drivers/net/ethernet/litex/litex_liteeth.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * LiteX Liteeth Ethernet
  *
  * Copyright 2017 Joel Stanley <joel@jms.id.au>
  *
  */

 #include <linux/etherdevice.h>
 #include <linux/interrupt.h>
 #include <linux/litex.h>
 #include <linux/module.h>
 #include <linux/of_net.h>
 #include <linux/platform_device.h>

 #define LITEETH_WRITER_SLOT       0x00
 #define LITEETH_WRITER_LENGTH     0x04
 #define LITEETH_WRITER_ERRORS     0x08
 #define LITEETH_WRITER_EV_STATUS  0x0C
 #define LITEETH_WRITER_EV_PENDING 0x10
 #define LITEETH_WRITER_EV_ENABLE  0x14
 #define LITEETH_READER_START      0x18
 #define LITEETH_READER_READY      0x1C
 #define LITEETH_READER_LEVEL      0x20
 #define LITEETH_READER_SLOT       0x24
 #define LITEETH_READER_LENGTH     0x28
 #define LITEETH_READER_EV_STATUS  0x2C
 #define LITEETH_READER_EV_PENDING 0x30
 #define LITEETH_READER_EV_ENABLE  0x34
 #define LITEETH_PREAMBLE_CRC      0x38
 #define LITEETH_PREAMBLE_ERRORS   0x3C
 #define LITEETH_CRC_ERRORS        0x40

 #define LITEETH_PHY_CRG_RESET     0x00
 #define LITEETH_MDIO_W            0x04
 #define LITEETH_MDIO_R            0x0C

 #define DRV_NAME	"liteeth"

 struct liteeth {
 	void __iomem *base;
 	struct net_device *netdev;
 	struct device *dev;
 	u32 slot_size;

 	/* Tx */
 	u32 tx_slot;
 	u32 num_tx_slots;
 	void __iomem *tx_base;

 	/* Rx */
 	u32 rx_slot;
 	u32 num_rx_slots;
 	void __iomem *rx_base;
 };

 static int liteeth_rx(struct net_device *netdev)
 {
 	struct liteeth *priv = netdev_priv(netdev);
 	struct sk_buff *skb;
 	unsigned char *data;
 	u8 rx_slot;
 	int len;

 	rx_slot = litex_read8(priv->base + LITEETH_WRITER_SLOT);
 	len = litex_read32(priv->base + LITEETH_WRITER_LENGTH);

 	if (len == 0 || len > 2048)
 		goto rx_drop;

 	skb = netdev_alloc_skb_ip_align(netdev, len);
 	if (!skb) {
 		netdev_err(netdev, "couldn't get memory\n");
 		goto rx_drop;
 	}

 	data = skb_put(skb, len);
 	memcpy_fromio(data, priv->rx_base + rx_slot * priv->slot_size, len);
 	skb->protocol = eth_type_trans(skb, netdev);

 	dev_sw_netstats_rx_add(netdev, len);

 	return netif_rx(skb);

 rx_drop:
 	netdev->stats.rx_dropped++;
 	netdev->stats.rx_errors++;

 	return NET_RX_DROP;
 }

 static irqreturn_t liteeth_interrupt(int irq, void *dev_id)
 {
 	struct net_device *netdev = dev_id;
 	struct liteeth *priv = netdev_priv(netdev);
 	u8 reg;

 	reg = litex_read8(priv->base + LITEETH_READER_EV_PENDING);
 	if (reg) {
 		if (netif_queue_stopped(netdev))
 			netif_wake_queue(netdev);
 		litex_write8(priv->base + LITEETH_READER_EV_PENDING, reg);
 	}

 	reg = litex_read8(priv->base + LITEETH_WRITER_EV_PENDING);
 	if (reg) {
 		liteeth_rx(netdev);
 		litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, reg);
 	}

 	return IRQ_HANDLED;
 }

 static int liteeth_open(struct net_device *netdev)
 {
 	struct liteeth *priv = netdev_priv(netdev);
 	int err;

