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Message-ID: <2eecee82-2143-0da6-6132-5514336ebc6b@arm.com>
Date:   Tue, 4 Apr 2023 14:04:40 +0100
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Subject: Re: [PATCH v3 13/13] coresight: Fix CTI module refcount leak by
 making it a helper device
Content-Language: en-US
From:   James Clark <james.clark@arm.com>
To:     Suzuki K Poulose <suzuki.poulose@arm.com>,
        coresight@lists.linaro.org, quic_jinlmao@quicinc.com,
        mike.leach@linaro.org
Cc:     Mathieu Poirier <mathieu.poirier@linaro.org>,
        Leo Yan <leo.yan@linaro.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com
References: <20230329115329.2747724-1-james.clark@arm.com>
 <20230329115329.2747724-14-james.clark@arm.com>
 <77d890a9-9927-da8e-1460-54513784683d@arm.com>
 <61bb4e6d-5451-2f01-19b2-76c396854c23@arm.com>
In-Reply-To: <61bb4e6d-5451-2f01-19b2-76c396854c23@arm.com>
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Precedence: bulk


On 04/04/2023 13:55, James Clark wrote:
> 
> 
> On 04/04/2023 10:21, Suzuki K Poulose wrote:
>> On 29/03/2023 12:53, James Clark wrote:
>>> The CTI module has some hard coded refcounting code that has a leak.
>>> For example running perf and then trying to unload it fails:
>>>
>>>    perf record -e cs_etm// -a -- ls
>>>    rmmod coresight_cti
>>>
>>>    rmmod: ERROR: Module coresight_cti is in use
>>>
>>> The coresight core already handles references of devices in use, so by
>>> making CTI a normal helper device, we get working refcounting for free.
>>>
>>> Signed-off-by: James Clark <james.clark@arm.com>
>>> ---
>>>   drivers/hwtracing/coresight/coresight-core.c  | 99 ++++++-------------
>>>   .../hwtracing/coresight/coresight-cti-core.c  | 52 +++++-----
>>>   .../hwtracing/coresight/coresight-cti-sysfs.c |  4 +-
>>>   drivers/hwtracing/coresight/coresight-cti.h   |  4 +-
>>>   drivers/hwtracing/coresight/coresight-priv.h  |  4 +-
>>>   drivers/hwtracing/coresight/coresight-sysfs.c |  4 +
>>>   include/linux/coresight.h                     | 30 +-----
>>>   7 files changed, 70 insertions(+), 127 deletions(-)
>>>
>>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>>> b/drivers/hwtracing/coresight/coresight-core.c
>>> index 65f5bd8516d8..458d91b4e23f 100644
>>> --- a/drivers/hwtracing/coresight/coresight-core.c
>>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>>> @@ -254,60 +254,39 @@ void coresight_disclaim_device(struct
>>> coresight_device *csdev)
>>>   }
>>>   EXPORT_SYMBOL_GPL(coresight_disclaim_device);
>>>   -/* enable or disable an associated CTI device of the supplied CS
>>> device */
>>> -static int
>>> -coresight_control_assoc_ectdev(struct coresight_device *csdev, bool
>>> enable)
>>> -{
>>> -    int ect_ret = 0;
>>> -    struct coresight_device *ect_csdev = csdev->ect_dev;
>>> -    struct module *mod;
>>> -
>>> -    if (!ect_csdev)
>>> -        return 0;
>>> -    if ((!ect_ops(ect_csdev)->enable) || (!ect_ops(ect_csdev)->disable))
>>> -        return 0;
>>> -
>>> -    mod = ect_csdev->dev.parent->driver->owner;
>>> -    if (enable) {
>>> -        if (try_module_get(mod)) {
>>> -            ect_ret = ect_ops(ect_csdev)->enable(ect_csdev);
>>> -            if (ect_ret) {
>>> -                module_put(mod);
>>> -            } else {
>>> -                get_device(ect_csdev->dev.parent);
>>> -                csdev->ect_enabled = true;
>>> -            }
>>> -        } else
>>> -            ect_ret = -ENODEV;
>>> -    } else {
>>> -        if (csdev->ect_enabled) {
>>> -            ect_ret = ect_ops(ect_csdev)->disable(ect_csdev);
>>> -            put_device(ect_csdev->dev.parent);
>>> -            module_put(mod);
>>> -            csdev->ect_enabled = false;
>>> -        }
>>> -    }
>>> -
>>> -    /* output warning if ECT enable is preventing trace operation */
>>> -    if (ect_ret)
>>> -        dev_info(&csdev->dev, "Associated ECT device (%s) %s failed\n",
>>> -             dev_name(&ect_csdev->dev),
>>> -             enable ? "enable" : "disable");
>>> -    return ect_ret;
>>> -}
>>> -
>>>   /*
>>> - * Set the associated ect / cti device while holding the coresight_mutex
>>> + * Add a helper as an output device while holding the coresight_mutex
>>>    * to avoid a race with coresight_enable that may try to use this
>>> value.
