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/cache.h> 18 #include <linux/crc32.h> 19 #include <linux/mii.h> 20 #include <linux/regulator/consumer.h> 21 22 #include <linux/spi/spi.h> 23 #include <linux/gpio.h> 24 #include <linux/of_gpio.h> 25 #include <linux/of_net.h> 26 27 #include "ks8851.h" 28 29 static int msg_enable; 30 31 /** 32 * struct ks8851_net_spi - KS8851 SPI driver private data 33 * @lock: Lock to ensure that the device is not accessed when busy. 34 * @tx_work: Work queue for tx packets 35 * @ks8851: KS8851 driver common private data 36 * @spidev: The spi device we're bound to. 37 * @spi_msg1: pre-setup SPI transfer with one message, @spi_xfer1. 38 * @spi_msg2: pre-setup SPI transfer with two messages, @spi_xfer2. 39 * @spi_xfer1: @spi_msg1 SPI transfer structure 40 * @spi_xfer2: @spi_msg2 SPI transfer structure 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 ccessible until the transfer is finished and 45 * the DMA has been de-asserted. 46 */ 47 struct ks8851_net_spi { 48 struct ks8851_net ks8851; 49 struct mutex lock; 50 struct work_struct tx_work; 51 struct spi_device *spidev; 52 struct spi_message spi_msg1; 53 struct spi_message spi_msg2; 54 struct spi_transfer spi_xfer1; 55 struct spi_transfer spi_xfer2[2]; 56 }; 57 58 #define to_ks8851_spi(ks) container_of((ks), struct ks8851_net_spi, ks8851) 59 60 /* SPI frame opcodes */ 61 #define KS_SPIOP_RD 0x00 62 #define KS_SPIOP_WR 0x40 63 #define KS_SPIOP_RXFIFO 0x80 64 #define KS_SPIOP_TXFIFO 0xC0 65 66 /* shift for byte-enable data */ 67 #define BYTE_EN(_x) ((_x) << 2) 68 69 /* turn register number and byte-enable mask into data for start of packet */ 70 #define MK_OP(_byteen, _reg) \ 71 (BYTE_EN(_byteen) | (_reg) << (8 + 2) | (_reg) >> 6) 72 73 /** 74 * ks8851_lock_spi - register access lock 75 * @ks: The chip state 76 * @flags: Spinlock flags 77 * 78 * Claim chip register access lock 79 */ 80 static void ks8851_lock_spi(struct ks8851_net *ks, unsigned long *flags) 81 { 82 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 83 84 mutex_lock(&kss->lock); 85 } 86 87 /** 88 * ks8851_unlock_spi - register access unlock 89 * @ks: The chip state 90 * @flags: Spinlock flags 91 * 92 * Release chip register access lock 93 */ 94 static void ks8851_unlock_spi(struct ks8851_net *ks, unsigned long *flags) 95 { 96 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 97 98 mutex_unlock(&kss->lock); 99 } 100 101 /* SPI register read/write calls. 102 * 103 * All these calls issue SPI transactions to access the chip's registers. They 104 * all require that the necessary lock is held to prevent accesses when the 105 * chip is busy transferring packet data (RX/TX FIFO accesses). 106 */ 107 108 /** 109 * ks8851_wrreg16_spi - write 16bit register value to chip via SPI 110 * @ks: The chip state 111 * @reg: The register address 112 * @val: The value to write 113 * 114 * Issue a write to put the value @val into the register specified in @reg. 115 */ 116 static void ks8851_wrreg16_spi(struct ks8851_net *ks, unsigned int reg, 117 unsigned int val) 118 { 119 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 120 struct spi_transfer *xfer = &kss->spi_xfer1; 121 struct spi_message *msg = &kss->spi_msg1; 122 __le16 txb[2]; 123 int ret; 124 125 txb[0] = cpu_to_le16(MK_OP(reg & 2 ? 