 	/* Clear pending events */
 	litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, 1);
 	litex_write8(priv->base + LITEETH_READER_EV_PENDING, 1);

 	err = request_irq(netdev->irq, liteeth_interrupt, 0, netdev->name, netdev);
 	if (err) {
 		netdev_err(netdev, "failed to request irq %d\n", netdev->irq);
 		return err;
 	}

 	/* Enable IRQs */
 	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 1);
 	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 1);

 	netif_carrier_on(netdev);
 	netif_start_queue(netdev);

 	return 0;
 }

 static int liteeth_stop(struct net_device *netdev)
 {
 	struct liteeth *priv = netdev_priv(netdev);

 	netif_stop_queue(netdev);
 	netif_carrier_off(netdev);

 	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 0);
 	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 0);

 	free_irq(netdev->irq, netdev);

 	return 0;
 }

 static netdev_tx_t liteeth_start_xmit(struct sk_buff *skb,
 				      struct net_device *netdev)
 {
 	struct liteeth *priv = netdev_priv(netdev);
 	void __iomem *txbuffer;

 	if (!litex_read8(priv->base + LITEETH_READER_READY)) {
 		if (net_ratelimit())
 			netdev_err(netdev, "LITEETH_READER_READY not ready\n");

 		netif_stop_queue(netdev);

 		return NETDEV_TX_BUSY;
 	}

 	/* Reject oversize packets */
 	if (unlikely(skb->len > priv->slot_size)) {
 		if (net_ratelimit())
 			netdev_err(netdev, "tx packet too big\n");

 		dev_kfree_skb_any(skb);
 		netdev->stats.tx_dropped++;
 		netdev->stats.tx_errors++;

 		return NETDEV_TX_OK;
 	}

 	txbuffer = priv->tx_base + priv->tx_slot * priv->slot_size;
 	memcpy_toio(txbuffer, skb->data, skb->len);
 	litex_write8(priv->base + LITEETH_READER_SLOT, priv->tx_slot);
 	litex_write16(priv->base + LITEETH_READER_LENGTH, skb->len);
 	litex_write8(priv->base + LITEETH_READER_START, 1);

 	dev_sw_netstats_tx_add(netdev, 1, skb->len);

 	priv->tx_slot = (priv->tx_slot + 1) % priv->num_tx_slots;
 	dev_kfree_skb_any(skb);

 	return NETDEV_TX_OK;
 }

 static void
 liteeth_get_stats64(struct net_device *netdev, struct rtnl_link_stats64 *stats)
 {
 	netdev_stats_to_stats64(stats, &netdev->stats);
 	dev_fetch_sw_netstats(stats, netdev->tstats);
 }

 static const struct net_device_ops liteeth_netdev_ops = {
 	.ndo_open		= liteeth_open,
 	.ndo_stop		= liteeth_stop,
 	.ndo_get_stats64	= liteeth_get_stats64,
 	.ndo_start_xmit         = liteeth_start_xmit,
 };

 static void liteeth_setup_slots(struct liteeth *priv)
 {
 	struct device_node *np = priv->dev->of_node;
 	int err;

 	err = of_property_read_u32(np, "litex,rx-slots", &priv->num_rx_slots);
 	if (err) {
 		dev_dbg(priv->dev, "unable to get litex,rx-slots, using 2\n");
 		priv->num_rx_slots = 2;
 	}

 	err = of_property_read_u32(np, "litex,tx-slots", &priv->num_tx_slots);
 	if (err) {
 		dev_dbg(priv->dev, "unable to get litex,tx-slots, using 2\n");
 		priv->num_tx_slots = 2;
 	}

 	err = of_property_read_u32(np, "litex,slot-size", &priv->slot_size);
 	if (err) {
 		dev_dbg(priv->dev, "unable to get litex,slot-size, using 0x800\n");
 		priv->slot_size = 0x800;
 	}
 }

 static int liteeth_probe(struct platform_device *pdev)
 {
 	struct net_device *netdev;
 	void __iomem *buf_base;
 	struct liteeth *priv;
 	int irq, err;

 	netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv));
 	if (!netdev)
 		return -ENOMEM;

