[intelxl] Split out ring creation from context programming

The virtual function driver will use the same transmit and receive
descriptor ring structures, but will not itself construct and program
the ring context.  Split out ring creation and destruction from the
programming of the ring context, to allow code to be shared between
physical and virtual function drivers.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/intelxl.c

  ******************************************************************************
  */
 
+/**
+ * Allocate descriptor ring
+ *
+ * @v intelxl		Intel device
+ * @v ring		Descriptor ring
+ * @ret rc		Return status code
+ */
+static int intelxl_alloc_ring ( struct intelxl_nic *intelxl,
+				struct intelxl_ring *ring ) {
+	physaddr_t address;
+	int rc;
+
+	/* Allocate descriptor ring */
+	ring->desc.raw = malloc_dma ( ring->len, INTELXL_ALIGN );
+	if ( ! ring->desc.raw ) {
+		rc = -ENOMEM;
+		goto err_alloc;
+	}
+	address = virt_to_bus ( ring->desc.raw );
+
+	/* Initialise descriptor ring */
+	memset ( ring->desc.raw, 0, ring->len );
+
+	/* Reset tail pointer */
+	writel ( 0, ( intelxl->regs + ring->tail ) );
+
+	/* Reset counters */
+	ring->prod = 0;
+	ring->cons = 0;
+
+	DBGC ( intelxl, "INTELXL %p ring %06x is at [%08llx,%08llx)\n",
+	       intelxl, ( ring->reg + ring->tail ),
+	       ( ( unsigned long long ) address ),
+	       ( ( unsigned long long ) address + ring->len ) );
+
+	return 0;
+
+	free_dma ( ring->desc.raw, ring->len );
+ err_alloc:
+	return rc;
+}
+
+/**
+ * Free descriptor ring
+ *
+ * @v intelxl		Intel device
+ * @v ring		Descriptor ring
+ */
+static void intelxl_free_ring ( struct intelxl_nic *intelxl __unused,
+				struct intelxl_ring *ring ) {
+
+	/* Free descriptor ring */
+	free_dma ( ring->desc.raw, ring->len );
+	ring->desc.raw = NULL;
+}
+
 /**
  * Dump queue context (for debugging)
  *
 	int rc;
 
 	/* Allocate descriptor ring */
-	ring->desc.raw = malloc_dma ( ring->len, INTELXL_ALIGN );
-	if ( ! ring->desc.raw ) {
-		rc = -ENOMEM;
+	if ( ( rc = intelxl_alloc_ring ( intelxl, ring ) ) != 0 )
 		goto err_alloc;
-	}
-
-	/* Initialise descriptor ring */
-	memset ( ring->desc.raw, 0, ring->len );
-
-	/* Reset tail pointer */
-	writel ( 0, ( intelxl->regs + ring->tail ) );
 
 	/* Program queue context */
 	address = virt_to_bus ( ring->desc.raw );
 	if ( ( rc = intelxl_enable_ring ( intelxl, ring ) ) != 0 )
 		goto err_enable;
 
-	/* Reset counters */
-	ring->prod = 0;
-	ring->cons = 0;
-
-	DBGC ( intelxl, "INTELXL %p ring %06x is at [%08llx,%08llx)\n",
-	       intelxl, ( ring->reg + ring->tail ),
-	       ( ( unsigned long long ) address ),
-	       ( ( unsigned long long ) address + ring->len ) );
-
 	return 0;
 
 	intelxl_disable_ring ( intelxl, ring );
  err_enable:
  err_context:
-	free_dma ( ring->desc.raw, ring->len );
+	intelxl_free_ring ( intelxl, ring );
  err_alloc:
 	return rc;
 }
 	}
 
 	/* Free descriptor ring */
-	free_dma ( ring->desc.raw, ring->len );
-	ring->desc.raw = NULL;
+	intelxl_free_ring ( intelxl, ring );
 }
 
 /**
 	}
 }
 
+/**
+ * Discard unused receive I/O buffers
+ *
+ * @v intelxl		Intel device
+ */
+static void intelxl_empty_rx ( struct intelxl_nic *intelxl ) {
+	unsigned int i;
+
+	/* Discard any unused receive buffers */
+	for ( i = 0 ; i < INTELXL_RX_NUM_DESC ; i++ ) {
+		if ( intelxl->rx_iobuf[i] )
+			free_iob ( intelxl->rx_iobuf[i] );
+		intelxl->rx_iobuf[i] = NULL;
+	}
+}
+
 /******************************************************************************
  *
  * Network device interface
 static void intelxl_close ( struct net_device *netdev ) {
 	struct intelxl_nic *intelxl = netdev->priv;
 	unsigned int queue;
-	unsigned int i;
 
 	/* Dump contexts (for debugging) */
 	intelxl_context_dump ( intelxl, INTELXL_PFCM_LANCTXCTL_TYPE_TX,
 	intelxl_destroy_ring ( intelxl, &intelxl->rx );
 
 	/* Discard any unused receive buffers */
-	for ( i = 0 ; i < INTELXL_RX_NUM_DESC ; i++ ) {
-		if ( intelxl->rx_iobuf[i] )
-			free_iob ( intelxl->rx_iobuf[i] );
-		intelxl->rx_iobuf[i] = NULL;
-	}
+	intelxl_empty_rx ( intelxl );
 }
 
 /**