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 #define DRV_NAME	"arc_emac"
30 #define DRV_VERSION	"1.0"
31 
32 /**
33  * arc_emac_adjust_link - Adjust the PHY link duplex.
34  * @ndev:	Pointer to the net_device structure.
35  *
36  * This function is called to change the duplex setting after auto negotiation
37  * is done by the PHY.
38  */
39 static void arc_emac_adjust_link(struct net_device *ndev)
40 {
41 	struct arc_emac_priv *priv = netdev_priv(ndev);
42 	struct phy_device *phy_dev = priv->phy_dev;
43 	unsigned int reg, state_changed = 0;
44 
45 	if (priv->link != phy_dev->link) {
46 		priv->link = phy_dev->link;
47 		state_changed = 1;
48 	}
49 
50 	if (priv->speed != phy_dev->speed) {
51 		priv->speed = phy_dev->speed;
52 		state_changed = 1;
53 	}
54 
55 	if (priv->duplex != phy_dev->duplex) {
56 		reg = arc_reg_get(priv, R_CTRL);
57 
58 		if (DUPLEX_FULL == phy_dev->duplex)
59 			reg |= ENFL_MASK;
60 		else
61 			reg &= ~ENFL_MASK;
62 
63 		arc_reg_set(priv, R_CTRL, reg);
64 		priv->duplex = phy_dev->duplex;
65 		state_changed = 1;
66 	}
67 
68 	if (state_changed)
69 		phy_print_status(phy_dev);
70 }
71 
72 /**
73  * arc_emac_get_settings - Get PHY settings.
74  * @ndev:	Pointer to net_device structure.
75  * @cmd:	Pointer to ethtool_cmd structure.
76  *
77  * This implements ethtool command for getting PHY settings. If PHY could
78  * not be found, the function returns -ENODEV. This function calls the
79  * relevant PHY ethtool API to get the PHY settings.
80  * Issue "ethtool ethX" under linux prompt to execute this function.
81  */
82 static int arc_emac_get_settings(struct net_device *ndev,
83 				 struct ethtool_cmd *cmd)
84 {
85 	struct arc_emac_priv *priv = netdev_priv(ndev);
86 
87 	return phy_ethtool_gset(priv->phy_dev, cmd);
88 }
89 
90 /**
91  * arc_emac_set_settings - Set PHY settings as passed in the argument.
92  * @ndev:	Pointer to net_device structure.
93  * @cmd:	Pointer to ethtool_cmd structure.
94  *
95  * This implements ethtool command for setting various PHY settings. If PHY
96  * could not be found, the function returns -ENODEV. This function calls the
97  * relevant PHY ethtool API to set the PHY.
98  * Issue e.g. "ethtool -s ethX speed 1000" under linux prompt to execute this
99  * function.
100  */
101 static int arc_emac_set_settings(struct net_device *ndev,
102 				 struct ethtool_cmd *cmd)
103 {
104 	struct arc_emac_priv *priv = netdev_priv(ndev);
105 
106 	if (!capable(CAP_NET_ADMIN))
107 		return -EPERM;
108 
109 	return phy_ethtool_sset(priv->phy_dev, cmd);
110 }
111 
112 /**
113  * arc_emac_get_drvinfo - Get EMAC driver information.
114  * @ndev:	Pointer to net_device structure.
115  * @info:	Pointer to ethtool_drvinfo structure.
116  *
117  * This implements ethtool command for getting the driver information.
118  * Issue "ethtool -i ethX" under linux prompt to execute this function.
119  */
120 static void arc_emac_get_drvinfo(struct net_device *ndev,
121 				 struct ethtool_drvinfo *info)
122 {
123 	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
124 	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
125 }
126 
127 static const struct ethtool_ops arc_emac_ethtool_ops = {
128 	.get_settings	= arc_emac_get_settings,
129 	.set_settings	= arc_emac_set_settings,
130 	.get_drvinfo	= arc_emac_get_drvinfo,
131 	.get_link	= ethtool_op_get_link,
132 };
133 
134 #define FIRST_OR_LAST_MASK	(FIRST_MASK | LAST_MASK)
135 
136 /**
137  * arc_emac_tx_clean - clears processed by EMAC Tx BDs.
