1 /*
2  * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * Driver for the ARC EMAC 10100 (hardware revision 5)
9  *
10  * Contributors:
11  *		Amit Bhor
12  *		Sameer Dhavale
13  *		Vineet Gupta
14  */
15 
16 #include <linux/crc32.h>
17 #include <linux/etherdevice.h>
18 #include <linux/interrupt.h>
19 #include <linux/io.h>
20 #include <linux/module.h>
21 #include <linux/of_address.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_mdio.h>
24 #include <linux/of_net.h>
25 #include <linux/of_platform.h>
26 
27 #include "emac.h"
28 
29 
30 /**
31  * arc_emac_tx_avail - Return the number of available slots in the tx ring.
32  * @priv: Pointer to ARC EMAC private data structure.
33  *
34  * returns: the number of slots available for transmission in tx the ring.
35  */
36 static inline int arc_emac_tx_avail(struct arc_emac_priv *priv)
37 {
38 	return (priv->txbd_dirty + TX_BD_NUM - priv->txbd_curr - 1) % TX_BD_NUM;
39 }
40 
41 /**
42  * arc_emac_adjust_link - Adjust the PHY link duplex.
43  * @ndev:	Pointer to the net_device structure.
44  *
45  * This function is called to change the duplex setting after auto negotiation
46  * is done by the PHY.
47  */
48 static void arc_emac_adjust_link(struct net_device *ndev)
49 {
50 	struct arc_emac_priv *priv = netdev_priv(ndev);
51 	struct phy_device *phy_dev = priv->phy_dev;
52 	unsigned int reg, state_changed = 0;
53 
54 	if (priv->link != phy_dev->link) {
55 		priv->link = phy_dev->link;
56 		state_changed = 1;
57 	}
58 
59 	if (priv->speed != phy_dev->speed) {
60 		priv->speed = phy_dev->speed;
61 		state_changed = 1;
62 		if (priv->set_mac_speed)
63 			priv->set_mac_speed(priv, priv->speed);
64 	}
65 
66 	if (priv->duplex != phy_dev->duplex) {
67 		reg = arc_reg_get(priv, R_CTRL);
68 
69 		if (DUPLEX_FULL == phy_dev->duplex)
70 			reg |= ENFL_MASK;
71 		else
72 			reg &= ~ENFL_MASK;
73 
74 		arc_reg_set(priv, R_CTRL, reg);
75 		priv->duplex = phy_dev->duplex;
76 		state_changed = 1;
77 	}
78 
79 	if (state_changed)
80 		phy_print_status(phy_dev);
81 }
82 
83 /**
84  * arc_emac_get_settings - Get PHY settings.
85  * @ndev:	Pointer to net_device structure.
86  * @cmd:	Pointer to ethtool_cmd structure.
87  *
88  * This implements ethtool command for getting PHY settings. If PHY could
89  * not be found, the function returns -ENODEV. This function calls the
90  * relevant PHY ethtool API to get the PHY settings.
91  * Issue "ethtool ethX" under linux prompt to execute this function.
92  */
93 static int arc_emac_get_settings(struct net_device *ndev,
94 				 struct ethtool_cmd *cmd)
95 {
96 	struct arc_emac_priv *priv = netdev_priv(ndev);
97 
98 	return phy_ethtool_gset(priv->phy_dev, cmd);
99 }
100 
101 /**
102  * arc_emac_set_settings - Set PHY settings as passed in the argument.
103  * @ndev:	Pointer to net_device structure.
104  * @cmd:	Pointer to ethtool_cmd structure.
105  *
106  * This implements ethtool command for setting various PHY settings. If PHY
107  * could not be found, the function returns -ENODEV. This function calls the
108  * relevant PHY ethtool API to set the PHY.
109  * Issue e.g. "ethtool -s ethX speed 1000" under linux prompt to execute this
110  * function.
111  */
112 static int arc_emac_set_settings(struct net_device *ndev,
113 				 struct ethtool_cmd *cmd)
114 {
115 	struct arc_emac_priv *priv = netdev_priv(ndev);
116 
117 	if (!capable(CAP_NET_ADMIN))
118 		return -EPERM;
119 
120 	return phy_ethtool_sset(priv->phy_dev, cmd);
121 }
122 
123 /**
124  * arc_emac_get_drvinfo - Get EMAC driver information.
