[PATCH] coresight: core: Add sysfs node to reset all sources and sinks

[Mike Leach]

Quick correction - you need to look for enable_source  / enable_sink
files and disable those that are currently '1'

Mike

On Wed, 8 Feb 2023 at 16:16, Mike Leach <mike.leach at linaro.org> wrote:
>
> Hi
>
> As this is a sysfs only update - would it not be easier to simply use
> a shell script to iterate through coresight/devices/ looking for
> disable_source / disable_sink files and setting those accordingly?
>
> See tools/perf/tests/shell/test_arm_coresight.sh for an example of a
> script that does similar iteration to test coresight in perf
>
> Regards
>
> Mike
>
> On Wed, 8 Feb 2023 at 11:16, Mao Jinlong <quic_jinlmao at quicinc.com> wrote:
> >
> > Add sysfs node to reset all the sources and sinks. When mltiple
> > sources are enabled, write 1 to reset_source_sink node to disable
> > all sources and sinks.
> >
> > Signed-off-by: Mao Jinlong <quic_jinlmao at quicinc.com>
> > ---
> >  drivers/hwtracing/coresight/coresight-core.c | 106 +++++++++++++++++--
> >  1 file changed, 99 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> > index d3bf82c0de1d..06741ed2dee7 100644
> > --- a/drivers/hwtracing/coresight/coresight-core.c
> > +++ b/drivers/hwtracing/coresight/coresight-core.c
> > @@ -458,6 +458,28 @@ static bool coresight_disable_source(struct coresight_device *csdev)
> >         return !csdev->enable;
> >  }
> >
> > +/**
> > + * coresight_get_source - Get the source from the path
> > + *
> > + * @path: The list of devices.
> > + *
> > + * Returns the soruce csdev.
> > + *
> > + */
> > +static struct coresight_device *coresight_get_source(struct list_head *path)
> > +{
> > +       struct coresight_device *csdev;
> > +
> > +       if (!path)
> > +               return NULL;
> > +
> > +       csdev = list_first_entry(path, struct coresight_node, link)->csdev;
> > +       if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
> > +               return NULL;
> > +
> > +       return csdev;
> > +}
> > +
> >  /*
> >   * coresight_disable_path_from : Disable components in the given path beyond
> >   * @nd in the list. If @nd is NULL, all the components, except the SOURCE are
> > @@ -1159,20 +1181,18 @@ int coresight_enable(struct coresight_device *csdev)
> >  }
> >  EXPORT_SYMBOL_GPL(coresight_enable);
> >
> > -void coresight_disable(struct coresight_device *csdev)
> > +static void _coresight_disable(struct coresight_device *csdev)
> >  {
> >         int cpu, ret;
> >         struct list_head *path = NULL;
> >         u32 hash;
> >
> > -       mutex_lock(&coresight_mutex);
> > -
> >         ret = coresight_validate_source(csdev, __func__);
> >         if (ret)
> > -               goto out;
> > +               return;
> >
> >         if (!csdev->enable || !coresight_disable_source(csdev))
> > -               goto out;
> > +               return;
> >
> >         switch (csdev->subtype.source_subtype) {
> >         case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
> > @@ -1187,7 +1207,7 @@ void coresight_disable(struct coresight_device *csdev)
> >                 path = idr_find(&path_idr, hash);
> >                 if (path == NULL) {
> >                         pr_err("Path is not found for %s\n", dev_name(&csdev->dev));
> > -                       goto out;
> > +                       return;
> >                 }
> >                 idr_remove(&path_idr, hash);
> >                 break;
> > @@ -1198,8 +1218,12 @@ void coresight_disable(struct coresight_device *csdev)
> >
> >         coresight_disable_path(path);
> >         coresight_release_path(path);
> > +}
> >
> > -out:
> > +void coresight_disable(struct coresight_device *csdev)
> > +{
> > +       mutex_lock(&coresight_mutex);
> > +       _coresight_disable(csdev);
> >         mutex_unlock(&coresight_mutex);
> >  }
> >  EXPORT_SYMBOL_GPL(coresight_disable);
> > @@ -1761,8 +1785,76 @@ char *coresight_alloc_device_name(struct coresight_dev_list *dict,
> >  }
> >  EXPORT_SYMBOL_GPL(coresight_alloc_device_name);
> >
> > +/*
> > + * Set the sink active status to false.
> > + */
> > +static int coresight_reset_sink(struct device *dev, void *data)
> > +{
> > +       struct coresight_device *csdev = to_coresight_device(dev);
> > +
> > +       if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
> > +               csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
> > +               csdev->activated)
> > +               csdev->activated = false;
> > +
> > +       return 0;
> > +}
> > +
> > +static void coresight_reset_all_sink(void)
> > +{
> > +       bus_for_each_dev(&coresight_bustype, NULL, NULL, coresight_reset_sink);
> > +}
> > +
> > +static ssize_t reset_source_sink_store(struct bus_type *bus,
> > +                                      const char *buf, size_t size)
> > +{
> > +       int id, cpu, ret = 0;
> > +       unsigned long val;
> > +       struct coresight_device *csdev;
> > +       struct list_head *path = NULL;
> > +
> > +       ret = kstrtoul(buf, 10, &val);
> > +       if (ret)
> > +               return ret;
> > +
> > +       mutex_lock(&coresight_mutex);
> > +
> > +       /* Disable all per cpu sources */
> > +       for_each_present_cpu(cpu) {
> > +               path = per_cpu(tracer_path, cpu);
> > +               if (path) {
> > +                       csdev = coresight_get_source(path);
> > +                       if (!csdev)
> > +                               continue;
> > +               }
> > +               _coresight_disable(csdev);
> > +       }
> > +
> > +       /* Disable all sources which aren't associated with CPU */
> > +       idr_for_each_entry (&path_idr, path, id) {
> > +               csdev = coresight_get_source(path);
> > +               if (!csdev)
> > +                       continue;
> > +
> > +               _coresight_disable(csdev);
> > +       }
> > +       /* Reset all activated sinks */
> > +       coresight_reset_all_sink();
> > +
> > +       mutex_unlock(&coresight_mutex);
> > +       return size;
> > +}
> > +static BUS_ATTR_WO(reset_source_sink);
> > +
> > +static struct attribute *coresight_reset_source_sink_attrs[] = {
> > +       &bus_attr_reset_source_sink.attr,
> > +       NULL,
> > +};
> > +ATTRIBUTE_GROUPS(coresight_reset_source_sink);
> > +
> >  struct bus_type coresight_bustype = {
> >         .name   = "coresight",
> > +       .bus_groups     = coresight_reset_source_sink_groups,
> >  };
> >
> >  static int __init coresight_init(void)
> > --
> > 2.39.0
> >
>
>
> --
> Mike Leach
> Principal Engineer, ARM Ltd.
> Manchester Design Centre. UK



-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK