Re: [PATCH v4 2/4] coresight: Add support for trace filtering by source

On 24/10/2024 07:53, Tao Zhang wrote:

Some replicators have hard coded filtering of "trace" data, based on the source device. This is different from the trace filtering based on TraceID, available in the standard programmable replicators. e.g., Qualcomm replicators have filtering based on custom trace protocol format and is not programmable.

The source device could be connected to the replicator via intermediate components (e.g., a funnel). Thus we need platform information from the firmware tables to decide the source device corresponding to a given output port from the replicator. Given this affects "trace path building" and traversing the path back from the sink to source, add the concept of "filtering by source" to the generic coresight connection.

The specified source will be marked like below in the Devicetree. test-replicator { ... ... ... ... out-ports { ... ... ... ... port@0 { reg = <0>; xxx: endpoint { remote-endpoint = <&xxx>;

That looks like bad example. remote-enpdoint is the same node ? As you have the same lable for the endpoint ?

             filter_src = <&xxx>; <-- To specify the source to
         };                           be filtered out here.
     };

     port@1 {
         reg = <1>;
         yyy: endpoint {
             remote-endpoint = <&yyy>;

Similarly here ?

             filter_src = <&yyy>; <-- To specify the source to
         };                           be filtered out here.
     };
 };

};

Signed-off-by: Tao Zhang quic_taozha@quicinc.com

drivers/hwtracing/coresight/coresight-core.c | 117 +++++++++++++++--- .../hwtracing/coresight/coresight-platform.c | 18 +++ include/linux/coresight.h | 5 + 3 files changed, 121 insertions(+), 19 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c index ea38ecf26fcb..d9d256b3e8aa 100644 --- a/drivers/hwtracing/coresight/coresight-core.c +++ b/drivers/hwtracing/coresight/coresight-core.c @@ -75,22 +75,57 @@ struct coresight_device *coresight_get_percpu_sink(int cpu) } EXPORT_SYMBOL_GPL(coresight_get_percpu_sink); +static struct coresight_device *coresight_get_source(struct list_head *path) +{

• struct coresight_device *csdev;
• if (!path)

• return NULL;
  

• csdev = list_first_entry(path, struct coresight_node, link)->csdev;
• if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE)

• return NULL;
  

• return csdev;

+}

+/**

• • coresight_block_source - checks whether the connection matches the source

minor nit: s/block/blocks => coresight_blocks_source()

• • of path if connection is binded to specific source.

minor nit: s/binded/bound/

• • @src: The source device of the trace path
• • @conn: The connection of one outport
• • Return false if the connection doesn't have a source binded or source of the
• • path matches the source binds to connection.
• */

+static bool coresight_block_source(struct coresight_device *src,

• 		    struct coresight_connection *conn)
  

+{

• if (conn->filter_src_fwnode && (conn->filter_src_dev != src))

• return true;
  

• else

• return false;
  

minor nit:

return conn->filter_src_fwnode && (conn->filter_src_dev != src);

+}

• static struct coresight_connection *

-coresight_find_out_connection(struct coresight_device *src_dev,

• 	      struct coresight_device *dest_dev)
  

+coresight_find_out_connection(struct coresight_device *csdev,

• 	      struct coresight_device *out_dev,
  

• 	      struct coresight_device *trace_src)
  

  { int i; struct coresight_connection *conn;

• for (i = 0; i < src_dev->pdata->nr_outconns; i++) {

• conn = src_dev->pdata->out_conns[i];
  

• if (conn->dest_dev == dest_dev)
  

• for (i = 0; i < csdev->pdata->nr_outconns; i++) {

• conn = csdev->pdata->out_conns[i];
  

• if (coresight_block_source(trace_src, conn))
  

• 	continue;
  

• if (conn->dest_dev == out_dev)
  return conn;
  

  }

• dev_err(&src_dev->dev,

• "couldn't find output connection, src_dev: %s, dest_dev: %s\n",
  

• dev_name(&src_dev->dev), dev_name(&dest_dev->dev));
  

• dev_err(&csdev->dev,

• "couldn't find output connection, csdev: %s, out_dev: %s\n",
  

• dev_name(&csdev->dev), dev_name(&out_dev->dev));
  

return ERR_PTR(-ENODEV); } @@ -251,7 +286,8 @@ static void coresight_disable_sink(struct coresight_device *csdev) static int coresight_enable_link(struct coresight_device *csdev, struct coresight_device *parent,

• 		 struct coresight_device *child)
  

• 		 struct coresight_device *child,
  

• 		 struct coresight_device *source)
  

