net: bcmgenet: fix uncleaned dma flags

Clean the dma flags of multiq ring buffer int the interface stop
process. This patch fixes that the genet is not running while the
interface is re-enabled.

$ ifup eth0 - running after booting
$ ifdown eth0
$ ifup eth0 - not running and occur tx_timeout

The bcmgenet_dma_disable() in bcmgenet_open() do clean ring16 dma flag
only. If the genet has multiq, the dma register is not cleaned. and
bcmgenet_init_dma() is not done correctly. in case
GENET_V2(tx_queues=4), tdma_ctrl has 0x1e after running
bcmgenet_dma_disable().

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet.c

@@ -2126,6 +2126,8 @@ static int bcmgenet_dma_teardown(struct bcmgenet_priv *priv)
 	int ret = 0;
 	int timeout = 0;
 	u32 reg;
+	u32 dma_ctrl;
+	int i;
 
 	/* Disable TDMA to stop add more frames in TX DMA */
 	reg = bcmgenet_tdma_readl(priv, DMA_CTRL);
@@ -2169,6 +2171,20 @@ static int bcmgenet_dma_teardown(struct bcmgenet_priv *priv)
 		ret = -ETIMEDOUT;
 	}
 
+	dma_ctrl = 0;
+	for (i = 0; i < priv->hw_params->rx_queues; i++)
+		dma_ctrl |= (1 << (i + DMA_RING_BUF_EN_SHIFT));
+	reg = bcmgenet_rdma_readl(priv, DMA_CTRL);
+	reg &= ~dma_ctrl;
+	bcmgenet_rdma_writel(priv, reg, DMA_CTRL);
+
+	dma_ctrl = 0;
+	for (i = 0; i < priv->hw_params->tx_queues; i++)
+		dma_ctrl |= (1 << (i + DMA_RING_BUF_EN_SHIFT));
+	reg = bcmgenet_tdma_readl(priv, DMA_CTRL);
+	reg &= ~dma_ctrl;
+	bcmgenet_tdma_writel(priv, reg, DMA_CTRL);
+
 	return ret;
 }