138  * @ndev:	Pointer to the network device.
139  */
140 static void arc_emac_tx_clean(struct net_device *ndev)
141 {
142 	struct arc_emac_priv *priv = netdev_priv(ndev);
143 	struct net_device_stats *stats = &ndev->stats;
144 	unsigned int i;
145 
146 	for (i = 0; i < TX_BD_NUM; i++) {
147 		unsigned int *txbd_dirty = &priv->txbd_dirty;
148 		struct arc_emac_bd *txbd = &priv->txbd[*txbd_dirty];
149 		struct buffer_state *tx_buff = &priv->tx_buff[*txbd_dirty];
150 		struct sk_buff *skb = tx_buff->skb;
151 		unsigned int info = le32_to_cpu(txbd->info);
152 
153 		if ((info & FOR_EMAC) || !txbd->data)
154 			break;
155 
156 		if (unlikely(info & (DROP | DEFR | LTCL | UFLO))) {
157 			stats->tx_errors++;
158 			stats->tx_dropped++;
159 
160 			if (info & DEFR)
161 				stats->tx_carrier_errors++;
162 
163 			if (info & LTCL)
164 				stats->collisions++;
165 
166 			if (info & UFLO)
167 				stats->tx_fifo_errors++;
168 		} else if (likely(info & FIRST_OR_LAST_MASK)) {
169 			stats->tx_packets++;
170 			stats->tx_bytes += skb->len;
171 		}
172 
173 		dma_unmap_single(&ndev->dev, dma_unmap_addr(tx_buff, addr),
174 				 dma_unmap_len(tx_buff, len), DMA_TO_DEVICE);
175 
176 		/* return the sk_buff to system */
177 		dev_kfree_skb_irq(skb);
178 
179 		txbd->data = 0;
180 		txbd->info = 0;
181 
182 		*txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
183 
184 		if (netif_queue_stopped(ndev))
185 			netif_wake_queue(ndev);
186 	}
187 }
188 
189 /**
190  * arc_emac_rx - processing of Rx packets.
191  * @ndev:	Pointer to the network device.
192  * @budget:	How many BDs to process on 1 call.
193  *
194  * returns:	Number of processed BDs
195  *
196  * Iterate through Rx BDs and deliver received packages to upper layer.
197  */
198 static int arc_emac_rx(struct net_device *ndev, int budget)
199 {
200 	struct arc_emac_priv *priv = netdev_priv(ndev);
201 	unsigned int work_done;
202 
203 	for (work_done = 0; work_done < budget; work_done++) {
204 		unsigned int *last_rx_bd = &priv->last_rx_bd;
205 		struct net_device_stats *stats = &ndev->stats;
206 		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
207 		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
208 		unsigned int pktlen, info = le32_to_cpu(rxbd->info);
209 		struct sk_buff *skb;
210 		dma_addr_t addr;
211 
212 		if (unlikely((info & OWN_MASK) == FOR_EMAC))
213 			break;
214 
215 		/* Make a note that we saw a packet at this BD.
216 		 * So next time, driver starts from this + 1
217 		 */
218 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
219 
220 		if (unlikely((info & FIRST_OR_LAST_MASK) !=
221 			     FIRST_OR_LAST_MASK)) {
222 			/* We pre-allocate buffers of MTU size so incoming
223 			 * packets won't be split/chained.