>>>    */
>>> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>>> -                      struct coresight_device *ect_csdev)
>>> +void coresight_add_helper_mutex(struct coresight_device *csdev,
>>> +                struct coresight_device *helper)
>>
>> minor nit: It may be a good idea to rename this, in line with the
>> kernel naming convention :
>>
>>     coresight_add_helper_unlocked()
>>
>> Or if this is the only variant, it is OK to leave it as :
>>     coresight_add_helper()
>> with a big fat comment in the function description to indicate
>> that it takes the mutex and may be even add a :
>>
> There is already a bit of a comment in the description but I can expand
> on it more.
> 
>> might_sleep() and lockdep_assert_not_held(&coresight_mutex);
>>
>> in the function.
>>
> 
> I'm not sure if lockdep_assert_not_held() would be right because
> sometimes it could be held if another device is being created at the
> same time? Or something like a session is started at the same time a CTI
> device is added.
> 

Oh I see it's not for any task, it's just for the current one. That
makes sense then I can add it.

Although it looks like it only warns when lockdep is enabled, but don't
you get a warning anyway if you try to take the lock twice with lockdep
enabled? So I'm not sure why we would add lockdep_assert_not_held() here
and not on all the mutex_lock() calls?

>>>   {
>>> +    int i;
>>> +    struct coresight_connection conn = {};
>>> +
>>>       mutex_lock(&coresight_mutex);
>>> -    csdev->ect_dev = ect_csdev;
>>> +    conn.dest_fwnode = fwnode_handle_get(dev_fwnode(&helper->dev));
>>> +    conn.dest_dev = helper;
>>> +    conn.dest_port = conn.src_port = -1;
>>> +    conn.src_dev = csdev;
>>> +
>>> +    /*
>>> +     * Check for duplicates because this is called every time a helper
>>> +     * device is re-loaded. Existing connections will get re-linked
>>> +     * automatically.
>>> +     */
>>
>> Thanks for adding this comment here. It does look like the already added
>> output connection to the "origin" device would automatically resolve the
>> connection and add in the "in-connection" to the CTI device.
>>
>>> +    for (i = 0; i < csdev->pdata->nr_outconns; ++i)
>>> +        if (csdev->pdata->out_conns[i]->dest_fwnode == conn.dest_fwnode)
>>> +            goto unlock;
>>> +
>>> +    coresight_add_out_conn(csdev->dev.parent, csdev->pdata, &conn);
>>
>> This makes me wonder if we should return the new connection in
>> coresight_add_out_conn() in case of success, rather than assuming the
>> last one (which is always the case though.).
>>
>> i.e.,
>>     new_conn = coresight_add_out_conn(...)
>>     if (new_conn)
>>         coresight_add_in_conn(new_conn);
>>
> 
> Yeah I thought about doing that too, will change it.
