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// 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 int liteeth_remove(struct platform_device *pdev)
{
struct net_device *netdev = platform_get_drvdata(pdev);
unregister_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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