224 			 */
225 			if (net_ratelimit())
226 				netdev_err(ndev, "incomplete packet received\n");
227 
228 			/* Return ownership to EMAC */
229 			rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
230 			stats->rx_errors++;
231 			stats->rx_length_errors++;
232 			continue;
233 		}
234 
235 		pktlen = info & LEN_MASK;
236 		stats->rx_packets++;
237 		stats->rx_bytes += pktlen;
238 		skb = rx_buff->skb;
239 		skb_put(skb, pktlen);
240 		skb->dev = ndev;
241 		skb->protocol = eth_type_trans(skb, ndev);
242 
243 		dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),
244 				 dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);
245 
246 		/* Prepare the BD for next cycle */
247 		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
248 							 EMAC_BUFFER_SIZE);
249 		if (unlikely(!rx_buff->skb)) {
250 			stats->rx_errors++;
251 			/* Because receive_skb is below, increment rx_dropped */
252 			stats->rx_dropped++;
253 			continue;
254 		}
255 
256 		/* receive_skb only if new skb was allocated to avoid holes */
257 		netif_receive_skb(skb);
258 
259 		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
260 				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
261 		if (dma_mapping_error(&ndev->dev, addr)) {
262 			if (net_ratelimit())
263 				netdev_err(ndev, "cannot dma map\n");
264 			dev_kfree_skb(rx_buff->skb);
265 			stats->rx_errors++;
266 			continue;
267 		}
268 		dma_unmap_addr_set(rx_buff, addr, addr);
269 		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
270 
271 		rxbd->data = cpu_to_le32(addr);
272 
273 		/* Make sure pointer to data buffer is set */
274 		wmb();
275 
276 		/* Return ownership to EMAC */
277 		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
278 	}
279 
280 	return work_done;
281 }
282 
283 /**
284  * arc_emac_poll - NAPI poll handler.
285  * @napi:	Pointer to napi_struct structure.
286  * @budget:	How many BDs to process on 1 call.
287  *
288  * returns:	Number of processed BDs
289  */
290 static int arc_emac_poll(struct napi_struct *napi, int budget)
291 {
292 	struct net_device *ndev = napi->dev;
293 	struct arc_emac_priv *priv = netdev_priv(ndev);
294 	unsigned int work_done;
295 
296 	arc_emac_tx_clean(ndev);
297 
298 	work_done = arc_emac_rx(ndev, budget);
299 	if (work_done < budget) {
300 		napi_complete(napi);
301 		arc_reg_or(priv, R_ENABLE, RXINT_MASK);
302 	}
303 
304 	return work_done;
305 }
306 
307 /**
308  * arc_emac_intr - Global interrupt handler for EMAC.
309  * @irq:		irq number.
310  * @dev_instance:	device instance.
311  *
312  * returns: IRQ_HANDLED for all cases.
313  *
314  * ARC EMAC has only 1 interrupt line, and depending on bits raised in
315  * STATUS register we may tell what is a reason for interrupt to fire.
316  */
317 static irqreturn_t arc_emac_intr(int irq, void *dev_instance)
318 {
319 	struct net_device *ndev = dev_instance;
320 	struct arc_emac_priv *priv = netdev_priv(ndev);
321 	struct net_device_stats *stats = &ndev->stats;
322 	unsigned int status;
323 
324 	status = arc_reg_get(priv, R_STATUS);
325 	status &= ~MDIO_MASK;
326 
327 	/* Reset all flags except "MDIO complete" */
328 	arc_reg_set(priv, R_STATUS, status);
329 
330 	if (status & RXINT_MASK) {
331 		if (likely(napi_schedule_prep(&priv->napi))) {
332 			arc_reg_clr(priv, R_ENABLE, RXINT_MASK);
333 			__napi_schedule(&priv->napi);
334 		}
335 	}
336 
337 	if (status & ERR_MASK) {
338 		/* MSER/RXCR/RXFR/RXFL interrupt fires on corresponding
339 		 * 8-bit error counter overrun.
340 		 */
341 
342 		if (status & MSER_MASK) {
343 			stats->rx_missed_errors += 0x100;
344 			stats->rx_errors += 0x100;
345 		}
346 
347 		if (status & RXCR_MASK) {
348 			stats->rx_crc_errors += 0x100;
349 			stats->rx_errors += 0x100;
350 		}
351 
352 		if (status & RXFR_MASK) {
353 			stats->rx_frame_errors += 0x100;
354 			stats->rx_errors += 0x100;
355 		}
356 
357 		if (status & RXFL_MASK) {
358 			stats->rx_over_errors += 0x100;
359 			stats->rx_errors += 0x100;
360 		}
361 	}
362 
363 	return IRQ_HANDLED;
364 }
365 
366 #ifdef CONFIG_NET_POLL_CONTROLLER
367 static void arc_emac_poll_controller(struct net_device *dev)
368 {
369 	disable_irq(dev->irq);
370 	arc_emac_intr(dev->irq, dev);
371 	enable_irq(dev->irq);
372 }
373 #endif
374 
375 /**
376  * arc_emac_open - Open the network device.
