Re: [PATCH v9 08/15] coresight: cti: Enable CTI associated with devices.

Mike Leach
2020-02-25T15:03:33Z

As using devm_... for allocation, there is no need to explicitly free
up tc->con_dev_name, also the lifetime of the connection is linked to
the lifetime of csdev, so we can drop the devm_kstrdup in the csdev
case so this becomes

/* match: so swap in csdev name & dev */
tc->con_dev_name = dev_name(&csdev->dev);
tc->con_dev = csdev;
return true;

Same true for similar link in patch 1, removing 2 un-needed
allocations, leaving 1 to be fixed up with error checking

Mike

On Fri, 21 Feb 2020 at 16:51, Mathieu Poirier
<mathieu.poirier@linaro.org> wrote:
>
> On Fri, Feb 21, 2020 at 12:20:17AM +0000, Suzuki K Poulose wrote:
> > Hi Mike
> >
> > Sorry for the delay. one minor comment below.
> >
> > On 02/10/2020 09:39 PM, Mike Leach wrote:
> > > The CoreSight subsystem enables a path of devices from source to sink.
> > > Any CTI devices associated with the path devices must be enabled at the
> > > same time.
> > >
> > > This patch adds an associated coresight_device element to the main
> > > coresight device structure, and uses this to create associations between
> > > the CTI and other devices based on the device tree data. The associated
> > > device element is used to enable CTI in conjunction with the path elements.
> > >
> > > CTI devices are reference counted so where a single CTI is associated with
> > > multiple elements on the path, it will be enabled on the first associated
> > > device enable, and disabled with the last associated device disable.
> > >
> > > Signed-off-by: Mike Leach <mike.leach@linaro.org>
> > > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> > > ---
> > > drivers/hwtracing/coresight/coresight-cti.c | 129 +++++++++++++++++++
> > > drivers/hwtracing/coresight/coresight-cti.h | 1 +
> > > drivers/hwtracing/coresight/coresight-priv.h | 12 ++
> > > drivers/hwtracing/coresight/coresight.c | 71 +++++++++-
> > > include/linux/coresight.h | 4 +
> > > 5 files changed, 212 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
> > > index 77c2af247917..c4494923d030 100644
> > > --- a/drivers/hwtracing/coresight/coresight-cti.c
> > > +++ b/drivers/hwtracing/coresight/coresight-cti.c
> > > @@ -4,6 +4,7 @@
> > > * Author: Mike Leach <mike.leach@linaro.org>
> > > */
> > > +#include <linux/property.h>
> > > #include "coresight-cti.h"
> > > /**
> > > @@ -440,6 +441,131 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op,
> > > return err;
> > > }
> > > +/*
> > > + * Look for a matching connection device name in the list of connections.
> > > + * If found then swap in the csdev name, set trig con association pointer
> > > + * and return found.
> > > + */
> > > +static bool
> > > +cti_match_fixup_csdev(struct cti_device *ctidev, const char *node_name,
> > > + struct coresight_device *csdev)
> > > +{
> > > + struct cti_trig_con *tc;
> > > + const char *csdev_name;
> > > +
> > > + list_for_each_entry(tc, &ctidev->trig_cons, node) {
> > > + if (tc->con_dev_name) {
> > > + if (!strcmp(node_name, tc->con_dev_name)) {
> > > + /* match: so swap in csdev name & dev */
> > > + csdev_name = dev_name(&csdev->dev);
> > > + tc->con_dev_name =
> > > + devm_kstrdup(&csdev->dev, csdev_name,
> > > + GFP_KERNEL);
> >
> > In the extreme rare case of an allocation failure, we may want to
> > check if the allocation was successful or not, rather than silently
> > ignoring it. With that fixed,
>
> Line 419 and 423 in patch 1 need the same attention.
>
> >
> > Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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