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/cache.h> 20 #include <linux/crc32.h> 21 #include <linux/mii.h> 22 #include <linux/regulator/consumer.h> 23 24 #include <linux/spi/spi.h> 25 #include <linux/gpio.h> 26 #include <linux/of_gpio.h> 27 #include <linux/of_net.h> 28 29 #include "ks8851.h" 30 31 static int msg_enable; 32 33 /** 34 * struct ks8851_net_spi - KS8851 SPI driver private data 35 * @lock: Lock to ensure that the device is not accessed when busy. 36 * @tx_work: Work queue for tx packets 37 * @ks8851: KS8851 driver common private data 38 * @spidev: The spi device we're bound to. 39 * @spi_msg1: pre-setup SPI transfer with one message, @spi_xfer1. 40 * @spi_msg2: pre-setup SPI transfer with two messages, @spi_xfer2. 41 * @spi_xfer1: @spi_msg1 SPI transfer structure 42 * @spi_xfer2: @spi_msg2 SPI transfer structure 43 * 44 * The @lock ensures that the chip is protected when certain operations are 45 * in progress. When the read or write packet transfer is in progress, most 46 * of the chip registers are not ccessible until the transfer is finished and 47 * the DMA has been de-asserted. 48 */ 49 struct ks8851_net_spi { 50 struct ks8851_net ks8851; 51 struct mutex lock; 52 struct work_struct tx_work; 53 struct spi_device *spidev; 54 struct spi_message spi_msg1; 55 struct spi_message spi_msg2; 56 struct spi_transfer spi_xfer1; 57 struct spi_transfer spi_xfer2[2]; 58 }; 59 60 #define to_ks8851_spi(ks) container_of((ks), struct ks8851_net_spi, ks8851) 61 62 /* SPI frame opcodes */ 63 #define KS_SPIOP_RD 0x00 64 #define KS_SPIOP_WR 0x40 65 #define KS_SPIOP_RXFIFO 0x80 66 #define KS_SPIOP_TXFIFO 0xC0 67 68 /* shift for byte-enable data */ 69 #define BYTE_EN(_x) ((_x) << 2) 70 71 /* turn register number and byte-enable mask into data for start of packet */ 72 #define MK_OP(_byteen, _reg) \ 73 (BYTE_EN(_byteen) | (_reg) << (8 + 2) | (_reg) >> 6) 74 75 /** 76 * ks8851_lock_spi - register access lock 77 * @ks: The chip state 78 * @flags: Spinlock flags 79 * 80 * Claim chip register access lock 81 */ 82 static void ks8851_lock_spi(struct ks8851_net *ks, unsigned long *flags) 83 { 84 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 85 86 mutex_lock(&kss->lock); 87 } 88 89 /** 90 * ks8851_unlock_spi - register access unlock 91 * @ks: The chip state 92 * @flags: Spinlock flags 93 * 94 * Release chip register access lock 95 */ 96 static void ks8851_unlock_spi(struct ks8851_net *ks, unsigned long *flags) 97 { 98 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 99 100 mutex_unlock(&kss->lock); 101 } 102 103 /* SPI register read/write calls. 104 * 105 * All these calls issue SPI transactions to access the chip's registers. They 106 * all require that the necessary lock is held to prevent accesses when the 107 * chip is busy transferring packet data (RX/TX FIFO accesses). 108 */ 109 110 /** 111 * ks8851_wrreg16_spi - write 16bit register value to chip via SPI 112 * @ks: The chip state 113 * @reg: The register address 114 * @val: The value to write 115 * 116 * Issue a write to put the value @val into the register specified in @reg. 117 */ 118 static void ks8851_wrreg16_spi(struct ks8851_net *ks, unsigned int reg, 119 unsigned int val) 120 { 121 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 122 struct spi_transfer *xfer = &kss->spi_xfer1; 123 struct spi_message *msg = &kss->spi_msg1; 124 __le16 txb[2]; 125 int ret; 126 127 txb[0] = cpu_to_le16(MK_OP(reg & 2 ? 