xref: /linux/drivers/net/ethernet/arc/emac_main.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
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)
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 
195 		*txbd_dirty = (*txbd_dirty + 1) % TX_BD_NUM;
196 	}
197 
198 	/* Ensure that txbd_dirty is visible to tx() before checking
199 	 * for queue stopped.
200 	 */
201 	smp_mb();
202 
203 	if (netif_queue_stopped(ndev) && arc_emac_tx_avail(priv))
204 		netif_wake_queue(ndev);
205 }
206 
207 /**
208  * arc_emac_rx - processing of Rx packets.
209  * @ndev:	Pointer to the network device.
210  * @budget:	How many BDs to process on 1 call.
211  *
212  * returns:	Number of processed BDs
213  *
214  * Iterate through Rx BDs and deliver received packages to upper layer.
215  */
216 static int arc_emac_rx(struct net_device *ndev, int budget)
217 {
218 	struct arc_emac_priv *priv = netdev_priv(ndev);
219 	unsigned int work_done;
220 
221 	for (work_done = 0; work_done < budget; work_done++) {
222 		unsigned int *last_rx_bd = &priv->last_rx_bd;
223 		struct net_device_stats *stats = &ndev->stats;
224 		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
225 		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
226 		unsigned int pktlen, info = le32_to_cpu(rxbd->info);
227 		struct sk_buff *skb;
228 		dma_addr_t addr;
229 
230 		if (unlikely((info & OWN_MASK) == FOR_EMAC))
231 			break;
232 
233 		/* Make a note that we saw a packet at this BD.
234 		 * So next time, driver starts from this + 1
235 		 */
236 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
237 
238 		if (unlikely((info & FIRST_OR_LAST_MASK) !=
239 			     FIRST_OR_LAST_MASK)) {
240 			/* We pre-allocate buffers of MTU size so incoming
241 			 * packets won't be split/chained.
242 			 */
243 			if (net_ratelimit())
244 				netdev_err(ndev, "incomplete packet received\n");
245 
246 			/* Return ownership to EMAC */
247 			rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
248 			stats->rx_errors++;
249 			stats->rx_length_errors++;
250 			continue;
251 		}
252 
253 		pktlen = info & LEN_MASK;
254 		stats->rx_packets++;
255 		stats->rx_bytes += pktlen;
256 		skb = rx_buff->skb;
257 		skb_put(skb, pktlen);
258 		skb->dev = ndev;
259 		skb->protocol = eth_type_trans(skb, ndev);
260 
261 		dma_unmap_single(&ndev->dev, dma_unmap_addr(rx_buff, addr),
262 				 dma_unmap_len(rx_buff, len), DMA_FROM_DEVICE);
263 
264 		/* Prepare the BD for next cycle */
265 		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
266 							 EMAC_BUFFER_SIZE);
267 		if (unlikely(!rx_buff->skb)) {
268 			stats->rx_errors++;
269 			/* Because receive_skb is below, increment rx_dropped */
270 			stats->rx_dropped++;
271 			continue;
272 		}
273 
274 		/* receive_skb only if new skb was allocated to avoid holes */
275 		netif_receive_skb(skb);
276 
277 		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
278 				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
279 		if (dma_mapping_error(&ndev->dev, addr)) {
280 			if (net_ratelimit())
281 				netdev_err(ndev, "cannot dma map\n");
282 			dev_kfree_skb(rx_buff->skb);
283 			stats->rx_errors++;
284 			continue;
285 		}
286 		dma_unmap_addr_set(rx_buff, addr, addr);
287 		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
288 
289 		rxbd->data = cpu_to_le32(addr);
290 
291 		/* Make sure pointer to data buffer is set */
292 		wmb();
293 
294 		/* Return ownership to EMAC */
295 		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
296 	}
297 
298 	return work_done;
299 }
300 
301 /**
302  * arc_emac_poll - NAPI poll handler.
303  * @napi:	Pointer to napi_struct structure.
304  * @budget:	How many BDs to process on 1 call.
