net: ethernet: mediatek: add HW LRO functions of PDMA RX rings

The codes add the large receive offload (LRO) functions by hardware as below:
1) PDMA has total four RX rings that one is the normal ring, and others can
   be configured as LRO rings.
2) Only TCP/IP RX flows can be offloaded. The hardware can set four IP
   addresses at most, if the destination IP of the RX flow matches one of
   them, it has the chance to be offloaded.
3) There three RX flows can be offloaded at most, and one flow is mapped to
   one RX ring.
4) If there are more than three candidate RX flows, the hardware can
   choose three of them by throughput comparison results.

Signed-off-by: Nelson Chang <nelson.chang@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Nelson Chang

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -820,11 +820,51 @@ static int mtk_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	return NETDEV_TX_OK;
 }
 
+static struct mtk_rx_ring *mtk_get_rx_ring(struct mtk_eth *eth)
+{
+	int i;
+	struct mtk_rx_ring *ring;
+	int idx;
+
+	if (!eth->hwlro)
+		return &eth->rx_ring[0];
+
+	for (i = 0; i < MTK_MAX_RX_RING_NUM; i++) {
+		ring = &eth->rx_ring[i];
+		idx = NEXT_RX_DESP_IDX(ring->calc_idx, ring->dma_size);
+		if (ring->dma[idx].rxd2 & RX_DMA_DONE) {
+			ring->calc_idx_update = true;
+			return ring;
+		}
+	}
+
+	return NULL;
+}
+
+static void mtk_update_rx_cpu_idx(struct mtk_eth *eth)
+{
+	struct mtk_rx_ring *ring;
+	int i;
+
+	if (!eth->hwlro) {
+		ring = &eth->rx_ring[0];
+		mtk_w32(eth, ring->calc_idx, ring->crx_idx_reg);
+	} else {
+		for (i = 0; i < MTK_MAX_RX_RING_NUM; i++) {
+			ring = &eth->rx_ring[i];
+			if (ring->calc_idx_update) {
+				ring->calc_idx_update = false;
+				mtk_w32(eth, ring->calc_idx, ring->crx_idx_reg);
+			}
+		}
+	}
+}
+
 static int mtk_poll_rx(struct napi_struct *napi, int budget,
 		       struct mtk_eth *eth)
 {
-	struct mtk_rx_ring *ring = &eth->rx_ring;
-	int idx = ring->calc_idx;
+	struct mtk_rx_ring *ring;
+	int idx;
 	struct sk_buff *skb;
 	u8 *data, *new_data;
 	struct mtk_rx_dma *rxd, trxd;
@@ -836,7 +876,11 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 		dma_addr_t dma_addr;
 		int mac = 0;
 
-		idx = NEXT_RX_DESP_IDX(idx);
+		ring = mtk_get_rx_ring(eth);
+		if (unlikely(!ring))
+			goto rx_done;
+
+		idx = NEXT_RX_DESP_IDX(ring->calc_idx, ring->dma_size);
 		rxd = &ring->dma[idx];
 		data = ring->data[idx];
 
@@ -907,12 +951,13 @@ static int mtk_poll_rx(struct napi_struct *napi, int budget,
 		done++;
 	}
 
+rx_done:
 	if (done) {
 		/* make sure that all changes to the dma ring are flushed before
 		 * we continue
 		 */
 		wmb();
-		mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
+		mtk_update_rx_cpu_idx(eth);
 	}
 
 	return done;
@@ -1135,32 +1180,41 @@ static void mtk_tx_clean(struct mtk_eth *eth)
 	}
 }
 
-static int mtk_rx_alloc(struct mtk_eth *eth)
+static int mtk_rx_alloc(struct mtk_eth *eth, int ring_no, int rx_flag)
 {
-	struct mtk_rx_ring *ring = &eth->rx_ring;
+	struct mtk_rx_ring *ring = &eth->rx_ring[ring_no];
+	int rx_data_len, rx_dma_size;
 	int i;
 