377  * @ndev:	Pointer to the network device.
378  *
379  * returns: 0, on success or non-zero error value on failure.
380  *
381  * This function sets the MAC address, requests and enables an IRQ
382  * for the EMAC device and starts the Tx queue.
383  * It also connects to the phy device.
384  */
385 static int arc_emac_open(struct net_device *ndev)
386 {
387 	struct arc_emac_priv *priv = netdev_priv(ndev);
388 	struct phy_device *phy_dev = priv->phy_dev;
389 	int i;
390 
391 	phy_dev->autoneg = AUTONEG_ENABLE;
392 	phy_dev->speed = 0;
393 	phy_dev->duplex = 0;
394 	phy_dev->advertising &= phy_dev->supported;
395 
396 	priv->last_rx_bd = 0;
397 
398 	/* Allocate and set buffers for Rx BD's */
399 	for (i = 0; i < RX_BD_NUM; i++) {
400 		dma_addr_t addr;
401 		unsigned int *last_rx_bd = &priv->last_rx_bd;
402 		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
403 		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
404 
405 		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
406 							 EMAC_BUFFER_SIZE);
407 		if (unlikely(!rx_buff->skb))
408 			return -ENOMEM;
409 
410 		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
411 				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
412 		if (dma_mapping_error(&ndev->dev, addr)) {
413 			netdev_err(ndev, "cannot dma map\n");
414 			dev_kfree_skb(rx_buff->skb);
415 			return -ENOMEM;
416 		}
417 		dma_unmap_addr_set(rx_buff, addr, addr);
418 		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
419 
420 		rxbd->data = cpu_to_le32(addr);
421 
422 		/* Make sure pointer to data buffer is set */
423 		wmb();
424 
425 		/* Return ownership to EMAC */
426 		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
427 
428 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
429 	}
430 
431 	/* Clean Tx BD's */
432 	memset(priv->txbd, 0, TX_RING_SZ);
433 
434 	/* Initialize logical address filter */
435 	arc_reg_set(priv, R_LAFL, 0);
436 	arc_reg_set(priv, R_LAFH, 0);
437 
438 	/* Set BD ring pointers for device side */
439 	arc_reg_set(priv, R_RX_RING, (unsigned int)priv->rxbd_dma);
440 	arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma);
441 
442 	/* Enable interrupts */
443 	arc_reg_set(priv, R_ENABLE, RXINT_MASK | ERR_MASK);
444 
445 	/* Set CONTROL */
446 	arc_reg_set(priv, R_CTRL,
447 		     (RX_BD_NUM << 24) |	/* RX BD table length */
448 		     (TX_BD_NUM << 16) |	/* TX BD table length */
449 		     TXRN_MASK | RXRN_MASK);
450 
451 	napi_enable(&priv->napi);
452 
453 	/* Enable EMAC */
454 	arc_reg_or(priv, R_CTRL, EN_MASK);
455 
456 	phy_start_aneg(priv->phy_dev);
457 
458 	netif_start_queue(ndev);
459 
460 	return 0;
461 }
462 
463 /**
464  * arc_emac_set_rx_mode - Change the receive filtering mode.
465  * @ndev:	Pointer to the network device.
466  *
467  * This function enables/disables promiscuous or all-multicast mode
468  * and updates the multicast filtering list of the network device.