305  *
306  * returns:	Number of processed BDs
307  */
308 static int arc_emac_poll(struct napi_struct *napi, int budget)
309 {
310 	struct net_device *ndev = napi->dev;
311 	struct arc_emac_priv *priv = netdev_priv(ndev);
312 	unsigned int work_done;
313 
314 	arc_emac_tx_clean(ndev);
315 
316 	work_done = arc_emac_rx(ndev, budget);
317 	if (work_done < budget) {
318 		napi_complete(napi);
319 		arc_reg_or(priv, R_ENABLE, RXINT_MASK | TXINT_MASK);
320 	}
321 
322 	return work_done;
323 }
324 
325 /**
326  * arc_emac_intr - Global interrupt handler for EMAC.
327  * @irq:		irq number.
328  * @dev_instance:	device instance.
329  *
330  * returns: IRQ_HANDLED for all cases.
331  *
332  * ARC EMAC has only 1 interrupt line, and depending on bits raised in
333  * STATUS register we may tell what is a reason for interrupt to fire.
334  */
335 static irqreturn_t arc_emac_intr(int irq, void *dev_instance)
336 {
337 	struct net_device *ndev = dev_instance;
338 	struct arc_emac_priv *priv = netdev_priv(ndev);
339 	struct net_device_stats *stats = &ndev->stats;
340 	unsigned int status;
341 
342 	status = arc_reg_get(priv, R_STATUS);
343 	status &= ~MDIO_MASK;
344 
345 	/* Reset all flags except "MDIO complete" */
346 	arc_reg_set(priv, R_STATUS, status);
347 
348 	if (status & (RXINT_MASK | TXINT_MASK)) {
349 		if (likely(napi_schedule_prep(&priv->napi))) {
350 			arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK);
351 			__napi_schedule(&priv->napi);
352 		}
353 	}
354 
355 	if (status & ERR_MASK) {
356 		/* MSER/RXCR/RXFR/RXFL interrupt fires on corresponding
357 		 * 8-bit error counter overrun.
358 		 */
359 
360 		if (status & MSER_MASK) {
361 			stats->rx_missed_errors += 0x100;
362 			stats->rx_errors += 0x100;
363 		}
364 
365 		if (status & RXCR_MASK) {
366 			stats->rx_crc_errors += 0x100;
367 			stats->rx_errors += 0x100;
368 		}
369 
370 		if (status & RXFR_MASK) {
371 			stats->rx_frame_errors += 0x100;
372 			stats->rx_errors += 0x100;
373 		}
374 
375 		if (status & RXFL_MASK) {
376 			stats->rx_over_errors += 0x100;
377 			stats->rx_errors += 0x100;
378 		}
379 	}
380 
381 	return IRQ_HANDLED;
382 }
383 
384 #ifdef CONFIG_NET_POLL_CONTROLLER
385 static void arc_emac_poll_controller(struct net_device *dev)
386 {
387 	disable_irq(dev->irq);
388 	arc_emac_intr(dev->irq, dev);
389 	enable_irq(dev->irq);
390 }
391 #endif
392 
393 /**
394  * arc_emac_open - Open the network device.
395  * @ndev:	Pointer to the network device.
396  *
397  * returns: 0, on success or non-zero error value on failure.
398  *
399  * This function sets the MAC address, requests and enables an IRQ
400  * for the EMAC device and starts the Tx queue.
401  * It also connects to the phy device.
