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SubjectRe: [PATCH v2 02/10] coresight: platform: Refactor graph endpoint parsing
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@linaro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.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.

> + } 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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