dma: bcm6348: check if driver is enabled before send/recv

This patch prevents errors when running tftpput.
Signed-off-by: NÁlvaro Fernández Rojas <noltari@gmail.com>

drivers/dma/bcm6348-iudma.c

@@ -324,6 +324,9 @@ static int bcm6348_iudma_receive(struct dma *dma, void **dst, void *metadata)
 	struct bcm6348_dma_desc *dma_desc = dma_desc = ch_priv->dma_ring;
 	int ret;
 
+	if (!ch_priv->running)
+		return -EINVAL;
+
 	/* get dma ring descriptor address */
 	dma_desc += ch_priv->desc_id;
 
@@ -369,6 +372,9 @@ static int bcm6348_iudma_send(struct dma *dma, void *src, size_t len,
 	struct bcm6348_dma_desc *dma_desc;
 	uint16_t status;
 
+	if (!ch_priv->running)
+                return -EINVAL;
+
 	/* flush cache */
 	bcm6348_iudma_fdc(src, len);