1 // SPDX-License-Identifier: GPL-2.0-only 2 /* drivers/net/ethernet/micrel/ks8851.c 3 * 4 * Copyright 2009 Simtec Electronics 5 * http://www.simtec.co.uk/ 6 * Ben Dooks <ben@simtec.co.uk> 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #define DEBUG 12 13 #include <linux/interrupt.h> 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <linux/netdevice.h> 17 #include <linux/etherdevice.h> 18 #include <linux/ethtool.h> 19 #include <linux/iopoll.h> 20 #include <linux/mii.h> 21 22 #include <linux/platform_device.h> 23 #include <linux/of_net.h> 24 25 #include "ks8851.h" 26 27 static int msg_enable; 28 29 #define BE3 0x8000 /* Byte Enable 3 */ 30 #define BE2 0x4000 /* Byte Enable 2 */ 31 #define BE1 0x2000 /* Byte Enable 1 */ 32 #define BE0 0x1000 /* Byte Enable 0 */ 33 34 /** 35 * struct ks8851_net_par - KS8851 Parallel driver private data 36 * @ks8851: KS8851 driver common private data 37 * @lock: Lock to ensure that the device is not accessed when busy. 38 * @hw_addr : start address of data register. 39 * @hw_addr_cmd : start address of command register. 40 * @cmd_reg_cache : command register cached. 41 * 42 * The @lock ensures that the chip is protected when certain operations are 43 * in progress. When the read or write packet transfer is in progress, most 44 * of the chip registers are not accessible until the transfer is finished 45 * and the DMA has been de-asserted. 46 */ 47 struct ks8851_net_par { 48 struct ks8851_net ks8851; 49 spinlock_t lock; 50 void __iomem *hw_addr; 51 void __iomem *hw_addr_cmd; 52 u16 cmd_reg_cache; 53 }; 54 55 #define to_ks8851_par(ks) container_of((ks), struct ks8851_net_par, ks8851) 56 57 /** 58 * ks8851_lock_par - register access lock 59 * @ks: The chip state 60 * @flags: Spinlock flags 61 * 62 * Claim chip register access lock 63 */ 64 static void ks8851_lock_par(struct ks8851_net *ks, unsigned long *flags) 65 { 66 struct ks8851_net_par *ksp = to_ks8851_par(ks); 67 68 spin_lock_irqsave(&ksp->lock, *flags); 69 } 70 71 /** 72 * ks8851_unlock_par - register access unlock 73 * @ks: The chip state 74 * @flags: Spinlock flags 75 * 76 * Release chip register access lock 77 */ 78 static void ks8851_unlock_par(struct ks8851_net *ks, unsigned long *flags) 79 { 80 struct ks8851_net_par *ksp = to_ks8851_par(ks); 81 82 spin_unlock_irqrestore(&ksp->lock, *flags); 83 } 84 85 /** 86 * ks_check_endian - Check whether endianness of the bus is correct 87 * @ks : The chip information 88 * 89 * The KS8851-16MLL EESK pin allows selecting the endianness of the 16bit 90 * bus. To maintain optimum performance, the bus endianness should be set 91 * such that it matches the endianness of the CPU. 92 */ 93 static int ks_check_endian(struct ks8851_net *ks) 94 { 95 struct ks8851_net_par *ksp = to_ks8851_par(ks); 96 u16 cider; 97 98 /* 99 * Read CIDER register first, however read it the "wrong" way around. 100 * If the endian strap on the KS8851-16MLL in incorrect and the chip 101 * is operating in different endianness than the CPU, then the meaning 102 * of BE[3:0] byte-enable bits is also swapped such that: 103 * BE[3,2,1,0] becomes BE[1,0,3,2] 104 * 105 * Luckily for us, the byte-enable bits are the top four MSbits of 106 * the address register and the CIDER register is at offset 0xc0. 107 * Hence, by reading address 0xc0c0, which is not impacted by endian 108 * swapping, we assert either BE[3:2] or BE[1:0] while reading the 109 * CIDER register. 110 * 111 * If the bus configuration is correct, reading 0xc0c0 asserts 112 * BE[3:2] and this read returns 0x0000, because to read register 113 * with bottom two LSbits of address set to 0, BE[1:0] must be 114 * asserted. 