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Message-ID: <8254b93b-0d18-4bd9-817b-b885de6a480d@arm.com>
Date: Tue, 9 Jul 2024 14:42:57 +0100
From: Suzuki K Poulose <suzuki.poulose@....com>
To: Tao Zhang <quic_taozha@...cinc.com>,
Mathieu Poirier <mathieu.poirier@...aro.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Mike Leach <mike.leach@...aro.org>, Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
James Clark <james.clark@....com>, james.clark@...aro.org
Cc: Jinlong Mao <quic_jinlmao@...cinc.com>, Leo Yan <leo.yan@...aro.org>,
coresight@...ts.linaro.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
Tingwei Zhang <quic_tingweiz@...cinc.com>,
Yuanfang Zhang <quic_yuanfang@...cinc.com>,
Trilok Soni <quic_tsoni@...cinc.com>, Song Chai <quic_songchai@...cinc.com>,
linux-arm-msm@...r.kernel.org, Jie Gan <quic_jiegan@...cinc.com>
Subject: Re: [PATCH v1 2/3] coresight: Add source filtering for multi-port
output
On 05/07/2024 09:51, Tao Zhang wrote:
> In order to enable the output ports of multi-port output devices,
> such as static replicator, to correspond to designated sources,
> a mechanism for filtering data sources is introduced for the
> output ports.
>
> The specified source will be marked like below in the Devicetree.
> test-replicator {
> ... ... ... ...
> out-ports {
> ... ... ... ...
> port@0 {
> reg = <0>;
> xxx: endpoint {
> remote-endpoint = <&xxx>;
> filter_src = <&xxx>; <-- To specify the source to
> }; be filtered out here.
> };
>
> port@1 {
> reg = <1>;
> yyy: endpoint {
> remote-endpoint = <&yyy>;
> filter_src = <&yyy>; <-- To specify the source to
> }; be filtered out here.
> };
> };
> };
>
> Then driver will find the expected source marked in the Devicetree, and
> save it to the coresight path. When the function needs to filter the
> source, it could obtain it from coresight path parameter. Finally,
> the output port knows which source it corresponds to, and it also knows
> which input port it corresponds to.
>
> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 89 ++++++++++++++++---
> .../hwtracing/coresight/coresight-platform.c | 13 +++
> include/linux/coresight.h | 5 ++
> 3 files changed, 94 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 5dde597403b3..1c58b64f0031 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -113,15 +113,62 @@ 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_source_filter - checks whether the connection matches the source
> + * of path if connection is binded to specific source.
> + * @path: The list of devices
> + * @conn: The connection of one outport
> + *
> + * Return zero if the connection doesn't have a source binded or source of the
> + * path matches the source binds to connection.
> + */
> +static int coresight_source_filter(struct list_head *path,
Instead of path, you may need to switch to "source" device. See below.
> + struct coresight_connection *conn)
> +{
> + int ret = 0;
> + struct coresight_device *source = NULL;
> +
> + if (!conn->filter_src_dev)
> + return ret;
> +
> + source = coresight_get_source(path);
> + if (!source)
> + return ret;
> +
> + if (conn->filter_src_dev == source)
> + ret = 0;
> + else
> + ret = -1;
> +
> + return ret;
> +}
> +
> static struct coresight_connection *
> coresight_find_out_connection(struct coresight_device *src_dev,
> - struct coresight_device *dest_dev)
> + struct coresight_device *dest_dev,
> + struct list_head *path)
> {
> int i;
> struct coresight_connection *conn;
>
> for (i = 0; i < src_dev->pdata->nr_outconns; i++) {
> conn = src_dev->pdata->out_conns[i];
> + if (coresight_source_filter(path, conn))
> + continue;
> if (conn->dest_dev == dest_dev)
> return conn;
> }
> @@ -312,7 +359,8 @@ 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 list_head *path)
> {
> int ret = 0;
> int link_subtype;
> @@ -321,8 +369,8 @@ 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, path);
> + outconn = coresight_find_out_connection(csdev, child, path);
> link_subtype = csdev->subtype.link_subtype;
>
> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && IS_ERR(inconn))
> @@ -341,7 +389,8 @@ 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 list_head *path)
> {
> int i;
> int link_subtype;
> @@ -350,8 +399,8 @@ static void coresight_disable_link(struct coresight_device *csdev,
> 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, path);
> + outconn = coresight_find_out_connection(csdev, child, path);
> link_subtype = csdev->subtype.link_subtype;
>
> if (link_ops(csdev)->disable) {
> @@ -507,7 +556,7 @@ 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, path);
> break;
Disable path from could be called with a "partial path" with the
"source" stripped off. e.g, if the enabling of the components failed
mid-point in the path. So, source_from_path() above is WRONG csdev.
Instead you should make sure we pass the "source", which must be
available with the caller.
> default:
> break;
> @@ -588,7 +637,7 @@ 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, path);
> if (ret)
> goto err;
> break;
> @@ -802,7 +851,8 @@ static void coresight_drop_device(struct coresight_device *csdev)
> */
> static int _coresight_build_path(struct coresight_device *csdev,
> struct coresight_device *sink,
> - struct list_head *path)
> + struct list_head *path,
> + struct coresight_device *trace_source)
> {
> int i, ret;
> bool found = false;
> @@ -814,7 +864,7 @@ 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, sink, path, trace_source) == 0) {
> found = true;
> goto out;
> }
> @@ -825,8 +875,13 @@ static int _coresight_build_path(struct coresight_device *csdev,
> struct coresight_device *child_dev;
>
> child_dev = csdev->pdata->out_conns[i]->dest_dev;
> +
> + if (csdev->pdata->out_conns[i]->filter_src_dev
> + && (csdev->pdata->out_conns[i]->filter_src_dev != trace_source))
> + continue;
> +
> if (child_dev &&
> - _coresight_build_path(child_dev, sink, path) == 0) {
> + _coresight_build_path(child_dev, sink, path, trace_source) == 0) {
> found = true;
> break;
> }
> @@ -871,7 +926,7 @@ 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, sink, path, source);
> if (rc) {
> kfree(path);
> return ERR_PTR(rc);
> @@ -1395,6 +1450,9 @@ static int coresight_orphan_match(struct device *dev, void *data)
> /* This component still has an orphan */
> still_orphan = true;
> }
> + if ((conn->filter_src_fwnode) && dst_csdev
> + && (conn->filter_src_fwnode == dst_csdev->dev.fwnode))
> + conn->filter_src_dev = dst_csdev;
> }
>
> src_csdev->orphan = still_orphan;
> @@ -1424,6 +1482,11 @@ static void coresight_remove_conns(struct coresight_device *csdev)
> */
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> conn = csdev->pdata->out_conns[i];
> + if (conn->filter_src_dev) {
> + conn->filter_src_dev = NULL;
> + conn->filter_src_fwnode = NULL;
> + }
> +
Similarly we should reset the "filter_src_dev" if the "src" csdev is
being removed. You may need a new function for that, which scans
through all devices and looks for a conn->filter_src_dev == csdev.
Something like:
> if (!conn->dest_dev)
> continue;
>
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 9d550f5697fa..a9f5b0700310 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -243,6 +243,19 @@ 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;
> + else
> + conn.filter_src_dev =
> + coresight_find_csdev_by_fwnode(conn.filter_src_fwnode);
We should warn, if the filter_src_dev is of not the type DEV_TYPE_SOURCE.
> +
> 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 e8b6e388218c..0a7ec0978605 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -171,6 +171,9 @@ 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.
> @@ -199,6 +202,8 @@ 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;
> };
Suzuki
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