> 
>>> +    coresight_add_in_conn(
>>> +        csdev->pdata->out_conns[csdev->pdata->nr_outconns - 1]);
>>> +
>>> +unlock:
>>>       mutex_unlock(&coresight_mutex);
>>>   }
>>> -EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
>>> +EXPORT_SYMBOL_GPL(coresight_add_helper_mutex);
>>>     static int coresight_enable_sink(struct coresight_device *csdev,
>>>                    enum cs_mode mode, void *data)
>>> @@ -321,12 +300,8 @@ static int coresight_enable_sink(struct
>>> coresight_device *csdev,
>>>       if (!sink_ops(csdev)->enable)
>>>           return -EINVAL;
>>>   -    ret = coresight_control_assoc_ectdev(csdev, true);
>>> -    if (ret)
>>> -        return ret;
>>>       ret = sink_ops(csdev)->enable(csdev, mode, data);
>>>       if (ret) {
>>> -        coresight_control_assoc_ectdev(csdev, false);
>>>           return ret;
>>>       }
>>>       csdev->enable = true;
>>> @@ -344,7 +319,6 @@ static void coresight_disable_sink(struct
>>> coresight_device *csdev)
>>>       ret = sink_ops(csdev)->disable(csdev);
>>>       if (ret)
>>>           return;
>>> -    coresight_control_assoc_ectdev(csdev, false);
>>>       csdev->enable = false;
>>>   }
>>>   @@ -369,17 +343,11 @@ static int coresight_enable_link(struct
>>> coresight_device *csdev,
>>>           return PTR_ERR(outconn);
>>>         if (link_ops(csdev)->enable) {
>>> -        ret = coresight_control_assoc_ectdev(csdev, true);
>>> -        if (!ret) {
>>> -            ret = link_ops(csdev)->enable(csdev, inconn, outconn);
>>> -            if (ret)
>>> -                coresight_control_assoc_ectdev(csdev, false);
>>> -        }
>>> +        ret = link_ops(csdev)->enable(csdev, inconn, outconn);
>>> +        if (!ret)
>>> +            csdev->enable = true;
>>>       }
>>>   -    if (!ret)
>>> -        csdev->enable = true;
>>> -
>>>       return ret;
>>>   }
>>>   @@ -400,7 +368,6 @@ static void coresight_disable_link(struct
>>> coresight_device *csdev,
>>>         if (link_ops(csdev)->disable) {
>>>           link_ops(csdev)->disable(csdev, inconn, outconn);
>>> -        coresight_control_assoc_ectdev(csdev, false);
>>>       }
>>>         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
>>> @@ -428,14 +395,9 @@ int coresight_enable_source(struct
>>> coresight_device *csdev, void *data,
>>>         if (!csdev->enable) {
>>>           if (source_ops(csdev)->enable) {
>>> -            ret = coresight_control_assoc_ectdev(csdev, true);
>>> -            if (ret)
>>> -                return ret;
>>>               ret = source_ops(csdev)->enable(csdev, data, mode);
>>> -            if (ret) {
>>> -                coresight_control_assoc_ectdev(csdev, false);
>>> +            if (ret)
>>>                   return ret;
>>> -            }
>>>           }
>>>           csdev->enable = true;
>>>       }
>>> @@ -499,7 +461,6 @@ bool coresight_disable_source(struct
>>> coresight_device *csdev, void *data)
>>>       if (atomic_dec_return(&csdev->refcnt) == 0) {
>>>           if (source_ops(csdev)->disable)
>>>               source_ops(csdev)->disable(csdev, data);
>>> -        coresight_control_assoc_ectdev(csdev, false);
>>>           coresight_disable_helpers(csdev);
>>>           csdev->enable = false;
>>>       }
>>> diff --git a/drivers/hwtracing/coresight/coresight-cti-core.c
>>> b/drivers/hwtracing/coresight/coresight-cti-core.c
>>> index 277c890a1f1f..db7a2212ec18 100644
>>> --- a/drivers/hwtracing/coresight/coresight-cti-core.c
>>> +++ b/drivers/hwtracing/coresight/coresight-cti-core.c
>>> @@ -555,7 +555,10 @@ static void cti_add_assoc_to_csdev(struct
>>> coresight_device *csdev)
>>>       mutex_lock(&ect_mutex);
>>>         /* exit if current is an ECT device.*/
>>> -    if ((csdev->type == CORESIGHT_DEV_TYPE_ECT) || list_empty(&ect_net))
>>> +    if ((csdev->type == CORESIGHT_DEV_TYPE_HELPER &&
>>> +         csdev->subtype.helper_subtype ==
>>> +             CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI) ||
>>> +        list_empty(&ect_net))
>>>           goto cti_add_done;
>>>         /* if we didn't find the csdev previously we used the fwnode
>>> name */
>>> @@ -571,8 +574,7 @@ static void cti_add_assoc_to_csdev(struct
>>> coresight_device *csdev)
>>>                * if we found a matching csdev then update the ECT
>>>                * association pointer for the device with this CTI.
>>>                */
>>> -            coresight_set_assoc_ectdev_mutex(csdev,
>>> -                             ect_item->csdev);
>>> +            coresight_add_helper_mutex(csdev, ect_item->csdev);
>>>               break;
>>>           }
>>>       }
>>> @@ -582,26 +584,30 @@ static void cti_add_assoc_to_csdev(struct
>>> coresight_device *csdev)
>>>     /*
>>>    * Removing the associated devices is easier.