 	SET_NETDEV_DEV(netdev, &pdev->dev);
 	platform_set_drvdata(pdev, netdev);

 	priv = netdev_priv(netdev);
 	priv->netdev = netdev;
 	priv->dev = &pdev->dev;

 	netdev->tstats = devm_netdev_alloc_pcpu_stats(&pdev->dev,
 						      struct pcpu_sw_netstats);
 	if (!netdev->tstats)
 		return -ENOMEM;

 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return irq;
 	netdev->irq = irq;

 	priv->base = devm_platform_ioremap_resource_byname(pdev, "mac");
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);

 	buf_base = devm_platform_ioremap_resource_byname(pdev, "buffer");
 	if (IS_ERR(buf_base))
 		return PTR_ERR(buf_base);

 	liteeth_setup_slots(priv);

 	/* Rx slots */
 	priv->rx_base = buf_base;
 	priv->rx_slot = 0;

 	/* Tx slots come after Rx slots */
 	priv->tx_base = buf_base + priv->num_rx_slots * priv->slot_size;
 	priv->tx_slot = 0;

 	err = of_get_ethdev_address(pdev->dev.of_node, netdev);
 	if (err)
 		eth_hw_addr_random(netdev);

 	netdev->netdev_ops = &liteeth_netdev_ops;

 	err = register_netdev(netdev);
 	if (err) {
 		dev_err(&pdev->dev, "Failed to register netdev %d\n", err);
 		return err;
 	}

 	netdev_info(netdev, "irq %d slots: tx %d rx %d size %d\n",
 		    netdev->irq, priv->num_tx_slots, priv->num_rx_slots, priv->slot_size);

 	return 0;
 }

 static void liteeth_remove(struct platform_device *pdev)
 {
 	struct net_device *netdev = platform_get_drvdata(pdev);

 	unregister_netdev(netdev);
 }

 static const struct of_device_id liteeth_of_match[] = {
 	{ .compatible = "litex,liteeth" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, liteeth_of_match);

 static struct platform_driver liteeth_driver = {
 	.probe = liteeth_probe,
 	.remove_new = liteeth_remove,
 	.driver = {
 		.name = DRV_NAME,
 		.of_match_table = liteeth_of_match,
 	},
 };
 module_platform_driver(liteeth_driver);

 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
 MODULE_DESCRIPTION("LiteX Liteeth Ethernet driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* LiteX Liteeth Ethernet
	*
	* Copyright 2017 Joel Stanley <joel@jms.id.au>
	*
	*/

	#include <linux/etherdevice.h>
	#include <linux/interrupt.h>
	#include <linux/litex.h>
	#include <linux/module.h>
	#include <linux/of_net.h>
	#include <linux/platform_device.h>

	#define LITEETH_WRITER_SLOT 0x00
	#define LITEETH_WRITER_LENGTH 0x04
	#define LITEETH_WRITER_ERRORS 0x08
	#define LITEETH_WRITER_EV_STATUS 0x0C
	#define LITEETH_WRITER_EV_PENDING 0x10
	#define LITEETH_WRITER_EV_ENABLE 0x14
	#define LITEETH_READER_START 0x18
	#define LITEETH_READER_READY 0x1C
	#define LITEETH_READER_LEVEL 0x20
	#define LITEETH_READER_SLOT 0x24
	#define LITEETH_READER_LENGTH 0x28
	#define LITEETH_READER_EV_STATUS 0x2C
	#define LITEETH_READER_EV_PENDING 0x30
	#define LITEETH_READER_EV_ENABLE 0x34
	#define LITEETH_PREAMBLE_CRC 0x38
	#define LITEETH_PREAMBLE_ERRORS 0x3C
	#define LITEETH_CRC_ERRORS 0x40

	#define LITEETH_PHY_CRG_RESET 0x00
	#define LITEETH_MDIO_W 0x04
	#define LITEETH_MDIO_R 0x0C

	#define DRV_NAME "liteeth"

	struct liteeth {
	void __iomem *base;
	struct net_device *netdev;
	struct device *dev;
	u32 slot_size;

	/* Tx */
	u32 tx_slot;
	u32 num_tx_slots;
	void __iomem *tx_base;

