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->controller->flags & SPI_CONTROLLER_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->controller->flags & SPI_CONTROLLER_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 * calc_txlen - calculate size of message to send packet 291 * @len: Length of data 292 * 293 * Returns the size of the TXFIFO message needed to send 294 * this packet. 295 */ 296 static unsigned int calc_txlen(unsigned int len) 297 { 298 return ALIGN(len + 4, 4); 299 } 300 301 /** 302 * ks8851_tx_work - process tx packet(s) 303 * @work: The work strucutre what was scheduled. 304 * 305 * This is called when a number of packets have been scheduled for 306 * transmission and need to be sent to the device. 307 */ 308 static void ks8851_tx_work(struct work_struct *work) 309 { 310 unsigned int dequeued_len = 0; 311 struct ks8851_net_spi *kss; 312 unsigned short tx_space; 313 struct ks8851_net *ks; 314 unsigned long flags; 315 struct sk_buff *txb; 316 bool last; 317 318 kss = container_of(work, struct ks8851_net_spi, tx_work); 319 ks = &kss->ks8851; 320 last = skb_queue_empty(&ks->txq); 321 322 ks8851_lock_spi(ks, &flags); 323 324 while (!last) { 325 txb = skb_dequeue(&ks->txq); 326 last = skb_queue_empty(&ks->txq); 327 328 if (txb) { 329 dequeued_len += calc_txlen(txb->len); 330 331 ks8851_wrreg16_spi(ks, KS_RXQCR, 332 ks->rc_rxqcr | RXQCR_SDA); 333 ks8851_wrfifo_spi(ks, txb, last); 334 ks8851_wrreg16_spi(ks, KS_RXQCR, ks->rc_rxqcr); 335 ks8851_wrreg16_spi(ks, KS_TXQCR, TXQCR_METFE); 336 337 ks8851_done_tx(ks, txb); 338 } 339 } 340 341 tx_space = ks8851_rdreg16_spi(ks, KS_TXMIR); 342 343 spin_lock(&ks->statelock); 344 ks->queued_len -= dequeued_len; 345 ks->tx_space = tx_space; 346 spin_unlock(&ks->statelock); 347 348 ks8851_unlock_spi(ks, &flags); 349 } 350 351 /** 352 * ks8851_flush_tx_work_spi - flush outstanding TX work 353 * @ks: The device state 354 */ 355 static void ks8851_flush_tx_work_spi(struct ks8851_net *ks) 356 { 357 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 358 359 flush_work(&kss->tx_work); 360 } 361 362 /** 363 * ks8851_start_xmit_spi - transmit packet using SPI 364 * @skb: The buffer to transmit 365 * @dev: The device used to transmit the packet. 366 * 367 * Called by the network layer to transmit the @skb. Queue the packet for 368 * the device and schedule the necessary work to transmit the packet when 369 * it is free. 370 * 371 * We do this to firstly avoid sleeping with the network device locked, 372 * and secondly so we can round up more than one packet to transmit which 373 * means we can try and avoid generating too many transmit done interrupts. 374 */ 375 static netdev_tx_t ks8851_start_xmit_spi(struct sk_buff *skb, 376 struct net_device *dev) 377 { 378 unsigned int needed = calc_txlen(skb->len); 379 struct ks8851_net *ks = netdev_priv(dev); 380 netdev_tx_t ret = NETDEV_TX_OK; 381 struct ks8851_net_spi *kss; 382 383 kss = to_ks8851_spi(ks); 384 385 netif_dbg(ks, tx_queued, ks->netdev, 386 "%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data); 387 388 spin_lock(&ks->statelock); 389 390 if (ks->queued_len + needed > ks->tx_space) { 391 netif_stop_queue(dev); 392 ret = NETDEV_TX_BUSY; 393 } else { 394 ks->queued_len += needed; 395 skb_queue_tail(&ks->txq, skb); 396 } 397 398 spin_unlock(&ks->statelock); 399 if (ret == NETDEV_TX_OK) 400 schedule_work(&kss->tx_work); 401 402 return ret; 403 } 404 405 static int ks8851_probe_spi(struct spi_device *spi) 406 { 407 struct device *dev = &spi->dev; 408 struct ks8851_net_spi *kss; 409 struct net_device *netdev; 410 struct ks8851_net *ks; 411 412 netdev = devm_alloc_etherdev(dev, sizeof(struct ks8851_net_spi)); 413 if (!netdev) 414 return -ENOMEM; 415 416 spi->bits_per_word = 8; 417 418 kss = netdev_priv(netdev); 419 ks = &kss->ks8851; 420 421 ks->lock = ks8851_lock_spi; 422 ks->unlock = ks8851_unlock_spi; 423 ks->rdreg16 = ks8851_rdreg16_spi; 424 ks->wrreg16 = ks8851_wrreg16_spi; 425 ks->rdfifo = ks8851_rdfifo_spi; 426 ks->wrfifo = ks8851_wrfifo_spi; 427 ks->start_xmit = ks8851_start_xmit_spi; 428 ks->flush_tx_work = ks8851_flush_tx_work_spi; 429 430 #define STD_IRQ (IRQ_LCI | /* Link Change */ \ 431 IRQ_TXI | /* TX done */ \ 432 IRQ_RXI | /* RX done */ \ 433 IRQ_SPIBEI | /* SPI bus error */ \ 434 IRQ_TXPSI | /* TX process stop */ \ 435 IRQ_RXPSI) /* RX process stop */ 436 ks->rc_ier = STD_IRQ; 437 438 kss->spidev = spi; 439 mutex_init(&kss->lock); 440 INIT_WORK(&kss->tx_work, ks8851_tx_work); 441 442 /* initialise pre-made spi transfer messages */ 443 spi_message_init(&kss->spi_msg1); 444 spi_message_add_tail(&kss->spi_xfer1, &kss->spi_msg1); 445 446 spi_message_init(&kss->spi_msg2); 447 spi_message_add_tail(&kss->spi_xfer2[0], &kss->spi_msg2); 448 spi_message_add_tail(&kss->spi_xfer2[1], &kss->spi_msg2); 449 450 netdev->irq = spi->irq; 451 452 return ks8851_probe_common(netdev, dev, msg_enable); 453 } 454 455 static void ks8851_remove_spi(struct spi_device *spi) 456 { 457 ks8851_remove_common(&spi->dev); 458 } 459 460 static const struct of_device_id ks8851_match_table[] = { 461 { .compatible = "micrel,ks8851" }, 462 { } 463 }; 464 MODULE_DEVICE_TABLE(of, ks8851_match_table); 465 466 static struct spi_driver ks8851_driver = { 467 .driver = { 468 .name = "ks8851", 469 .of_match_table = ks8851_match_table, 470 .pm = &ks8851_pm_ops, 471 }, 472 .probe = ks8851_probe_spi, 473 .remove = ks8851_remove_spi, 474 }; 475 module_spi_driver(ks8851_driver); 476 477 MODULE_DESCRIPTION("KS8851 Network driver"); 478 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 479 MODULE_LICENSE("GPL"); 480 481 module_param_named(message, msg_enable, int, 0); 482 MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)"); 483 MODULE_ALIAS("spi:ks8851"); 484