402  */
403 static int arc_emac_open(struct net_device *ndev)
404 {
405 	struct arc_emac_priv *priv = netdev_priv(ndev);
406 	struct phy_device *phy_dev = priv->phy_dev;
407 	int i;
408 
409 	phy_dev->autoneg = AUTONEG_ENABLE;
410 	phy_dev->speed = 0;
411 	phy_dev->duplex = 0;
412 	phy_dev->advertising &= phy_dev->supported;
413 
414 	priv->last_rx_bd = 0;
415 
416 	/* Allocate and set buffers for Rx BD's */
417 	for (i = 0; i < RX_BD_NUM; i++) {
418 		dma_addr_t addr;
419 		unsigned int *last_rx_bd = &priv->last_rx_bd;
420 		struct arc_emac_bd *rxbd = &priv->rxbd[*last_rx_bd];
421 		struct buffer_state *rx_buff = &priv->rx_buff[*last_rx_bd];
422 
423 		rx_buff->skb = netdev_alloc_skb_ip_align(ndev,
424 							 EMAC_BUFFER_SIZE);
425 		if (unlikely(!rx_buff->skb))
426 			return -ENOMEM;
427 
428 		addr = dma_map_single(&ndev->dev, (void *)rx_buff->skb->data,
429 				      EMAC_BUFFER_SIZE, DMA_FROM_DEVICE);
430 		if (dma_mapping_error(&ndev->dev, addr)) {
431 			netdev_err(ndev, "cannot dma map\n");
432 			dev_kfree_skb(rx_buff->skb);
433 			return -ENOMEM;
434 		}
435 		dma_unmap_addr_set(rx_buff, addr, addr);
436 		dma_unmap_len_set(rx_buff, len, EMAC_BUFFER_SIZE);
437 
438 		rxbd->data = cpu_to_le32(addr);
439 
440 		/* Make sure pointer to data buffer is set */
441 		wmb();
442 
443 		/* Return ownership to EMAC */
444 		rxbd->info = cpu_to_le32(FOR_EMAC | EMAC_BUFFER_SIZE);
445 
446 		*last_rx_bd = (*last_rx_bd + 1) % RX_BD_NUM;
447 	}
448 
449 	/* Clean Tx BD's */
450 	memset(priv->txbd, 0, TX_RING_SZ);
451 
452 	/* Initialize logical address filter */
453 	arc_reg_set(priv, R_LAFL, 0);
454 	arc_reg_set(priv, R_LAFH, 0);
455 
456 	/* Set BD ring pointers for device side */
457 	arc_reg_set(priv, R_RX_RING, (unsigned int)priv->rxbd_dma);
458 	arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma);
459 
460 	/* Enable interrupts */
461 	arc_reg_set(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK);
462 
463 	/* Set CONTROL */
464 	arc_reg_set(priv, R_CTRL,
465 		     (RX_BD_NUM << 24) |	/* RX BD table length */
466 		     (TX_BD_NUM << 16) |	/* TX BD table length */
467 		     TXRN_MASK | RXRN_MASK);
468 
469 	napi_enable(&priv->napi);
470 
471 	/* Enable EMAC */
472 	arc_reg_or(priv, R_CTRL, EN_MASK);
473 
474 	phy_start_aneg(priv->phy_dev);
475 
476 	netif_start_queue(ndev);
477 
478 	return 0;
479 }
480 
481 /**
482  * arc_emac_set_rx_mode - Change the receive filtering mode.
483  * @ndev:	Pointer to the network device.
484  *
485  * This function enables/disables promiscuous or all-multicast mode
486  * and updates the multicast filtering list of the network device.
487  */
488 static void arc_emac_set_rx_mode(struct net_device *ndev)
489 {
490 	struct arc_emac_priv *priv = netdev_priv(ndev);
491 
492 	if (ndev->flags & IFF_PROMISC) {
493 		arc_reg_or(priv, R_CTRL, PROM_MASK);
494 	} else {
495 		arc_reg_clr(priv, R_CTRL, PROM_MASK);
496 
497 		if (ndev->flags & IFF_ALLMULTI) {
498 			arc_reg_set(priv, R_LAFL, ~0);
499 			arc_reg_set(priv, R_LAFH, ~0);
500 		} else {
501 			struct netdev_hw_addr *ha;
502 			unsigned int filter[2] = { 0, 0 };
503 			int bit;
504 
505 			netdev_for_each_mc_addr(ha, ndev) {
506 				bit = ether_crc_le(ETH_ALEN, ha->addr) >> 26;
507 				filter[bit >> 5] |= 1 << (bit & 31);
508 			}
509 
510 			arc_reg_set(priv, R_LAFL, filter[0]);
511 			arc_reg_set(priv, R_LAFH, filter[1]);
512 		}
513 	}
514 }
515 
516 /**
517  * arc_emac_stop - Close the network device.
518  * @ndev:	Pointer to the network device.
519  *
520  * This function stops the Tx queue, disables interrupts and frees the IRQ for
521  * the EMAC device.
522  * It also disconnects the PHY device associated with the EMAC device.
523  */
524 static int arc_emac_stop(struct net_device *ndev)
525 {
526 	struct arc_emac_priv *priv = netdev_priv(ndev);
527 
528 	napi_disable(&priv->napi);
529 	netif_stop_queue(ndev);
530 
531 	/* Disable interrupts */
532 	arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK);
533 
534 	/* Disable EMAC */
535 	arc_reg_clr(priv, R_CTRL, EN_MASK);
536 
537 	return 0;
538 }
539 
540 /**
541  * arc_emac_stats - Get system network statistics.