0xC : 0x03, reg) | KS_SPIOP_WR); 126 txb[1] = cpu_to_le16(val); 127 128 xfer->tx_buf = txb; 129 xfer->rx_buf = NULL; 130 xfer->len = 4; 131 132 ret = spi_sync(kss->spidev, msg); 133 if (ret < 0) 134 netdev_err(ks->netdev, "spi_sync() failed\n"); 135 } 136 137 /** 138 * ks8851_rdreg - issue read register command and return the data 139 * @ks: The device state 140 * @op: The register address and byte enables in message format. 141 * @rxb: The RX buffer to return the result into 142 * @rxl: The length of data expected. 143 * 144 * This is the low level read call that issues the necessary spi message(s) 145 * to read data from the register specified in @op. 146 */ 147 static void ks8851_rdreg(struct ks8851_net *ks, unsigned int op, 148 u8 *rxb, unsigned int rxl) 149 { 150 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 151 struct spi_transfer *xfer; 152 struct spi_message *msg; 153 __le16 *txb = (__le16 *)ks->txd; 154 u8 *trx = ks->rxd; 155 int ret; 156 157 txb[0] = cpu_to_le16(op | KS_SPIOP_RD); 158 159 if (kss->spidev->master->flags & SPI_MASTER_HALF_DUPLEX) { 160 msg = &kss->spi_msg2; 161 xfer = kss->spi_xfer2; 162 163 xfer->tx_buf = txb; 164 xfer->rx_buf = NULL; 165 xfer->len = 2; 166 167 xfer++; 168 xfer->tx_buf = NULL; 169 xfer->rx_buf = trx; 170 xfer->len = rxl; 171 } else { 172 msg = &kss->spi_msg1; 173 xfer = &kss->spi_xfer1; 174 175 xfer->tx_buf = txb; 176 xfer->rx_buf = trx; 177 xfer->len = rxl + 2; 178 } 179 180 ret = spi_sync(kss->spidev, msg); 181 if (ret < 0) 182 netdev_err(ks->netdev, "read: spi_sync() failed\n"); 183 else if (kss->spidev->master->flags & SPI_MASTER_HALF_DUPLEX) 184 memcpy(rxb, trx, rxl); 185 else 186 memcpy(rxb, trx + 2, rxl); 187 } 188 189 /** 190 * ks8851_rdreg16_spi - read 16 bit register from device via SPI 191 * @ks: The chip information 192 * @reg: The register address 193 * 194 * Read a 16bit register from the chip, returning the result 195 */ 196 static unsigned int ks8851_rdreg16_spi(struct ks8851_net *ks, unsigned int reg) 197 { 198 __le16 rx = 0; 199 200 ks8851_rdreg(ks, MK_OP(reg & 2 ? 0xC : 0x3, reg), (u8 *)&rx, 2); 201 return le16_to_cpu(rx); 202 } 203 204 /** 205 * ks8851_rdfifo_spi - read data from the receive fifo via SPI 206 * @ks: The device state. 207 * @buff: The buffer address 208 * @len: The length of the data to read 209 * 210 * Issue an RXQ FIFO read command and read the @len amount of data from 211 * the FIFO into the buffer specified by @buff. 212 */ 213 static void ks8851_rdfifo_spi(struct ks8851_net *ks, u8 *buff, unsigned int len) 214 { 215 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 216 struct spi_transfer *xfer = kss->spi_xfer2; 217 struct spi_message *msg = &kss->spi_msg2; 218 u8 txb[1]; 219 int ret; 220 221 netif_dbg(ks, rx_status, ks->netdev, 222 "%s: %d@%p\n", __func__, len, buff); 223 224 /* set the operation we're issuing */ 225 txb[0] = KS_SPIOP_RXFIFO; 226 227 xfer->tx_buf = txb; 228 xfer->rx_buf = NULL; 229 xfer->len = 1; 230 231 xfer++; 232 xfer->rx_buf = buff; 233 xfer->tx_buf = NULL; 234 xfer->len = len; 235 236 ret = spi_sync(kss->spidev, msg); 237 if (ret < 0) 238 netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__); 239 } 240 241 /** 242 * ks8851_wrfifo_spi - write packet to TX FIFO via SPI 243 * @ks: The device state. 244 * @txp: The sk_buff to transmit. 245 * @irq: IRQ on completion of the packet. 