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Message-ID: <94096b6e-1a4c-4fc4-8294-316b38b35e99@arm.com>
Date: Mon, 18 Nov 2024 09:56:09 +0000
From: Suzuki K Poulose <suzuki.poulose@....com>
To: Tao Zhang <quic_taozha@...cinc.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 v5 3/4] coresight: Add support for trace filtering by
 source

On 18/11/2024 09:28, Tao Zhang wrote:
> 
> On 11/15/2024 5:40 PM, Suzuki K Poulose wrote:
>> On 15/11/2024 09:18, Tao Zhang wrote:
>>>
>>> On 11/13/2024 9:39 PM, Suzuki K Poulose wrote:
>>>> On 30/10/2024 09:32, 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>;
>>>>>              xyz: endpoint {
>>>>>                  remote-endpoint = <&zyx>;
>>>>>                  filter-source = <&source_1>; <-- To specify the 
>>>>> source to
>>>>>              };                           be filtered out here.
>>>>>          };
>>>>>
>>>>>          port@1 {
>>>>>              reg = <1>;
>>>>>              abc: endpoint {
>>>>>                  remote-endpoint = <&cba>;
>>>>>                  filter-source = <&source_2>; <-- To specify the 
>>>>> source to
>>>>>              };                           be filtered out here.
>>>>>          };
>>>>>      };
>>>>> };
>>>>>
>>>>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
>>>>> ---
>>>>>   drivers/hwtracing/coresight/coresight-core.c  | 113 +++++++++++++ 
>>>>> ++---
>>>>>   .../hwtracing/coresight/coresight-platform.c  |  18 +++
>>>>>   include/linux/coresight.h                     |   5 +
>>>>>   3 files changed, 117 insertions(+), 19 deletions(-)
>>>>>
>>>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/ 
>>>>> drivers/hwtracing/coresight/coresight-core.c
>>>>> index ea38ecf26fcb..0a9380350fb5 100644
>>>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>>>> @@ -75,22 +75,54 @@ 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 (!coresight_is_device_source(csdev))
>>>>> +        return NULL;
>>>>> +
>>>>> +    return csdev;
>>>>> +}
>>>>> +
>>>>> +/**
>>>>> + * coresight_blocks_source - checks whether the connection matches 
>>>>> the source
>>>>> + * of path if connection is bound 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_blocks_source(struct coresight_device *src,
>>>>> +                    struct coresight_connection *conn)
>>>>> +{
>>>>> +    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_blocks_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 +283,8 @@ 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 +292,8 @@ 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 +306,16 @@ 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 +409,8 @@ 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 +453,9 @@ 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 +493,7 @@ 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 +656,7 @@ 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 +666,7 @@ 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 +680,7 @@ 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 +691,12 @@ 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_blocks_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 +741,7 @@ 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 +970,16 @@ 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 && !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;
>>>>> @@ -977,18 +1030,40 @@ 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 (coresight_is_device_source(csdev))
>>>>> +        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..d5532caa9e92 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-source", 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 &&
>>>>> + !coresight_is_device_source(conn.filter_src_dev))
>>>>> +                dev_warn(&conn.filter_src_dev->dev,
>>>>> +                  "Filter source is not a source device\n");
>>>>
>>>> Do we need to reset the conn.filter_src_fwnode ? Otherwise, we can 
>>>> warn from other places too.
>>>
>>> Agree, we need to reset conn.filter_src_fwnode and 
>>> conn.filter_src_dev here if it is not a SOURCE
>>>
>>> type device.
>>>
>>> I will update the following code to the next patch series. Could you 
>>> help check if it is fine to you?
>>
>> This looks good.
>>
>>>
>>> +            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");
>>
>> minor nit: It would be good to indicate which device has this 
>> "filtering". i.e,
>>           dev_warn(dev, "Filter source is not a trace source : %s\n", 
>> dev_name(&conn.filter_src_dev->dev));
> Sure, I will update this to the next patch series.

Also, it may be helpful, if we specify the "port number" which has this
wrong handle. I guess something like:

dev_warn(dev, "port %d: Filter handle is not a trace source : %s\n",
	 conn.src_port, dev_name(&conn.filter_src_dev->dev));

Suzuki
	
>>
>>> +                conn.filter_src_dev = NULL;
>>> +                conn.filter_src_dev = NULL;
> 
> Sorry for my mistake here. I also want to set "filter_src_fwnode " to 
> NULL if it is not a trace source.
> 
> conn.filter_src_fwnode = NULL;


> 
> 
> Best,
> 
> Tao
> 
>>
>> Duplicated line ^
>>
>> Suzuki
>>
>>> +            }
>>>
>>> Best,
>>>
>>> Tao
>>>
>>>>
>>>> Suzuki
>>>>
>>>>> +        }
>>>>> +
>>>>>           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 9311df8538fc..f372c01ae2fc 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;
>>>>>   };
>>>>
>>


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