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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2012, The Linux Foundation. All rights reserved.
  */
 
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/err.h>
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/stringhash.h>
 #include <linux/mutex.h>
 #include <linux/clk.h>
 #include <linux/coresight.h>
 #include <linux/of_platform.h>
 #include <linux/delay.h>
 #include <linux/pm_runtime.h>
 
 #include "coresight-etm-perf.h"
 #include "coresight-priv.h"
 #include "coresight-syscfg.h"
 
 static DEFINE_MUTEX(coresight_mutex);
 static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
 
 /**
  * struct coresight_node - elements of a path, from source to sink
  * @csdev:  Address of an element.
  * @link:   hook to the list.
  */
 struct coresight_node {
     struct coresight_device *csdev;
     struct list_head link;
 };
 
 /*
  * When operating Coresight drivers from the sysFS interface, only a single
  * path can exist from a tracer (associated to a CPU) to a sink.
  */
 static DEFINE_PER_CPU(struct list_head *, tracer_path);
 
 /*
  * As of this writing only a single STM can be found in CS topologies.  Since
  * there is no way to know if we'll ever see more and what kind of
  * configuration they will enact, for the time being only define a single path
  * for STM.
  */
 static struct list_head *stm_path;
 
 /*
  * When losing synchronisation a new barrier packet needs to be inserted at the
  * beginning of the data collected in a buffer.  That way the decoder knows that
  * it needs to look for another sync sequence.
  */
 const u32 coresight_barrier_pkt[4] = {0x7fffffff, 0x7fffffff, 0x7fffffff, 0x7fffffff};
 EXPORT_SYMBOL_GPL(coresight_barrier_pkt);
 
 static const struct cti_assoc_op *cti_assoc_ops;
 
 void coresight_set_cti_ops(const struct cti_assoc_op *cti_op)
 {
     cti_assoc_ops = cti_op;
 }
 EXPORT_SYMBOL_GPL(coresight_set_cti_ops);
 
 void coresight_remove_cti_ops(void)
 {
     cti_assoc_ops = NULL;
 }
 EXPORT_SYMBOL_GPL(coresight_remove_cti_ops);
 
 void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev)
 {
     per_cpu(csdev_sink, cpu) = csdev;
 }
 EXPORT_SYMBOL_GPL(coresight_set_percpu_sink);
 
 struct coresight_device *coresight_get_percpu_sink(int cpu)
 {
     return per_cpu(csdev_sink, cpu);
 }
 EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
 
 static int coresight_id_match(struct device *dev, void *data)
 {
     int trace_id, i_trace_id;
     struct coresight_device *csdev, *i_csdev;
 
     csdev = data;
     i_csdev = to_coresight_device(dev);
 
     /*
      * No need to care about oneself and components that are not
      * sources or not enabled
      */
     if (i_csdev == csdev || !i_csdev->enable ||
         i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
         return 0;
 
     /* Get the source ID for both components */
     trace_id = source_ops(csdev)->trace_id(csdev);
     i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);
 
     /* All you need is one */
     if (trace_id == i_trace_id)
         return 1;
 
     return 0;
 }
 
 static int coresight_source_is_unique(struct coresight_device *csdev)
 {
     int trace_id = source_ops(csdev)->trace_id(csdev);
 
     /* this shouldn't happen */
     if (trace_id < 0)
         return 0;
 
     return !bus_for_each_dev(&coresight_bustype, NULL,
                  csdev, coresight_id_match);
 }
 
 static int coresight_find_link_inport(struct coresight_device *csdev,
                       struct coresight_device *parent)
 {
     int i;
     struct coresight_connection *conn;
 
     for (i = 0; i < parent->pdata->nr_outport; i++) {
         conn = &parent->pdata->conns[i];
         if (conn->child_dev == csdev)
             return conn->child_port;
     }
 
     dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
         dev_name(&parent->dev), dev_name(&csdev->dev));
 
     return -ENODEV;
 }
 
 static int coresight_find_link_outport(struct coresight_device *csdev,
                        struct coresight_device *child)
 {
     int i;
     struct coresight_connection *conn;
 
     for (i = 0; i < csdev->pdata->nr_outport; i++) {
         conn = &csdev->pdata->conns[i];
         if (conn->child_dev == child)
             return conn->outport;
     }
 
     dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
         dev_name(&csdev->dev), dev_name(&child->dev));
 
     return -ENODEV;
 }
 
 static inline u32 coresight_read_claim_tags(struct coresight_device *csdev)
 {
     return csdev_access_relaxed_read32(&csdev->access, CORESIGHT_CLAIMCLR);
 }
 
 static inline bool coresight_is_claimed_self_hosted(struct coresight_device *csdev)
 {
     return coresight_read_claim_tags(csdev) == CORESIGHT_CLAIM_SELF_HOSTED;
 }
 
 static inline bool coresight_is_claimed_any(struct coresight_device *csdev)
 {
     return coresight_read_claim_tags(csdev) != 0;
 }
 
 static inline void coresight_set_claim_tags(struct coresight_device *csdev)
 {
     csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
                      CORESIGHT_CLAIMSET);
     isb();
 }
 
 static inline void coresight_clear_claim_tags(struct coresight_device *csdev)
 {
     csdev_access_relaxed_write32(&csdev->access, CORESIGHT_CLAIM_SELF_HOSTED,
                      CORESIGHT_CLAIMCLR);
     isb();
 }
 
 /*
  * coresight_claim_device_unlocked : Claim the device for self-hosted usage
  * to prevent an external tool from touching this device. As per PSCI
  * standards, section "Preserving the execution context" => "Debug and Trace
  * save and Restore", DBGCLAIM[1] is reserved for Self-hosted debug/trace and
  * DBGCLAIM[0] is reserved for external tools.
  *
  * Called with CS_UNLOCKed for the component.
  * Returns : 0 on success
  */
 int coresight_claim_device_unlocked(struct coresight_device *csdev)
 {
     if (WARN_ON(!csdev))
         return -EINVAL;
 
     if (coresight_is_claimed_any(csdev))
         return -EBUSY;
 
     coresight_set_claim_tags(csdev);
     if (coresight_is_claimed_self_hosted(csdev))
         return 0;
     /* There was a race setting the tags, clean up and fail */
     coresight_clear_claim_tags(csdev);
     return -EBUSY;
 }
 EXPORT_SYMBOL_GPL(coresight_claim_device_unlocked);
 
 int coresight_claim_device(struct coresight_device *csdev)
 {
     int rc;
 
     if (WARN_ON(!csdev))
         return -EINVAL;
 
