staging: fsl-mc: add counter to track number of root DPRCs

Add a counter to track the number of root DPRCs.
When this counter is greater then 0 it means that at least
one root DPRC device exists.

Signed-off-by: Itai Katz <itai.katz@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/fsl-mc/bus/mc-bus.c b/drivers/staging/fsl-mc/bus/mc-bus.c
index 37f51f30be980c1ecaf723ca2a9daacbdd7fd951..8a2b99c9f8228c97abeaaef0f23e8ec06a7cb024 100644 (file)
--- a/drivers/staging/fsl-mc/bus/mc-bus.c
+++ b/drivers/staging/fsl-mc/bus/mc-bus.c
@@ -109,6 +109,8 @@ struct bus_type fsl_mc_bus_type = {
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_type);
 
+static atomic_t root_dprc_count = ATOMIC_INIT(0);
+
 static int fsl_mc_driver_probe(struct device *dev)
 {
        struct fsl_mc_driver *mc_drv;
@@ -213,7 +215,7 @@ EXPORT_SYMBOL_GPL(fsl_mc_driver_unregister);
  */
 bool fsl_mc_bus_exists(void)
 {
-       return fsl_mc_bus_type.dev_root;
+       return atomic_read(&root_dprc_count) > 0;
 }
 EXPORT_SYMBOL_GPL(fsl_mc_bus_exists);
 
@@ -458,6 +460,8 @@ int fsl_mc_device_add(struct dprc_obj_desc *obj_desc,
 
                        if (!fsl_mc_bus_exists())
                                fsl_mc_bus_type.dev_root = &mc_dev->dev;
+
+                       atomic_inc(&root_dprc_count);
                }
 
                error = get_dprc_icid(mc_io2, obj_desc->id, &mc_dev->icid);
@@ -540,8 +544,13 @@ void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
                        mc_dev->mc_io = NULL;
                }
 
-               if (fsl_mc_is_root_dprc(&mc_dev->dev))
+               if (fsl_mc_is_root_dprc(&mc_dev->dev)) {
                        fsl_mc_bus_type.dev_root = NULL;
+                       if (atomic_read(&root_dprc_count) > 0)
+                               atomic_dec(&root_dprc_count);
+                       else
+                               WARN_ON(1);
+               }
        }
 
        if (mc_bus)