>>> - * A CTI will not have a value for csdev->ect_dev.
>>>    */
>>>   static void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
>>>   {
>>>       struct cti_drvdata *ctidrv;
>>>       struct cti_trig_con *tc;
>>> +    union coresight_dev_subtype cti_subtype = {
>>> +        .helper_subtype = CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
>>> +    };
>>> +    struct coresight_device *cti_csdev = coresight_find_output_type(
>>> +        csdev->pdata, CORESIGHT_DEV_TYPE_HELPER, cti_subtype);
>>
>> minor nit: Please could we split the initialisation ? Or at least move
>> this after the next variable declaration below ?
>>
>>
>> Rest looks fine to me.
>>
>> Suzuki
>>
>>>       struct cti_device *ctidev;
>>>   +    if (!cti_csdev)
>>> +        return;
>>> +
>>>       mutex_lock(&ect_mutex);
>>> -    if (csdev->ect_dev) {
>>> -        ctidrv = csdev_to_cti_drvdata(csdev->ect_dev);
>>> -        ctidev = &ctidrv->ctidev;
>>> -        list_for_each_entry(tc, &ctidev->trig_cons, node) {
>>> -            if (tc->con_dev == csdev) {
>>> -                cti_remove_sysfs_link(ctidrv, tc);
>>> -                tc->con_dev = NULL;
>>> -                break;
>>> -            }
>>> +    ctidrv = csdev_to_cti_drvdata(cti_csdev);
>>> +    ctidev = &ctidrv->ctidev;
>>> +    list_for_each_entry(tc, &ctidev->trig_cons, node) {
>>> +        if (tc->con_dev == csdev) {
>>> +            cti_remove_sysfs_link(ctidrv, tc);
>>> +            tc->con_dev = NULL;
>>> +            break;
>>>           }
>>> -        csdev->ect_dev = NULL;
>>>       }
>>>       mutex_unlock(&ect_mutex);
>>>   }
>>> @@ -630,8 +636,8 @@ static void cti_update_conn_xrefs(struct
>>> cti_drvdata *drvdata)
>>>               /* if we can set the sysfs link */
>>>               if (cti_add_sysfs_link(drvdata, tc))
>>>                   /* set the CTI/csdev association */
>>> -                coresight_set_assoc_ectdev_mutex(tc->con_dev,
>>> -                             drvdata->csdev);
>>> +                coresight_add_helper_mutex(tc->con_dev,
>>> +                               drvdata->csdev);
>>>               else
>>>                   /* otherwise remove reference from CTI */
>>>                   tc->con_dev = NULL;
>>> @@ -646,8 +652,6 @@ static void cti_remove_conn_xrefs(struct
>>> cti_drvdata *drvdata)
>>>         list_for_each_entry(tc, &ctidev->trig_cons, node) {
>>>           if (tc->con_dev) {
>>> -            coresight_set_assoc_ectdev_mutex(tc->con_dev,
>>> -                             NULL);
>>>               cti_remove_sysfs_link(drvdata, tc);
>>>               tc->con_dev = NULL;
>>>           }
>>> @@ -795,27 +799,27 @@ static void cti_pm_release(struct cti_drvdata
>>> *drvdata)
>>>   }
>>>     /** cti ect operations **/
>>> -int cti_enable(struct coresight_device *csdev)
>>> +int cti_enable(struct coresight_device *csdev, enum cs_mode mode,
>>> void *data)
>>>   {
>>>       struct cti_drvdata *drvdata = csdev_to_cti_drvdata(csdev);
>>>         return cti_enable_hw(drvdata);
>>>   }
>>>   -int cti_disable(struct coresight_device *csdev)
>>> +int cti_disable(struct coresight_device *csdev, void *data)
>>>   {
>>>       struct cti_drvdata *drvdata = csdev_to_cti_drvdata(csdev);
>>>         return cti_disable_hw(drvdata);
>>>   }
>>>   -static const struct coresight_ops_ect cti_ops_ect = {
>>> +static const struct coresight_ops_helper cti_ops_ect = {
>>>       .enable = cti_enable,
>>>       .disable = cti_disable,
>>>   };
>>>     static const struct coresight_ops cti_ops = {
>>> -    .ect_ops = &cti_ops_ect,
>>> +    .helper_ops = &cti_ops_ect,
>>>   };
>>>     /*
>>> @@ -922,8 +926,8 @@ static int cti_probe(struct amba_device *adev,
>>> const struct amba_id *id)
>>>         /* set up coresight component description */
>>>       cti_desc.pdata = pdata;