125  * @ndev:	Pointer to net_device structure.
126  * @info:	Pointer to ethtool_drvinfo structure.
127  *
128  * This implements ethtool command for getting the driver information.
129  * Issue "ethtool -i ethX" under linux prompt to execute this function.
130  */
131 static void arc_emac_get_drvinfo(struct net_device *ndev,
132 				 struct ethtool_drvinfo *info)
133 {
134 	struct arc_emac_priv *priv = netdev_priv(ndev);
135 
136 	strlcpy(info->driver, priv->drv_name, sizeof(info->driver));
137 	strlcpy(info->version, priv->drv_version, sizeof(info->version));
138 }
139 
140 static const struct ethtool_ops arc_emac_ethtool_ops = {
141 	.get_settings	= arc_emac_get_settings,
142 	.set_settings	= arc_emac_set_settings,
143 	.get_drvinfo	= arc_emac_get_drvinfo,
144 	.get_link	= ethtool_op_get_link,
145 };
146 
147 #define FIRST_OR_LAST_MASK	(FIRST_MASK | LAST_MASK)
148 
149 /**
150  * arc_emac_tx_clean - clears processed by EMAC Tx BDs.
151  * @ndev:	Pointer to the network device.
152  */
153 static void arc_emac_tx_clean(struct net_device *ndev)
154 {
155 	struct arc_emac_priv *priv = netdev_priv(ndev);
156 	struct net_device_stats *stats = &ndev->stats;
157 	unsigned int i;
158 
159 	for (i = 0; i < TX_BD_NUM; i++) {
160 		unsigned int *txbd_dirty = &priv->txbd_dirty;
161 		struct arc_emac_bd *txbd = &priv->txbd[*txbd_dirty];
162 		struct buffer_state *tx_buff = &priv->tx_buff[*txbd_dirty];
163 		struct sk_buff *skb = tx_buff->skb;
164 		unsigned int info = le32_to_cpu(txbd->info);
165 
166 		if ((info & FOR_EMAC) || !txbd->data || !skb)
167 			break;
168 
169 		if (unlikely(info & (DROP | DEFR | LTCL | UFLO))) {
170 			stats->tx_errors++;
171 			stats->tx_dropped++;
172 
173 			if (info & DEFR)
174 				stats->tx_carrier_errors++;
175 
176 			if (info & LTCL)
177 				stats->collisions++;
178 
179 			if (info & UFLO)
180 				stats->tx_fifo_errors++;
181 		} else if (likely(info & FIRST_OR_LAST_MASK)) {
182 			stats->tx_packets++;
183 			stats->tx_bytes += skb->len;
184 		}
185 
186 		dma_unmap_single(&ndev->dev, dma_unmap_addr(tx_buff, addr),
187 				 dma_unmap_len(tx_buff, len), DMA_TO_DEVICE);
188 
189 		/* return the sk_buff to system */
190 		dev_kfree_skb_irq(skb);
191 
192 		txbd->data = 0;
193 		txbd->info = 0;
194 		tx_buff->skb = NULL;
195 
196 		*txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
197 	}
198 
199 	/* Ensure that txbd_dirty is visible to tx() before checking
200 	 * for queue stopped.
201 	 */
202 	smp_mb();
203 
204 	if (netif_queue_stopped(ndev) && arc_emac_tx_avail(priv))
205 		netif_wake_queue(ndev);
206 }
207 
208 /**
209  * arc_emac_rx - processing of Rx packets.
210  * @ndev:	Pointer to the network device.
211  * @budget:	How many BDs to process on 1 call.
212  *
213  * returns:	Number of processed BDs
214  *
215  * Iterate through Rx BDs and deliver received packages to upper layer.
216  */
217 static int arc_emac_rx(struct net_device *ndev, int budget)
218 {
219 	struct arc_emac_priv *priv = netdev_priv(ndev);
220 	unsigned int work_done;
221 
222 	for (work_done = 0; work_done < budget; work_done++) {
223 		unsigned int *last_rx_bd = &priv->last_rx_bd;
224 		struct net_device_stats *stats = &ndev->stats;
225 		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
226 		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
227 		unsigned int pktlen, info = le32_to_cpu(rxbd->info);
228 		struct sk_buff *skb;
229 		dma_addr_t addr;
230 
231 		if (unlikely((info & OWN_MASK) == FOR_EMAC))
232 			break;
233 
234 		/* Make a note that we saw a packet at this BD.