469  */
470 static void arc_emac_set_rx_mode(struct net_device *ndev)
471 {
472 	struct arc_emac_priv *priv = netdev_priv(ndev);
473 
474 	if (ndev->flags & IFF_PROMISC) {
475 		arc_reg_or(priv, R_CTRL, PROM_MASK);
476 	} else {
477 		arc_reg_clr(priv, R_CTRL, PROM_MASK);
478 
479 		if (ndev->flags & IFF_ALLMULTI) {
480 			arc_reg_set(priv, R_LAFL, ~0);
481 			arc_reg_set(priv, R_LAFH, ~0);
482 		} else {
483 			struct netdev_hw_addr *ha;
484 			unsigned int filter[2] = { 0, 0 };
485 			int bit;
486 
487 			netdev_for_each_mc_addr(ha, ndev) {
488 				bit = ether_crc_le(ETH_ALEN, ha->addr) >> 26;
489 				filter[bit >> 5] |= 1 << (bit & 31);
490 			}
491 
492 			arc_reg_set(priv, R_LAFL, filter[0]);
493 			arc_reg_set(priv, R_LAFH, filter[1]);
494 		}
495 	}
496 }
497 
498 /**
499  * arc_emac_stop - Close the network device.
500  * @ndev:	Pointer to the network device.
501  *
502  * This function stops the Tx queue, disables interrupts and frees the IRQ for
503  * the EMAC device.
504  * It also disconnects the PHY device associated with the EMAC device.
505  */
506 static int arc_emac_stop(struct net_device *ndev)
507 {
508 	struct arc_emac_priv *priv = netdev_priv(ndev);
509 
510 	napi_disable(&priv->napi);
511 	netif_stop_queue(ndev);
512 
513 	/* Disable interrupts */
514 	arc_reg_clr(priv, R_ENABLE, RXINT_MASK | ERR_MASK);
515 
516 	/* Disable EMAC */
517 	arc_reg_clr(priv, R_CTRL, EN_MASK);
518 
519 	return 0;
520 }
521 
522 /**
523  * arc_emac_stats - Get system network statistics.
524  * @ndev:	Pointer to net_device structure.
525  *
526  * Returns the address of the device statistics structure.
527  * Statistics are updated in interrupt handler.
528  */
529 static struct net_device_stats *arc_emac_stats(struct net_device *ndev)
530 {
531 	struct arc_emac_priv *priv = netdev_priv(ndev);
532 	struct net_device_stats *stats = &ndev->stats;
533 	unsigned long miss, rxerr;
534 	u8 rxcrc, rxfram, rxoflow;
535 
536 	rxerr = arc_reg_get(priv, R_RXERR);
537 	miss = arc_reg_get(priv, R_MISS);
538 
539 	rxcrc = rxerr;
540 	rxfram = rxerr >> 8;
541 	rxoflow = rxerr >> 16;
542 
543 	stats->rx_errors += miss;
544 	stats->rx_errors += rxcrc + rxfram + rxoflow;
545 
546 	stats->rx_over_errors += rxoflow;
547 	stats->rx_frame_errors += rxfram;
548 	stats->rx_crc_errors += rxcrc;
549 	stats->rx_missed_errors += miss;
550 
551 	return stats;
552 }
553 
554 /**
555  * arc_emac_tx - Starts the data transmission.
556  * @skb:	sk_buff pointer that contains data to be Transmitted.
557  * @ndev:	Pointer to net_device structure.
558  *
559  * returns: NETDEV_TX_OK, on success
560  *		NETDEV_TX_BUSY, if any of the descriptors are not free.
561  *
562  * This function is invoked from upper layers to initiate transmission.
563  */
564 static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
565 {
566 	struct arc_emac_priv *priv = netdev_priv(ndev);
567 	unsigned int len, *txbd_curr = &priv->txbd_curr;
568 	struct net_device_stats *stats = &ndev->stats;
569 	__le32 *info = &priv->txbd[*txbd_curr].info;
570 	dma_addr_t addr;
571 
572 	if (skb_padto(skb, ETH_ZLEN))
573 		return NETDEV_TX_OK;
574 
575 	len = max_t(unsigned int, ETH_ZLEN, skb->len);
576 
577 	/* EMAC still holds this buffer in its possession.
