1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * LiteX Liteeth Ethernet 4 * 5 * Copyright 2017 Joel Stanley <joel@jms.id.au> 6 * 7 */ 8 9 #include <linux/etherdevice.h> 10 #include <linux/interrupt.h> 11 #include <linux/litex.h> 12 #include <linux/module.h> 13 #include <linux/of_net.h> 14 #include <linux/platform_device.h> 15 16 #define LITEETH_WRITER_SLOT 0x00 17 #define LITEETH_WRITER_LENGTH 0x04 18 #define LITEETH_WRITER_ERRORS 0x08 19 #define LITEETH_WRITER_EV_STATUS 0x0C 20 #define LITEETH_WRITER_EV_PENDING 0x10 21 #define LITEETH_WRITER_EV_ENABLE 0x14 22 #define LITEETH_READER_START 0x18 23 #define LITEETH_READER_READY 0x1C 24 #define LITEETH_READER_LEVEL 0x20 25 #define LITEETH_READER_SLOT 0x24 26 #define LITEETH_READER_LENGTH 0x28 27 #define LITEETH_READER_EV_STATUS 0x2C 28 #define LITEETH_READER_EV_PENDING 0x30 29 #define LITEETH_READER_EV_ENABLE 0x34 30 #define LITEETH_PREAMBLE_CRC 0x38 31 #define LITEETH_PREAMBLE_ERRORS 0x3C 32 #define LITEETH_CRC_ERRORS 0x40 33 34 #define LITEETH_PHY_CRG_RESET 0x00 35 #define LITEETH_MDIO_W 0x04 36 #define LITEETH_MDIO_R 0x0C 37 38 #define DRV_NAME "liteeth" 39 40 struct liteeth { 41 void __iomem *base; 42 struct net_device *netdev; 43 struct device *dev; 44 u32 slot_size; 45 46 /* Tx */ 47 u32 tx_slot; 48 u32 num_tx_slots; 49 void __iomem *tx_base; 50 51 /* Rx */ 52 u32 rx_slot; 53 u32 num_rx_slots; 54 void __iomem *rx_base; 55 }; 56 57 static int liteeth_rx(struct net_device *netdev) 58 { 59 struct liteeth *priv = netdev_priv(netdev); 60 struct sk_buff *skb; 61 unsigned char *data; 62 u8 rx_slot; 63 int len; 64 65 rx_slot = litex_read8(priv->base + LITEETH_WRITER_SLOT); 66 len = litex_read32(priv->base + LITEETH_WRITER_LENGTH); 67 68 if (len == 0 || len > 2048) 69 goto rx_drop; 70 71 skb = netdev_alloc_skb_ip_align(netdev, len); 72 if (!skb) { 73 netdev_err(netdev, "couldn't get memory\n"); 74 goto rx_drop; 75 } 76 77 data = skb_put(skb, len); 78 memcpy_fromio(data, priv->rx_base + rx_slot * priv->slot_size, len); 79 skb->protocol = eth_type_trans(skb, netdev); 80 81 netdev->stats.rx_packets++; 82 netdev->stats.rx_bytes += len; 83 84 return netif_rx(skb); 85 86 rx_drop: 87 netdev->stats.rx_dropped++; 88 netdev->stats.rx_errors++; 89 90 return NET_RX_DROP; 91 } 92 93 static irqreturn_t liteeth_interrupt(int irq, void *dev_id) 94 { 95 struct net_device *netdev = dev_id; 96 struct liteeth *priv = netdev_priv(netdev); 97 u8 reg; 98 99 reg = litex_read8(priv->base + LITEETH_READER_EV_PENDING); 100 if (reg) { 101 if (netif_queue_stopped(netdev)) 102 netif_wake_queue(netdev); 103 litex_write8(priv->base + LITEETH_READER_EV_PENDING, reg); 104 } 105 106 reg = litex_read8(priv->base + LITEETH_WRITER_EV_PENDING); 107 if (reg) { 108 liteeth_rx(netdev); 109 litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, reg); 110 } 111 112 return IRQ_HANDLED; 113 } 114 115 static int liteeth_open(struct net_device *netdev) 116 { 117 struct liteeth *priv = netdev_priv(netdev); 118 int err; 119 120 /* Clear pending events */ 121 litex_write8(priv->base + LITEETH_WRITER_EV_PENDING, 1); 122 litex_write8(priv->base + LITEETH_READER_EV_PENDING, 1); 123 124 err = request_irq(netdev->irq, liteeth_interrupt, 0, netdev->name, netdev); 125 if (err) { 126 netdev_err(netdev, "failed to request irq %d\n", netdev->irq); 127 return err; 128 } 129 130 /* Enable IRQs */ 131 litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 1); 132 litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 1); 133 134 netif_carrier_on(netdev); 135 netif_start_queue(netdev); 136 137 return 0; 138 } 139 140 static int liteeth_stop(struct net_device *netdev) 141 { 142 struct liteeth *priv = netdev_priv(netdev); 143 144 netif_stop_queue(netdev); 145 netif_carrier_off(netdev); 146 147 litex_write8(priv->base + LITEETH_WRITER_EV_ENABLE, 0); 148 litex_write8(priv->base + LITEETH_READER_EV_ENABLE, 0); 149 150 free_irq(netdev->irq, netdev); 151 152 return 0; 153 } 154 155 static int liteeth_start_xmit(struct sk_buff *skb, struct net_device *netdev) 156 { 157 struct liteeth *priv = netdev_priv(netdev); 158 void __iomem *txbuffer; 159 160 if (!litex_read8(priv->base + LITEETH_READER_READY)) { 161 if (net_ratelimit()) 162 netdev_err(netdev, "LITEETH_READER_READY not ready\n"); 163 164 netif_stop_queue(netdev); 165 166 return NETDEV_TX_BUSY; 167 } 168 169 /* Reject oversize packets */ 170 if (unlikely(skb->len > priv->slot_size)) { 171 if (net_ratelimit()) 172 netdev_err(netdev, "tx packet too big\n"); 173 174 dev_kfree_skb_any(skb); 175 netdev->stats.tx_dropped++; 176 netdev->stats.tx_errors++; 177 178 return NETDEV_TX_OK; 179 } 180 181 txbuffer = priv->tx_base + priv->tx_slot * priv->slot_size; 182 memcpy_toio(txbuffer, skb->data, skb->len); 183 litex_write8(priv->base + LITEETH_READER_SLOT, priv->tx_slot); 184 litex_write16(priv->base + LITEETH_READER_LENGTH, skb->len); 185 litex_write8(priv->base + LITEETH_READER_START, 1); 186 187 netdev->stats.tx_bytes += skb->len; 188 netdev->stats.tx_packets++; 189 190 priv->tx_slot = (priv->tx_slot + 1) % priv->num_tx_slots; 191 dev_kfree_skb_any(skb); 192 193 return NETDEV_TX_OK; 194 } 195 196 static const struct net_device_ops liteeth_netdev_ops = { 197 .ndo_open = liteeth_open, 198 .ndo_stop = liteeth_stop, 199 .ndo_start_xmit = liteeth_start_xmit, 200 }; 201 202 static void liteeth_setup_slots(struct liteeth *priv) 203 { 204 struct device_node *np = priv->dev->of_node; 205 int err; 206 207 err = of_property_read_u32(np, "litex,rx-slots", &priv->num_rx_slots); 208 if (err) { 209 dev_dbg(priv->dev, "unable to get litex,rx-slots, using 2\n"); 210 priv->num_rx_slots = 2; 211 } 212 213 err = of_property_read_u32(np, "litex,tx-slots", &priv->num_tx_slots); 214 if (err) { 215 dev_dbg(priv->dev, "unable to get litex,tx-slots, using 2\n"); 216 priv->num_tx_slots = 2; 217 } 218 219 err = of_property_read_u32(np, "litex,slot-size", &priv->slot_size); 220 if (err) { 221 dev_dbg(priv->dev, "unable to get litex,slot-size, using 0x800\n"); 222 priv->slot_size = 0x800; 223 } 224 } 225 226 static int liteeth_probe(struct platform_device *pdev) 227 { 228 struct net_device *netdev; 229 void __iomem *buf_base; 230 struct liteeth *priv; 231 int irq, err; 232 233 netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv)); 234 if (!netdev) 235 return -ENOMEM; 236 237 SET_NETDEV_DEV(netdev, &pdev->dev); 238 platform_set_drvdata(pdev, netdev); 239 240 priv = netdev_priv(netdev); 241 priv->netdev = netdev; 242 priv->dev = &pdev->dev; 243 244 irq = platform_get_irq(pdev, 0); 245 if (irq < 0) { 246 dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq); 247 return irq; 248 } 249 netdev->irq = irq; 250 251 priv->base = devm_platform_ioremap_resource_byname(pdev, "mac"); 252 if (IS_ERR(priv->base)) 253 return PTR_ERR(priv->base); 254 255 buf_base = devm_platform_ioremap_resource_byname(pdev, "buffer"); 256 if (IS_ERR(buf_base)) 257 return PTR_ERR(buf_base); 258 259 liteeth_setup_slots(priv); 260 261 /* Rx slots */ 262 priv->rx_base = buf_base; 263 priv->rx_slot = 0; 264 265 /* Tx slots come after Rx slots */ 266 priv->tx_base = buf_base + priv->num_rx_slots * priv->slot_size; 267 priv->tx_slot = 0; 268 269 err = of_get_mac_address(pdev->dev.of_node, netdev->dev_addr); 270 if (err) 271 eth_hw_addr_random(netdev); 272 273 netdev->netdev_ops = &liteeth_netdev_ops; 274 275 err = register_netdev(netdev); 276 if (err) { 277 dev_err(&pdev->dev, "Failed to register netdev %d\n", err); 278 return err; 279 } 280 281 netdev_info(netdev, "irq %d slots: tx %d rx %d size %d\n", 282 netdev->irq, priv->num_tx_slots, priv->num_rx_slots, priv->slot_size); 283 284 return 0; 285 } 286 287 static int liteeth_remove(struct platform_device *pdev) 288 { 289 struct net_device *netdev = platform_get_drvdata(pdev); 290 291 unregister_netdev(netdev); 292 free_netdev(netdev); 293 294 return 0; 295 } 296 297 static const struct of_device_id liteeth_of_match[] = { 298 { .compatible = "litex,liteeth" }, 299 { } 300 }; 301 MODULE_DEVICE_TABLE(of, liteeth_of_match); 302 303 static struct platform_driver liteeth_driver = { 304 .probe = liteeth_probe, 305 .remove = liteeth_remove, 306 .driver = { 307 .name = DRV_NAME, 308 .of_match_table = liteeth_of_match, 309 }, 310 }; 311 module_platform_driver(liteeth_driver); 312 313 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>"); 314 MODULE_LICENSE("GPL"); 315