HID: intel-ish-hid: ishtp: add helper functions for client buffer operation

Add helper ishtp_cl_tx_empty() and ishtp_cl_rx_get_rb() to hide internal
details from callers, who needs this functionality.

Signed-off-by: Even Xu <even.xu@intel.com>
Reviewed-by: Andriy Shevchenko <andriy.shevchenko@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/intel-ish-hid/ishtp/client-buffers.c

@@ -255,3 +255,48 @@ int ishtp_cl_io_rb_recycle(struct ishtp_cl_rb *rb)
 	return	rets;
 }
 EXPORT_SYMBOL(ishtp_cl_io_rb_recycle);
+
+/**
+ * ishtp_cl_tx_empty() -test whether client device tx buffer is empty
+ * @cl: Pointer to client device instance
+ *
+ * Look client device tx buffer list, and check whether this list is empty
+ *
+ * Return: true if client tx buffer list is empty else false
+ */
+bool ishtp_cl_tx_empty(struct ishtp_cl *cl)
+{
+	int tx_list_empty;
+	unsigned long tx_flags;
+
+	spin_lock_irqsave(&cl->tx_list_spinlock, tx_flags);
+	tx_list_empty = list_empty(&cl->tx_list.list);
+	spin_unlock_irqrestore(&cl->tx_list_spinlock, tx_flags);
+
+	return !!tx_list_empty;
+}
+EXPORT_SYMBOL(ishtp_cl_tx_empty);
+
+/**
+ * ishtp_cl_rx_get_rb() -Get a rb from client device rx buffer list
+ * @cl: Pointer to client device instance
+ *
+ * Check client device in-processing buffer list and get a rb from it.
+ *
+ * Return: rb pointer if buffer list isn't empty else NULL
+ */
+struct ishtp_cl_rb *ishtp_cl_rx_get_rb(struct ishtp_cl *cl)
+{
+	unsigned long rx_flags;
+	struct ishtp_cl_rb *rb;
+
+	spin_lock_irqsave(&cl->in_process_spinlock, rx_flags);
+	rb = list_first_entry_or_null(&cl->in_process_list.list,
+				struct ishtp_cl_rb, list);
+	if (rb)
+		list_del_init(&rb->list);
+	spin_unlock_irqrestore(&cl->in_process_spinlock, rx_flags);
+
+	return rb;
+}
+EXPORT_SYMBOL(ishtp_cl_rx_get_rb);

drivers/hid/intel-ish-hid/ishtp/client.h

@@ -178,5 +178,7 @@ int ishtp_cl_flush_queues(struct ishtp_cl *cl);
 
 /* exported functions from ISHTP client buffer management scope */
 int ishtp_cl_io_rb_recycle(struct ishtp_cl_rb *rb);
+bool ishtp_cl_tx_empty(struct ishtp_cl *cl);
+struct ishtp_cl_rb *ishtp_cl_rx_get_rb(struct ishtp_cl *cl);
 
 #endif /* _ISHTP_CLIENT_H_ */