0xC : 0x03, reg) | KS_SPIOP_WR); 128 txb[1] = cpu_to_le16(val); 129 130 xfer->tx_buf = txb; 131 xfer->rx_buf = NULL; 132 xfer->len = 4; 133 134 ret = spi_sync(kss->spidev, msg); 135 if (ret < 0) 136 netdev_err(ks->netdev, "spi_sync() failed\n"); 137 } 138 139 /** 140 * ks8851_rdreg - issue read register command and return the data 141 * @ks: The device state 142 * @op: The register address and byte enables in message format. 143 * @rxb: The RX buffer to return the result into 144 * @rxl: The length of data expected. 145 * 146 * This is the low level read call that issues the necessary spi message(s) 147 * to read data from the register specified in @op. 148 */ 149 static void ks8851_rdreg(struct ks8851_net *ks, unsigned int op, 150 u8 *rxb, unsigned int rxl) 151 { 152 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 153 struct spi_transfer *xfer; 154 struct spi_message *msg; 155 __le16 *txb = (__le16 *)ks->txd; 156 u8 *trx = ks->rxd; 157 int ret; 158 159 txb[0] = cpu_to_le16(op | KS_SPIOP_RD); 160 161 if (kss->spidev->master->flags & SPI_MASTER_HALF_DUPLEX) { 162 msg = &kss->spi_msg2; 163 xfer = kss->spi_xfer2; 164 165 xfer->tx_buf = txb; 166 xfer->rx_buf = NULL; 167 xfer->len = 2; 168 169 xfer++; 170 xfer->tx_buf = NULL; 171 xfer->rx_buf = trx; 172 xfer->len = rxl; 173 } else { 174 msg = &kss->spi_msg1; 175 xfer = &kss->spi_xfer1; 176 177 xfer->tx_buf = txb; 178 xfer->rx_buf = trx; 179 xfer->len = rxl + 2; 180 } 181 182 ret = spi_sync(kss->spidev, msg); 183 if (ret < 0) 184 netdev_err(ks->netdev, "read: spi_sync() failed\n"); 185 else if (kss->spidev->master->flags & SPI_MASTER_HALF_DUPLEX) 186 memcpy(rxb, trx, rxl); 187 else 188 memcpy(rxb, trx + 2, rxl); 189 } 190 191 /** 192 * ks8851_rdreg16_spi - read 16 bit register from device via SPI 193 * @ks: The chip information 194 * @reg: The register address 195 * 196 * Read a 16bit register from the chip, returning the result 197 */ 198 static unsigned int ks8851_rdreg16_spi(struct ks8851_net *ks, unsigned int reg) 199 { 200 __le16 rx = 0; 201 202 ks8851_rdreg(ks, MK_OP(reg & 2 ? 0xC : 0x3, reg), (u8 *)&rx, 2); 203 return le16_to_cpu(rx); 204 } 205 206 /** 207 * ks8851_rdfifo_spi - read data from the receive fifo via SPI 208 * @ks: The device state. 209 * @buff: The buffer address 210 * @len: The length of the data to read 211 * 212 * Issue an RXQ FIFO read command and read the @len amount of data from 213 * the FIFO into the buffer specified by @buff. 214 */ 215 static void ks8851_rdfifo_spi(struct ks8851_net *ks, u8 *buff, unsigned int len) 216 { 217 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 218 struct spi_transfer *xfer = kss->spi_xfer2; 219 struct spi_message *msg = &kss->spi_msg2; 220 u8 txb[1]; 221 int ret; 222 223 netif_dbg(ks, rx_status, ks->netdev, 224 "%s: %d@%p\n", __func__, len, buff); 225 226 /* set the operation we're issuing */ 227 txb[0] = KS_SPIOP_RXFIFO; 228 229 xfer->tx_buf = txb; 230 xfer->rx_buf = NULL; 231 xfer->len = 1; 232 233 xfer++; 234 xfer->rx_buf = buff; 235 xfer->tx_buf = NULL; 236 xfer->len = len; 237 238 ret = spi_sync(kss->spidev, msg); 239 if (ret < 0) 240 netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__); 241 } 242 243 /** 244 * ks8851_wrfifo_spi - write packet to TX FIFO via SPI 245 * @ks: The device state. 