     CS_UNLOCK(csdev->access.base);
     rc = coresight_claim_device_unlocked(csdev);
     CS_LOCK(csdev->access.base);
 
     return rc;
 }
 EXPORT_SYMBOL_GPL(coresight_claim_device);
 
 /*
  * coresight_disclaim_device_unlocked : Clear the claim tags for the device.
  * Called with CS_UNLOCKed for the component.
  */
 void coresight_disclaim_device_unlocked(struct coresight_device *csdev)
 {
 
     if (WARN_ON(!csdev))
         return;
 
     if (coresight_is_claimed_self_hosted(csdev))
         coresight_clear_claim_tags(csdev);
     else
         /*
          * The external agent may have not honoured our claim
          * and has manipulated it. Or something else has seriously
          * gone wrong in our driver.
          */
         WARN_ON_ONCE(1);
 }
 EXPORT_SYMBOL_GPL(coresight_disclaim_device_unlocked);
 
 void coresight_disclaim_device(struct coresight_device *csdev)
 {
     if (WARN_ON(!csdev))
         return;
 
     CS_UNLOCK(csdev->access.base);
     coresight_disclaim_device_unlocked(csdev);
     CS_LOCK(csdev->access.base);
 }
 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
  * 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)
 {
     mutex_lock(&coresight_mutex);
     csdev->ect_dev = ect_csdev;
     mutex_unlock(&coresight_mutex);
 }
 EXPORT_SYMBOL_GPL(coresight_set_assoc_ectdev_mutex);
 
 static int coresight_enable_sink(struct coresight_device *csdev,
                  u32 mode, void *data)
 {
     int ret;
 
     /*
      * We need to make sure the "new" session is compatible with the
      * existing "mode" of operation.
      */
     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;
 
     return 0;
 }
 
 static void coresight_disable_sink(struct coresight_device *csdev)
 {
     int ret;
 
     if (!sink_ops(csdev)->disable)
         return;
 
     ret = sink_ops(csdev)->disable(csdev);
     if (ret)
         return;
     coresight_control_assoc_ectdev(csdev, false);
     csdev->enable = false;
 }
 
 static int coresight_enable_link(struct coresight_device *csdev,
                  struct coresight_device *parent,
                  struct coresight_device *child)
 {
     int ret = 0;
     int link_subtype;
     int inport, outport;
 
     if (!parent || !child)
         return -EINVAL;
 
     inport = coresight_find_link_inport(csdev, parent);
     outport = coresight_find_link_outport(csdev, child);
     link_subtype = csdev->subtype.link_subtype;
 
     if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG && inport < 0)
         return inport;
     if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && outport < 0)
         return outport;
 
     if (link_ops(csdev)->enable) {
         ret = coresight_control_assoc_ectdev(csdev, true);
         if (!ret) {
             ret = link_ops(csdev)->enable(csdev, inport, outport);
             if (ret)
                 coresight_control_assoc_ectdev(csdev, false);
         }
     }
 
     if (!ret)
         csdev->enable = true;
 
     return ret;
 }
 
 static void coresight_disable_link(struct coresight_device *csdev,
                    struct coresight_device *parent,
                    struct coresight_device *child)
 {
     int i, nr_conns;
     int link_subtype;
     int inport, outport;
 
     if (!parent || !child)
         return;
 
     inport = coresight_find_link_inport(csdev, parent);
     outport = coresight_find_link_outport(csdev, child);
     link_subtype = csdev->subtype.link_subtype;
 
     if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
         nr_conns = csdev->pdata->nr_inport;
     } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
         nr_conns = csdev->pdata->nr_outport;
     } else {
         nr_conns = 1;
     }
 
     if (link_ops(csdev)->disable) {
         link_ops(csdev)->disable(csdev, inport, outport);
         coresight_control_assoc_ectdev(csdev, false);
     }
 
     for (i = 0; i < nr_conns; i++)
         if (atomic_read(&csdev->refcnt[i]) != 0)
             return;
 
     csdev->enable = false;
 }
 
 static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
 {
     int ret;
 
     if (!coresight_source_is_unique(csdev)) {
         dev_warn(&csdev->dev, "traceID %d not unique\n",
              source_ops(csdev)->trace_id(csdev));
         return -EINVAL;
     }
 
     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, NULL, mode);
             if (ret) {
                 coresight_control_assoc_ectdev(csdev, false);
                 return ret;
             }
         }
         csdev->enable = true;
     }
 
     atomic_inc(csdev->refcnt);
 
     return 0;
 }
 
 /**
  *  coresight_disable_source - Drop the reference count by 1 and disable
  *  the device if there are no users left.
  *
  *  @csdev: The coresight device to disable
  *
  *  Returns true if the device has been disabled.
  */
 static bool coresight_disable_source(struct coresight_device *csdev)
 {
     if (atomic_dec_return(csdev->refcnt) == 0) {
         if (source_ops(csdev)->disable)
             source_ops(csdev)->disable(csdev, NULL);
         coresight_control_assoc_ectdev(csdev, false);
         csdev->enable = false;
     }
     return !csdev->enable;
 }
 
 /*
  * coresight_disable_path_from : Disable components in the given path beyond
  * @nd in the list. If @nd is NULL, all the components, except the SOURCE are
  * disabled.
  */
 static void coresight_disable_path_from(struct list_head *path,
                     struct coresight_node *nd)
 {
     u32 type;
     struct coresight_device *csdev, *parent, *child;
 
     if (!nd)
         nd = list_first_entry(path, struct coresight_node, link);
 
     list_for_each_entry_continue(nd, path, link) {
         csdev = nd->csdev;
         type = csdev->type;
 
