Re: [PATCH v2 02/10] coresight: platform: Refactor graph endpoint parsing

[Suzuki K Poulose]

On 07/24/2018 10:34 PM, Mathieu Poirier wrote:
> On Tue, 24 Jul 2018 at 15:30, Mathieu Poirier
> <mathieu.poirier@xxxxxxxxxx> wrote:
> > Good afternoon,
> >
> > On Thu, Jul 19, 2018 at 11:55:06AM +0100, Suzuki K Poulose wrote:
> > > Refactor the of graph endpoint parsing code, to make the error
> > > handling easier.
> > >
> > > Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> > > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > > ---
> > > Changes since v1:
> > >   - Splitted from the of_node refcounting fix, part1
> > > ---
> > >   drivers/hwtracing/coresight/of_coresight.c | 129 +++++++++++++++++------------
> > >   1 file changed, 75 insertions(+), 54 deletions(-)
> > >
> > > diff --git a/drivers/hwtracing/coresight/of_coresight.c b/drivers/hwtracing/coresight/of_coresight.c
> > > index 6880bee..68faaf8 100644
> > > --- a/drivers/hwtracing/coresight/of_coresight.c
> > > +++ b/drivers/hwtracing/coresight/of_coresight.c
> > > @@ -114,17 +114,69 @@ int of_coresight_get_cpu(const struct device_node *node)
> > >   }
> > >   EXPORT_SYMBOL_GPL(of_coresight_get_cpu);
> > >
> > > +/*
> > > + * of_coresight_parse_endpoint : Parse the given output endpoint @ep
> > > + * and fill the connection information in @pdata[*@i].
> > > + *
> > > + * Parses the local port, remote device name and the remote port. Also
> > > + * updates *@i to point to the next index, when an entry is added.
> > > + *
> > > + * Returns :
> > > + *    0      - If the parsing completed without any fatal errors.
> > > + *   -Errno  - Fatal error, abort the scanning.
> > > + */
> > > +static int of_coresight_parse_endpoint(struct device *dev,
> > > +                                    struct device_node *ep,
> > > +                                    struct coresight_platform_data *pdata,
> > > +                                    int *i)
> > > +{
> > > +     int ret = 0;
> > > +     struct of_endpoint endpoint, rendpoint;
> > > +     struct device_node *rparent = NULL;
> > > +     struct device_node *rport = NULL;
> > > +     struct device *rdev = NULL;
> > > +
> > > +     do {
> > > +             /* Parse the local port details */
> > > +             if (of_graph_parse_endpoint(ep, &endpoint))
> > > +                     break;
> > > +             /*
> > > +              * Get a handle on the remote port and parent
> > > +              * attached to it.
> > > +              */
> > > +             rparent = of_graph_get_remote_port_parent(ep);
> > > +             if (!rparent)
> > > +                     break;
> > > +             rport = of_graph_get_remote_port(ep);
> > > +             if (!rport)
> > > +                     break;
> > > +             if (of_graph_parse_endpoint(rport, &rendpoint))
> > > +                     break;
> > > +
> > > +             /* If the remote device is not available, defer probing */
> > > +             rdev = of_coresight_get_endpoint_device(rparent);
> > > +             if (!rdev) {
> > > +                     ret = -EPROBE_DEFER;
> > > +                     break;
> > > +             }
> > > +
> > > +             pdata->outports[*i] = endpoint.port;
> > > +             pdata->child_names[*i] = dev_name(rdev);
> > > +             pdata->child_ports[*i] = rendpoint.id;
> > > +             /* Move the index */
> > > +             (*i)++;
> >
> > Not a big fan, makes the code needlessly complex.  Incrementation of the index
> > can be done in the while loop of of_get_coresight_platform_data().  See below.

Me neither..

> Void that - it properly deals with the first of_parse_endpoint().

Or may be we could do something with the return value :

	  1 - Successfully parsed and populated a connection entry
	  0 - No errors in parsing
	< 0 - Errors in parsing

> > > @@ -132,64 +184,33 @@ of_get_coresight_platform_data(struct device *dev,


> > > +     while ((ep = of_graph_get_next_endpoint(node, ep))) {
> > > +             /*
> > > +              * No need to deal with input ports, processing for as
> > > +              * processing for output ports will deal with them.
> > > +              */
> >
> > This comment has been broken for a while... It should read:
> >
> >                  /*
> >                   * No need to deal with input ports, as processing
> >                   * for output ports will deal with them.
> >                   */

Sure, will fix it.


Suzuki