Message-Id: <1460053499-53659-1-git-send-email-blogic@openwrt.org>
Date:	Thu,  7 Apr 2016 20:24:59 +0200
From:	John Crispin <blogic@...nwrt.org>
To:	"David S. Miller" <davem@...emloft.net>
Cc:	Felix Fietkau <nbd@...nwrt.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	netdev@...r.kernel.org, linux-mediatek@...ts.infradead.org,
	linux-kernel@...r.kernel.org, John Crispin <blogic@...nwrt.org>
Subject: [PATCH] net-next: mediatek: add support for IRQ grouping

The ethernet core has 3 IRQs. Using the IRQ grouping registers we are able
to separate TX and RX IRQs, which allows us to service them on separate
cores. This patch splits the IRQ handler into 2 separate functions, one
for TX and another for RX. The TX housekeeping is split out of the NAPI
handler. Instead we use a tasklet to handle housekeeping.

Signed-off-by: John Crispin <blogic@...nwrt.org>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c |  115 +++++++++++++++++----------
 drivers/net/ethernet/mediatek/mtk_eth_soc.h |   12 ++-
 2 files changed, 86 insertions(+), 41 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 8163047..6387516 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -756,7 +756,7 @@ drop:
 }
 
 static int mtk_poll_rx(struct napi_struct *napi, int budget,
-		       struct mtk_eth *eth, u32 rx_intr)
+		       struct mtk_eth *eth)
 {
 	struct mtk_rx_ring *ring = &eth->rx_ring;
 	int idx = ring->calc_idx;
@@ -842,12 +842,12 @@ release_desc:
 	}
 
 	if (done < budget)
-		mtk_w32(eth, rx_intr, MTK_QMTK_INT_STATUS);
+		mtk_w32(eth, MTK_RX_DONE_INT, MTK_QMTK_INT_STATUS);
 
 	return done;
 }
 
-static int mtk_poll_tx(struct mtk_eth *eth, int budget, bool *tx_again)
+static int mtk_poll_tx(struct mtk_eth *eth, int budget)
 {
 	struct mtk_tx_ring *ring = &eth->tx_ring;
 	struct mtk_tx_dma *desc;
@@ -910,9 +910,7 @@ static int mtk_poll_tx(struct mtk_eth *eth, int budget, bool *tx_again)
 	}
 
 	/* read hw index again make sure no new tx packet */
-	if (cpu != dma || cpu != mtk_r32(eth, MTK_QTX_DRX_PTR))
-		*tx_again = true;
-	else
+	if (cpu == dma && cpu == mtk_r32(eth, MTK_QTX_DRX_PTR))
 		mtk_w32(eth, MTK_TX_DONE_INT, MTK_QMTK_INT_STATUS);
 
 	if (!total)
@@ -924,27 +922,27 @@ static int mtk_poll_tx(struct mtk_eth *eth, int budget, bool *tx_again)
 	return total;
 }
 
+static void mtk_clean_tx_tasklet(unsigned long arg)
+{
+	struct mtk_eth *eth = (struct mtk_eth *)arg;
+
+	if (mtk_poll_tx(eth, MTK_NAPI_WEIGHT) > 0)
+		tasklet_schedule(&eth->tx_clean_tasklet);
+	else
+		mtk_irq_enable(eth, MTK_TX_DONE_INT);
+}
+
 static int mtk_poll(struct napi_struct *napi, int budget)
 {
 	struct mtk_eth *eth = container_of(napi, struct mtk_eth, rx_napi);
-	u32 status, status2, mask, tx_intr, rx_intr, status_intr;
-	int tx_done, rx_done;
-	bool tx_again = false;
+	u32 status, status2, mask, status_intr;
+	int rx_done = 0;
 
 	status = mtk_r32(eth, MTK_QMTK_INT_STATUS);
 	status2 = mtk_r32(eth, MTK_INT_STATUS2);
-	tx_intr = MTK_TX_DONE_INT;
-	rx_intr = MTK_RX_DONE_INT;
 	status_intr = (MTK_GDM1_AF | MTK_GDM2_AF);
-	tx_done = 0;
-	rx_done = 0;
-	tx_again = 0;
 
-	if (status & tx_intr)
-		tx_done = mtk_poll_tx(eth, budget, &tx_again);
-
-	if (status & rx_intr)
-		rx_done = mtk_poll_rx(napi, budget, eth, rx_intr);
+	rx_done = mtk_poll_rx(napi, budget, eth);
 
 	if (unlikely(status2 & status_intr)) {
 		mtk_stats_update(eth);
@@ -953,20 +951,20 @@ static int mtk_poll(struct napi_struct *napi, int budget)
 
 	if (unlikely(netif_msg_intr(eth))) {
 		mask = mtk_r32(eth, MTK_QDMA_INT_MASK);
-		netdev_info(eth->netdev[0],
-			    "done tx %d, rx %d, intr 0x%08x/0x%x\n",
-			    tx_done, rx_done, status, mask);
+		dev_info(eth->dev,
+			 "done rx %d, intr 0x%08x/0x%x\n",
+			 rx_done, status, mask);
 	}
 