         /*
          * ETF devices are tricky... They can be a link or a sink,
          * depending on how they are configured.  If an ETF has been
          * "activated" it will be configured as a sink, otherwise
          * go ahead with the link configuration.
          */
         if (type == CORESIGHT_DEV_TYPE_LINKSINK)
             type = (csdev == coresight_get_sink(path)) ?
                         CORESIGHT_DEV_TYPE_SINK :
                         CORESIGHT_DEV_TYPE_LINK;
 
         switch (type) {
         case CORESIGHT_DEV_TYPE_SINK:
             coresight_disable_sink(csdev);
             break;
         case CORESIGHT_DEV_TYPE_SOURCE:
             /*
              * We skip the first node in the path assuming that it
              * is the source. So we don't expect a source device in
              * the middle of a path.
              */
             WARN_ON(1);
             break;
         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);
             break;
         default:
             break;
         }
     }
 }
 
 void coresight_disable_path(struct list_head *path)
 {
     coresight_disable_path_from(path, NULL);
 }
 EXPORT_SYMBOL_GPL(coresight_disable_path);
 
 int coresight_enable_path(struct list_head *path, u32 mode, void *sink_data)
 {
 
     int ret = 0;
     u32 type;
     struct coresight_node *nd;
     struct coresight_device *csdev, *parent, *child;
 
     list_for_each_entry_reverse(nd, path, link) {
         csdev = nd->csdev;
         type = csdev->type;
 
         /*
          * ETF devices are tricky... They can be a link or a sink,
          * depending on how they are configured.  If an ETF has been
          * "activated" it will be configured as a sink, otherwise
          * go ahead with the link configuration.
          */
         if (type == CORESIGHT_DEV_TYPE_LINKSINK)
             type = (csdev == coresight_get_sink(path)) ?
                         CORESIGHT_DEV_TYPE_SINK :
                         CORESIGHT_DEV_TYPE_LINK;
 
         switch (type) {
         case CORESIGHT_DEV_TYPE_SINK:
             ret = coresight_enable_sink(csdev, mode, sink_data);
             /*
              * Sink is the first component turned on. If we
              * failed to enable the sink, there are no components
              * that need disabling. Disabling the path here
              * would mean we could disrupt an existing session.
              */
             if (ret)
                 goto out;
             break;
         case CORESIGHT_DEV_TYPE_SOURCE:
             /* sources are enabled from either sysFS or Perf */
             break;
         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);
             if (ret)
                 goto err;
             break;
         default:
             goto err;
         }
     }
 
 out:
     return ret;
 err:
     coresight_disable_path_from(path, nd);
     goto out;
 }
 
 struct coresight_device *coresight_get_sink(struct list_head *path)
 {
     struct coresight_device *csdev;
 
     if (!path)
         return NULL;
 
     csdev = list_last_entry(path, struct coresight_node, link)->csdev;
     if (csdev->type != CORESIGHT_DEV_TYPE_SINK &&
         csdev->type != CORESIGHT_DEV_TYPE_LINKSINK)
         return NULL;
 
     return csdev;
 }
 
 static struct coresight_device *
 coresight_find_enabled_sink(struct coresight_device *csdev)
 {
     int i;
     struct coresight_device *sink = NULL;
 
     if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
          csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
          csdev->activated)
         return csdev;
 
     /*
      * Recursively explore each port found on this element.
      */
     for (i = 0; i < csdev->pdata->nr_outport; i++) {
         struct coresight_device *child_dev;
 
         child_dev = csdev->pdata->conns[i].child_dev;
         if (child_dev)
             sink = coresight_find_enabled_sink(child_dev);
         if (sink)
             return sink;
     }
 
     return NULL;
 }
 
 /**
  * coresight_get_enabled_sink - returns the first enabled sink using
  * connection based search starting from the source reference
  *
  * @source: Coresight source device reference
  */
 struct coresight_device *
 coresight_get_enabled_sink(struct coresight_device *source)
 {
     if (!source)
         return NULL;
 
     return coresight_find_enabled_sink(source);
 }
 
 static int coresight_sink_by_id(struct device *dev, const void *data)
 {
     struct coresight_device *csdev = to_coresight_device(dev);
     unsigned long hash;
 
     if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
          csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
 
         if (!csdev->ea)
             return 0;
         /*
          * See function etm_perf_add_symlink_sink() to know where
          * this comes from.
          */
         hash = (unsigned long)csdev->ea->var;
 
         if ((u32)hash == *(u32 *)data)
             return 1;
     }
 
     return 0;
 }
 
 /**
  * coresight_get_sink_by_id - returns the sink that matches the id
  * @id: Id of the sink to match
  *
  * The name of a sink is unique, whether it is found on the AMBA bus or
  * otherwise.  As such the hash of that name can easily be used to identify
  * a sink.
  */
 struct coresight_device *coresight_get_sink_by_id(u32 id)
 {
     struct device *dev = NULL;
 
     dev = bus_find_device(&coresight_bustype, NULL, &id,
                   coresight_sink_by_id);
 
     return dev ? to_coresight_device(dev) : NULL;
 }
 
 /**
  * coresight_get_ref- Helper function to increase reference count to module
  * and device.
  *
  * @csdev: The coresight device to get a reference on.
  *
  * Return true in successful case and power up the device.
  * Return false when failed to get reference of module.
  */
 static inline bool coresight_get_ref(struct coresight_device *csdev)
 {
     struct device *dev = csdev->dev.parent;
 
     /* Make sure the driver can't be removed */
     if (!try_module_get(dev->driver->owner))
         return false;
     /* Make sure the device can't go away */
     get_device(dev);
     pm_runtime_get_sync(dev);
     return true;
 }
 