-	ring->frag_size = mtk_max_frag_size(ETH_DATA_LEN);
+	if (rx_flag == MTK_RX_FLAGS_HWLRO) {
+		rx_data_len = MTK_MAX_LRO_RX_LENGTH;
+		rx_dma_size = MTK_HW_LRO_DMA_SIZE;
+	} else {
+		rx_data_len = ETH_DATA_LEN;
+		rx_dma_size = MTK_DMA_SIZE;
+	}
+
+	ring->frag_size = mtk_max_frag_size(rx_data_len);
 	ring->buf_size = mtk_max_buf_size(ring->frag_size);
-	ring->data = kcalloc(MTK_DMA_SIZE, sizeof(*ring->data),
+	ring->data = kcalloc(rx_dma_size, sizeof(*ring->data),
 			     GFP_KERNEL);
 	if (!ring->data)
 		return -ENOMEM;
 
-	for (i = 0; i < MTK_DMA_SIZE; i++) {
+	for (i = 0; i < rx_dma_size; i++) {
 		ring->data[i] = netdev_alloc_frag(ring->frag_size);
 		if (!ring->data[i])
 			return -ENOMEM;
 	}
 
 	ring->dma = dma_alloc_coherent(eth->dev,
-				       MTK_DMA_SIZE * sizeof(*ring->dma),
+				       rx_dma_size * sizeof(*ring->dma),
 				       &ring->phys,
 				       GFP_ATOMIC | __GFP_ZERO);
 	if (!ring->dma)
 		return -ENOMEM;
 
-	for (i = 0; i < MTK_DMA_SIZE; i++) {
+	for (i = 0; i < rx_dma_size; i++) {
 		dma_addr_t dma_addr = dma_map_single(eth->dev,
 				ring->data[i] + NET_SKB_PAD,
 				ring->buf_size,
@@ -1171,27 +1225,30 @@ static int mtk_rx_alloc(struct mtk_eth *eth)
 
 		ring->dma[i].rxd2 = RX_DMA_PLEN0(ring->buf_size);
 	}
-	ring->calc_idx = MTK_DMA_SIZE - 1;
+	ring->dma_size = rx_dma_size;
+	ring->calc_idx_update = false;
+	ring->calc_idx = rx_dma_size - 1;
+	ring->crx_idx_reg = MTK_PRX_CRX_IDX_CFG(ring_no);
 	/* make sure that all changes to the dma ring are flushed before we
 	 * continue
 	 */
 	wmb();
 
-	mtk_w32(eth, eth->rx_ring.phys, MTK_PRX_BASE_PTR0);
-	mtk_w32(eth, MTK_DMA_SIZE, MTK_PRX_MAX_CNT0);
-	mtk_w32(eth, eth->rx_ring.calc_idx, MTK_PRX_CRX_IDX0);
-	mtk_w32(eth, MTK_PST_DRX_IDX0, MTK_PDMA_RST_IDX);
+	mtk_w32(eth, ring->phys, MTK_PRX_BASE_PTR_CFG(ring_no));
+	mtk_w32(eth, rx_dma_size, MTK_PRX_MAX_CNT_CFG(ring_no));
+	mtk_w32(eth, ring->calc_idx, ring->crx_idx_reg);
+	mtk_w32(eth, MTK_PST_DRX_IDX_CFG(ring_no), MTK_PDMA_RST_IDX);
 
 	return 0;
 }
 
-static void mtk_rx_clean(struct mtk_eth *eth)
+static void mtk_rx_clean(struct mtk_eth *eth, int ring_no)
 {
-	struct mtk_rx_ring *ring = &eth->rx_ring;
+	struct mtk_rx_ring *ring = &eth->rx_ring[ring_no];
 	int i;
 
 	if (ring->data && ring->dma) {
-		for (i = 0; i < MTK_DMA_SIZE; i++) {
+		for (i = 0; i < ring->dma_size; i++) {
 			if (!ring->data[i])
 				continue;
 			if (!ring->dma[i].rxd1)
@@ -1208,13 +1265,98 @@ static void mtk_rx_clean(struct mtk_eth *eth)
 
 	if (ring->dma) {
 		dma_free_coherent(eth->dev,
-				  MTK_DMA_SIZE * sizeof(*ring->dma),
+				  ring->dma_size * sizeof(*ring->dma),
 				  ring->dma,
 				  ring->phys);
 		ring->dma = NULL;
 	}
 }
 