246 * 247 * Send the @txp to the chip. This means creating the relevant packet header 248 * specifying the length of the packet and the other information the chip 249 * needs, such as IRQ on completion. Send the header and the packet data to 250 * the device. 251 */ 252 static void ks8851_wrfifo_spi(struct ks8851_net *ks, struct sk_buff *txp, 253 bool irq) 254 { 255 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 256 struct spi_transfer *xfer = kss->spi_xfer2; 257 struct spi_message *msg = &kss->spi_msg2; 258 unsigned int fid = 0; 259 int ret; 260 261 netif_dbg(ks, tx_queued, ks->netdev, "%s: skb %p, %d@%p, irq %d\n", 262 __func__, txp, txp->len, txp->data, irq); 263 264 fid = ks->fid++; 265 fid &= TXFR_TXFID_MASK; 266 267 if (irq) 268 fid |= TXFR_TXIC; /* irq on completion */ 269 270 /* start header at txb[1] to align txw entries */ 271 ks->txh.txb[1] = KS_SPIOP_TXFIFO; 272 ks->txh.txw[1] = cpu_to_le16(fid); 273 ks->txh.txw[2] = cpu_to_le16(txp->len); 274 275 xfer->tx_buf = &ks->txh.txb[1]; 276 xfer->rx_buf = NULL; 277 xfer->len = 5; 278 279 xfer++; 280 xfer->tx_buf = txp->data; 281 xfer->rx_buf = NULL; 282 xfer->len = ALIGN(txp->len, 4); 283 284 ret = spi_sync(kss->spidev, msg); 285 if (ret < 0) 286 netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__); 287 } 288 289 /** 290 * ks8851_rx_skb_spi - receive skbuff 291 * @ks: The device state 292 * @skb: The skbuff 293 */ 294 static void ks8851_rx_skb_spi(struct ks8851_net *ks, struct sk_buff *skb) 295 { 296 netif_rx(skb); 297 } 298 299 /** 300 * ks8851_tx_work - process tx packet(s) 301 * @work: The work strucutre what was scheduled. 302 * 303 * This is called when a number of packets have been scheduled for 304 * transmission and need to be sent to the device. 305 */ 306 static void ks8851_tx_work(struct work_struct *work) 307 { 308 struct ks8851_net_spi *kss; 309 struct ks8851_net *ks; 310 unsigned long flags; 311 struct sk_buff *txb; 312 bool last; 313 314 kss = container_of(work, struct ks8851_net_spi, tx_work); 315 ks = &kss->ks8851; 316 last = skb_queue_empty(&ks->txq); 317 318 ks8851_lock_spi(ks, &flags); 319 320 while (!last) { 321 txb = skb_dequeue(&ks->txq); 322 last = skb_queue_empty(&ks->txq); 323 324 if (txb) { 325 ks8851_wrreg16_spi(ks, KS_RXQCR, 326 ks->rc_rxqcr | RXQCR_SDA); 327 ks8851_wrfifo_spi(ks, txb, last); 328 ks8851_wrreg16_spi(ks, KS_RXQCR, ks->rc_rxqcr); 329 ks8851_wrreg16_spi(ks, KS_TXQCR, TXQCR_METFE); 330 331 ks8851_done_tx(ks, txb); 332 } 333 } 334 335 ks8851_unlock_spi(ks, &flags); 336 } 337 338 /** 339 * ks8851_flush_tx_work_spi - flush outstanding TX work 340 * @ks: The device state 341 */ 342 static void ks8851_flush_tx_work_spi(struct ks8851_net *ks) 343 { 344 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 345 346 flush_work(&kss->tx_work); 347 } 348 349 /** 350 * calc_txlen - calculate size of message to send packet 351 * @len: Length of data 352 * 353 * Returns the size of the TXFIFO message needed to send 354 * this packet. 355 */ 356 static unsigned int calc_txlen(unsigned int len) 357 { 358 return ALIGN(len + 4, 4); 359 } 360 361 /** 362 * ks8851_start_xmit_spi - transmit packet using SPI 363 * @skb: The buffer to transmit 364 * @dev: The device used to transmit the packet. 