 /**
  * coresight_put_ref- Helper function to decrease reference count to module
  * and device. Power off the device.
  *
  * @csdev: The coresight device to decrement a reference from.
  */
 static inline void coresight_put_ref(struct coresight_device *csdev)
 {
     struct device *dev = csdev->dev.parent;
 
     pm_runtime_put(dev);
     put_device(dev);
     module_put(dev->driver->owner);
 }
 
 /*
  * coresight_grab_device - Power up this device and any of the helper
  * devices connected to it for trace operation. Since the helper devices
  * don't appear on the trace path, they should be handled along with the
  * master device.
  */
 static int coresight_grab_device(struct coresight_device *csdev)
 {
     int i;
 
     for (i = 0; i < csdev->pdata->nr_outport; i++) {
         struct coresight_device *child;
 
         child  = csdev->pdata->conns[i].child_dev;
         if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
             if (!coresight_get_ref(child))
                 goto err;
     }
     if (coresight_get_ref(csdev))
         return 0;
 err:
     for (i--; i >= 0; i--) {
         struct coresight_device *child;
 
         child  = csdev->pdata->conns[i].child_dev;
         if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
             coresight_put_ref(child);
     }
     return -ENODEV;
 }
 
 /*
  * coresight_drop_device - Release this device and any of the helper
  * devices connected to it.
  */
 static void coresight_drop_device(struct coresight_device *csdev)
 {
     int i;
 
     coresight_put_ref(csdev);
     for (i = 0; i < csdev->pdata->nr_outport; i++) {
         struct coresight_device *child;
 
         child  = csdev->pdata->conns[i].child_dev;
         if (child && child->type == CORESIGHT_DEV_TYPE_HELPER)
             coresight_put_ref(child);
     }
 }
 
 /**
  * _coresight_build_path - recursively build a path from a @csdev to a sink.
  * @csdev:  The device to start from.
  * @sink:   The final sink we want in this path.
  * @path:   The list to add devices to.
  *
  * The tree of Coresight device is traversed until an activated sink is
  * found.  From there the sink is added to the list along with all the
  * devices that led to that point - the end result is a list from source
  * to sink. In that list the source is the first device and the sink the
  * last one.
  */
 static int _coresight_build_path(struct coresight_device *csdev,
                  struct coresight_device *sink,
                  struct list_head *path)
 {
     int i, ret;
     bool found = false;
     struct coresight_node *node;
 
     /* An activated sink has been found.  Enqueue the element */
     if (csdev == sink)
         goto out;
 
     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) {
             found = true;
             goto out;
         }
     }
 
     /* Not a sink - recursively explore each port found on this element */
     for (i = 0; i < csdev->pdata->nr_outport; i++) {
         struct coresight_device *child_dev;
 
         child_dev = csdev->pdata->conns[i].child_dev;
         if (child_dev &&
             _coresight_build_path(child_dev, sink, path) == 0) {
             found = true;
             break;
         }
     }
 
     if (!found)
         return -ENODEV;
 
 out:
     /*
      * A path from this element to a sink has been found.  The elements
      * leading to the sink are already enqueued, all that is left to do
      * is tell the PM runtime core we need this element and add a node
      * for it.
      */
     ret = coresight_grab_device(csdev);
     if (ret)
         return ret;
 
     node = kzalloc(sizeof(struct coresight_node), GFP_KERNEL);
     if (!node)
         return -ENOMEM;
 
     node->csdev = csdev;
     list_add(&node->link, path);
 
     return 0;
 }
 
 struct list_head *coresight_build_path(struct coresight_device *source,
                        struct coresight_device *sink)
 {
     struct list_head *path;
     int rc;
 
     if (!sink)
         return ERR_PTR(-EINVAL);
 
     path = kzalloc(sizeof(struct list_head), GFP_KERNEL);
     if (!path)
         return ERR_PTR(-ENOMEM);
 
     INIT_LIST_HEAD(path);
 
     rc = _coresight_build_path(source, sink, path);
     if (rc) {
         kfree(path);
         return ERR_PTR(rc);
     }
 
     return path;
 }
 
 /**
  * coresight_release_path - release a previously built path.
  * @path:   the path to release.
  *
  * Go through all the elements of a path and 1) removed it from the list and
  * 2) free the memory allocated for each node.
  */
 void coresight_release_path(struct list_head *path)
 {
     struct coresight_device *csdev;
     struct coresight_node *nd, *next;
 
     list_for_each_entry_safe(nd, next, path, link) {
         csdev = nd->csdev;
 
         coresight_drop_device(csdev);
         list_del(&nd->link);
         kfree(nd);
     }
 
     kfree(path);
 }
 
 /* return true if the device is a suitable type for a default sink */
 static inline bool coresight_is_def_sink_type(struct coresight_device *csdev)
 {
     /* sink & correct subtype */
     if (((csdev->type == CORESIGHT_DEV_TYPE_SINK) ||
          (csdev->type == CORESIGHT_DEV_TYPE_LINKSINK)) &&
         (csdev->subtype.sink_subtype >= CORESIGHT_DEV_SUBTYPE_SINK_BUFFER))
         return true;
     return false;
 }
 
 /**
  * coresight_select_best_sink - return the best sink for use as default from
  * the two provided.
  *
  * @sink:   current best sink.
  * @depth:      search depth where current sink was found.
  * @new_sink:   new sink for comparison with current sink.
  * @new_depth:  search depth where new sink was found.
  *
  * Sinks prioritised according to coresight_dev_subtype_sink, with only
  * subtypes CORESIGHT_DEV_SUBTYPE_SINK_BUFFER or higher being used.
  *
  * Where two sinks of equal priority are found, the sink closest to the
  * source is used (smallest search depth).
  *
  * return @new_sink & update @depth if better than @sink, else return @sink.
  */
 static struct coresight_device *
 coresight_select_best_sink(struct coresight_device *sink, int *depth,
                struct coresight_device *new_sink, int new_depth)
 {
     bool update = false;
 
     if (!sink) {
         /* first found at this level */
         update = true;
     } else if (new_sink->subtype.sink_subtype >
            sink->subtype.sink_subtype) {
         /* found better sink */
         update = true;
     } else if ((new_sink->subtype.sink_subtype ==
             sink->subtype.sink_subtype) &&
            (*depth > new_depth)) {
         /* found same but closer sink */
         update = true;
     }
 
     if (update)
         *depth = new_depth;
     return update ? new_sink : sink;
 }
 