>>> -    cti_desc.type = CORESIGHT_DEV_TYPE_ECT;
>>> -    cti_desc.subtype.ect_subtype = CORESIGHT_DEV_SUBTYPE_ECT_CTI;
>>> +    cti_desc.type = CORESIGHT_DEV_TYPE_HELPER;
>>> +    cti_desc.subtype.helper_subtype =
>>> CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI;
>>>       cti_desc.ops = &cti_ops;
>>>       cti_desc.groups = drvdata->ctidev.con_groups;
>>>       cti_desc.dev = dev;
>>> diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
>>> b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
>>> index e528cff9d4e2..d25dd2737b49 100644
>>> --- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
>>> +++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
>>> @@ -112,11 +112,11 @@ static ssize_t enable_store(struct device *dev,
>>>           ret = pm_runtime_resume_and_get(dev->parent);
>>>           if (ret)
>>>               return ret;
>>> -        ret = cti_enable(drvdata->csdev);
>>> +        ret = cti_enable(drvdata->csdev, CS_MODE_SYSFS, NULL);
>>>           if (ret)
>>>               pm_runtime_put(dev->parent);
>>>       } else {
>>> -        ret = cti_disable(drvdata->csdev);
>>> +        ret = cti_disable(drvdata->csdev, NULL);
>>>           if (!ret)
>>>               pm_runtime_put(dev->parent);
>>>       }
>>> diff --git a/drivers/hwtracing/coresight/coresight-cti.h
>>> b/drivers/hwtracing/coresight/coresight-cti.h
>>> index 8b106b13a244..cb9ee616d01f 100644
>>> --- a/drivers/hwtracing/coresight/coresight-cti.h
>>> +++ b/drivers/hwtracing/coresight/coresight-cti.h
>>> @@ -215,8 +215,8 @@ int cti_add_connection_entry(struct device *dev,
>>> struct cti_drvdata *drvdata,
>>>                    const char *assoc_dev_name);
>>>   struct cti_trig_con *cti_allocate_trig_con(struct device *dev, int
>>> in_sigs,
>>>                          int out_sigs);
>>> -int cti_enable(struct coresight_device *csdev);
>>> -int cti_disable(struct coresight_device *csdev);
>>> +int cti_enable(struct coresight_device *csdev, enum cs_mode mode,
>>> void *data);
>>> +int cti_disable(struct coresight_device *csdev, void *data);
>>>   void cti_write_all_hw_regs(struct cti_drvdata *drvdata);
>>>   void cti_write_intack(struct device *dev, u32 ackval);
>>>   void cti_write_single_reg(struct cti_drvdata *drvdata, int offset,
>>> u32 value);
>>> diff --git a/drivers/hwtracing/coresight/coresight-priv.h
>>> b/drivers/hwtracing/coresight/coresight-priv.h
>>> index a843f9d5c737..fff565d1cb42 100644
>>> --- a/drivers/hwtracing/coresight/coresight-priv.h
>>> +++ b/drivers/hwtracing/coresight/coresight-priv.h
>>> @@ -211,8 +211,8 @@ void coresight_release_platform_data(struct
>>> coresight_device *csdev,
>>>                        struct coresight_platform_data *pdata);
>>>   struct coresight_device *
>>>   coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode);
>>> -void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev,
>>> -                      struct coresight_device *ect_csdev);
>>> +void coresight_add_helper_mutex(struct coresight_device *csdev,
>>> +                struct coresight_device *helper);
>>>     void coresight_set_percpu_sink(int cpu, struct coresight_device
>>> *csdev);
>>>   struct coresight_device *coresight_get_percpu_sink(int cpu);
>>> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c
>>> b/drivers/hwtracing/coresight/coresight-sysfs.c
>>> index 464ba5e1343b..dd78e9fcfc4d 100644
>>> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
>>> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
>>> @@ -148,6 +148,10 @@ int coresight_make_links(struct coresight_device
>>> *orig,
>>>       char *outs = NULL, *ins = NULL;
>>>       struct coresight_sysfs_link *link = NULL;
>>>   +    /* Helper devices aren't shown in sysfs */
>>> +    if (conn->dest_port == -1 && conn->src_port == -1)
>>> +        return 0;
>>> +
>>>       do {