365 * 366 * Called by the network layer to transmit the @skb. Queue the packet for 367 * the device and schedule the necessary work to transmit the packet when 368 * it is free. 369 * 370 * We do this to firstly avoid sleeping with the network device locked, 371 * and secondly so we can round up more than one packet to transmit which 372 * means we can try and avoid generating too many transmit done interrupts. 373 */ 374 static netdev_tx_t ks8851_start_xmit_spi(struct sk_buff *skb, 375 struct net_device *dev) 376 { 377 unsigned int needed = calc_txlen(skb->len); 378 struct ks8851_net *ks = netdev_priv(dev); 379 netdev_tx_t ret = NETDEV_TX_OK; 380 struct ks8851_net_spi *kss; 381 382 kss = to_ks8851_spi(ks); 383 384 netif_dbg(ks, tx_queued, ks->netdev, 385 "%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data); 386 387 spin_lock(&ks->statelock); 388 389 if (needed > ks->tx_space) { 390 netif_stop_queue(dev); 391 ret = NETDEV_TX_BUSY; 392 } else { 393 ks->tx_space -= needed; 394 skb_queue_tail(&ks->txq, skb); 395 } 396 397 spin_unlock(&ks->statelock); 398 schedule_work(&kss->tx_work); 399 400 return ret; 401 } 402 403 static int ks8851_probe_spi(struct spi_device *spi) 404 { 405 struct device *dev = &spi->dev; 406 struct ks8851_net_spi *kss; 407 struct net_device *netdev; 408 struct ks8851_net *ks; 409 410 netdev = devm_alloc_etherdev(dev, sizeof(struct ks8851_net_spi)); 411 if (!netdev) 412 return -ENOMEM; 413 414 spi->bits_per_word = 8; 415 416 kss = netdev_priv(netdev); 417 ks = &kss->ks8851; 418 419 ks->lock = ks8851_lock_spi; 420 ks->unlock = ks8851_unlock_spi; 421 ks->rdreg16 = ks8851_rdreg16_spi; 422 ks->wrreg16 = ks8851_wrreg16_spi; 423 ks->rdfifo = ks8851_rdfifo_spi; 424 ks->wrfifo = ks8851_wrfifo_spi; 425 ks->start_xmit = ks8851_start_xmit_spi; 426 ks->rx_skb = ks8851_rx_skb_spi; 427 ks->flush_tx_work = ks8851_flush_tx_work_spi; 428 429 #define STD_IRQ (IRQ_LCI | /* Link Change */ \ 430 IRQ_TXI | /* TX done */ \ 431 IRQ_RXI | /* RX done */ \ 432 IRQ_SPIBEI | /* SPI bus error */ \ 433 IRQ_TXPSI | /* TX process stop */ \ 434 IRQ_RXPSI) /* RX process stop */ 435 ks->rc_ier = STD_IRQ; 436 437 kss->spidev = spi; 438 mutex_init(&kss->lock); 439 INIT_WORK(&kss->tx_work, ks8851_tx_work); 440 441 /* initialise pre-made spi transfer messages */ 442 spi_message_init(&kss->spi_msg1); 443 spi_message_add_tail(&kss->spi_xfer1, &kss->spi_msg1); 444 445 spi_message_init(&kss->spi_msg2); 446 spi_message_add_tail(&kss->spi_xfer2[0], &kss->spi_msg2); 447 spi_message_add_tail(&kss->spi_xfer2[1], &kss->spi_msg2); 448 449 netdev->irq = spi->irq; 450 451 return ks8851_probe_common(netdev, dev, msg_enable); 452 } 453 454 static void ks8851_remove_spi(struct spi_device *spi) 455 { 456 ks8851_remove_common(&spi->dev); 457 } 458 459 static const struct of_device_id ks8851_match_table[] = { 460 { .compatible = "micrel,ks8851" }, 461 { } 462 }; 463 MODULE_DEVICE_TABLE(of, ks8851_match_table); 464 465 static struct spi_driver ks8851_driver = { 466 .driver = { 467 .name = "ks8851", 468 .of_match_table = ks8851_match_table, 469 .pm = &ks8851_pm_ops, 470 }, 471 .probe = ks8851_probe_spi, 472 .remove = ks8851_remove_spi, 473 }; 474 module_spi_driver(ks8851_driver); 475 476 MODULE_DESCRIPTION("KS8851 Network driver"); 477 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 478 MODULE_LICENSE("GPL"); 479 480 module_param_named(message, msg_enable, int, 0); 481 MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)"); 482 MODULE_ALIAS("spi:ks8851"); 483