 /**
  * coresight_find_sink - recursive function to walk trace connections from
  * source to find a suitable default sink.
  *
  * @csdev: source / current device to check.
  * @depth: [in] search depth of calling dev, [out] depth of found sink.
  *
  * This will walk the connection path from a source (ETM) till a suitable
  * sink is encountered and return that sink to the original caller.
  *
  * If current device is a plain sink return that & depth, otherwise recursively
  * call child connections looking for a sink. Select best possible using
  * coresight_select_best_sink.
  *
  * return best sink found, or NULL if not found at this node or child nodes.
  */
 static struct coresight_device *
 coresight_find_sink(struct coresight_device *csdev, int *depth)
 {
     int i, curr_depth = *depth + 1, found_depth = 0;
     struct coresight_device *found_sink = NULL;
 
     if (coresight_is_def_sink_type(csdev)) {
         found_depth = curr_depth;
         found_sink = csdev;
         if (csdev->type == CORESIGHT_DEV_TYPE_SINK)
             goto return_def_sink;
         /* look past LINKSINK for something better */
     }
 
     /*
      * Not a sink we want - or possible child sink may be better.
      * recursively explore each port found on this element.
      */
     for (i = 0; i < csdev->pdata->nr_outport; i++) {
         struct coresight_device *child_dev, *sink = NULL;
         int child_depth = curr_depth;
 
         child_dev = csdev->pdata->conns[i].child_dev;
         if (child_dev)
             sink = coresight_find_sink(child_dev, &child_depth);
 
         if (sink)
             found_sink = coresight_select_best_sink(found_sink,
                                 &found_depth,
                                 sink,
                                 child_depth);
     }
 
 return_def_sink:
     /* return found sink and depth */
     if (found_sink)
         *depth = found_depth;
     return found_sink;
 }
 
 /**
  * coresight_find_default_sink: Find a sink suitable for use as a
  * default sink.
  *
  * @csdev: starting source to find a connected sink.
  *
  * Walks connections graph looking for a suitable sink to enable for the
  * supplied source. Uses CoreSight device subtypes and distance from source
  * to select the best sink.
  *
  * If a sink is found, then the default sink for this device is set and
  * will be automatically used in future.
  *
  * Used in cases where the CoreSight user (perf / sysfs) has not selected a
  * sink.
  */
 struct coresight_device *
 coresight_find_default_sink(struct coresight_device *csdev)
 {
     int depth = 0;
 
     /* look for a default sink if we have not found for this device */
     if (!csdev->def_sink) {
         if (coresight_is_percpu_source(csdev))
             csdev->def_sink = per_cpu(csdev_sink, source_ops(csdev)->cpu_id(csdev));
         if (!csdev->def_sink)
             csdev->def_sink = coresight_find_sink(csdev, &depth);
     }
     return csdev->def_sink;
 }
 
 static int coresight_remove_sink_ref(struct device *dev, void *data)
 {
     struct coresight_device *sink = data;
     struct coresight_device *source = to_coresight_device(dev);
 
     if (source->def_sink == sink)
         source->def_sink = NULL;
     return 0;
 }
 
 /**
  * coresight_clear_default_sink: Remove all default sink references to the
  * supplied sink.
  *
  * If supplied device is a sink, then check all the bus devices and clear
  * out all the references to this sink from the coresight_device def_sink
  * parameter.
  *
  * @csdev: coresight sink - remove references to this from all sources.
  */
 static void coresight_clear_default_sink(struct coresight_device *csdev)
 {
     if ((csdev->type == CORESIGHT_DEV_TYPE_SINK) ||
         (csdev->type == CORESIGHT_DEV_TYPE_LINKSINK)) {
         bus_for_each_dev(&coresight_bustype, NULL, csdev,
                  coresight_remove_sink_ref);
     }
 }
 
 /** coresight_validate_source - make sure a source has the right credentials
  *  @csdev: the device structure for a source.
  *  @function:  the function this was called from.
  *
  * Assumes the coresight_mutex is held.
  */
 static int coresight_validate_source(struct coresight_device *csdev,
                      const char *function)
 {
     u32 type, subtype;
 
     type = csdev->type;
     subtype = csdev->subtype.source_subtype;
 
     if (type != CORESIGHT_DEV_TYPE_SOURCE) {
         dev_err(&csdev->dev, "wrong device type in %s\n", function);
         return -EINVAL;
     }
 
     if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
         subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE) {
         dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
         return -EINVAL;
     }
 
     return 0;
 }
 
 int coresight_enable(struct coresight_device *csdev)
 {
     int cpu, ret = 0;
     struct coresight_device *sink;
     struct list_head *path;
     enum coresight_dev_subtype_source subtype;
 
     subtype = csdev->subtype.source_subtype;
 
     mutex_lock(&coresight_mutex);
 
     ret = coresight_validate_source(csdev, __func__);
     if (ret)
         goto out;
 
     if (csdev->enable) {
         /*
          * There could be multiple applications driving the software
          * source. So keep the refcount for each such user when the
          * source is already enabled.
          */
         if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
             atomic_inc(csdev->refcnt);
         goto out;
     }
 
     sink = coresight_get_enabled_sink(csdev);
     if (!sink) {
         ret = -EINVAL;
         goto out;
     }
 
     path = coresight_build_path(csdev, sink);
     if (IS_ERR(path)) {
         pr_err("building path(s) failed\n");
         ret = PTR_ERR(path);
         goto out;
     }
 
     ret = coresight_enable_path(path, CS_MODE_SYSFS, NULL);
     if (ret)
         goto err_path;
 
     ret = coresight_enable_source(csdev, CS_MODE_SYSFS);
     if (ret)
         goto err_source;
 