235 		 * So next time, driver starts from this + 1
236 		 */
237 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
238 
239 		if (unlikely((info & FIRST_OR_LAST_MASK) !=
240 			     FIRST_OR_LAST_MASK)) {
241 			/* We pre-allocate buffers of MTU size so incoming
242 			 * packets won't be split/chained.
243 			 */
244 			if (net_ratelimit())
245 				netdev_err(ndev, "incomplete packet received\n");
246 
247 			/* Return ownership to EMAC */
248 			rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
249 			stats->rx_errors++;
250 			stats->rx_length_errors++;
251 			continue;
252 		}
253 
254 		pktlen = info & LEN_MASK;
255 		stats->rx_packets++;
256 		stats->rx_bytes += pktlen;
257 		skb = rx_buff->skb;
258 		skb_put(skb, pktlen);
259 		skb->dev = ndev;
260 		skb->protocol = eth_type_trans(skb, ndev);
261 
262 		dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),
263 				 dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);
264 
265 		/* Prepare the BD for next cycle */
266 		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
267 							 EMAC_BUFFER_SIZE);
268 		if (unlikely(!rx_buff->skb)) {
269 			stats->rx_errors++;
270 			/* Because receive_skb is below, increment rx_dropped */
271 			stats->rx_dropped++;
272 			continue;
273 		}
274 
275 		/* receive_skb only if new skb was allocated to avoid holes */
276 		netif_receive_skb(skb);
277 
278 		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
279 				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
280 		if (dma_mapping_error(&ndev->dev, addr)) {
281 			if (net_ratelimit())
282 				netdev_err(ndev, "cannot dma map\n");
283 			dev_kfree_skb(rx_buff->skb);
284 			stats->rx_errors++;
285 			continue;
286 		}
287 		dma_unmap_addr_set(rx_buff, addr, addr);
288 		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
289 
290 		rxbd->data = cpu_to_le32(addr);
291 
292 		/* Make sure pointer to data buffer is set */
293 		wmb();
294 
295 		/* Return ownership to EMAC */
296 		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
297 	}
298 
299 	return work_done;
300 }
301 
302 /**
303  * arc_emac_poll - NAPI poll handler.
304  * @napi:	Pointer to napi_struct structure.
305  * @budget:	How many BDs to process on 1 call.
306  *
307  * returns:	Number of processed BDs
308  */
309 static int arc_emac_poll(struct napi_struct *napi, int budget)
310 {
311 	struct net_device *ndev = napi->dev;
312 	struct arc_emac_priv *priv = netdev_priv(ndev);
313 	unsigned int work_done;
314 
315 	arc_emac_tx_clean(ndev);
316 
317 	work_done = arc_emac_rx(ndev, budget);
318 	if (work_done < budget) {
319 		napi_complete(napi);
320 		arc_reg_or(priv, R_ENABLE, RXINT_MASK | TXINT_MASK);
321 	}
322 
323 	return work_done;
324 }
325 
326 /**
327  * arc_emac_intr - Global interrupt handler for EMAC.
328  * @irq:		irq number.
329  * @dev_instance:	device instance.
330  *
331  * returns: IRQ_HANDLED for all cases.
332  *
333  * ARC EMAC has only 1 interrupt line, and depending on bits raised in
334  * STATUS register we may tell what is a reason for interrupt to fire.
335  */
336 static irqreturn_t arc_emac_intr(int irq, void *dev_instance)
337 {
338 	struct net_device *ndev = dev_instance;
339 	struct arc_emac_priv *priv = netdev_priv(ndev);
340 	struct net_device_stats *stats = &ndev->stats;
341 	unsigned int status;
342 
343 	status = arc_reg_get(priv, R_STATUS);
344 	status &= ~MDIO_MASK;
345 
346 	/* Reset all flags except "MDIO complete" */
347 	arc_reg_set(priv, R_STATUS, status);
348 
349 	if (status & (RXINT_MASK | TXINT_MASK)) {
350 		if (likely(napi_schedule_prep(&priv->napi))) {
351 			arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK);
352 			__napi_schedule(&priv->napi);
353 		}
354 	}
355 
356 	if (status & ERR_MASK) {
357 		/* MSER/RXCR/RXFR/RXFL interrupt fires on corresponding
358 		 * 8-bit error counter overrun.
