1 files changed, 314 insertions, 0 deletions

diff --git a/drivers/net/ethernet/litex/litex_liteeth.c b/drivers/net/ethernet/litex/litex_liteeth.c
new file mode 100644
index 000000000000..a9bdbf0dcfe1
--- /dev/null
+++ b/drivers/net/ethernet/litex/litex_liteeth.c
@@ -0,0 +1,314 @@
+// 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);
+
+	netdev->stats.rx_packets++;
+	netdev->stats.rx_bytes += 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 int 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);
+
+	netdev->stats.tx_bytes += skb->len;
+	netdev->stats.tx_packets++;
+
+	priv->tx_slot = (priv->tx_slot + 1) % priv->num_tx_slots;
+	dev_kfree_skb_any(skb);
+
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops liteeth_netdev_ops = {
+	.ndo_open		= liteeth_open,
+	.ndo_stop		= liteeth_stop,
+	.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;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq);
+		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_mac_address(pdev->dev.of_node, netdev->dev_addr);
+	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 int liteeth_remove(struct platform_device *pdev)
+{
+	struct net_device *netdev = platform_get_drvdata(pdev);
+
+	unregister_netdev(netdev);
+	free_netdev(netdev);
+
+	return 0;
+}
+
+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 = 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_LICENSE("GPL");