     switch (subtype) {
     case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
         /*
          * When working from sysFS it is important to keep track
          * of the paths that were created so that they can be
          * undone in 'coresight_disable()'.  Since there can only
          * be a single session per tracer (when working from sysFS)
          * a per-cpu variable will do just fine.
          */
         cpu = source_ops(csdev)->cpu_id(csdev);
         per_cpu(tracer_path, cpu) = path;
         break;
     case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
         stm_path = path;
         break;
     default:
         /* We can't be here */
         break;
     }
 
 out:
     mutex_unlock(&coresight_mutex);
     return ret;
 
 err_source:
     coresight_disable_path(path);
 
 err_path:
     coresight_release_path(path);
     goto out;
 }
 EXPORT_SYMBOL_GPL(coresight_enable);
 
 void coresight_disable(struct coresight_device *csdev)
 {
     int cpu, ret;
     struct list_head *path = NULL;
 
     mutex_lock(&coresight_mutex);
 
     ret = coresight_validate_source(csdev, __func__);
     if (ret)
         goto out;
 
     if (!csdev->enable || !coresight_disable_source(csdev))
         goto out;
 
     switch (csdev->subtype.source_subtype) {
     case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
         cpu = source_ops(csdev)->cpu_id(csdev);
         path = per_cpu(tracer_path, cpu);
         per_cpu(tracer_path, cpu) = NULL;
         break;
     case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
         path = stm_path;
         stm_path = NULL;
         break;
     default:
         /* We can't be here */
         break;
     }
 
     coresight_disable_path(path);
     coresight_release_path(path);
 
 out:
     mutex_unlock(&coresight_mutex);
 }
 EXPORT_SYMBOL_GPL(coresight_disable);
 
 static ssize_t enable_sink_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
 {
     struct coresight_device *csdev = to_coresight_device(dev);
 
     return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->activated);
 }
 
 static ssize_t enable_sink_store(struct device *dev,
                  struct device_attribute *attr,
                  const char *buf, size_t size)
 {
     int ret;
     unsigned long val;
     struct coresight_device *csdev = to_coresight_device(dev);
 
     ret = kstrtoul(buf, 10, &val);
     if (ret)
         return ret;
 
     if (val)
         csdev->activated = true;
     else
         csdev->activated = false;
 
     return size;
 
 }
 static DEVICE_ATTR_RW(enable_sink);
 
 static ssize_t enable_source_show(struct device *dev,
                   struct device_attribute *attr, char *buf)
 {
     struct coresight_device *csdev = to_coresight_device(dev);
 
     return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
 }
 
 static ssize_t enable_source_store(struct device *dev,
                    struct device_attribute *attr,
                    const char *buf, size_t size)
 {
     int ret = 0;
     unsigned long val;
     struct coresight_device *csdev = to_coresight_device(dev);
 
     ret = kstrtoul(buf, 10, &val);
     if (ret)
         return ret;
 
     if (val) {
         ret = coresight_enable(csdev);
         if (ret)
             return ret;
     } else {
         coresight_disable(csdev);
     }
 
     return size;
 }
 static DEVICE_ATTR_RW(enable_source);
 
 static struct attribute *coresight_sink_attrs[] = {
     &dev_attr_enable_sink.attr,
     NULL,
 };
 ATTRIBUTE_GROUPS(coresight_sink);
 
 static struct attribute *coresight_source_attrs[] = {
     &dev_attr_enable_source.attr,
     NULL,
 };
 ATTRIBUTE_GROUPS(coresight_source);
 
 static struct device_type coresight_dev_type[] = {
     {
         .name = "sink",
         .groups = coresight_sink_groups,
     },
     {
         .name = "link",
     },
     {
         .name = "linksink",
         .groups = coresight_sink_groups,
     },
     {
         .name = "source",
         .groups = coresight_source_groups,
     },
     {
         .name = "helper",
     },
     {
         .name = "ect",
     },
 };
 
 static void coresight_device_release(struct device *dev)
 {
     struct coresight_device *csdev = to_coresight_device(dev);
 
     fwnode_handle_put(csdev->dev.fwnode);
     kfree(csdev->refcnt);
     kfree(csdev);
 }
 
 static int coresight_orphan_match(struct device *dev, void *data)
 {
     int i, ret = 0;
     bool still_orphan = false;
     struct coresight_device *csdev, *i_csdev;
     struct coresight_connection *conn;
 
     csdev = data;
     i_csdev = to_coresight_device(dev);
 
     /* No need to check oneself */
     if (csdev == i_csdev)
         return 0;
 
     /* Move on to another component if no connection is orphan */
     if (!i_csdev->orphan)
         return 0;
     /*
      * Circle throuch all the connection of that component.  If we find
      * an orphan connection whose name matches @csdev, link it.
      */
     for (i = 0; i < i_csdev->pdata->nr_outport; i++) {
         conn = &i_csdev->pdata->conns[i];
 
         /* Skip the port if FW doesn't describe it */
         if (!conn->child_fwnode)
             continue;
         /* We have found at least one orphan connection */
         if (conn->child_dev == NULL) {
             /* Does it match this newly added device? */
             if (conn->child_fwnode == csdev->dev.fwnode) {
                 ret = coresight_make_links(i_csdev,
                                conn, csdev);
                 if (ret)
                     return ret;
             } else {
                 /* This component still has an orphan */
                 still_orphan = true;
             }
         }
     }
 
     i_csdev->orphan = still_orphan;
 
     /*
      * Returning '0' in case we didn't encounter any error,
      * ensures that all known component on the bus will be checked.
      */
     return 0;
 }
 
 static int coresight_fixup_orphan_conns(struct coresight_device *csdev)
 {
     return bus_for_each_dev(&coresight_bustype, NULL,
              csdev, coresight_orphan_match);
 }
 
 
 static int coresight_fixup_device_conns(struct coresight_device *csdev)
 {
     int i, ret = 0;
 
     for (i = 0; i < csdev->pdata->nr_outport; i++) {
         struct coresight_connection *conn = &csdev->pdata->conns[i];
 
         if (!conn->child_fwnode)
             continue;
         conn->child_dev =
             coresight_find_csdev_by_fwnode(conn->child_fwnode);
         if (conn->child_dev && conn->child_dev->has_conns_grp) {
             ret = coresight_make_links(csdev, conn,
                            conn->child_dev);
             if (ret)
                 break;
         } else {
             csdev->orphan = true;
         }
     }
 
     return ret;
 }
 
 static int coresight_remove_match(struct device *dev, void *data)
 {
     int i;
     struct coresight_device *csdev, *iterator;
     struct coresight_connection *conn;
 
     csdev = data;
     iterator = to_coresight_device(dev);
 