  { int link_subtype; struct coresight_connection *inconn, *outconn;

@@ -259,8 +295,8 @@ static int coresight_enable_link(struct coresight_device *csdev, if (!parent || !child) return -EINVAL;

• inconn = coresight_find_out_connection(parent, csdev);
• outconn = coresight_find_out_connection(csdev, child);

• inconn = coresight_find_out_connection(parent, csdev, source);
• outconn = coresight_find_out_connection(csdev, child, source); link_subtype = csdev->subtype.link_subtype;

if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && IS_ERR(inconn)) @@ -273,15 +309,16 @@ static int coresight_enable_link(struct coresight_device *csdev, static void coresight_disable_link(struct coresight_device *csdev, struct coresight_device *parent,

• 		   struct coresight_device *child)
  

• 		   struct coresight_device *child,
  

• 		   struct coresight_device *source)
  

  { struct coresight_connection *inconn, *outconn;

if (!parent || !child) return;

• inconn = coresight_find_out_connection(parent, csdev);
• outconn = coresight_find_out_connection(csdev, child);

• inconn = coresight_find_out_connection(parent, csdev, source);
• outconn = coresight_find_out_connection(csdev, child, source);

link_ops(csdev)->disable(csdev, inconn, outconn); } @@ -375,7 +412,8 @@ static void coresight_disable_path_from(struct list_head *path, case CORESIGHT_DEV_TYPE_LINK: parent = list_prev_entry(nd, link)->csdev; child = list_next_entry(nd, link)->csdev;

• 	coresight_disable_link(csdev, parent, child);
  

• 	coresight_disable_link(csdev, parent, child,
  

• 			       coresight_get_source(path));
  break;
  

  default: break;

@@ -418,7 +456,9 @@ int coresight_enable_path(struct list_head *path, enum cs_mode mode, u32 type; struct coresight_node *nd; struct coresight_device *csdev, *parent, *child;

• struct coresight_device *source;

• source = coresight_get_source(path); list_for_each_entry_reverse(nd, path, link) { csdev = nd->csdev; type = csdev->type;

@@ -456,7 +496,7 @@ int coresight_enable_path(struct list_head *path, enum cs_mode mode, case CORESIGHT_DEV_TYPE_LINK: parent = list_prev_entry(nd, link)->csdev; child = list_next_entry(nd, link)->csdev;

• 	ret = coresight_enable_link(csdev, parent, child);
  

• 	ret = coresight_enable_link(csdev, parent, child, source);
  if (ret)
  	goto err;
  break;
  

@@ -619,6 +659,7 @@ static void coresight_drop_device(struct coresight_device *csdev) /**

• _coresight_build_path - recursively build a path from a @csdev to a sink.
• @csdev: The device to start from.

• • @source: The trace source device of the path.
  • @sink: The final sink we want in this path.
  • @path: The list to add devices to.

@@ -628,6 +669,7 @@ static void coresight_drop_device(struct coresight_device *csdev)

• the source is the first device and the sink the last one.

*/ static int _coresight_build_path(struct coresight_device *csdev,

• 		 struct coresight_device *source,
  	 struct coresight_device *sink,
  	 struct list_head *path)
  

  {

@@ -641,7 +683,7 @@ static int _coresight_build_path(struct coresight_device *csdev, if (coresight_is_percpu_source(csdev) && coresight_is_percpu_sink(sink) && sink == per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev))) {

• if (_coresight_build_path(sink, sink, path) == 0) {
  

• if (_coresight_build_path(sink, source, sink, path) == 0) {
  found = true;
  goto out;
  

  }

@@ -652,8 +694,12 @@ static int _coresight_build_path(struct coresight_device *csdev, struct coresight_device *child_dev; child_dev = csdev->pdata->out_conns[i]->dest_dev;

• if (coresight_block_source(source, csdev->pdata->out_conns[i]))
  

• 	continue;
  

• if (child_dev &&

•     _coresight_build_path(child_dev, sink, path) == 0) {
  

•     _coresight_build_path(child_dev, source, sink, path) == 0) {
  found = true;
  break;
  

  }

@@ -698,7 +744,7 @@ struct list_head *coresight_build_path(struct coresight_device *source, INIT_LIST_HEAD(path);

• rc = _coresight_build_path(source, sink, path);

• rc = _coresight_build_path(source, source, sink, path); if (rc) { kfree(path); return ERR_PTR(rc);

@@ -927,6 +973,17 @@ static int coresight_orphan_match(struct device *dev, void *data) for (i = 0; i < src_csdev->pdata->nr_outconns; i++) { conn = src_csdev->pdata->out_conns[i];