359 		 */
360 
361 		if (status & MSER_MASK) {
362 			stats->rx_missed_errors += 0x100;
363 			stats->rx_errors += 0x100;
364 		}
365 
366 		if (status & RXCR_MASK) {
367 			stats->rx_crc_errors += 0x100;
368 			stats->rx_errors += 0x100;
369 		}
370 
371 		if (status & RXFR_MASK) {
372 			stats->rx_frame_errors += 0x100;
373 			stats->rx_errors += 0x100;
374 		}
375 
376 		if (status & RXFL_MASK) {
377 			stats->rx_over_errors += 0x100;
378 			stats->rx_errors += 0x100;
379 		}
380 	}
381 
382 	return IRQ_HANDLED;
383 }
384 
385 #ifdef CONFIG_NET_POLL_CONTROLLER
386 static void arc_emac_poll_controller(struct net_device *dev)
387 {
388 	disable_irq(dev->irq);
389 	arc_emac_intr(dev->irq, dev);
390 	enable_irq(dev->irq);
391 }
392 #endif
393 
394 /**
395  * arc_emac_open - Open the network device.
396  * @ndev:	Pointer to the network device.
397  *
398  * returns: 0, on success or non-zero error value on failure.
399  *
400  * This function sets the MAC address, requests and enables an IRQ
401  * for the EMAC device and starts the Tx queue.
402  * It also connects to the phy device.
403  */
404 static int arc_emac_open(struct net_device *ndev)
405 {
406 	struct arc_emac_priv *priv = netdev_priv(ndev);
407 	struct phy_device *phy_dev = priv->phy_dev;
408 	int i;
409 
410 	phy_dev->autoneg = AUTONEG_ENABLE;
411 	phy_dev->speed = 0;
412 	phy_dev->duplex = 0;
413 	phy_dev->advertising &= phy_dev->supported;
414 
415 	priv->last_rx_bd = 0;
416 
417 	/* Allocate and set buffers for Rx BD's */
418 	for (i = 0; i < RX_BD_NUM; i++) {
419 		dma_addr_t addr;
420 		unsigned int *last_rx_bd = &priv->last_rx_bd;
421 		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
422 		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
423 
424 		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
425 							 EMAC_BUFFER_SIZE);
426 		if (unlikely(!rx_buff->skb))
427 			return -ENOMEM;
428 
429 		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
430 				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
431 		if (dma_mapping_error(&ndev->dev, addr)) {
432 			netdev_err(ndev, "cannot dma map\n");
433 			dev_kfree_skb(rx_buff->skb);
434 			return -ENOMEM;
435 		}
436 		dma_unmap_addr_set(rx_buff, addr, addr);
437 		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
438 
439 		rxbd->data = cpu_to_le32(addr);
440 
441 		/* Make sure pointer to data buffer is set */
442 		wmb();
443 
444 		/* Return ownership to EMAC */
445 		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
446 
447 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
448 	}
449 
450 	priv->txbd_curr = 0;
451 	priv->txbd_dirty = 0;
452 
453 	/* Clean Tx BD's */
454 	memset(priv->txbd, 0, TX_RING_SZ);
455 
456 	/* Initialize logical address filter */
457 	arc_reg_set(priv, R_LAFL, 0);
458 	arc_reg_set(priv, R_LAFH, 0);
459 
460 	/* Set BD ring pointers for device side */
461 	arc_reg_set(priv, R_RX_RING, (unsigned int)priv->rxbd_dma);
462 	arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma);
463 
464 	/* Enable interrupts */
465 	arc_reg_set(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK);
466 
467 	/* Set CONTROL */
468 	arc_reg_set(priv, R_CTRL,
469 		     (RX_BD_NUM << 24) |	/* RX BD table length */
470 		     (TX_BD_NUM << 16) |	/* TX BD table length */
471 		     TXRN_MASK | RXRN_MASK);
472 
473 	napi_enable(&priv->napi);
474 
475 	/* Enable EMAC */
476 	arc_reg_or(priv, R_CTRL, EN_MASK);
477 
478 	phy_start_aneg(priv->phy_dev);
479 
480 	netif_start_queue(ndev);
481 
482 	return 0;
483 }
484 
485 /**
486  * arc_emac_set_rx_mode - Change the receive filtering mode.
487  * @ndev:	Pointer to the network device.