115 * 116 * If the bus configuration is NOT correct, reading 0xc0c0 asserts 117 * BE[1:0] and this read returns non-zero 0x8872 value. 118 */ 119 iowrite16(BE3 | BE2 | KS_CIDER, ksp->hw_addr_cmd); 120 cider = ioread16(ksp->hw_addr); 121 if (!cider) 122 return 0; 123 124 netdev_err(ks->netdev, "incorrect EESK endian strap setting\n"); 125 126 return -EINVAL; 127 } 128 129 /** 130 * ks8851_wrreg16_par - write 16bit register value to chip 131 * @ks: The chip state 132 * @reg: The register address 133 * @val: The value to write 134 * 135 * Issue a write to put the value @val into the register specified in @reg. 136 */ 137 static void ks8851_wrreg16_par(struct ks8851_net *ks, unsigned int reg, 138 unsigned int val) 139 { 140 struct ks8851_net_par *ksp = to_ks8851_par(ks); 141 142 ksp->cmd_reg_cache = (u16)reg | ((BE1 | BE0) << (reg & 0x02)); 143 iowrite16(ksp->cmd_reg_cache, ksp->hw_addr_cmd); 144 iowrite16(val, ksp->hw_addr); 145 } 146 147 /** 148 * ks8851_rdreg16_par - read 16 bit register from chip 149 * @ks: The chip information 150 * @reg: The register address 151 * 152 * Read a 16bit register from the chip, returning the result 153 */ 154 static unsigned int ks8851_rdreg16_par(struct ks8851_net *ks, unsigned int reg) 155 { 156 struct ks8851_net_par *ksp = to_ks8851_par(ks); 157 158 ksp->cmd_reg_cache = (u16)reg | ((BE1 | BE0) << (reg & 0x02)); 159 iowrite16(ksp->cmd_reg_cache, ksp->hw_addr_cmd); 160 return ioread16(ksp->hw_addr); 161 } 162 163 /** 164 * ks8851_rdfifo_par - read data from the receive fifo 165 * @ks: The device state. 166 * @buff: The buffer address 167 * @len: The length of the data to read 168 * 169 * Issue an RXQ FIFO read command and read the @len amount of data from 170 * the FIFO into the buffer specified by @buff. 171 */ 172 static void ks8851_rdfifo_par(struct ks8851_net *ks, u8 *buff, unsigned int len) 173 { 174 struct ks8851_net_par *ksp = to_ks8851_par(ks); 175 176 netif_dbg(ks, rx_status, ks->netdev, 177 "%s: %d@%p\n", __func__, len, buff); 178 179 ioread16_rep(ksp->hw_addr, (u16 *)buff + 1, len / 2); 180 } 181 182 /** 183 * ks8851_wrfifo_par - write packet to TX FIFO 184 * @ks: The device state. 185 * @txp: The sk_buff to transmit. 186 * @irq: IRQ on completion of the packet. 187 * 188 * Send the @txp to the chip. This means creating the relevant packet header 189 * specifying the length of the packet and the other information the chip 190 * needs, such as IRQ on completion. Send the header and the packet data to 191 * the device. 192 */ 193 static void ks8851_wrfifo_par(struct ks8851_net *ks, struct sk_buff *txp, 194 bool irq) 195 { 196 struct ks8851_net_par *ksp = to_ks8851_par(ks); 197 unsigned int len = ALIGN(txp->len, 4); 198 unsigned int fid = 0; 199 200 netif_dbg(ks, tx_queued, ks->netdev, "%s: skb %p, %d@%p, irq %d\n", 201 __func__, txp, txp->len, txp->data, irq); 202 203 fid = ks->fid++; 204 fid &= TXFR_TXFID_MASK; 205 206 if (irq) 207 fid |= TXFR_TXIC; /* irq on completion */ 208 209 iowrite16(fid, ksp->hw_addr); 210 iowrite16(txp->len, ksp->hw_addr); 211 212 iowrite16_rep(ksp->hw_addr, txp->data, len / 2); 213 } 214 215 /** 216 * ks8851_rx_skb_par - receive skbuff 217 * @ks: The device state. 218 * @skb: The skbuff 219 */ 220 static void ks8851_rx_skb_par(struct ks8851_net *ks, struct sk_buff *skb) 221 { 222 netif_rx(skb); 223 } 224 225 static unsigned int ks8851_rdreg16_par_txqcr(struct ks8851_net *ks) 226 { 227 return ks8851_rdreg16_par(ks, KS_TXQCR); 228 } 229 230 /** 231 * ks8851_start_xmit_par - transmit packet 232 * @skb: The buffer to transmit 233 * @dev: The device used to transmit the packet. 