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Message-ID: <a76bf942-e36f-467d-a436-0a1d8e682c10@quicinc.com>
Date: Fri, 23 Aug 2024 00:44:31 +0800
From: Tao Zhang <quic_taozha@...cinc.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
Mike Leach
<mike.leach@...aro.org>, James Clark <james.clark@....com>,
Rob Herring
<robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley
<conor+dt@...nel.org>,
Mathieu Poirier <mathieu.poirier@...aro.org>,
Leo Yan
<leo.yan@...ux.dev>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>
CC: <coresight@...ts.linaro.org>, <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH v3 2/3] coresight: Add support for trace filtering by
source
On 8/21/2024 11:23 PM, Suzuki K Poulose wrote:
> Hi Tao
>
> On 21/08/2024 04:13, 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.
>>
>
> This looks good, except for some minor comments below.
OK, I will remove the comments below in the next version.
>
>> 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.
>> };
>> };
>> };
>>
>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
>> ---
>> drivers/hwtracing/coresight/coresight-core.c | 136 +++++++++++++++---
>> .../hwtracing/coresight/coresight-platform.c | 18 +++
>> include/linux/coresight.h | 5 +
>> 3 files changed, 136 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>> b/drivers/hwtracing/coresight/coresight-core.c
>> index 9fc6f6b863e0..d09266a4dd1c 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
>> + * of path if connection is binded to specific source.
>> + * @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;
>> +}
>> +
>> 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);
>> }
>> @@ -337,7 +374,8 @@ EXPORT_SYMBOL_GPL(coresight_disable_source);
>> * disabled.
>> */
>> static void coresight_disable_path_from(struct list_head *path,
>> - struct coresight_node *nd)
>> + struct coresight_node *nd,
>> + struct coresight_device *source)
>
> Apologies, I may not have been clear enough. But we concluded that the
> path here is suitable for coresight_get_source(path) and as such we
> don't need to explicitly pass the source.
Do you mean we don't need to explicitly pass the source on
"coresight_disable_path_from",
we can pass the "source" to "coresight_disable_link" by the following way?
coresight_disable_link(csdev, parent, child, coresight_get_source(path));
>
>> {
>> u32 type;
>> struct coresight_device *csdev, *parent, *child;
>> @@ -375,7 +413,7 @@ 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, source);
>> break;
>> default:
>> break;
>> @@ -388,7 +426,10 @@ static void coresight_disable_path_from(struct
>> list_head *path,
>> void coresight_disable_path(struct list_head *path)
>> {
>> - coresight_disable_path_from(path, NULL);
>> + struct coresight_device *source;
>> +
>> + source = coresight_get_source(path);
>> + coresight_disable_path_from(path, NULL, source);
>> }
>> EXPORT_SYMBOL_GPL(coresight_disable_path);
>> @@ -418,7 +459,9 @@ 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 +499,7 @@ 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;
>> @@ -468,7 +511,7 @@ int coresight_enable_path(struct list_head *path,
>> enum cs_mode mode,
>> out:
>> return ret;
>> err:
>> - coresight_disable_path_from(path, nd);
>> + coresight_disable_path_from(path, nd, source);
>> goto out;
>> }
>> @@ -619,6 +662,7 @@ static void coresight_drop_device(struct
>> coresight_device *csdev)
>> * @csdev: The device to start from.
>> * @sink: The final sink we want in this path.
>> * @path: The list to add devices to.
>> + * @source: The trace source device of the path.
>> *
>> * The tree of Coresight device is traversed until @sink is found.
>> * From there the sink is added to the list along with all the
>> devices that led
>> @@ -627,7 +671,8 @@ 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 *source)
>
> minor nit: Please could we reorder the parameter order :
>
> _coresight_build_path(csdev, source, sink, path) ?
>
> That makes it much better to read : build a path from "source" to
> "sink", from "csdev"
All right, I will update in the next version.
>
>> {
>> int i, ret;
>> bool found = false;
>> @@ -639,7 +684,7 @@ 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, source) == 0) {
>> found = true;
>> goto out;
>> }
>> @@ -650,8 +695,13 @@ 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 != source))
>> + continue;
>
> Please reuse coresight_block_source(). i.e.,
>
> if (coresight_block_source(source, csdev->pdata->cout_conns[i]))
> continue;
OK, I will update in the next version.
>
>> +
>> if (child_dev &&
>> - _coresight_build_path(child_dev, sink, path) == 0) {
>> + _coresight_build_path(child_dev, sink, path, source) ==
>> 0) {
>> found = true;
>> break;
>> }
>> @@ -696,7 +746,7 @@ 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);
>> @@ -924,6 +974,16 @@ 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) && dst_csdev
>
> minor nit: unnecessary () around conn->filter_src_fwnode
OK, I will update in the next version.
>
>> + && (conn->filter_src_fwnode == dst_csdev->dev.fwnode)) {
>> + if (dst_csdev->type == CORESIGHT_DEV_TYPE_SOURCE)
>> + conn->filter_src_dev = dst_csdev;
>> + else
>> + dev_warn(&conn->filter_src_dev->dev,
>> + "Filter source is not a source device\n");
>> + }
>
> We could set the still_orphan here instead of down below.
>
> /* Fixup filter source link */
> 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;
> }
>
> minor nit: Also I think it is high time we add a helper to check if a
> devices is SOURCE, something like we did for is_device_tpdm(). e.g.,
>
>
> static inline bool coresight_is_device_source(struct coresight_device
> *csdev)
> {
> return csdev && (csdev->type == CORESIGHT_DEV_TYPE_SOURCE);
> }
Could you help review the following approach?
I will add the helper to coresight-priv.h
static inline bool coresight_is_device_source(struct coresight_device
*csdev)
{
return (csdev && (csdev->type == CORESIGHT_DEV_TYPE_SOURCE));
}
Then, calling the help to check if a device is SOURCE in
coresight-platform.c and coresight-core.c
coresight-platform.c
... ... ... ...
else {
conn.filter_src_dev =
coresight_find_csdev_by_fwnode(conn.filter_src_fwnode);
if (conn.filter_src_dev &&
!coresight_is_device_source(conn.filter_src_dev))
dev_warn(&conn.filter_src_dev->dev,
"Filter source is not a source device\n");
}
coresight-core.c
... ... ... ...
if (conn->filter_src_fwnode && !conn->filter_src_dev) {
if (dst_csdev && (conn->filter_src_fwnode ==
dst_csdev->dev.fwnode)
&& !WARN_ON_ONCE(!coresight_is_device_source(dst_csdev)))
conn->filter_src_dev = dst_csdev;
else
still_orphan = true;
}
>
>
>> +
>> /* Skip the port if it's already connected. */
>> if (conn->dest_dev)
>> continue;
>> @@ -953,6 +1013,14 @@ static int coresight_orphan_match(struct device
>> *dev, void *data)
>> ret = coresight_add_in_conn(conn);
>> if (ret)
>> return ret;
>> +
>> + /*
>> + * Make sure the device still orphan if there is a
>> + * filter source firmware node but the filter source
>> + * device is null.
>> + */
>> + if (conn->filter_src_fwnode && !conn->filter_src_dev)
>> + still_orphan = true;
>
> Could we not move this to the place where we fixup the filter_src_dev
> ? See above.
OK, I will update in the next version.
>
>> } else {
>> /* This component still has an orphan */
>> still_orphan = true;
>> @@ -974,18 +1042,40 @@ 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;
>> + 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 f09ace92176e..91a689b4514b 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;
>> };
>
>
> Suzuki
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