	/* Rx */
	u32 rx_slot;
	u32 num_rx_slots;
	void __iomem *rx_base;
	};

	static int liteeth_rx(struct net_device *netdev)
	{
	struct liteeth *priv = netdev_priv(netdev);
	struct sk_buff *skb;
	unsigned char *data;
	u8 rx_slot;
	int len;

	rx_slot = litex_read8(priv->base + LITEETH_WRITER_SLOT);
	len = litex_read32(priv->base + LITEETH_WRITER_LENGTH);

	if (len == 0 \|\| len > 2048)
	goto rx_drop;

	skb = netdev_alloc_skb_ip_align(netdev, len);
	if (!skb) {
	netdev_err(netdev, "couldn't get memory\n");
	goto rx_drop;
	}

	data = skb_put(skb, len);
	memcpy_fromio(data, priv->rx_base + rx_slot * priv->slot_size, len);
	skb->protocol = eth_type_trans(skb, netdev);

	dev_sw_netstats_rx_add(netdev, len);

	return netif_rx(skb);

	rx_drop:
	netdev->stats.rx_dropped++;
	netdev->stats.rx_errors++;

	return NET_RX_DROP;
	}

	static irqreturn_t liteeth_interrupt(int irq, void *dev_id)
	{
	struct net_device *netdev = dev_id;
	struct liteeth *priv = netdev_priv(netdev);
	u8 reg;

	reg = litex_read8(priv->base + LITEETH_READER_EV_PENDING);
	if (reg) {
	if (netif_queue_stopped(netdev))
	netif_wake_queue(netdev);
	litex_write8(priv->base + LITEETH_READER_EV_PENDING, reg);
	}

	reg = litex_read8(priv->base + LITEETH_WRITER_EV_PENDING);
	if (reg) {
	liteeth_rx(netdev);
	litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, reg);
	}

	return IRQ_HANDLED;
	}

	static int liteeth_open(struct net_device *netdev)
	{
	struct liteeth *priv = netdev_priv(netdev);
	int err;

	/* Clear pending events */
	litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, 1);
	litex_write8(priv->base + LITEETH_READER_EV_PENDING, 1);

	err = request_irq(netdev->irq, liteeth_interrupt, 0, netdev->name, netdev);
	if (err) {
	netdev_err(netdev, "failed to request irq %d\n", netdev->irq);
	return err;
	}

	/* Enable IRQs */
	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 1);
	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 1);

	netif_carrier_on(netdev);
	netif_start_queue(netdev);

	return 0;
	}

	static int liteeth_stop(struct net_device *netdev)
	{
	struct liteeth *priv = netdev_priv(netdev);

	netif_stop_queue(netdev);
	netif_carrier_off(netdev);

	litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 0);
	litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 0);

	free_irq(netdev->irq, netdev);

	return 0;
	}

	static netdev_tx_t liteeth_start_xmit(struct sk_buff *skb,
	struct net_device *netdev)
	{
	struct liteeth *priv = netdev_priv(netdev);
	void __iomem *txbuffer;

	if (!litex_read8(priv->base + LITEETH_READER_READY)) {
	if (net_ratelimit())
	netdev_err(netdev, "LITEETH_READER_READY not ready\n");

	netif_stop_queue(netdev);

	return NETDEV_TX_BUSY;
	}

	/* Reject oversize packets */
	if (unlikely(skb->len > priv->slot_size)) {
	if (net_ratelimit())
	netdev_err(netdev, "tx packet too big\n");

	dev_kfree_skb_any(skb);
	netdev->stats.tx_dropped++;
	netdev->stats.tx_errors++;

	return NETDEV_TX_OK;
	}

	txbuffer = priv->tx_base + priv->tx_slot * priv->slot_size;
	memcpy_toio(txbuffer, skb->data, skb->len);
	litex_write8(priv->base + LITEETH_READER_SLOT, priv->tx_slot);
	litex_write16(priv->base + LITEETH_READER_LENGTH, skb->len);
	litex_write8(priv->base + LITEETH_READER_START, 1);

	dev_sw_netstats_tx_add(netdev, 1, skb->len);

	priv->tx_slot = (priv->tx_slot + 1) % priv->num_tx_slots;
	dev_kfree_skb_any(skb);