>>>           outs = devm_kasprintf(&orig->dev, GFP_KERNEL,
>>>                         "out:%d", conn->src_port);
>>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>>> index d2739a0286f1..ed37552761e4 100644
>>> --- a/include/linux/coresight.h
>>> +++ b/include/linux/coresight.h
>>> @@ -40,8 +40,7 @@ enum coresight_dev_type {
>>>       CORESIGHT_DEV_TYPE_LINK,
>>>       CORESIGHT_DEV_TYPE_LINKSINK,
>>>       CORESIGHT_DEV_TYPE_SOURCE,
>>> -    CORESIGHT_DEV_TYPE_HELPER,
>>> -    CORESIGHT_DEV_TYPE_ECT,
>>> +    CORESIGHT_DEV_TYPE_HELPER
>>>   };
>>>     enum coresight_dev_subtype_sink {
>>> @@ -66,12 +65,7 @@ enum coresight_dev_subtype_source {
>>>     enum coresight_dev_subtype_helper {
>>>       CORESIGHT_DEV_SUBTYPE_HELPER_CATU,
>>> -};
>>> -
>>> -/* Embedded Cross Trigger (ECT) sub-types */
>>> -enum coresight_dev_subtype_ect {
>>> -    CORESIGHT_DEV_SUBTYPE_ECT_NONE,
>>> -    CORESIGHT_DEV_SUBTYPE_ECT_CTI,
>>> +    CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
>>>   };
>>>     /**
>>> @@ -84,8 +78,6 @@ enum coresight_dev_subtype_ect {
>>>    *            by @coresight_dev_subtype_source.
>>>    * @helper_subtype:    type of helper this component is, as defined
>>>    *            by @coresight_dev_subtype_helper.
>>> - * @ect_subtype:        type of cross trigger this component is, as
>>> - *            defined by @coresight_dev_subtype_ect
>>>    */
>>>   union coresight_dev_subtype {
>>>       /* We have some devices which acts as LINK and SINK */
>>> @@ -95,7 +87,6 @@ union coresight_dev_subtype {
>>>       };
>>>       enum coresight_dev_subtype_source source_subtype;
>>>       enum coresight_dev_subtype_helper helper_subtype;
>>> -    enum coresight_dev_subtype_ect ect_subtype;
>>>   };
>>>     /**
>>> @@ -237,8 +228,6 @@ struct coresight_sysfs_link {
>>>    *        from source to that sink.
>>>    * @ea:        Device attribute for sink representation under PMU
>>> directory.
>>>    * @def_sink:    cached reference to default sink found for this
>>> device.
>>> - * @ect_dev:    Associated cross trigger device. Not part of the
>>> trace data
>>> - *        path or connections.
>>>    * @nr_links:   number of sysfs links created to other components
>>> from this
>>>    *        device. These will appear in the "connections" group.
>>>    * @has_conns_grp: Have added a "connections" group for sysfs links.
>>> @@ -261,12 +250,9 @@ struct coresight_device {
>>>       bool activated;    /* true only if a sink is part of a path */
>>>       struct dev_ext_attribute *ea;
>>>       struct coresight_device *def_sink;
>>> -    /* cross trigger handling */
>>> -    struct coresight_device *ect_dev;
>>>       /* sysfs links between components */
>>>       int nr_links;
>>>       bool has_conns_grp;
>>> -    bool ect_enabled; /* true only if associated ect device is
>>> enabled */
>>>       /* system configuration and feature lists */
>>>       struct list_head feature_csdev_list;
>>>       struct list_head config_csdev_list;
>>> @@ -378,23 +364,11 @@ struct coresight_ops_helper {
>>>       int (*disable)(struct coresight_device *csdev, void *data);
>>>   };
>>>   -/**
>>> - * struct coresight_ops_ect - Ops for an embedded cross trigger device
>>> - *
>>> - * @enable    : Enable the device
>>> - * @disable    : Disable the device
>>> - */
>>> -struct coresight_ops_ect {
>>> -    int (*enable)(struct coresight_device *csdev);
>>> -    int (*disable)(struct coresight_device *csdev);
>>> -};
>>> -
>>>   struct coresight_ops {
>>>       const struct coresight_ops_sink *sink_ops;
>>>       const struct coresight_ops_link *link_ops;
>>>       const struct coresight_ops_source *source_ops;
>>>       const struct coresight_ops_helper *helper_ops;
>>> -    const struct coresight_ops_ect *ect_ops;
>>>   };
>>>     #if IS_ENABLED(CONFIG_CORESIGHT)
>>