488  *
489  * This function enables/disables promiscuous or all-multicast mode
490  * and updates the multicast filtering list of the network device.
491  */
492 static void arc_emac_set_rx_mode(struct net_device *ndev)
493 {
494 	struct arc_emac_priv *priv = netdev_priv(ndev);
495 
496 	if (ndev->flags & IFF_PROMISC) {
497 		arc_reg_or(priv, R_CTRL, PROM_MASK);
498 	} else {
499 		arc_reg_clr(priv, R_CTRL, PROM_MASK);
500 
501 		if (ndev->flags & IFF_ALLMULTI) {
502 			arc_reg_set(priv, R_LAFL, ~0);
503 			arc_reg_set(priv, R_LAFH, ~0);
504 		} else {
505 			struct netdev_hw_addr *ha;
506 			unsigned int filter[2] = { 0, 0 };
507 			int bit;
508 
509 			netdev_for_each_mc_addr(ha, ndev) {
510 				bit = ether_crc_le(ETH_ALEN, ha->addr) >> 26;
511 				filter[bit >> 5] |= 1 << (bit & 31);
512 			}
513 
514 			arc_reg_set(priv, R_LAFL, filter[0]);
515 			arc_reg_set(priv, R_LAFH, filter[1]);
516 		}
517 	}
518 }
519 
520 /**
521  * arc_free_tx_queue - free skb from tx queue
522  * @ndev:	Pointer to the network device.
523  *
524  * This function must be called while EMAC disable
525  */
526 static void arc_free_tx_queue(struct net_device *ndev)
527 {
528 	struct arc_emac_priv *priv = netdev_priv(ndev);
529 	unsigned int i;
530 
531 	for (i = 0; i < TX_BD_NUM; i++) {
532 		struct arc_emac_bd *txbd = &priv->txbd[i];
533 		struct buffer_state *tx_buff = &priv->tx_buff[i];
534 
535 		if (tx_buff->skb) {
536 			dma_unmap_single(&ndev->dev, dma_unmap_addr(tx_buff, addr),
537 					 dma_unmap_len(tx_buff, len), DMA_TO_DEVICE);
538 
539 			/* return the sk_buff to system */
540 			dev_kfree_skb_irq(tx_buff->skb);
541 		}
542 
543 		txbd->info = 0;
544 		txbd->data = 0;
545 		tx_buff->skb = NULL;
546 	}
547 }
548 
549 /**
550  * arc_free_rx_queue - free skb from rx queue
551  * @ndev:	Pointer to the network device.
552  *
553  * This function must be called while EMAC disable
554  */
555 static void arc_free_rx_queue(struct net_device *ndev)
556 {
557 	struct arc_emac_priv *priv = netdev_priv(ndev);
558 	unsigned int i;
559 
560 	for (i = 0; i < RX_BD_NUM; i++) {
561 		struct arc_emac_bd *rxbd = &priv->rxbd[i];
562 		struct buffer_state *rx_buff = &priv->rx_buff[i];
563 
564 		if (rx_buff->skb) {
565 			dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),
566 					dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);
567 
568 			/* return the sk_buff to system */
569 			dev_kfree_skb_irq(rx_buff->skb);
570 		}
571 
572 		rxbd->info = 0;
573 		rxbd->data = 0;
574 		rx_buff->skb = NULL;
575 	}
576 }
577 
578 /**
579  * arc_emac_stop - Close the network device.
580  * @ndev:	Pointer to the network device.
581  *
582  * This function stops the Tx queue, disables interrupts and frees the IRQ for
583  * the EMAC device.
584  * It also disconnects the PHY device associated with the EMAC device.
585  */
586 static int arc_emac_stop(struct net_device *ndev)
587 {
588 	struct arc_emac_priv *priv = netdev_priv(ndev);
589 
590 	napi_disable(&priv->napi);
591 	netif_stop_queue(ndev);
592 
593 	/* Disable interrupts */
594 	arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK);
595 
596 	/* Disable EMAC */
597 	arc_reg_clr(priv, R_CTRL, EN_MASK);
598 
599 	/* Return the sk_buff to system */
600 	arc_free_tx_queue(ndev);
601 	arc_free_rx_queue(ndev);
602 
603 	return 0;
604 }
605 
606 /**
607  * arc_emac_stats - Get system network statistics.
608  * @ndev:	Pointer to net_device structure.