246 * @txp: The sk_buff to transmit. 247 * @irq: IRQ on completion of the packet. 248 * 249 * Send the @txp to the chip. This means creating the relevant packet header 250 * specifying the length of the packet and the other information the chip 251 * needs, such as IRQ on completion. Send the header and the packet data to 252 * the device. 253 */ 254 static void ks8851_wrfifo_spi(struct ks8851_net *ks, struct sk_buff *txp, 255 bool irq) 256 { 257 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 258 struct spi_transfer *xfer = kss->spi_xfer2; 259 struct spi_message *msg = &kss->spi_msg2; 260 unsigned int fid = 0; 261 int ret; 262 263 netif_dbg(ks, tx_queued, ks->netdev, "%s: skb %p, %d@%p, irq %d\n", 264 __func__, txp, txp->len, txp->data, irq); 265 266 fid = ks->fid++; 267 fid &= TXFR_TXFID_MASK; 268 269 if (irq) 270 fid |= TXFR_TXIC; /* irq on completion */ 271 272 /* start header at txb[1] to align txw entries */ 273 ks->txh.txb[1] = KS_SPIOP_TXFIFO; 274 ks->txh.txw[1] = cpu_to_le16(fid); 275 ks->txh.txw[2] = cpu_to_le16(txp->len); 276 277 xfer->tx_buf = &ks->txh.txb[1]; 278 xfer->rx_buf = NULL; 279 xfer->len = 5; 280 281 xfer++; 282 xfer->tx_buf = txp->data; 283 xfer->rx_buf = NULL; 284 xfer->len = ALIGN(txp->len, 4); 285 286 ret = spi_sync(kss->spidev, msg); 287 if (ret < 0) 288 netdev_err(ks->netdev, "%s: spi_sync() failed\n", __func__); 289 } 290 291 /** 292 * ks8851_rx_skb_spi - receive skbuff 293 * @ks: The device state 294 * @skb: The skbuff 295 */ 296 static void ks8851_rx_skb_spi(struct ks8851_net *ks, struct sk_buff *skb) 297 { 298 netif_rx_ni(skb); 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 struct ks8851_net_spi *kss; 311 struct ks8851_net *ks; 312 unsigned long flags; 313 struct sk_buff *txb; 314 bool last; 315 316 kss = container_of(work, struct ks8851_net_spi, tx_work); 317 ks = &kss->ks8851; 318 last = skb_queue_empty(&ks->txq); 319 320 ks8851_lock_spi(ks, &flags); 321 322 while (!last) { 323 txb = skb_dequeue(&ks->txq); 324 last = skb_queue_empty(&ks->txq); 325 326 if (txb) { 327 ks8851_wrreg16_spi(ks, KS_RXQCR, 328 ks->rc_rxqcr | RXQCR_SDA); 329 ks8851_wrfifo_spi(ks, txb, last); 330 ks8851_wrreg16_spi(ks, KS_RXQCR, ks->rc_rxqcr); 331 ks8851_wrreg16_spi(ks, KS_TXQCR, TXQCR_METFE); 332 333 ks8851_done_tx(ks, txb); 334 } 335 } 336 337 ks8851_unlock_spi(ks, &flags); 338 } 339 340 /** 341 * ks8851_flush_tx_work_spi - flush outstanding TX work 342 * @ks: The device state 343 */ 344 static void ks8851_flush_tx_work_spi(struct ks8851_net *ks) 345 { 346 struct ks8851_net_spi *kss = to_ks8851_spi(ks); 347 348 flush_work(&kss->tx_work); 349 } 350 351 /** 352 * calc_txlen - calculate size of message to send packet 353 * @len: Length of data 354 * 355 * Returns the size of the TXFIFO message needed to send 356 * this packet. 