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 netdev_tx_t liteeth_start_xmit(struct sk_buff *skb, 156 struct net_device *netdev) 157 { 158 struct liteeth *priv = netdev_priv(netdev); 159 void __iomem *txbuffer; 160 161 if (!litex_read8(priv->base + LITEETH_READER_READY)) { 162 if (net_ratelimit()) 163 netdev_err(netdev, "LITEETH_READER_READY not ready\n"); 164 165 netif_stop_queue(netdev); 166 167 return NETDEV_TX_BUSY; 168 } 169 170 /* Reject oversize packets */ 171 if (unlikely(skb->len > priv->slot_size)) { 172 if (net_ratelimit()) 173 netdev_err(netdev, "tx packet too big\n"); 174 175 dev_kfree_skb_any(skb); 176 netdev->stats.tx_dropped++; 177 netdev->stats.tx_errors++; 178 179 return NETDEV_TX_OK; 180 } 181 182 txbuffer = priv->tx_base + priv->tx_slot * priv->slot_size; 183 memcpy_toio(txbuffer, skb->data, skb->len); 184 litex_write8(priv->base + LITEETH_READER_SLOT, priv->tx_slot); 185 litex_write16(priv->base + LITEETH_READER_LENGTH, skb->len); 186 litex_write8(priv->base + LITEETH_READER_START, 1); 187 188 netdev->stats.tx_bytes += skb->len; 189 netdev->stats.tx_packets++; 190 191 priv->tx_slot = (priv->tx_slot + 1) % priv->num_tx_slots; 192 dev_kfree_skb_any(skb); 193 194 return NETDEV_TX_OK; 195 } 196 197 static const struct net_device_ops liteeth_netdev_ops = { 198 .ndo_open = liteeth_open, 199 .ndo_stop = liteeth_stop, 200 .ndo_start_xmit = liteeth_start_xmit, 201 }; 202 203 static void liteeth_setup_slots(struct liteeth *priv) 204 { 205 struct device_node *np = priv->dev->of_node; 206 int err; 207 208 err = of_property_read_u32(np, "litex,rx-slots", &priv->num_rx_slots); 209 if (err) { 210 dev_dbg(priv->dev, "unable to get litex,rx-slots, using 2\n"); 211 priv->num_rx_slots = 2; 212 } 213 214 err = of_property_read_u32(np, "litex,tx-slots", &priv->num_tx_slots); 215 if (err) { 216 dev_dbg(priv->dev, "unable to get litex,tx-slots, using 2\n"); 217 priv->num_tx_slots = 2; 218 } 219 220 err = of_property_read_u32(np, "litex,slot-size", &priv->slot_size); 221 if (err) { 222 dev_dbg(priv->dev, "unable to get litex,slot-size, using 0x800\n"); 223 priv->slot_size = 0x800; 224 } 225 } 226 227 static int liteeth_probe(struct platform_device *pdev) 228 { 229 struct net_device *netdev; 230 void __iomem *buf_base; 231 struct liteeth *priv; 232 int irq, err; 233 234 netdev = devm_alloc_etherdev(&pdev->dev, sizeof(*priv)); 235 if (!netdev) 236 return -ENOMEM; 237 238 SET_NETDEV_DEV(netdev, &pdev->dev); 239 platform_set_drvdata(pdev, netdev); 240 241 priv = netdev_priv(netdev); 242 priv->netdev = netdev; 243 priv->dev = &pdev->dev; 244 245 irq = platform_get_irq(pdev, 0); 246 if (irq < 0) 247 return irq; 248 netdev->irq = irq; 249 250 priv->base = devm_platform_ioremap_resource_byname(pdev, "mac"); 251 if (IS_ERR(priv->base)) 252 return PTR_ERR(priv->base); 253 254 buf_base = devm_platform_ioremap_resource_byname(pdev, "buffer"); 255 if (IS_ERR(buf_base)) 256 return PTR_ERR(buf_base); 257 258 liteeth_setup_slots(priv); 259 260 /* Rx slots */ 261 priv->rx_base = buf_base; 262 priv->rx_slot = 0; 263 264 /* Tx slots come after Rx slots */ 265 priv->tx_base = buf_base + priv->num_rx_slots * priv->slot_size; 266 priv->tx_slot = 0; 267 268 err = of_get_ethdev_address(pdev->dev.of_node, netdev); 269 if (err) 270 eth_hw_addr_random(netdev); 271 272 netdev->netdev_ops = &liteeth_netdev_ops; 273 274 err = register_netdev(netdev); 275 if (err) { 276 dev_err(&pdev->dev, "Failed to register netdev %d\n", err); 277 return err; 278 } 279 280 netdev_info(netdev, "irq %d slots: tx %d rx %d size %d\n", 281 netdev->irq, priv->num_tx_slots, priv->num_rx_slots, priv->slot_size); 282 283 return 0; 284 } 285 286 static int liteeth_remove(struct platform_device *pdev) 287 { 288 struct net_device *netdev = platform_get_drvdata(pdev); 289 290 unregister_netdev(netdev); 291 292 return 0; 293 } 294 295 static const struct of_device_id liteeth_of_match[] = { 296 { .compatible = "litex,liteeth" }, 297 { } 298 }; 299 MODULE_DEVICE_TABLE(of, liteeth_of_match); 300 301 static struct platform_driver liteeth_driver = { 302 .probe = liteeth_probe, 303 .remove = liteeth_remove, 304 .driver = { 305 .name = DRV_NAME, 306 .of_match_table = liteeth_of_match, 307 }, 308 }; 309 module_platform_driver(liteeth_driver); 310 311 MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>"); 312 MODULE_LICENSE("GPL"); 313