578 	 * CPU must not modify this buffer descriptor
579 	 */
580 	if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC)) {
581 		netif_stop_queue(ndev);
582 		return NETDEV_TX_BUSY;
583 	}
584 
585 	addr = dma_map_single(&ndev->dev, (void *)skb->data, len,
586 			      DMA_TO_DEVICE);
587 
588 	if (unlikely(dma_mapping_error(&ndev->dev, addr))) {
589 		stats->tx_dropped++;
590 		stats->tx_errors++;
591 		dev_kfree_skb(skb);
592 		return NETDEV_TX_OK;
593 	}
594 	dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], addr, addr);
595 	dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);
596 
597 	priv->tx_buff[*txbd_curr].skb = skb;
598 	priv->txbd[*txbd_curr].data = cpu_to_le32(addr);
599 
600 	/* Make sure pointer to data buffer is set */
601 	wmb();
602 
603 	skb_tx_timestamp(skb);
604 
605 	*info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);
606 
607 	/* Increment index to point to the next BD */
608 	*txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;
609 
610 	/* Get "info" of the next BD */
611 	info = &priv->txbd[*txbd_curr].info;
612 
613 	/* Check if if Tx BD ring is full - next BD is still owned by EMAC */
614 	if (unlikely((le32_to_cpu(*info) & OWN_MASK) == FOR_EMAC))
615 		netif_stop_queue(ndev);
616 
617 	arc_reg_set(priv, R_STATUS, TXPL_MASK);
618 
619 	return NETDEV_TX_OK;
620 }
621 
622 static void arc_emac_set_address_internal(struct net_device *ndev)
623 {
624 	struct arc_emac_priv *priv = netdev_priv(ndev);
625 	unsigned int addr_low, addr_hi;
626 
627 	addr_low = le32_to_cpu(*(__le32 *) &ndev->dev_addr[0]);
628 	addr_hi = le16_to_cpu(*(__le16 *) &ndev->dev_addr[4]);
629 
630 	arc_reg_set(priv, R_ADDRL, addr_low);
631 	arc_reg_set(priv, R_ADDRH, addr_hi);
632 }
633 
634 /**
635  * arc_emac_set_address - Set the MAC address for this device.
636  * @ndev:	Pointer to net_device structure.
637  * @p:		6 byte Address to be written as MAC address.
638  *
639  * This function copies the HW address from the sockaddr structure to the
640  * net_device structure and updates the address in HW.
641  *
642  * returns:	-EBUSY if the net device is busy or 0 if the address is set
643  *		successfully.
644  */
645 static int arc_emac_set_address(struct net_device *ndev, void *p)
646 {
647 	struct sockaddr *addr = p;
648 
649 	if (netif_running(ndev))
650 		return -EBUSY;
651 
652 	if (!is_valid_ether_addr(addr->sa_data))
653 		return -EADDRNOTAVAIL;
654 
655 	memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
656 
657 	arc_emac_set_address_internal(ndev);
658 
659 	return 0;
660 }
661 
662 static const struct net_device_ops arc_emac_netdev_ops = {
663 	.ndo_open		= arc_emac_open,
664 	.ndo_stop		= arc_emac_stop,
665 	.ndo_start_xmit		= arc_emac_tx,
666 	.ndo_set_mac_address	= arc_emac_set_address,
667 	.ndo_get_stats		= arc_emac_stats,
668 	.ndo_set_rx_mode	= arc_emac_set_rx_mode,
669 #ifdef CONFIG_NET_POLL_CONTROLLER
670 	.ndo_poll_controller	= arc_emac_poll_controller,
671 #endif
672 };
673 
674 static int arc_emac_probe(struct platform_device *pdev)
675 {
676 	struct resource res_regs;
677 	struct device_node *phy_node;