609  *
610  * Returns the address of the device statistics structure.
611  * Statistics are updated in interrupt handler.
612  */
613 static struct net_device_stats *arc_emac_stats(struct net_device *ndev)
614 {
615 	struct arc_emac_priv *priv = netdev_priv(ndev);
616 	struct net_device_stats *stats = &ndev->stats;
617 	unsigned long miss, rxerr;
618 	u8 rxcrc, rxfram, rxoflow;
619 
620 	rxerr = arc_reg_get(priv, R_RXERR);
621 	miss = arc_reg_get(priv, R_MISS);
622 
623 	rxcrc = rxerr;
624 	rxfram = rxerr >> 8;
625 	rxoflow = rxerr >> 16;
626 
627 	stats->rx_errors += miss;
628 	stats->rx_errors += rxcrc + rxfram + rxoflow;
629 
630 	stats->rx_over_errors += rxoflow;
631 	stats->rx_frame_errors += rxfram;
632 	stats->rx_crc_errors += rxcrc;
633 	stats->rx_missed_errors += miss;
634 
635 	return stats;
636 }
637 
638 /**
639  * arc_emac_tx - Starts the data transmission.
640  * @skb:	sk_buff pointer that contains data to be Transmitted.
641  * @ndev:	Pointer to net_device structure.
642  *
643  * returns: NETDEV_TX_OK, on success
644  *		NETDEV_TX_BUSY, if any of the descriptors are not free.
645  *
646  * This function is invoked from upper layers to initiate transmission.
647  */
648 static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
649 {
650 	struct arc_emac_priv *priv = netdev_priv(ndev);
651 	unsigned int len, *txbd_curr = &priv->txbd_curr;
652 	struct net_device_stats *stats = &ndev->stats;
653 	__le32 *info = &priv->txbd[*txbd_curr].info;
654 	dma_addr_t addr;
655 
656 	if (skb_padto(skb, ETH_ZLEN))
657 		return NETDEV_TX_OK;
658 
659 	len = max_t(unsigned int, ETH_ZLEN, skb->len);
660 
661 	if (unlikely(!arc_emac_tx_avail(priv))) {
662 		netif_stop_queue(ndev);
663 		netdev_err(ndev, "BUG! Tx Ring full when queue awake!\n");
664 		return NETDEV_TX_BUSY;
665 	}
666 
667 	addr = dma_map_single(&ndev->dev, (void *)skb->data, len,
668 			      DMA_TO_DEVICE);
669 
670 	if (unlikely(dma_mapping_error(&ndev->dev, addr))) {
671 		stats->tx_dropped++;
672 		stats->tx_errors++;
673 		dev_kfree_skb(skb);
674 		return NETDEV_TX_OK;
675 	}
676 	dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], addr, addr);
677 	dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);
678 
679 	priv->txbd[*txbd_curr].data = cpu_to_le32(addr);
680 
681 	/* Make sure pointer to data buffer is set */
682 	wmb();
683 
684 	skb_tx_timestamp(skb);
685 
686 	*info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);
687 
688 	/* Make sure info word is set */
689 	wmb();
690 
691 	priv->tx_buff[*txbd_curr].skb = skb;
692 
693 	/* Increment index to point to the next BD */
694 	*txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;
695 
696 	/* Ensure that tx_clean() sees the new txbd_curr before
697 	 * checking the queue status. This prevents an unneeded wake
698 	 * of the queue in tx_clean().
699 	 */
700 	smp_mb();
701 
702 	if (!arc_emac_tx_avail(priv)) {
703 		netif_stop_queue(ndev);
704 		/* Refresh tx_dirty */
705 		smp_mb();
706 		if (arc_emac_tx_avail(priv))
707 			netif_start_queue(ndev);
708 	}
709 
710 	arc_reg_set(priv, R_STATUS, TXPL_MASK);
711 
712 	return NETDEV_TX_OK;
713 }
714 
715 static void arc_emac_set_address_internal(struct net_device *ndev)
716 {
717 	struct arc_emac_priv *priv = netdev_priv(ndev);
718 	unsigned int addr_low, addr_hi;
719 
720 	addr_low = le32_to_cpu(*(__le32 *) &ndev->dev_addr[0]);
721 	addr_hi = le16_to_cpu(*(__le16 *) &ndev->dev_addr[4]);
722 
723 	arc_reg_set(priv, R_ADDRL, addr_low);
724 	arc_reg_set(priv, R_ADDRH, addr_hi);
725 }
726 
727 /**
728  * arc_emac_set_address - Set the MAC address for this device.