     /* No need to check oneself */
     if (csdev == iterator)
         return 0;
 
     /*
      * Circle throuch all the connection of that component.  If we find
      * a connection whose name matches @csdev, remove it.
      */
     for (i = 0; i < iterator->pdata->nr_outport; i++) {
         conn = &iterator->pdata->conns[i];
 
         if (conn->child_dev == NULL || conn->child_fwnode == NULL)
             continue;
 
         if (csdev->dev.fwnode == conn->child_fwnode) {
             iterator->orphan = true;
             coresight_remove_links(iterator, conn);
             /*
              * Drop the reference to the handle for the remote
              * device acquired in parsing the connections from
              * platform data.
              */
             fwnode_handle_put(conn->child_fwnode);
             conn->child_fwnode = NULL;
             /* No need to continue */
             break;
         }
     }
 
     /*
      * Returning '0' ensures that all known component on the
      * bus will be checked.
      */
     return 0;
 }
 
 /*
  * coresight_remove_conns - Remove references to this given devices
  * from the connections of other devices.
  */
 static void coresight_remove_conns(struct coresight_device *csdev)
 {
     /*
      * Another device will point to this device only if there is
      * an output port connected to this one. i.e, if the device
      * doesn't have at least one input port, there is no point
      * in searching all the devices.
      */
     if (csdev->pdata->nr_inport)
         bus_for_each_dev(&coresight_bustype, NULL,
                  csdev, coresight_remove_match);
 }
 
 /**
  * coresight_timeout - loop until a bit has changed to a specific register
  *          state.
  * @csa: coresight device access for the device
  * @offset: Offset of the register from the base of the device.
  * @position: the position of the bit of interest.
  * @value: the value the bit should have.
  *
  * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
  * TIMEOUT_US has elapsed, which ever happens first.
  */
 int coresight_timeout(struct csdev_access *csa, u32 offset,
               int position, int value)
 {
     int i;
     u32 val;
 
     for (i = TIMEOUT_US; i > 0; i--) {
         val = csdev_access_read32(csa, offset);
         /* waiting on the bit to go from 0 to 1 */
         if (value) {
             if (val & BIT(position))
                 return 0;
         /* waiting on the bit to go from 1 to 0 */
         } else {
             if (!(val & BIT(position)))
                 return 0;
         }
 
         /*
          * Delay is arbitrary - the specification doesn't say how long
          * we are expected to wait.  Extra check required to make sure
          * we don't wait needlessly on the last iteration.
          */
         if (i - 1)
             udelay(1);
     }
 
     return -EAGAIN;
 }
 EXPORT_SYMBOL_GPL(coresight_timeout);
 
 u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset)
 {
     return csdev_access_relaxed_read32(&csdev->access, offset);
 }
 
 u32 coresight_read32(struct coresight_device *csdev, u32 offset)
 {
     return csdev_access_read32(&csdev->access, offset);
 }
 
 void coresight_relaxed_write32(struct coresight_device *csdev,
                    u32 val, u32 offset)
 {
     csdev_access_relaxed_write32(&csdev->access, val, offset);
 }
 
 void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset)
 {
     csdev_access_write32(&csdev->access, val, offset);
 }
 
 u64 coresight_relaxed_read64(struct coresight_device *csdev, u32 offset)
 {
     return csdev_access_relaxed_read64(&csdev->access, offset);
 }
 
 u64 coresight_read64(struct coresight_device *csdev, u32 offset)
 {
     return csdev_access_read64(&csdev->access, offset);
 }
 
 void coresight_relaxed_write64(struct coresight_device *csdev,
                    u64 val, u32 offset)
 {
     csdev_access_relaxed_write64(&csdev->access, val, offset);
 }
 
 void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
 {
     csdev_access_write64(&csdev->access, val, offset);
 }
 
 /*
  * coresight_release_platform_data: Release references to the devices connected
  * to the output port of this device.
  */
 void coresight_release_platform_data(struct coresight_device *csdev,
                      struct coresight_platform_data *pdata)
 {
     int i;
     struct coresight_connection *conns = pdata->conns;
 
     for (i = 0; i < pdata->nr_outport; i++) {
         /* If we have made the links, remove them now */
         if (csdev && conns[i].child_dev)
             coresight_remove_links(csdev, &conns[i]);
         /*
          * Drop the refcount and clear the handle as this device
          * is going away
          */
         if (conns[i].child_fwnode) {
             fwnode_handle_put(conns[i].child_fwnode);
             pdata->conns[i].child_fwnode = NULL;
         }
     }
     if (csdev)
         coresight_remove_conns_sysfs_group(csdev);
 }
 
 struct coresight_device *coresight_register(struct coresight_desc *desc)
 {
     int ret;
     int link_subtype;
     int nr_refcnts = 1;
     atomic_t *refcnts = NULL;
     struct coresight_device *csdev;
     bool registered = false;
 
     csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
     if (!csdev) {
         ret = -ENOMEM;
         goto err_out;
     }
 
     if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
         desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
         link_subtype = desc->subtype.link_subtype;
 
         if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
             nr_refcnts = desc->pdata->nr_inport;
         else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
             nr_refcnts = desc->pdata->nr_outport;
     }
 
     refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
     if (!refcnts) {
         ret = -ENOMEM;
         kfree(csdev);
         goto err_out;
     }
 
     csdev->refcnt = refcnts;
 
     csdev->pdata = desc->pdata;
 
     csdev->type = desc->type;
     csdev->subtype = desc->subtype;
     csdev->ops = desc->ops;
     csdev->access = desc->access;
     csdev->orphan = false;
 
     csdev->dev.type = &coresight_dev_type[desc->type];
     csdev->dev.groups = desc->groups;
     csdev->dev.parent = desc->dev;
     csdev->dev.release = coresight_device_release;
     csdev->dev.bus = &coresight_bustype;
     /*
      * Hold the reference to our parent device. This will be
      * dropped only in coresight_device_release().
      */
     csdev->dev.fwnode = fwnode_handle_get(dev_fwnode(desc->dev));
     dev_set_name(&csdev->dev, "%s", desc->name);
 