234 * 235 * Called by the network layer to transmit the @skb. Queue the packet for 236 * the device and schedule the necessary work to transmit the packet when 237 * it is free. 238 * 239 * We do this to firstly avoid sleeping with the network device locked, 240 * and secondly so we can round up more than one packet to transmit which 241 * means we can try and avoid generating too many transmit done interrupts. 242 */ 243 static netdev_tx_t ks8851_start_xmit_par(struct sk_buff *skb, 244 struct net_device *dev) 245 { 246 struct ks8851_net *ks = netdev_priv(dev); 247 netdev_tx_t ret = NETDEV_TX_OK; 248 unsigned long flags; 249 unsigned int txqcr; 250 u16 txmir; 251 int err; 252 253 netif_dbg(ks, tx_queued, ks->netdev, 254 "%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data); 255 256 ks8851_lock_par(ks, &flags); 257 258 txmir = ks8851_rdreg16_par(ks, KS_TXMIR) & 0x1fff; 259 260 if (likely(txmir >= skb->len + 12)) { 261 ks8851_wrreg16_par(ks, KS_RXQCR, ks->rc_rxqcr | RXQCR_SDA); 262 ks8851_wrfifo_par(ks, skb, false); 263 ks8851_wrreg16_par(ks, KS_RXQCR, ks->rc_rxqcr); 264 ks8851_wrreg16_par(ks, KS_TXQCR, TXQCR_METFE); 265 266 err = readx_poll_timeout_atomic(ks8851_rdreg16_par_txqcr, ks, 267 txqcr, !(txqcr & TXQCR_METFE), 268 5, 1000000); 269 if (err) 270 ret = NETDEV_TX_BUSY; 271 272 ks8851_done_tx(ks, skb); 273 } else { 274 ret = NETDEV_TX_BUSY; 275 } 276 277 ks8851_unlock_par(ks, &flags); 278 279 return ret; 280 } 281 282 static int ks8851_probe_par(struct platform_device *pdev) 283 { 284 struct device *dev = &pdev->dev; 285 struct ks8851_net_par *ksp; 286 struct net_device *netdev; 287 struct ks8851_net *ks; 288 int ret; 289 290 netdev = devm_alloc_etherdev(dev, sizeof(struct ks8851_net_par)); 291 if (!netdev) 292 return -ENOMEM; 293 294 ks = netdev_priv(netdev); 295 296 ks->lock = ks8851_lock_par; 297 ks->unlock = ks8851_unlock_par; 298 ks->rdreg16 = ks8851_rdreg16_par; 299 ks->wrreg16 = ks8851_wrreg16_par; 300 ks->rdfifo = ks8851_rdfifo_par; 301 ks->wrfifo = ks8851_wrfifo_par; 302 ks->start_xmit = ks8851_start_xmit_par; 303 ks->rx_skb = ks8851_rx_skb_par; 304 305 #define STD_IRQ (IRQ_LCI | /* Link Change */ \ 306 IRQ_RXI | /* RX done */ \ 307 IRQ_RXPSI) /* RX process stop */ 308 ks->rc_ier = STD_IRQ; 309 310 ksp = to_ks8851_par(ks); 311 spin_lock_init(&ksp->lock); 312 313 ksp->hw_addr = devm_platform_ioremap_resource(pdev, 0); 314 if (IS_ERR(ksp->hw_addr)) 315 return PTR_ERR(ksp->hw_addr); 316 317 ksp->hw_addr_cmd = devm_platform_ioremap_resource(pdev, 1); 318 if (IS_ERR(ksp->hw_addr_cmd)) 319 return PTR_ERR(ksp->hw_addr_cmd); 320 321 ret = ks_check_endian(ks); 322 if (ret) 323 return ret; 324 325 netdev->irq = platform_get_irq(pdev, 0); 326 327 return ks8851_probe_common(netdev, dev, msg_enable); 328 } 329 330 static int ks8851_remove_par(struct platform_device *pdev) 331 { 332 return ks8851_remove_common(&pdev->dev); 333 } 334 335 static const struct of_device_id ks8851_match_table[] = { 336 { .compatible = "micrel,ks8851-mll" }, 337 { } 338 }; 339 MODULE_DEVICE_TABLE(of, ks8851_match_table); 340 341 static struct platform_driver ks8851_driver = { 342 .driver = { 343 .name = "ks8851", 344 .of_match_table = ks8851_match_table, 345 .pm = &ks8851_pm_ops, 346 }, 347 .probe = ks8851_probe_par, 348 .remove = ks8851_remove_par, 349 }; 350 module_platform_driver(ks8851_driver); 351 352 MODULE_DESCRIPTION("KS8851 Network driver"); 353 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 354 MODULE_LICENSE("GPL"); 355 356 module_param_named(message, msg_enable, int, 0); 357 MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)"); 358