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

From: Suzuki K Poulose
Date: Wed Jul 25 2018 - 05:01:25 EST


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