678 	struct arc_emac_priv *priv;
679 	struct net_device *ndev;
680 	const char *mac_addr;
681 	unsigned int id, clock_frequency, irq;
682 	int err;
683 
684 	if (!pdev->dev.of_node)
685 		return -ENODEV;
686 
687 	/* Get PHY from device tree */
688 	phy_node = of_parse_phandle(pdev->dev.of_node, "phy", 0);
689 	if (!phy_node) {
690 		dev_err(&pdev->dev, "failed to retrieve phy description from device tree\n");
691 		return -ENODEV;
692 	}
693 
694 	/* Get EMAC registers base address from device tree */
695 	err = of_address_to_resource(pdev->dev.of_node, 0, &res_regs);
696 	if (err) {
697 		dev_err(&pdev->dev, "failed to retrieve registers base from device tree\n");
698 		return -ENODEV;
699 	}
700 
701 	/* Get IRQ from device tree */
702 	irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
703 	if (!irq) {
704 		dev_err(&pdev->dev, "failed to retrieve <irq> value from device tree\n");
705 		return -ENODEV;
706 	}
707 
708 	ndev = alloc_etherdev(sizeof(struct arc_emac_priv));
709 	if (!ndev)
710 		return -ENOMEM;
711 
712 	platform_set_drvdata(pdev, ndev);
713 	SET_NETDEV_DEV(ndev, &pdev->dev);
714 
715 	ndev->netdev_ops = &arc_emac_netdev_ops;
716 	ndev->ethtool_ops = &arc_emac_ethtool_ops;
717 	ndev->watchdog_timeo = TX_TIMEOUT;
718 	/* FIXME :: no multicast support yet */
719 	ndev->flags &= ~IFF_MULTICAST;
720 
721 	priv = netdev_priv(ndev);
722 	priv->dev = &pdev->dev;
723 
724 	priv->regs = devm_ioremap_resource(&pdev->dev, &res_regs);
725 	if (IS_ERR(priv->regs)) {
726 		err = PTR_ERR(priv->regs);
727 		goto out_netdev;
728 	}
729 	dev_dbg(&pdev->dev, "Registers base address is 0x%p\n", priv->regs);
730 
731 	priv->clk = of_clk_get(pdev->dev.of_node, 0);
732 	if (IS_ERR(priv->clk)) {
733 		/* Get CPU clock frequency from device tree */
734 		if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
735 					&clock_frequency)) {
736 			dev_err(&pdev->dev, "failed to retrieve <clock-frequency> from device tree\n");
737 			err = -EINVAL;
738 			goto out_netdev;
739 		}
740 	} else {
741 		err = clk_prepare_enable(priv->clk);
742 		if (err) {
743 			dev_err(&pdev->dev, "failed to enable clock\n");
744 			goto out_clkget;
745 		}
746 
747 		clock_frequency = clk_get_rate(priv->clk);
748 	}
749 
750 	id = arc_reg_get(priv, R_ID);
751 
752 	/* Check for EMAC revision 5 or 7, magic number */
753 	if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
754 		dev_err(&pdev->dev, "ARC EMAC not detected, id=0x%x\n", id);
755 		err = -ENODEV;
756 		goto out_clken;
757 	}
758 	dev_info(&pdev->dev, "ARC EMAC detected with id: 0x%x\n", id);
759 
760 	/* Set poll rate so that it polls every 1 ms */
761 	arc_reg_set(priv, R_POLLRATE, clock_frequency / 1000000);
762 
763 	ndev->irq = irq;
764 	dev_info(&pdev->dev, "IRQ is %d\n", ndev->irq);
765 
766 	/* Register interrupt handler for device */
767 	err = devm_request_irq(&pdev->dev, ndev->irq, arc_emac_intr, 0,
768 			       ndev->name, ndev);
769 	if (err) {
770 		dev_err(&pdev->dev, "could not allocate IRQ\n");
771 		goto out_clken;
772 	}
773 
774 	/* Get MAC address from device tree */
775 	mac_addr = of_get_mac_address(pdev->dev.of_node);