	return NETDEV_TX_OK;
	}

	static void
	liteeth_get_stats64(struct net_device netdev, struct rtnl_link_stats64 stats)
	{
	netdev_stats_to_stats64(stats, &netdev->stats);
	dev_fetch_sw_netstats(stats, netdev->tstats);
	}

	static const struct net_device_ops liteeth_netdev_ops = {
	.ndo_open = liteeth_open,
	.ndo_stop = liteeth_stop,
	.ndo_get_stats64 = liteeth_get_stats64,
	.ndo_start_xmit = liteeth_start_xmit,
	};

	static void liteeth_setup_slots(struct liteeth *priv)
	{
	struct device_node *np = priv->dev->of_node;
	int err;

	err = of_property_read_u32(np, "litex,rx-slots", &priv->num_rx_slots);
	if (err) {
	dev_dbg(priv->dev, "unable to get litex,rx-slots, using 2\n");
	priv->num_rx_slots = 2;
	}

	err = of_property_read_u32(np, "litex,tx-slots", &priv->num_tx_slots);
	if (err) {
	dev_dbg(priv->dev, "unable to get litex,tx-slots, using 2\n");
	priv->num_tx_slots = 2;
	}

	err = of_property_read_u32(np, "litex,slot-size", &priv->slot_size);
	if (err) {
	dev_dbg(priv->dev, "unable to get litex,slot-size, using 0x800\n");
	priv->slot_size = 0x800;
	}
	}

	static int liteeth_probe(struct platform_device *pdev)
	{
	struct net_device *netdev;
	void __iomem *buf_base;
	struct liteeth *priv;
	int irq, err;

	netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv));
	if (!netdev)
	return -ENOMEM;

	SET_NETDEV_DEV(netdev, &pdev->dev);
	platform_set_drvdata(pdev, netdev);

	priv = netdev_priv(netdev);
	priv->netdev = netdev;
	priv->dev = &pdev->dev;

	netdev->tstats = devm_netdev_alloc_pcpu_stats(&pdev->dev,
	struct pcpu_sw_netstats);
	if (!netdev->tstats)
	return -ENOMEM;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
	return irq;
	netdev->irq = irq;

	priv->base = devm_platform_ioremap_resource_byname(pdev, "mac");
	if (IS_ERR(priv->base))
	return PTR_ERR(priv->base);

	buf_base = devm_platform_ioremap_resource_byname(pdev, "buffer");
	if (IS_ERR(buf_base))
	return PTR_ERR(buf_base);

	liteeth_setup_slots(priv);

	/* Rx slots */
	priv->rx_base = buf_base;
	priv->rx_slot = 0;

	/* Tx slots come after Rx slots */
	priv->tx_base = buf_base + priv->num_rx_slots * priv->slot_size;
	priv->tx_slot = 0;

	err = of_get_ethdev_address(pdev->dev.of_node, netdev);
	if (err)
	eth_hw_addr_random(netdev);

	netdev->netdev_ops = &liteeth_netdev_ops;

	err = register_netdev(netdev);
	if (err) {
	dev_err(&pdev->dev, "Failed to register netdev %d\n", err);
	return err;
	}

	netdev_info(netdev, "irq %d slots: tx %d rx %d size %d\n",
	netdev->irq, priv->num_tx_slots, priv->num_rx_slots, priv->slot_size);

	return 0;
	}

	static void liteeth_remove(struct platform_device *pdev)
	{
	struct net_device *netdev = platform_get_drvdata(pdev);

	unregister_netdev(netdev);
	}

	static const struct of_device_id liteeth_of_match[] = {
	{ .compatible = "litex,liteeth" },
	{ }
	};
	MODULE_DEVICE_TABLE(of, liteeth_of_match);

	static struct platform_driver liteeth_driver = {
	.probe = liteeth_probe,
	.remove_new = liteeth_remove,
	.driver = {
	.name = DRV_NAME,
	.of_match_table = liteeth_of_match,
	},
	};
	module_platform_driver(liteeth_driver);

	MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
	MODULE_DESCRIPTION("LiteX Liteeth Ethernet driver");
	MODULE_LICENSE("GPL");