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Message-ID: <CANLsYkwDTM2pT0JCCnLdetKoYe6xsmj48Gyb5OJFxJMmRLrZ_g@mail.gmail.com>
Date: Tue, 24 Jul 2018 15:34:07 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: "Suzuki K. Poulose" <suzuki.poulose@....com>
Cc: linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Rob Herring <robh@...nel.org>,
Sudeep Holla <sudeep.holla@....com>,
Frank Rowand <frowand.list@...il.com>,
devicetree@...r.kernel.org, Mark Rutland <mark.rutland@....com>,
Matt Sealey <matt.sealey@....com>,
Charles Garcia-Tobin <charles.garcia-tobin@....com>,
coresight@...ts.linaro.org, John Horley <john.horley@....com>,
Mike Leach <mike.leach@...aro.org>
Subject: Re: [PATCH v2 02/10] coresight: platform: Refactor graph endpoint parsing
On Tue, 24 Jul 2018 at 15:30, Mathieu Poirier
<mathieu.poirier@...aro.org> 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@...aro.org>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> > ---
> > 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.
Void that - it properly deals with the first of_parse_endpoint().
>
> > + } while (0);
> > +
> > + return ret;
> > +}
> > +
> > struct coresight_platform_data *
> > of_get_coresight_platform_data(struct device *dev,
> > const struct device_node *node)
> > {
> > int i = 0, ret = 0;
> > struct coresight_platform_data *pdata;
> > - struct of_endpoint endpoint, rendpoint;
> > - struct device *rdev;
> > struct device_node *ep = NULL;
> > - struct device_node *rparent = NULL;
> > - struct device_node *rport = NULL;
> >
> > pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> > if (!pdata)
> > @@ -132,64 +184,33 @@ of_get_coresight_platform_data(struct device *dev,
> >
> > /* Use device name as sysfs handle */
> > pdata->name = dev_name(dev);
> > + pdata->cpu = of_coresight_get_cpu(node);
> >
> > /* Get the number of input and output port for this component */
> > of_coresight_get_ports(node, &pdata->nr_inport, &pdata->nr_outport);
> >
> > - if (pdata->nr_outport) {
> > - ret = of_coresight_alloc_memory(dev, pdata);
> > + /* If there are no output connections, we are done */
> > + if (!pdata->nr_outport)
> > + return pdata;
> > +
> > + ret = of_coresight_alloc_memory(dev, pdata);
> > + if (ret)
> > + return ERR_PTR(ret);
> > +
> > + /* Iterate through each port to discover topology */
> > + 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.
> */
>
> > + if (of_find_property(ep, "slave-mode", NULL))
> > + continue;
> > +
> > + ret = of_coresight_parse_endpoint(dev, ep, pdata, &i);
> > if (ret)
> > return ERR_PTR(ret);
>
> i++;
>
> > -
> > - /* Iterate through each port to discover topology */
> > - do {
> > - /* Get a handle on a port */
> > - ep = of_graph_get_next_endpoint(node, ep);
> > - if (!ep)
> > - break;
> > -
> > - /*
> > - * No need to deal with input ports, processing for as
> > - * processing for output ports will deal with them.
> > - */
> > - if (of_find_property(ep, "slave-mode", NULL))
> > - continue;
> > -
> > - /* Get a handle on the local endpoint */
> > - ret = of_graph_parse_endpoint(ep, &endpoint);
> > -
> > - if (ret)
> > - continue;
> > -
> > - /* The local out port number */
> > - pdata->outports[i] = endpoint.port;
> > -
> > - /*
> > - * Get a handle on the remote port and parent
> > - * attached to it.
> > - */
> > - rparent = of_graph_get_remote_port_parent(ep);
> > - rport = of_graph_get_remote_port(ep);
> > -
> > - if (!rparent || !rport)
> > - continue;
> > -
> > - if (of_graph_parse_endpoint(rport, &rendpoint))
> > - continue;
> > -
> > - rdev = of_coresight_get_endpoint_device(rparent);
> > - if (!rdev)
> > - return ERR_PTR(-EPROBE_DEFER);
> > -
> > - pdata->child_names[i] = dev_name(rdev);
> > - pdata->child_ports[i] = rendpoint.id;
> > -
> > - i++;
> > - } while (ep);
> > }
> >
> > - pdata->cpu = of_coresight_get_cpu(node);
> > -
> > return pdata;
> > }
> > EXPORT_SYMBOL_GPL(of_get_coresight_platform_data);
> > --
> > 2.7.4
> >
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