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Message-ID: <CANLsYkxcTPWbM75wHgiy8tC6FNhELsMcK=fu2TfvXG-3rM=hCA@mail.gmail.com>
Date: Wed, 25 Jul 2018 08:38:09 -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 Wed, 25 Jul 2018 at 03:01, Suzuki K Poulose <suzuki.poulose@....com> wrote:
>
> On 07/24/2018 10:34 PM, Mathieu Poirier wrote:
> > 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.
>
> 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
Right, that is another solution. I usually try to avoid those but I
think it is better than what we currently have.
>
> >>> @@ -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.
Thanks,
Mathieu
>
>
> Suzuki
> --
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