     /*
      * Make sure the device registration and the connection fixup
      * are synchronised, so that we don't see uninitialised devices
      * on the coresight bus while trying to resolve the connections.
      */
     mutex_lock(&coresight_mutex);
 
     ret = device_register(&csdev->dev);
     if (ret) {
         put_device(&csdev->dev);
         /*
          * All resources are free'd explicitly via
          * coresight_device_release(), triggered from put_device().
          */
         goto out_unlock;
     }
 
     if (csdev->type == CORESIGHT_DEV_TYPE_SINK ||
         csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) {
         ret = etm_perf_add_symlink_sink(csdev);
 
         if (ret) {
             device_unregister(&csdev->dev);
             /*
              * As with the above, all resources are free'd
              * explicitly via coresight_device_release() triggered
              * from put_device(), which is in turn called from
              * function device_unregister().
              */
             goto out_unlock;
         }
     }
     /* Device is now registered */
     registered = true;
 
     ret = coresight_create_conns_sysfs_group(csdev);
     if (!ret)
         ret = coresight_fixup_device_conns(csdev);
     if (!ret)
         ret = coresight_fixup_orphan_conns(csdev);
     if (!ret && cti_assoc_ops && cti_assoc_ops->add)
         cti_assoc_ops->add(csdev);
 
 out_unlock:
     mutex_unlock(&coresight_mutex);
     /* Success */
     if (!ret)
         return csdev;
 
     /* Unregister the device if needed */
     if (registered) {
         coresight_unregister(csdev);
         return ERR_PTR(ret);
     }
 
 err_out:
     /* Cleanup the connection information */
     coresight_release_platform_data(NULL, desc->pdata);
     return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(coresight_register);
 
 void coresight_unregister(struct coresight_device *csdev)
 {
     etm_perf_del_symlink_sink(csdev);
     /* Remove references of that device in the topology */
     if (cti_assoc_ops && cti_assoc_ops->remove)
         cti_assoc_ops->remove(csdev);
     coresight_remove_conns(csdev);
     coresight_clear_default_sink(csdev);
     coresight_release_platform_data(csdev, csdev->pdata);
     device_unregister(&csdev->dev);
 }
 EXPORT_SYMBOL_GPL(coresight_unregister);
 
 
 /*
  * coresight_search_device_idx - Search the fwnode handle of a device
  * in the given dev_idx list. Must be called with the coresight_mutex held.
  *
  * Returns the index of the entry, when found. Otherwise, -ENOENT.
  */
 static inline int coresight_search_device_idx(struct coresight_dev_list *dict,
                           struct fwnode_handle *fwnode)
 {
     int i;
 
     for (i = 0; i < dict->nr_idx; i++)
         if (dict->fwnode_list[i] == fwnode)
             return i;
     return -ENOENT;
 }
 
 bool coresight_loses_context_with_cpu(struct device *dev)
 {
     return fwnode_property_present(dev_fwnode(dev),
                        "arm,coresight-loses-context-with-cpu");
 }
 EXPORT_SYMBOL_GPL(coresight_loses_context_with_cpu);
 
 /*
  * coresight_alloc_device_name - Get an index for a given device in the
  * device index list specific to a driver. An index is allocated for a
  * device and is tracked with the fwnode_handle to prevent allocating
  * duplicate indices for the same device (e.g, if we defer probing of
  * a device due to dependencies), in case the index is requested again.
  */
 char *coresight_alloc_device_name(struct coresight_dev_list *dict,
                   struct device *dev)
 {
     int idx;
     char *name = NULL;
     struct fwnode_handle **list;
 
     mutex_lock(&coresight_mutex);
 
     idx = coresight_search_device_idx(dict, dev_fwnode(dev));
     if (idx < 0) {
         /* Make space for the new entry */
         idx = dict->nr_idx;
         list = krealloc_array(dict->fwnode_list,
                       idx + 1, sizeof(*dict->fwnode_list),
                       GFP_KERNEL);
         if (ZERO_OR_NULL_PTR(list)) {
             idx = -ENOMEM;
             goto done;
         }
 
         list[idx] = dev_fwnode(dev);
         dict->fwnode_list = list;
         dict->nr_idx = idx + 1;
     }
 
     name = devm_kasprintf(dev, GFP_KERNEL, "%s%d", dict->pfx, idx);
 done:
     mutex_unlock(&coresight_mutex);
     return name;
 }
 EXPORT_SYMBOL_GPL(coresight_alloc_device_name);
 
 struct bus_type coresight_bustype = {
     .name   = "coresight",
 };
 
 static int __init coresight_init(void)
 {
     int ret;
 
     ret = bus_register(&coresight_bustype);
     if (ret)
         return ret;
 
     ret = etm_perf_init();
     if (ret)
         goto exit_bus_unregister;
 
     /* initialise the coresight syscfg API */
     ret = cscfg_init();
     if (!ret)
         return 0;
 
     etm_perf_exit();
 exit_bus_unregister:
     bus_unregister(&coresight_bustype);
     return ret;
 }
 
 static void __exit coresight_exit(void)
 {
     cscfg_exit();
     etm_perf_exit();
     bus_unregister(&coresight_bustype);
 }
 
 module_init(coresight_init);
 module_exit(coresight_exit);
 
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
 MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
 MODULE_DESCRIPTION("Arm CoreSight tracer driver");

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