+static int mtk_hwlro_rx_init(struct mtk_eth *eth)
+{
+	int i;
+	u32 ring_ctrl_dw1 = 0, ring_ctrl_dw2 = 0, ring_ctrl_dw3 = 0;
+	u32 lro_ctrl_dw0 = 0, lro_ctrl_dw3 = 0;
+
+	/* set LRO rings to auto-learn modes */
+	ring_ctrl_dw2 |= MTK_RING_AUTO_LERAN_MODE;
+
+	/* validate LRO ring */
+	ring_ctrl_dw2 |= MTK_RING_VLD;
+
+	/* set AGE timer (unit: 20us) */
+	ring_ctrl_dw2 |= MTK_RING_AGE_TIME_H;
+	ring_ctrl_dw1 |= MTK_RING_AGE_TIME_L;
+
+	/* set max AGG timer (unit: 20us) */
+	ring_ctrl_dw2 |= MTK_RING_MAX_AGG_TIME;
+
+	/* set max LRO AGG count */
+	ring_ctrl_dw2 |= MTK_RING_MAX_AGG_CNT_L;
+	ring_ctrl_dw3 |= MTK_RING_MAX_AGG_CNT_H;
+
+	for (i = 1; i < MTK_MAX_RX_RING_NUM; i++) {
+		mtk_w32(eth, ring_ctrl_dw1, MTK_LRO_CTRL_DW1_CFG(i));
+		mtk_w32(eth, ring_ctrl_dw2, MTK_LRO_CTRL_DW2_CFG(i));
+		mtk_w32(eth, ring_ctrl_dw3, MTK_LRO_CTRL_DW3_CFG(i));
+	}
+
+	/* IPv4 checksum update enable */
+	lro_ctrl_dw0 |= MTK_L3_CKS_UPD_EN;
+
+	/* switch priority comparison to packet count mode */
+	lro_ctrl_dw0 |= MTK_LRO_ALT_PKT_CNT_MODE;
+
+	/* bandwidth threshold setting */
+	mtk_w32(eth, MTK_HW_LRO_BW_THRE, MTK_PDMA_LRO_CTRL_DW2);
+
+	/* auto-learn score delta setting */
+	mtk_w32(eth, MTK_HW_LRO_REPLACE_DELTA, MTK_PDMA_LRO_ALT_SCORE_DELTA);
+
+	/* set refresh timer for altering flows to 1 sec. (unit: 20us) */
+	mtk_w32(eth, (MTK_HW_LRO_TIMER_UNIT << 16) | MTK_HW_LRO_REFRESH_TIME,
+		MTK_PDMA_LRO_ALT_REFRESH_TIMER);
+
+	/* set HW LRO mode & the max aggregation count for rx packets */
+	lro_ctrl_dw3 |= MTK_ADMA_MODE | (MTK_HW_LRO_MAX_AGG_CNT & 0xff);
+
+	/* the minimal remaining room of SDL0 in RXD for lro aggregation */
+	lro_ctrl_dw3 |= MTK_LRO_MIN_RXD_SDL;
+
+	/* enable HW LRO */
+	lro_ctrl_dw0 |= MTK_LRO_EN;
+
+	mtk_w32(eth, lro_ctrl_dw3, MTK_PDMA_LRO_CTRL_DW3);
+	mtk_w32(eth, lro_ctrl_dw0, MTK_PDMA_LRO_CTRL_DW0);
+
+	return 0;
+}
+
+static void mtk_hwlro_rx_uninit(struct mtk_eth *eth)
+{
+	int i;
+	u32 val;
+
+	/* relinquish lro rings, flush aggregated packets */
+	mtk_w32(eth, MTK_LRO_RING_RELINQUISH_REQ, MTK_PDMA_LRO_CTRL_DW0);
+
+	/* wait for relinquishments done */
+	for (i = 0; i < 10; i++) {
+		val = mtk_r32(eth, MTK_PDMA_LRO_CTRL_DW0);
+		if (val & MTK_LRO_RING_RELINQUISH_DONE) {
+			msleep(20);
+			continue;
+		}
+	}
+
+	/* invalidate lro rings */
+	for (i = 1; i < MTK_MAX_RX_RING_NUM; i++)
+		mtk_w32(eth, 0, MTK_LRO_CTRL_DW2_CFG(i));
+
+	/* disable HW LRO */
+	mtk_w32(eth, 0, MTK_PDMA_LRO_CTRL_DW0);
+}
+
 /* wait for DMA to finish whatever it is doing before we start using it again */
 static int mtk_dma_busy_wait(struct mtk_eth *eth)
 {
@@ -1235,6 +1377,7 @@ static int mtk_dma_busy_wait(struct mtk_eth *eth)
 static int mtk_dma_init(struct mtk_eth *eth)
 {
 	int err;
+	u32 i;
 
