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Fri, 09 Aug 2024 10:21:53 +0000 (GMT) Received: from nalasex01c.na.qualcomm.com (nalasex01c.na.qualcomm.com [10.47.97.35]) by NALASPPMTA01.qualcomm.com (8.17.1.19/8.17.1.19) with ESMTPS id 479ALpt6008481 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 9 Aug 2024 10:21:51 GMT Received: from [10.239.133.211] (10.80.80.8) by nalasex01c.na.qualcomm.com (10.47.97.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Fri, 9 Aug 2024 03:21:48 -0700 Message-ID: <103157b0-976c-4e60-97fa-49eb713b7982@quicinc.com> Date: Fri, 9 Aug 2024 18:21:46 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/3] coresight: Add source filtering for multi-port output To: Suzuki K Poulose , Mike Leach , James Clark , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Mathieu Poirier , Leo Yan , Alexander Shishkin CC: , , , , References: <20240711081750.21792-1-quic_taozha@quicinc.com> <20240711081750.21792-3-quic_taozha@quicinc.com> Content-Language: en-US From: Tao Zhang In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: nasanex01a.na.qualcomm.com (10.52.223.231) To nalasex01c.na.qualcomm.com (10.47.97.35) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-ORIG-GUID: KZcWDf8mZs-eaF8LikPjuBl7aO0FrlnQ X-Proofpoint-GUID: KZcWDf8mZs-eaF8LikPjuBl7aO0FrlnQ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-08-09_07,2024-08-07_01,2024-05-17_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 malwarescore=0 bulkscore=0 clxscore=1015 suspectscore=0 phishscore=0 spamscore=0 adultscore=0 lowpriorityscore=0 mlxscore=0 priorityscore=1501 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2407110000 definitions=main-2408090075 On 7/11/2024 9:05 PM, Suzuki K Poulose wrote: > On 11/07/2024 09:17, Tao Zhang wrote: >> In order to enable the output ports of multi-port output devices, > > This has nothing to do with multi-port. You wanted to pain the picture > of a multi-port device, while the reality is different. > >> 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. > > Minor nit: I think the commit description is full of "How" you are > doing something, while it must rather be: "What and Why?" > > I would prefer something like : > > Subject: coresight: Add support for trace filtering by source > > 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. > > >> >> Signed-off-by: Tao Zhang >> --- >>   drivers/hwtracing/coresight/coresight-core.c  | 125 ++++++++++++++++-- >>   .../hwtracing/coresight/coresight-platform.c  |  18 +++ >>   include/linux/coresight.h                     |   5 + >>   3 files changed, 135 insertions(+), 13 deletions(-) >> >> diff --git a/drivers/hwtracing/coresight/coresight-core.c >> b/drivers/hwtracing/coresight/coresight-core.c >> index 9fc6f6b863e0..3f02a31b9328 100644 >> --- a/drivers/hwtracing/coresight/coresight-core.c >> +++ b/drivers/hwtracing/coresight/coresight-core.c >> @@ -75,15 +75,60 @@ 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; >> +} >> + > > Why is this still here ? Didn't agree to remove this and pass the source > directly ? I would like to discuss with you about passing the "source" directly. Since the APIs "coresight_enable_path" and "coresight_disable_path" are called in coresight-etm-perf.c as well. If passing the "source" to them directly, I need to modify the code in coresight-etm-perf.c as well. In order to reduce the modification, how about if I keep using "coresight_get_source" in "coresight_enable_path" and "coresight_disable_path" to get "source" for filtering the source in "coresight_block_source"? Best, Tao > >> +/** >> + * coresight_source_filter - checks whether the connection matches >> the source >> + * of path if connection is binded to specific source. >> + * @trace_source: The source device of the trace path >> + * @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 coresight_device >> *trace_source, >> +            struct coresight_connection *conn) > > This name is a bit confusing. It doesn't tell you, whether it > allows the trace or blocks it. > >> +{ >> +    int ret = 0; >> + >> +    if (!conn->filter_src_dev) >> +        return ret; > > This is not the correct check. It must be : > > if (!conn->filter_src_fwnode) > > Because, the device could have disappeared (or not appeared yet). > e.g., (TPDM) driver module unloaded/not - loaded. > >> + >> +    if (!trace_source) > > Is that possible ? > >> +        return -1; >> + >> +    if (conn->filter_src_dev == trace_source) >> +        ret = 0; >> +    else >> +        ret = -1; > > Couldn't this simply be : > > /* >  * Returns true, if the trace path is not possible through @conn >  * for trace originating from @src >  */ > static bool coresight_blocks_source(src, conn) > { >     return conn->filter_src_fwnode && >         (conn->filter_src_dev != src); > } > >> + >> +    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 coresight_device *trace_source) > > Please could you rename : > >     src_dev => csdev >     dest_dev => out_dev >     trace_source => trace_src ? > > Having src_dev and trace_source in the same list is confusing. > >>   { >>       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(trace_source, conn)) > >         