729  * @ndev:	Pointer to net_device structure.
730  * @p:		6 byte Address to be written as MAC address.
731  *
732  * This function copies the HW address from the sockaddr structure to the
733  * net_device structure and updates the address in HW.
734  *
735  * returns:	-EBUSY if the net device is busy or 0 if the address is set
736  *		successfully.
737  */
738 static int arc_emac_set_address(struct net_device *ndev, void *p)
739 {
740 	struct sockaddr *addr = p;
741 
742 	if (netif_running(ndev))
743 		return -EBUSY;
744 
745 	if (!is_valid_ether_addr(addr->sa_data))
746 		return -EADDRNOTAVAIL;
747 
748 	memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
749 
750 	arc_emac_set_address_internal(ndev);
751 
752 	return 0;
753 }
754 
755 static const struct net_device_ops arc_emac_netdev_ops = {
756 	.ndo_open		= arc_emac_open,
757 	.ndo_stop		= arc_emac_stop,
758 	.ndo_start_xmit		= arc_emac_tx,
759 	.ndo_set_mac_address	= arc_emac_set_address,
760 	.ndo_get_stats		= arc_emac_stats,
761 	.ndo_set_rx_mode	= arc_emac_set_rx_mode,
762 #ifdef CONFIG_NET_POLL_CONTROLLER
763 	.ndo_poll_controller	= arc_emac_poll_controller,
764 #endif
765 };
766 
767 int arc_emac_probe(struct net_device *ndev, int interface)
768 {
769 	struct device *dev = ndev->dev.parent;
770 	struct resource res_regs;
771 	struct device_node *phy_node;
772 	struct arc_emac_priv *priv;
773 	const char *mac_addr;
774 	unsigned int id, clock_frequency, irq;
775 	int err;
776 
777 
778 	/* Get PHY from device tree */
779 	phy_node = of_parse_phandle(dev->of_node, "phy", 0);
780 	if (!phy_node) {
781 		dev_err(dev, "failed to retrieve phy description from device tree\n");
782 		return -ENODEV;
783 	}
784 
785 	/* Get EMAC registers base address from device tree */
786 	err = of_address_to_resource(dev->of_node, 0, &res_regs);
787 	if (err) {
788 		dev_err(dev, "failed to retrieve registers base from device tree\n");
789 		return -ENODEV;
790 	}
791 
792 	/* Get IRQ from device tree */
793 	irq = irq_of_parse_and_map(dev->of_node, 0);
794 	if (!irq) {
795 		dev_err(dev, "failed to retrieve <irq> value from device tree\n");
796 		return -ENODEV;
797 	}
798 
799 
800 	ndev->netdev_ops = &arc_emac_netdev_ops;
801 	ndev->ethtool_ops = &arc_emac_ethtool_ops;
802 	ndev->watchdog_timeo = TX_TIMEOUT;
803 	/* FIXME :: no multicast support yet */
804 	ndev->flags &= ~IFF_MULTICAST;
805 
806 	priv = netdev_priv(ndev);
807 	priv->dev = dev;
808 
809 	priv->regs = devm_ioremap_resource(dev, &res_regs);
810 	if (IS_ERR(priv->regs)) {
811 		return PTR_ERR(priv->regs);
812 	}
813 	dev_dbg(dev, "Registers base address is 0x%p\n", priv->regs);
814 
815 	if (priv->clk) {
816 		err = clk_prepare_enable(priv->clk);
817 		if (err) {
818 			dev_err(dev, "failed to enable clock\n");
819 			return err;
820 		}
821 
822 		clock_frequency = clk_get_rate(priv->clk);
823 	} else {
824 		/* Get CPU clock frequency from device tree */
825 		if (of_property_read_u32(dev->of_node, "clock-frequency",
826 					 &clock_frequency)) {
827 			dev_err(dev, "failed to retrieve <clock-frequency> from device tree\n");
828 			return -EINVAL;
829 		}
830 	}
831 
832 	id = arc_reg_get(priv, R_ID);
833 