-	if (tx_again || rx_done == budget)
+	if (rx_done == budget)
 		return budget;
 
 	status = mtk_r32(eth, MTK_QMTK_INT_STATUS);
-	if (status & (tx_intr | rx_intr))
+	if (status & MTK_RX_DONE_INT)
 		return budget;
 
 	napi_complete(napi);
-	mtk_irq_enable(eth, tx_intr | rx_intr);
+	mtk_irq_enable(eth, MTK_RX_DONE_INT);
 
 	return rx_done;
 }
@@ -1195,22 +1193,43 @@ static void mtk_tx_timeout(struct net_device *dev)
 	schedule_work(&eth->pending_work);
 }
 
-static irqreturn_t mtk_handle_irq(int irq, void *_eth)
+static irqreturn_t mtk_handle_irq_rx(int irq, void *_eth)
 {
 	struct mtk_eth *eth = _eth;
 	u32 status;
 
 	status = mtk_r32(eth, MTK_QMTK_INT_STATUS);
+	status &= ~MTK_TX_DONE_INT;
+
 	if (unlikely(!status))
 		return IRQ_NONE;
 
-	if (likely(status & (MTK_RX_DONE_INT | MTK_TX_DONE_INT))) {
+	if (status & MTK_RX_DONE_INT) {
 		if (likely(napi_schedule_prep(&eth->rx_napi)))
 			__napi_schedule(&eth->rx_napi);
-	} else {
-		mtk_w32(eth, status, MTK_QMTK_INT_STATUS);
+		mtk_irq_disable(eth, MTK_RX_DONE_INT);
 	}
-	mtk_irq_disable(eth, (MTK_RX_DONE_INT | MTK_TX_DONE_INT));
+	mtk_w32(eth, status, MTK_QMTK_INT_STATUS);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mtk_handle_irq_tx(int irq, void *_eth)
+{
+	struct mtk_eth *eth = _eth;
+	u32 status;
+
+	status = mtk_r32(eth, MTK_QMTK_INT_STATUS);
+	status &= ~MTK_RX_DONE_INT;
+
+	if (unlikely(!status))
+		return IRQ_NONE;
+
+	if (status & MTK_TX_DONE_INT) {
+		tasklet_schedule(&eth->tx_clean_tasklet);
+		mtk_irq_disable(eth, MTK_TX_DONE_INT);
+	}
+	mtk_w32(eth, status, MTK_QMTK_INT_STATUS);
 
 	return IRQ_HANDLED;
 }
@@ -1223,7 +1242,7 @@ static void mtk_poll_controller(struct net_device *dev)
 	u32 int_mask = MTK_TX_DONE_INT | MTK_RX_DONE_INT;
 
 	mtk_irq_disable(eth, int_mask);
-	mtk_handle_irq(dev->irq, dev);
+	mtk_handle_irq(dev->irq[0], dev);
 	mtk_irq_enable(eth, int_mask);
 }
 #endif
@@ -1344,7 +1363,11 @@ static int __init mtk_hw_init(struct mtk_eth *eth)
 	/* Enable RX VLan Offloading */
 	mtk_w32(eth, 1, MTK_CDMP_EG_CTRL);
 
-	err = devm_request_irq(eth->dev, eth->irq, mtk_handle_irq, 0,
+	err = devm_request_irq(eth->dev, eth->irq[1], mtk_handle_irq_tx, 0,
+			       dev_name(eth->dev), eth);
+	if (err)
+		return err;
+	err = devm_request_irq(eth->dev, eth->irq[2], mtk_handle_irq_rx, 0,
 			       dev_name(eth->dev), eth);
 	if (err)
 		return err;
@@ -1360,7 +1383,11 @@ static int __init mtk_hw_init(struct mtk_eth *eth)
 	mtk_w32(eth, 0, MTK_RST_GL);
 