if (coresight_blocks_source(trace_source, conn)) >             continue; > >> +            continue; >>           if (conn->dest_dev == dest_dev) >>               return conn; >>       } >> @@ -251,7 +296,8 @@ 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 *trace_source) >>   { >>       int link_subtype; >>       struct coresight_connection *inconn, *outconn; >> @@ -259,8 +305,8 @@ 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, >> trace_source); >> +    outconn = coresight_find_out_connection(csdev, child, >> trace_source); >>       link_subtype = csdev->subtype.link_subtype; >>         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && >> IS_ERR(inconn)) >> @@ -273,15 +319,16 @@ 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 *trace_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, >> trace_source); >> +    outconn = coresight_find_out_connection(csdev, child, >> trace_source); >>         link_ops(csdev)->disable(csdev, inconn, outconn); >>   } >> @@ -341,6 +388,9 @@ static void coresight_disable_path_from(struct >> list_head *path, >>   { >>       u32 type; >>       struct coresight_device *csdev, *parent, *child; >> +    struct coresight_device *source; >> + >> +    source = coresight_get_source(path); > > Grr! This must come from the "caller of the > coresight_disable_path_from()", which was my comment. Please go back > and double check the comment on previous version. > > >>         if (!nd) >>           nd = list_first_entry(path, struct coresight_node, link); >> @@ -375,7 +425,7 @@ 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; >> @@ -418,6 +468,9 @@ 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; >> @@ -456,7 +509,7 @@ 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 +672,7 @@ 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. >> + * @trace_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 +681,8 @@ 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; >> @@ -639,7 +694,7 @@ 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; >>           } >> @@ -650,8 +705,13 @@ 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; >>           } >> @@ -696,7 +756,7 @@ 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); >> @@ -957,6 +1017,14 @@ 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; >> +            if (conn->filter_src_dev->type >> +                != CORESIGHT_DEV_TYPE_SOURCE) >> +                dev_warn(&conn->filter_src_dev->dev, >> +                  "Filter source is not a source device\n"); >> +        } > > Have you tested your code with the following order : > > 1) Build everything as module > 2) Load the replicator driver. > 3) Load the TPDM driver > > And are you able to get the trace working ? I suspect it doesn't work. > The csdev->orphan must be used to track if there is any missing link > with unresolved "filter_src_dev". > > >>       } >>         src_csdev->orphan = still_orphan; >> @@ -974,6 +1042,30 @@ static int coresight_fixup_orphan_conns(struct >> coresight_device *csdev) >>                csdev, coresight_orphan_match); >>   } >>   +/* reset_filter_src - Reset the filter source if the source is >> being removed */ >> +static int reset_filter_src(struct coresight_device *trace_source, >> +                struct coresight_connection *conn) >> +{ >> +    int i; >> +    int ret = -1; >> +    struct coresight_device *csdev; >> +    struct coresight_connection *output_conn; > > I don't think this is sufficient. I would rather walk through the > entire coresight bus and fixup the filter_src_dev, rather than > traversing the > paths. e.g., one of the devices in the path could have been removed. > See coresight_clear_default_sink() for e.g. You should have something > similar : > > coresight_clear_filter_source(); > > > Suzuki > > > >> + >> +    csdev = conn->dest_dev; >> +    for (i = 0; i < csdev->pdata->nr_outconns; i++) { >> +        output_conn = csdev->pdata->out_conns[i]; >> +        if (output_conn->filter_src_dev >> +            && (output_conn->filter_src_dev == trace_source)) { >> +            output_conn->filter_src_dev = NULL; >> +            return 0; >> +        } >> +        ret = reset_filter_src(trace_source, output_conn); >> +        if (!ret) >> +            return ret; >> +    } >> +    return ret; >> +} >> + >>   /* coresight_remove_conns - Remove other device's references to >> this device */ >>   static void coresight_remove_conns(struct coresight_device *csdev) >>   { >> @@ -986,6 +1078,13 @@ 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 (csdev->type == CORESIGHT_DEV_TYPE_SOURCE) >> +            reset_filter_src(csdev, conn); >> +        if (conn->filter_src_fwnode) { >> +            conn->filter_src_dev = NULL; >> +            conn->filter_src_fwnode = NULL; >> +        } >> + >>           if (!conn->dest_dev) >>               continue; >>   diff --git a/drivers/hwtracing/coresight/coresight-platform.c >> b/drivers/hwtracing/coresight/coresight-platform.c >> index 64e171eaad82..b3c3e2361d07 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 %s 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; >>   }; >