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