357 */ 358 static unsigned int calc_txlen(unsigned int len) 359 { 360 return ALIGN(len + 4, 4); 361 } 362 363 /** 364 * ks8851_start_xmit_spi - transmit packet using SPI 365 * @skb: The buffer to transmit 366 * @dev: The device used to transmit the packet. 367 * 368 * Called by the network layer to transmit the @skb. Queue the packet for 369 * the device and schedule the necessary work to transmit the packet when 370 * it is free. 371 * 372 * We do this to firstly avoid sleeping with the network device locked, 373 * and secondly so we can round up more than one packet to transmit which 374 * means we can try and avoid generating too many transmit done interrupts. 375 */ 376 static netdev_tx_t ks8851_start_xmit_spi(struct sk_buff *skb, 377 struct net_device *dev) 378 { 379 unsigned int needed = calc_txlen(skb->len); 380 struct ks8851_net *ks = netdev_priv(dev); 381 netdev_tx_t ret = NETDEV_TX_OK; 382 struct ks8851_net_spi *kss; 383 384 kss = to_ks8851_spi(ks); 385 386 netif_dbg(ks, tx_queued, ks->netdev, 387 "%s: skb %p, %d@%p\n", __func__, skb, skb->len, skb->data); 388 389 spin_lock(&ks->statelock); 390 391 if (needed > ks->tx_space) { 392 netif_stop_queue(dev); 393 ret = NETDEV_TX_BUSY; 394 } else { 395 ks->tx_space -= needed; 396 skb_queue_tail(&ks->txq, skb); 397 } 398 399 spin_unlock(&ks->statelock); 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 ks = netdev_priv(netdev); 419 420 ks->lock = ks8851_lock_spi; 421 ks->unlock = ks8851_unlock_spi; 422 ks->rdreg16 = ks8851_rdreg16_spi; 423 ks->wrreg16 = ks8851_wrreg16_spi; 424 ks->rdfifo = ks8851_rdfifo_spi; 425 ks->wrfifo = ks8851_wrfifo_spi; 426 ks->start_xmit = ks8851_start_xmit_spi; 427 ks->rx_skb = ks8851_rx_skb_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 = to_ks8851_spi(ks); 439 440 kss->spidev = spi; 441 mutex_init(&kss->lock); 442 INIT_WORK(&kss->tx_work, ks8851_tx_work); 443 444 /* initialise pre-made spi transfer messages */ 445 spi_message_init(&kss->spi_msg1); 446 spi_message_add_tail(&kss->spi_xfer1, &kss->spi_msg1); 447 448 spi_message_init(&kss->spi_msg2); 449 spi_message_add_tail(&kss->spi_xfer2[0], &kss->spi_msg2); 450 spi_message_add_tail(&kss->spi_xfer2[1], &kss->spi_msg2); 451 452 netdev->irq = spi->irq; 453 454 return ks8851_probe_common(netdev, dev, msg_enable); 455 } 456 457 static int ks8851_remove_spi(struct spi_device *spi) 458 { 459 return ks8851_remove_common(&spi->dev); 460 } 461 462 static const struct of_device_id ks8851_match_table[] = { 463 { .compatible = "micrel,ks8851" }, 464 { } 465 }; 466 MODULE_DEVICE_TABLE(of, ks8851_match_table); 467 468 static struct spi_driver ks8851_driver = { 469 .driver = { 470 .name = "ks8851", 471 .of_match_table = ks8851_match_table, 472 .pm = &ks8851_pm_ops, 473 }, 474 .probe = ks8851_probe_spi, 475 .remove = ks8851_remove_spi, 476 }; 477 module_spi_driver(ks8851_driver); 478 479 MODULE_DESCRIPTION("KS8851 Network driver"); 480 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 481 MODULE_LICENSE("GPL"); 482 483 module_param_named(message, msg_enable, int, 0); 484 MODULE_PARM_DESC(message, "Message verbosity level (0=none, 31=all)"); 485 MODULE_ALIAS("spi:ks8851"); 486