776 
777 	if (mac_addr)
778 		memcpy(ndev->dev_addr, mac_addr, ETH_ALEN);
779 	else
780 		eth_hw_addr_random(ndev);
781 
782 	arc_emac_set_address_internal(ndev);
783 	dev_info(&pdev->dev, "MAC address is now %pM\n", ndev->dev_addr);
784 
785 	/* Do 1 allocation instead of 2 separate ones for Rx and Tx BD rings */
786 	priv->rxbd = dmam_alloc_coherent(&pdev->dev, RX_RING_SZ + TX_RING_SZ,
787 					 &priv->rxbd_dma, GFP_KERNEL);
788 
789 	if (!priv->rxbd) {
790 		dev_err(&pdev->dev, "failed to allocate data buffers\n");
791 		err = -ENOMEM;
792 		goto out_clken;
793 	}
794 
795 	priv->txbd = priv->rxbd + RX_BD_NUM;
796 
797 	priv->txbd_dma = priv->rxbd_dma + RX_RING_SZ;
798 	dev_dbg(&pdev->dev, "EMAC Device addr: Rx Ring [0x%x], Tx Ring[%x]\n",
799 		(unsigned int)priv->rxbd_dma, (unsigned int)priv->txbd_dma);
800 
801 	err = arc_mdio_probe(pdev, priv);
802 	if (err) {
803 		dev_err(&pdev->dev, "failed to probe MII bus\n");
804 		goto out_clken;
805 	}
806 
807 	priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
808 				       PHY_INTERFACE_MODE_MII);
809 	if (!priv->phy_dev) {
810 		dev_err(&pdev->dev, "of_phy_connect() failed\n");
811 		err = -ENODEV;
812 		goto out_mdio;
813 	}
814 
815 	dev_info(&pdev->dev, "connected to %s phy with id 0x%x\n",
816 		 priv->phy_dev->drv->name, priv->phy_dev->phy_id);
817 
818 	netif_napi_add(ndev, &priv->napi, arc_emac_poll, ARC_EMAC_NAPI_WEIGHT);
819 
820 	err = register_netdev(ndev);
821 	if (err) {
822 		dev_err(&pdev->dev, "failed to register network device\n");
823 		goto out_netif_api;
824 	}
825 
826 	return 0;
827 
828 out_netif_api:
829 	netif_napi_del(&priv->napi);
830 	phy_disconnect(priv->phy_dev);
831 	priv->phy_dev = NULL;
832 out_mdio:
833 	arc_mdio_remove(priv);
834 out_clken:
835 	if (!IS_ERR(priv->clk))
836 		clk_disable_unprepare(priv->clk);
837 out_clkget:
838 	if (!IS_ERR(priv->clk))
839 		clk_put(priv->clk);
840 out_netdev:
841 	free_netdev(ndev);
842 	return err;
843 }
844 
845 static int arc_emac_remove(struct platform_device *pdev)
846 {
847 	struct net_device *ndev = platform_get_drvdata(pdev);
848 	struct arc_emac_priv *priv = netdev_priv(ndev);
849 
850 	phy_disconnect(priv->phy_dev);
851 	priv->phy_dev = NULL;
852 	arc_mdio_remove(priv);
853 	unregister_netdev(ndev);
854 	netif_napi_del(&priv->napi);
855 
856 	if (!IS_ERR(priv->clk)) {
857 		clk_disable_unprepare(priv->clk);
858 		clk_put(priv->clk);
859 	}
860 
861 	free_netdev(ndev);
862 
863 	return 0;
864 }
865 
866 static const struct of_device_id arc_emac_dt_ids[] = {
867 	{ .compatible = "snps,arc-emac" },
868 	{ /* Sentinel */ }
869 };
870 MODULE_DEVICE_TABLE(of, arc_emac_dt_ids);
871 
872 static struct platform_driver arc_emac_driver = {
873 	.probe = arc_emac_probe,
874 	.remove = arc_emac_remove,
875 	.driver = {
876 		.name = DRV_NAME,
877 		.owner = THIS_MODULE,
878 		.of_match_table  = arc_emac_dt_ids,
879 		},
880 };
881 
882 module_platform_driver(arc_emac_driver);
883 
884 MODULE_AUTHOR("Alexey Brodkin <abrodkin@synopsys.com>");
885 MODULE_DESCRIPTION("ARC EMAC driver");
886 MODULE_LICENSE("GPL");
887