--- /dev/null
+// 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 resource *res;
+ 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;
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mac");
+ priv->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "buffer");
+ buf_base = devm_ioremap_resource(&pdev->dev, res);
+ 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");
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