1 files changed, 24 insertions, 2 deletions

diff --git a/drivers/hwtracing/intel_th/gth.c b/drivers/hwtracing/intel_th/gth.c
index 33e09369a491..dd32d0bad687 100644
--- a/drivers/hwtracing/intel_th/gth.c
+++ b/drivers/hwtracing/intel_th/gth.c
@@ -564,6 +564,9 @@ static int intel_th_gth_assign(struct intel_th_device *thdev,
         struct gth_device *gth = dev_get_drvdata(&thdev->dev);
         int i, id;
 
+        if (thdev->host_mode)
+                return -EBUSY;
+
         if (othdev->type != INTEL_TH_OUTPUT)
                 return -EINVAL;
 
@@ -600,6 +603,9 @@ static void intel_th_gth_unassign(struct intel_th_device *thdev,
         struct gth_device *gth = dev_get_drvdata(&thdev->dev);
         int port = othdev->output.port;
 
+        if (thdev->host_mode)
+                return;
+
         spin_lock(&gth->gth_lock);
         othdev->output.port = -1;
         othdev->output.active = false;
@@ -654,9 +660,24 @@ static int intel_th_gth_probe(struct intel_th_device *thdev)
         gth->base = base;
         spin_lock_init(&gth->gth_lock);
 
+        /*
+         * Host mode can be signalled via SW means or via SCRPD_DEBUGGER_IN_USE
+         * bit. Either way, don't reset HW in this case, and don't export any
+         * capture configuration attributes. Also, refuse to assign output
+         * drivers to ports, see intel_th_gth_assign().
+         */
+        if (thdev->host_mode)
+                goto done;
+
         ret = intel_th_gth_reset(gth);
-        if (ret)
-                return ret;
+        if (ret) {
+                if (ret != -EBUSY)
+                        return ret;
+
+                thdev->host_mode = true;
+
+                goto done;
+        }
 
         for (i = 0; i < TH_CONFIGURABLE_MASTERS + 1; i++)
                 gth->master[i] = -1;
@@ -677,6 +698,7 @@ static int intel_th_gth_probe(struct intel_th_device *thdev)
                 return -ENOMEM;
         }
 
+done:
         dev_set_drvdata(dev, gth);
 
         return 0;