Re: [PATCH 5/8] coresight: etm4x: Improve usability of sysfs API.

[Mike Leach <mike.leach@linaro.org>]

Hi Mathieu, Leo,

Will split & fix comments.

Thanks

Mike

On Wed, 28 Aug 2019 at 04:37, Leo Yan <leo.yan@linaro.org> wrote:
>
> On Mon, Aug 19, 2019 at 09:57:17PM +0100, Mike Leach wrote:
> > Some changes to make the sysfs programming more intuitive.
> >
> > 1) Setting include / exclude on a range had to be done by setting
> > the bit in 'mode' before setting the range. However, setting this
> > bit also had the effect of altering the current range as well.
> >
> > Changed to only set include / exclude setting of a range at the point of
> > setting that range. Either use a 3rd input parameter as the include exclude
> > value, or if not present use the current value of 'mode'. Do not change
> > current range when 'mode' changes.
> >
> > 2) Context ID and VM ID masks required 2 value inputs, even when the
> > second value is ignored as insufficient CID / VMID comparators are
> > implemented.
> > Permit a single value to be used if that is sufficient to cover all
> > implemented comparators.
> >
> > Signed-off-by: Mike Leach <mike.leach@linaro.org>
> > ---
> >  .../coresight/coresight-etm4x-sysfs.c         | 24 +++++++++++++------
> >  1 file changed, 17 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > index 3bcc260c9e55..baac5b48b7ac 100644
> > --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
> > @@ -297,8 +297,6 @@ static ssize_t mode_store(struct device *dev,
> >
> >       spin_lock(&drvdata->spinlock);
> >       config->mode = val & ETMv4_MODE_ALL;
> > -     etm4_set_mode_exclude(drvdata,
> > -                           config->mode & ETM_MODE_EXCLUDE ? true : false);
> >
> >       if (drvdata->instrp0 == true) {
> >               /* start by clearing instruction P0 field */
> > @@ -972,8 +970,12 @@ static ssize_t addr_range_store(struct device *dev,
> >       unsigned long val1, val2;
> >       struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> >       struct etmv4_config *config = &drvdata->config;
> > +     int elements, exclude;
> >
> > -     if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
> > +     elements = sscanf(buf, "%lx %lx %x", &val1, &val2, &exclude);
> > +
> > +     /*  exclude is optional, but need at least two parameter */
> > +     if (elements < 2)
> >               return -EINVAL;
> >       /* lower address comparator cannot have a higher address value */
> >       if (val1 > val2)
> > @@ -1001,9 +1003,11 @@ static ssize_t addr_range_store(struct device *dev,
> >       /*
> >        * Program include or exclude control bits for vinst or vdata
> >        * whenever we change addr comparators to ETM_ADDR_TYPE_RANGE
> > +      * use supplied value, or default to bit set in 'mode'
> >        */
> > -     etm4_set_mode_exclude(drvdata,
> > -                           config->mode & ETM_MODE_EXCLUDE ? true : false);
> > +     if (elements != 3)
> > +             exclude = config->mode & ETM_MODE_EXCLUDE;
> > +     etm4_set_mode_exclude(drvdata, exclude ? true : false);
> >
> >       spin_unlock(&drvdata->spinlock);
> >       return size;
> > @@ -1787,6 +1791,7 @@ static ssize_t ctxid_masks_store(struct device *dev,
> >       unsigned long val1, val2, mask;
> >       struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> >       struct etmv4_config *config = &drvdata->config;
> > +     int nr_inputs;
> >
> >       /*
> >        * Don't use contextID tracing if coming from a PID namespace.  See
> > @@ -1802,7 +1807,9 @@ static ssize_t ctxid_masks_store(struct device *dev,
> >        */
> >       if (!drvdata->ctxid_size || !drvdata->numcidc)
> >               return -EINVAL;
> > -     if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
> > +     /* one mask if < 4 comparators, two for up to 8 */
>
> One maks is <= 4 comparators.
>
> > +     nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
> > +     if ((drvdata->numcidc > 4) && (nr_inputs != 2))
> >               return -EINVAL;
> >
> >       spin_lock(&drvdata->spinlock);
> > @@ -1976,6 +1983,7 @@ static ssize_t vmid_masks_store(struct device *dev,
> >       unsigned long val1, val2, mask;
> >       struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> >       struct etmv4_config *config = &drvdata->config;
> > +     int nr_inputs;
> >
> >       /*
> >        * only implemented when vmid tracing is enabled, i.e. at least one
> > @@ -1983,7 +1991,9 @@ static ssize_t vmid_masks_store(struct device *dev,
> >        */
> >       if (!drvdata->vmid_size || !drvdata->numvmidc)
> >               return -EINVAL;
> > -     if (sscanf(buf, "%lx %lx", &val1, &val2) != 2)
> > +     /* one mask if < 4 comparators, two for up to 8 */
>
> One maks is <= 4 comparators.
>
> > +     nr_inputs = sscanf(buf, "%lx %lx", &val1, &val2);
> > +     if ((drvdata->numvmidc > 4) && (nr_inputs != 2))
> >               return -EINVAL;
> >
> >       spin_lock(&drvdata->spinlock);
> > --
> > 2.17.1
> >
> > _______________________________________________
> > CoreSight mailing list
> > CoreSight@lists.linaro.org
> > https://lists.linaro.org/mailman/listinfo/coresight



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

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