From 14d4e308e0aa0b78dc7a059716861a4380de3535 Mon Sep 17 00:00:00 2001
From: Aleksander Jan Bajkowski <olek2@wp.pl>
Date: Tue, 14 Sep 2021 23:21:02 +0200
Subject: [PATCH 5/5] net: lantiq: configure the burst length in ethernet
 drivers

Configure the burst length in Ethernet drivers. This improves
Ethernet performance by 58%. According to the vendor BSP,
8W burst length is supported by ar9 and newer SoCs.

The NAT benchmark results on xRX200 (Down/Up):
* 2W: 330 Mb/s
* 4W: 432 Mb/s    372 Mb/s
* 8W: 520 Mb/s    389 Mb/s

Tested on xRX200 and xRX330.

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/lantiq_etop.c   | 21 ++++++++++++++++++---
 drivers/net/ethernet/lantiq_xrx200.c | 21 ++++++++++++++++++---
 2 files changed, 36 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/lantiq_etop.c
+++ b/drivers/net/ethernet/lantiq_etop.c
@@ -148,6 +148,9 @@ struct ltq_etop_priv {
 	struct ltq_etop_chan txch;
 	struct ltq_etop_chan rxch;
 
+	int tx_burst_len;
+	int rx_burst_len;
+
 	int tx_irq;
 	int rx_irq;
 
@@ -400,7 +403,7 @@ ltq_etop_dma_init(struct net_device *dev
 	int rx = priv->rx_irq - LTQ_DMA_ETOP;
 	int err;
 
-	ltq_dma_init_port(DMA_PORT_ETOP);
+	ltq_dma_init_port(DMA_PORT_ETOP, priv->tx_burst_len, rx_burst_len);
 
 	priv->txch.dma.nr = tx;
 	priv->txch.dma.dev = &priv->pdev->dev;
@@ -679,8 +682,8 @@ ltq_etop_tx(struct sk_buff *skb, struct
 		return NETDEV_TX_BUSY;
 	}
 
-	/* dma needs to start on a 16 byte aligned address */
-	byte_offset = CPHYSADDR(skb->data) % 16;
+	/* dma needs to start on a burst length value aligned address */
+	byte_offset = CPHYSADDR(skb->data) % (priv->tx_burst_len * 4);
 	priv->txch.skb[priv->txch.dma.desc] = skb;
 
 	netif_trans_update(dev);
@@ -928,6 +931,18 @@ static int ltq_etop_probe(struct platfor
 	spin_lock_init(&priv->lock);
 	SET_NETDEV_DEV(dev, &pdev->dev);
 
+	err = device_property_read_u32(&pdev->dev, "lantiq,tx-burst-length", &priv->tx_burst_len);
+	if (err < 0) {
+		dev_err(&pdev->dev, "unable to read tx-burst-length property\n");
+		return err;
+	}
+
+	err = device_property_read_u32(&pdev->dev, "lantiq,rx-burst-length", &priv->rx_burst_len);
+	if (err < 0) {
+		dev_err(&pdev->dev, "unable to read rx-burst-length property\n");
+		return err;
+	}
+
 	netif_napi_add(dev, &priv->txch.napi, ltq_etop_poll_tx, 8);
 	netif_napi_add(dev, &priv->rxch.napi, ltq_etop_poll_rx, 32);
 	priv->txch.netdev = dev;
--- a/drivers/net/ethernet/lantiq_xrx200.c
+++ b/drivers/net/ethernet/lantiq_xrx200.c
@@ -81,6 +81,9 @@ struct xrx200_priv {
 	struct net_device *net_dev;
 	struct device *dev;
 
+	int tx_burst_len;
+	int rx_burst_len;
+
 	__iomem void *pmac_reg;
 };
 
@@ -363,8 +366,8 @@ static netdev_tx_t xrx200_start_xmit(str
 	if (unlikely(dma_mapping_error(priv->dev, mapping)))
 		goto err_drop;
 
-	/* dma needs to start on a 16 byte aligned address */
-	byte_offset = mapping % 16;
+	/* dma needs to start on a burst length value aligned address */
+	byte_offset = mapping % (priv->tx_burst_len * 4);
 
 	desc->addr = mapping - byte_offset;
 	/* Make sure the address is written before we give it to HW */
@@ -465,7 +468,7 @@ static int xrx200_dma_init(struct xrx200
 	int ret = 0;
 	int i;
 
-	ltq_dma_init_port(DMA_PORT_ETOP);
+	ltq_dma_init_port(DMA_PORT_ETOP, priv->tx_burst_len, rx_burst_len);
 
 	ch_rx->dma.nr = XRX200_DMA_RX;
 	ch_rx->dma.dev = priv->dev;
@@ -575,6 +578,18 @@ static int xrx200_probe(struct platform_
 	if (err)
 		eth_hw_addr_random(net_dev);
 
+	err = device_property_read_u32(dev, "lantiq,tx-burst-length", &priv->tx_burst_len);
+	if (err < 0) {
+		dev_err(dev, "unable to read tx-burst-length property\n");
+		return err;
+	}
+
+	err = device_property_read_u32(dev, "lantiq,rx-burst-length", &priv->rx_burst_len);
+	if (err < 0) {
+		dev_err(dev, "unable to read rx-burst-length property\n");
+		return err;
+	}
+
 	/* bring up the dma engine and IP core */
 	err = xrx200_dma_init(priv);
 	if (err)