• /* Fix filter source device before skip the port */
  

• if (conn->filter_src_fwnode && !conn->filter_src_dev) {
  

• 	if (dst_csdev && (conn->filter_src_fwnode
  

• 	    == dst_csdev->dev.fwnode)
  

• 	    && !WARN_ON_ONCE(dst_csdev->type
  

• 	    != CORESIGHT_DEV_TYPE_SOURCE))
  

• 		conn->filter_src_dev = dst_csdev;
  

• 	else
  

• 		still_orphan = true;
  

• }
  

• /* Skip the port if it's already connected. */ if (conn->dest_dev) continue;

@@ -977,18 +1034,40 @@ static int coresight_fixup_orphan_conns(struct coresight_device *csdev) csdev, coresight_orphan_match); } +static int coresight_clear_filter_source(struct device *dev, void *data) +{

• int i;
• struct coresight_device *source = data;
• struct coresight_device *csdev = to_coresight_device(dev);
• for (i = 0; i < csdev->pdata->nr_outconns; ++i) {

• if (csdev->pdata->out_conns[i]->filter_src_dev == source)
  

• 	csdev->pdata->out_conns[i]->filter_src_dev = NULL;
  

• }
• return 0;

+}

• /* coresight_remove_conns - Remove other device's references to this device */ static void coresight_remove_conns(struct coresight_device *csdev) { int i, j; struct coresight_connection *conn;

• if (csdev->type == CORESIGHT_DEV_TYPE_SOURCE)

• bus_for_each_dev(&coresight_bustype, NULL, csdev,
  

• 		 coresight_clear_filter_source);
  

• /*
  • Remove the input connection references from the destination device
  • for each output connection.
  */ for (i = 0; i < csdev->pdata->nr_outconns; i++) { conn = csdev->pdata->out_conns[i];

• if (conn->filter_src_fwnode) {
  

• 	conn->filter_src_dev = NULL;
  

• 	fwnode_handle_put(conn->filter_src_fwnode);
  

• }
  

• if (!conn->dest_dev) continue;

diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c index 64e171eaad82..6ef4b26f04bb 100644 --- a/drivers/hwtracing/coresight/coresight-platform.c +++ b/drivers/hwtracing/coresight/coresight-platform.c @@ -243,6 +243,24 @@ static int of_coresight_parse_endpoint(struct device *dev, conn.dest_fwnode = fwnode_handle_get(rdev_fwnode); conn.dest_port = rendpoint.port;

• /*
  

•  * Get the firmware node of the filter source through the
  

•  * reference. This could be used to filter the source in
  

•  * building path.
  

•  */
  

• conn.filter_src_fwnode =
  

• 	fwnode_find_reference(&ep->fwnode, "filter-src", 0);
  

• if (IS_ERR(conn.filter_src_fwnode))
  

• 	conn.filter_src_fwnode = NULL;
  

Please use { }, when the else condition requires it.

• else {
  

• 	conn.filter_src_dev =
  

• 	 coresight_find_csdev_by_fwnode(conn.filter_src_fwnode);
  

• 	if (conn.filter_src_dev && (conn.filter_src_dev->type
  

• 	    != CORESIGHT_DEV_TYPE_SOURCE))
  

• 		dev_warn(&conn.filter_src_dev->dev,
  

• 		  "Filter source is not a source device\n");
  

• }
  

• new_conn = coresight_add_out_conn(dev, pdata, &conn); if (IS_ERR_VALUE(new_conn)) { fwnode_handle_put(conn.dest_fwnode);

diff --git a/include/linux/coresight.h b/include/linux/coresight.h index c13342594278..52f05f01b287 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -172,6 +172,9 @@ struct coresight_desc {

• @dest_dev: a @coresight_device representation of the component connected to @src_port. NULL until the device is created
• @link: Representation of the connection as a sysfs link.

• • @filter_src_fwnode: filter source component's fwnode handle.
• • @filter_src_dev: a @coresight_device representation of the component that

• needs to be filtered.
  

  • The full connection structure looks like this, where in_conns store
  • references to same connection as the source device's out_conns.

@@ -200,6 +203,8 @@ struct coresight_connection { struct coresight_device *dest_dev; struct coresight_sysfs_link *link; struct coresight_device *src_dev;

• struct fwnode_handle *filter_src_fwnode;
• struct coresight_device *filter_src_dev; atomic_t src_refcnt; atomic_t dest_refcnt; };

Rest looks fine to me.

Suzuki