rapidio: move rio_pw_enable into core code

Make rio_pw_enable() routine available to other RapidIO drivers.

Signed-off-by: Alexandre Bounine <[e-mail]>
Cc: Matt Porter <[e-mail]>
Cc: Aurelien Jacquiot <[e-mail]>
Cc: Andre van Herk <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/rapidio/rio-scan.c

···
 }
 
 /**
- * rio_pw_enable - Enables/disables port-write handling by a master port
- * @port: Master port associated with port-write handling
- * @enable:  1=enable,  0=disable
- */
-static void rio_pw_enable(struct rio_mport *port, int enable)
-{
-	if (port->ops->pwenable)
-		port->ops->pwenable(port, enable);
-}
-
-/**
  * rio_enum_mport- Start enumeration through a master port
  * @mport: Master port to send transactions
  * @flags: Enumeration control flags

drivers/rapidio/rio.c

···
 EXPORT_SYMBOL_GPL(rio_release_inb_pwrite);
 
 /**
+ * rio_pw_enable - Enables/disables port-write handling by a master port
+ * @mport: Master port associated with port-write handling
+ * @enable:  1=enable,  0=disable
+ */
+void rio_pw_enable(struct rio_mport *mport, int enable)
+{
+	if (mport->ops->pwenable) {
+		mutex_lock(&mport->lock);
+
+		if ((enable && ++mport->pwe_refcnt == 1) ||
+		    (!enable && mport->pwe_refcnt && --mport->pwe_refcnt == 0))
+			mport->ops->pwenable(mport, enable);
+		mutex_unlock(&mport->lock);
+	}
+}
+EXPORT_SYMBOL_GPL(rio_pw_enable);
+
+/**
  * rio_map_inb_region -- Map inbound memory region.
  * @mport: Master port.
  * @local: physical address of memory region to be mapped
···
 	mport->host_deviceid = rio_get_hdid(mport->id);
 	mport->nscan = NULL;
 	mutex_init(&mport->lock);
+	mport->pwe_refcnt = 0;
 
 	return 0;
 }

include/linux/rio.h

···
  * @dma: DMA device associated with mport
  * @nscan: RapidIO network enumeration/discovery operations
  * @state: mport device state
+ * @pwe_refcnt: port-write enable ref counter to track enable/disable requests
  */
 struct rio_mport {
 	struct list_head dbells;	/* list of doorbell events */
···
 #endif
 	struct rio_scan *nscan;
 	atomic_t state;
+	unsigned int pwe_refcnt;
 };
 
 static inline int rio_mport_is_running(struct rio_mport *mport)

include/linux/rio_drv.h

···
 			int (*)(struct rio_dev *, union rio_pw_msg*, int));
 extern int rio_release_inb_pwrite(struct rio_dev *);
 extern int rio_inb_pwrite_handler(union rio_pw_msg *pw_msg);
+extern void rio_pw_enable(struct rio_mport *mport, int enable);
 
 /* LDM support */
 int rio_register_driver(struct rio_driver *);