode 100644 > index 0000000..bc77dae > --- /dev/null > +++ b/drivers/stm/stm_trace_event.c > @@ -0,0 +1,46 @@ > +/* > + * Simple kernel driver to link kernel trace event and an STM device > + * Copyright (c) 2015, Linaro Ltd. > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms and conditions of the GNU General Public License, > + * version 2, as published by the Free Software Foundation. > + * > + * This program is distributed in the hope it will be useful, but WITHOUT > + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or > + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for > + * more details. > + */ > + > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/slab.h> > +#include <linux/console.h> > +#include <linux/stm.h> > + > +static struct stm_source_data stm_trace_event_data = { > + .name = "stm_trace_event", > + .nr_chans = 1,
One question is: do we want to cram ftrace data from all cpus into one channel or use a channel per cpu?
Regards, -- Alex
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