 	/* FE int grouping */
-	mtk_w32(eth, 0, MTK_FE_INT_GRP);
+	mtk_w32(eth, MTK_TX_DONE_INT, MTK_PDMA_INT_GRP1);
+	mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_GRP2);
+	mtk_w32(eth, MTK_TX_DONE_INT, MTK_QDMA_INT_GRP1);
+	mtk_w32(eth, MTK_RX_DONE_INT, MTK_QDMA_INT_GRP2);
+	mtk_w32(eth, 0x21021000, MTK_FE_INT_GRP);
 
 	for (i = 0; i < 2; i++) {
 		u32 val = mtk_r32(eth, MTK_GDMA_FWD_CFG(i));
@@ -1408,7 +1435,9 @@ static void mtk_uninit(struct net_device *dev)
 	phy_disconnect(mac->phy_dev);
 	mtk_mdio_cleanup(eth);
 	mtk_irq_disable(eth, ~0);
-	free_irq(dev->irq, dev);
+	free_irq(eth->irq[0], dev);
+	free_irq(eth->irq[1], dev);
+	free_irq(eth->irq[2], dev);
 }
 
 static int mtk_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
@@ -1682,10 +1711,10 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 		dev_err(eth->dev, "error bringing up device\n");
 		goto free_netdev;
 	}
-	eth->netdev[id]->irq = eth->irq;
+	eth->netdev[id]->irq = eth->irq[0];
 	netif_info(eth, probe, eth->netdev[id],
 		   "mediatek frame engine at 0x%08lx, irq %d\n",
-		   eth->netdev[id]->base_addr, eth->netdev[id]->irq);
+		   eth->netdev[id]->base_addr, eth->irq[0]);
 
 	return 0;
 
@@ -1702,6 +1731,7 @@ static int mtk_probe(struct platform_device *pdev)
 	struct mtk_soc_data *soc;
 	struct mtk_eth *eth;
 	int err;
+	int i;
 
 	match = of_match_device(of_mtk_match, &pdev->dev);
 	soc = (struct mtk_soc_data *)match->data;
@@ -1736,10 +1766,12 @@ static int mtk_probe(struct platform_device *pdev)
 		return PTR_ERR(eth->rstc);
 	}
 
-	eth->irq = platform_get_irq(pdev, 0);
-	if (eth->irq < 0) {
-		dev_err(&pdev->dev, "no IRQ resource found\n");
-		return -ENXIO;
+	for (i = 0; i < 3; i++) {
+		eth->irq[i] = platform_get_irq(pdev, i);
+		if (eth->irq[i] < 0) {
+			dev_err(&pdev->dev, "no IRQ%d resource found\n", i);
+			return -ENXIO;
+		}
 	}
 
 	eth->clk_ethif = devm_clk_get(&pdev->dev, "ethif");
@@ -1783,6 +1815,9 @@ static int mtk_probe(struct platform_device *pdev)
 	netif_napi_add(&eth->dummy_dev, &eth->rx_napi, mtk_poll,
 		       MTK_NAPI_WEIGHT);
 
+	tasklet_init(&eth->tx_clean_tasklet,
+		     mtk_clean_tx_tasklet, (unsigned long)eth);
+
 	platform_set_drvdata(pdev, eth);
 
 	return 0;
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index eed626d..4cfb40c 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -68,6 +68,10 @@
 /* Unicast Filter MAC Address Register - High */
 #define MTK_GDMA_MAC_ADRH(x)	(0x50C + (x * 0x1000))
 
+/* PDMA Interrupt grouping registers */
+#define MTK_PDMA_INT_GRP1	0xa50
+#define MTK_PDMA_INT_GRP2	0xa54
+
 /* QDMA TX Queue Configuration Registers */
 #define MTK_QTX_CFG(x)		(0x1800 + (x * 0x10))
 #define QDMA_RES_THRES		4
@@ -124,6 +128,11 @@
 #define MTK_TX_DONE_INT		(MTK_TX_DONE_INT0 | MTK_TX_DONE_INT1 | \
 				 MTK_TX_DONE_INT2 | MTK_TX_DONE_INT3)
 
+/* QDMA Interrupt grouping registers */
+#define MTK_QDMA_INT_GRP1	0x1a20
+#define MTK_QDMA_INT_GRP2	0x1a24
+#define MTK_RLS_DONE_INT	BIT(0)
+
 /* QDMA Interrupt Status Register */
 #define MTK_QDMA_INT_MASK	0x1A1C
 
@@ -374,7 +383,7 @@ struct mtk_eth {
 	struct net_device		dummy_dev;
 	struct net_device		*netdev[MTK_MAX_DEVS];
 	struct mtk_mac			*mac[MTK_MAX_DEVS];
-	int				irq;
+	int				irq[3];
 	u32				msg_enable;
 	unsigned long			sysclk;
 	struct regmap			*ethsys;
@@ -391,6 +400,7 @@ struct mtk_eth {
 	struct clk			*clk_gp2;
 	struct mii_bus			*mii_bus;
 	struct work_struct		pending_work;
+	struct tasklet_struct		tx_clean_tasklet;
 };
 
 /* struct mtk_mac -	the structure that holds the info about the MACs of the
-- 
1.7.10.4

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