834 	/* Check for EMAC revision 5 or 7, magic number */
835 	if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
836 		dev_err(dev, "ARC EMAC not detected, id=0x%x\n", id);
837 		err = -ENODEV;
838 		goto out_clken;
839 	}
840 	dev_info(dev, "ARC EMAC detected with id: 0x%x\n", id);
841 
842 	/* Set poll rate so that it polls every 1 ms */
843 	arc_reg_set(priv, R_POLLRATE, clock_frequency / 1000000);
844 
845 	ndev->irq = irq;
846 	dev_info(dev, "IRQ is %d\n", ndev->irq);
847 
848 	/* Register interrupt handler for device */
849 	err = devm_request_irq(dev, ndev->irq, arc_emac_intr, 0,
850 			       ndev->name, ndev);
851 	if (err) {
852 		dev_err(dev, "could not allocate IRQ\n");
853 		goto out_clken;
854 	}
855 
856 	/* Get MAC address from device tree */
857 	mac_addr = of_get_mac_address(dev->of_node);
858 
859 	if (mac_addr)
860 		memcpy(ndev->dev_addr, mac_addr, ETH_ALEN);
861 	else
862 		eth_hw_addr_random(ndev);
863 
864 	arc_emac_set_address_internal(ndev);
865 	dev_info(dev, "MAC address is now %pM\n", ndev->dev_addr);
866 
867 	/* Do 1 allocation instead of 2 separate ones for Rx and Tx BD rings */
868 	priv->rxbd = dmam_alloc_coherent(dev, RX_RING_SZ + TX_RING_SZ,
869 					 &priv->rxbd_dma, GFP_KERNEL);
870 
871 	if (!priv->rxbd) {
872 		dev_err(dev, "failed to allocate data buffers\n");
873 		err = -ENOMEM;
874 		goto out_clken;
875 	}
876 
877 	priv->txbd = priv->rxbd + RX_BD_NUM;
878 
879 	priv->txbd_dma = priv->rxbd_dma + RX_RING_SZ;
880 	dev_dbg(dev, "EMAC Device addr: Rx Ring [0x%x], Tx Ring[%x]\n",
881 		(unsigned int)priv->rxbd_dma, (unsigned int)priv->txbd_dma);
882 
883 	err = arc_mdio_probe(priv);
884 	if (err) {
885 		dev_err(dev, "failed to probe MII bus\n");
886 		goto out_clken;
887 	}
888 
889 	priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
890 				       interface);
891 	if (!priv->phy_dev) {
892 		dev_err(dev, "of_phy_connect() failed\n");
893 		err = -ENODEV;
894 		goto out_mdio;
895 	}
896 
897 	dev_info(dev, "connected to %s phy with id 0x%x\n",
898 		 priv->phy_dev->drv->name, priv->phy_dev->phy_id);
899 
900 	netif_napi_add(ndev, &priv->napi, arc_emac_poll, ARC_EMAC_NAPI_WEIGHT);
901 
902 	err = register_netdev(ndev);
903 	if (err) {
904 		dev_err(dev, "failed to register network device\n");
905 		goto out_netif_api;
906 	}
907 
908 	return 0;
909 
910 out_netif_api:
911 	netif_napi_del(&priv->napi);
912 	phy_disconnect(priv->phy_dev);
913 	priv->phy_dev = NULL;
914 out_mdio:
915 	arc_mdio_remove(priv);
916 out_clken:
917 	if (priv->clk)
918 		clk_disable_unprepare(priv->clk);
919 	return err;
920 }
921 EXPORT_SYMBOL_GPL(arc_emac_probe);
922 
923 int arc_emac_remove(struct net_device *ndev)
924 {
925 	struct arc_emac_priv *priv = netdev_priv(ndev);
926 
927 	phy_disconnect(priv->phy_dev);
928 	priv->phy_dev = NULL;
929 	arc_mdio_remove(priv);
930 	unregister_netdev(ndev);
931 	netif_napi_del(&priv->napi);
932 
933 	if (!IS_ERR(priv->clk)) {
934 		clk_disable_unprepare(priv->clk);
935 	}
936 
937 
938 	return 0;
939 }
940 EXPORT_SYMBOL_GPL(arc_emac_remove);
941 
942 MODULE_AUTHOR("Alexey Brodkin <abrodkin@synopsys.com>");
943 MODULE_DESCRIPTION("ARC EMAC driver");
944 MODULE_LICENSE("GPL");
945