Altera TSE: Work around unaligned DMA receive packet issue with Altera SGDMA

This patch works around a recently discovered unaligned receive dma problem
with the Altera SGMDA. The Altera SGDMA component cannot be configured to
DMA data to unaligned addresses for receive packet operations from the
Triple Speed Ethernet component because of a potential data transfer
corruption that can occur. This patch addresses this issue by
utilizing the shift 16 bits feature of the Altera Triple Speed Ethernet
component and modifying the receive buffer physical addresses accordingly
such that the target receive DMA address is always aligned on a 32-bit
boundary.

Signed-off-by: Vince Bridgers <vbridgers2013@gmail.com>
Tested-by: Matthew Gerlach <mgerlach@altera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 10 deletions

diff --git a/drivers/net/ethernet/altera/altera_tse_main.c b/drivers/net/ethernet/altera/altera_tse_main.c
index c70a29e0b9f7..dabba5ed67bd 100644
--- a/drivers/net/ethernet/altera/altera_tse_main.c
+++ b/drivers/net/ethernet/altera/altera_tse_main.c
@@ -224,6 +224,7 @@ static int tse_init_rx_buffer(struct altera_tse_private *priv,
 		dev_kfree_skb_any(rxbuffer->skb);
 		return -EINVAL;
 	}
+	rxbuffer->dma_addr &= (dma_addr_t)~3;
 	rxbuffer->len = len;
 	return 0;
 }
@@ -425,9 +426,10 @@ static int tse_rx(struct altera_tse_private *priv, int limit)
 		priv->dev->stats.rx_bytes += pktlength;
 
 		entry = next_entry;
+
+		tse_rx_refill(priv);
 	}
 
-	tse_rx_refill(priv);
 	return count;
 }
 
@@ -520,7 +522,6 @@ static irqreturn_t altera_isr(int irq, void *dev_id)
 	struct altera_tse_private *priv;
 	unsigned long int flags;
 
-
 	if (unlikely(!dev)) {
 		pr_err("%s: invalid dev pointer\n", __func__);
 		return IRQ_NONE;
@@ -868,13 +869,13 @@ static int init_mac(struct altera_tse_private *priv)
 	/* Disable RX/TX shift 16 for alignment of all received frames on 16-bit
 	 * start address
 	 */
-	tse_clear_bit(&mac->rx_cmd_stat, ALTERA_TSE_RX_CMD_STAT_RX_SHIFT16);
+	tse_set_bit(&mac->rx_cmd_stat, ALTERA_TSE_RX_CMD_STAT_RX_SHIFT16);
 	tse_clear_bit(&mac->tx_cmd_stat, ALTERA_TSE_TX_CMD_STAT_TX_SHIFT16 |
 					 ALTERA_TSE_TX_CMD_STAT_OMIT_CRC);
 
 	/* Set the MAC options */
 	cmd = ioread32(&mac->command_config);
-	cmd |= MAC_CMDCFG_PAD_EN;	/* Padding Removal on Receive */
+	cmd &= ~MAC_CMDCFG_PAD_EN;	/* No padding Removal on Receive */
 	cmd &= ~MAC_CMDCFG_CRC_FWD;	/* CRC Removal */
 	cmd |= MAC_CMDCFG_RX_ERR_DISC;	/* Automatically discard frames
 					 * with CRC errors
@@ -882,6 +883,12 @@ static int init_mac(struct altera_tse_private *priv)
 	cmd |= MAC_CMDCFG_CNTL_FRM_ENA;
 	cmd &= ~MAC_CMDCFG_TX_ENA;
 	cmd &= ~MAC_CMDCFG_RX_ENA;
+
+	/* Default speed and duplex setting, full/100 */
+	cmd &= ~MAC_CMDCFG_HD_ENA;
+	cmd &= ~MAC_CMDCFG_ETH_SPEED;
+	cmd &= ~MAC_CMDCFG_ENA_10;
+
 	iowrite32(cmd, &mac->command_config);
 
 	if (netif_msg_hw(priv))
@@ -1085,17 +1092,19 @@ static int tse_open(struct net_device *dev)
 
 	spin_unlock_irqrestore(&priv->rxdma_irq_lock, flags);
 
-	/* Start MAC Rx/Tx */
-	spin_lock(&priv->mac_cfg_lock);
-	tse_set_mac(priv, true);
-	spin_unlock(&priv->mac_cfg_lock);
-
 	if (priv->phydev)
 		phy_start(priv->phydev);
 
 	napi_enable(&priv->napi);
 	netif_start_queue(dev);
 
+	priv->dmaops->start_rxdma(priv);
+
+	/* Start MAC Rx/Tx */
+	spin_lock(&priv->mac_cfg_lock);
+	tse_set_mac(priv, true);
+	spin_unlock(&priv->mac_cfg_lock);
+
 	return 0;
 
 tx_request_irq_error:
@@ -1167,7 +1176,6 @@ static struct net_device_ops altera_tse_netdev_ops = {
 	.ndo_validate_addr	= eth_validate_addr,
 };
 
-
 static int request_and_map(struct platform_device *pdev, const char *name,
 			   struct resource **res, void __iomem **ptr)
 {
@@ -1496,6 +1504,7 @@ struct altera_dmaops altera_dtype_sgdma = {
 	.get_rx_status = sgdma_rx_status,
 	.init_dma = sgdma_initialize,
 	.uninit_dma = sgdma_uninitialize,
+	.start_rxdma = sgdma_start_rxdma,
 };
 
 struct altera_dmaops altera_dtype_msgdma = {
@@ -1514,6 +1523,7 @@ struct altera_dmaops altera_dtype_msgdma = {
 	.get_rx_status = msgdma_rx_status,
 	.init_dma = msgdma_initialize,
 	.uninit_dma = msgdma_uninitialize,
+	.start_rxdma = msgdma_start_rxdma,
 };
 
 static struct of_device_id altera_tse_ids[] = {