 	if (mtk_dma_busy_wait(eth))
 		return -EBUSY;
@@ -1250,10 +1393,21 @@ static int mtk_dma_init(struct mtk_eth *eth)
 	if (err)
 		return err;
 
-	err = mtk_rx_alloc(eth);
+	err = mtk_rx_alloc(eth, 0, MTK_RX_FLAGS_NORMAL);
 	if (err)
 		return err;
 
+	if (eth->hwlro) {
+		for (i = 1; i < MTK_MAX_RX_RING_NUM; i++) {
+			err = mtk_rx_alloc(eth, i, MTK_RX_FLAGS_HWLRO);
+			if (err)
+				return err;
+		}
+		err = mtk_hwlro_rx_init(eth);
+		if (err)
+			return err;
+	}
+
 	/* Enable random early drop and set drop threshold automatically */
 	mtk_w32(eth, FC_THRES_DROP_MODE | FC_THRES_DROP_EN | FC_THRES_MIN,
 		MTK_QDMA_FC_THRES);
@@ -1278,7 +1432,14 @@ static void mtk_dma_free(struct mtk_eth *eth)
 		eth->phy_scratch_ring = 0;
 	}
 	mtk_tx_clean(eth);
-	mtk_rx_clean(eth);
+	mtk_rx_clean(eth, 0);
+
+	if (eth->hwlro) {
+		mtk_hwlro_rx_uninit(eth);
+		for (i = 1; i < MTK_MAX_RX_RING_NUM; i++)
+			mtk_rx_clean(eth, i);
+	}
+
 	kfree(eth->scratch_head);
 }
 
@@ -1873,6 +2034,9 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 	mac->hw = eth;
 	mac->of_node = np;
 
+	memset(mac->hwlro_ip, 0, sizeof(mac->hwlro_ip));
+	mac->hwlro_ip_cnt = 0;
+
 	mac->hw_stats = devm_kzalloc(eth->dev,
 				     sizeof(*mac->hw_stats),
 				     GFP_KERNEL);
@@ -1889,6 +2053,11 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 	eth->netdev[id]->watchdog_timeo = 5 * HZ;
 	eth->netdev[id]->netdev_ops = &mtk_netdev_ops;
 	eth->netdev[id]->base_addr = (unsigned long)eth->base;
+
+	eth->netdev[id]->hw_features = MTK_HW_FEATURES;
+	if (eth->hwlro)
+		eth->netdev[id]->hw_features |= NETIF_F_LRO;
+
 	eth->netdev[id]->vlan_features = MTK_HW_FEATURES &
 		~(NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX);
 	eth->netdev[id]->features |= MTK_HW_FEATURES;
@@ -1941,6 +2110,8 @@ static int mtk_probe(struct platform_device *pdev)
 		return PTR_ERR(eth->pctl);
 	}
 
+	eth->hwlro = of_property_read_bool(pdev->dev.of_node, "mediatek,hwlro");
+
 	for (i = 0; i < 3; i++) {
 		eth->irq[i] = platform_get_irq(pdev, i);
 		if (eth->irq[i] < 0) {