diff options
Diffstat (limited to 'drivers/net/ethernet/litex/litex_liteeth.c')
| -rw-r--r-- | drivers/net/ethernet/litex/litex_liteeth.c | 314 |
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"); |