542  * @ndev:	Pointer to net_device structure.
543  *
544  * Returns the address of the device statistics structure.
545  * Statistics are updated in interrupt handler.
546  */
547 static struct net_device_stats *arc_emac_stats(struct net_device *ndev)
548 {
549 	struct arc_emac_priv *priv = netdev_priv(ndev);
550 	struct net_device_stats *stats = &ndev->stats;
551 	unsigned long miss, rxerr;
552 	u8 rxcrc, rxfram, rxoflow;
553 
554 	rxerr = arc_reg_get(priv, R_RXERR);
555 	miss = arc_reg_get(priv, R_MISS);
556 
557 	rxcrc = rxerr;
558 	rxfram = rxerr >> 8;
559 	rxoflow = rxerr >> 16;
560 
561 	stats->rx_errors += miss;
562 	stats->rx_errors += rxcrc + rxfram + rxoflow;
563 
564 	stats->rx_over_errors += rxoflow;
565 	stats->rx_frame_errors += rxfram;
566 	stats->rx_crc_errors += rxcrc;
567 	stats->rx_missed_errors += miss;
568 
569 	return stats;
570 }
571 
572 /**
573  * arc_emac_tx - Starts the data transmission.
574  * @skb:	sk_buff pointer that contains data to be Transmitted.
575  * @ndev:	Pointer to net_device structure.
576  *
577  * returns: NETDEV_TX_OK, on success
578  *		NETDEV_TX_BUSY, if any of the descriptors are not free.
579  *
580  * This function is invoked from upper layers to initiate transmission.
581  */
582 static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
583 {
584 	struct arc_emac_priv *priv = netdev_priv(ndev);
585 	unsigned int len, *txbd_curr = &priv->txbd_curr;
586 	struct net_device_stats *stats = &ndev->stats;
587 	__le32 *info = &priv->txbd[*txbd_curr].info;
588 	dma_addr_t addr;
589 
590 	if (skb_padto(skb, ETH_ZLEN))
591 		return NETDEV_TX_OK;
592 
593 	len = max_t(unsigned int, ETH_ZLEN, skb->len);
594 
595 	if (unlikely(!arc_emac_tx_avail(priv))) {
596 		netif_stop_queue(ndev);
597 		netdev_err(ndev, "BUG! Tx Ring full when queue awake!\n");
598 		return NETDEV_TX_BUSY;
599 	}
600 
601 	addr = dma_map_single(&ndev->dev, (void *)skb->data, len,
602 			      DMA_TO_DEVICE);
603 
604 	if (unlikely(dma_mapping_error(&ndev->dev, addr))) {
605 		stats->tx_dropped++;
606 		stats->tx_errors++;
607 		dev_kfree_skb(skb);
608 		return NETDEV_TX_OK;
609 	}
610 	dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], addr, addr);
611 	dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);
612 
613 	priv->tx_buff[*txbd_curr].skb = skb;
614 	priv->txbd[*txbd_curr].data = cpu_to_le32(addr);
615 
616 	/* Make sure pointer to data buffer is set */
617 	wmb();
618 
619 	skb_tx_timestamp(skb);
620 
621 	*info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);
622 
623 	/* Increment index to point to the next BD */
624 	*txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;
625 
626 	/* Ensure that tx_clean() sees the new txbd_curr before
627 	 * checking the queue status. This prevents an unneeded wake
628 	 * of the queue in tx_clean().
629 	 */
630 	smp_mb();
631 
632 	if (!arc_emac_tx_avail(priv)) {
633 		netif_stop_queue(ndev);
634 		/* Refresh tx_dirty */
635 		smp_mb();
636 		if (arc_emac_tx_avail(priv))
637 			netif_start_queue(ndev);
638 	}
639 
640 	arc_reg_set(priv, R_STATUS, TXPL_MASK);
641 
642 	return NETDEV_TX_OK;
643 }
644 
645 static void arc_emac_set_address_internal(struct net_device *ndev)
646 {
647 	struct arc_emac_priv *priv = netdev_priv(ndev);
648 	unsigned int addr_low, addr_hi;
649 
650 	addr_low = le32_to_cpu(*(__le32 *) &ndev->dev_addr[0]);
651 	addr_hi = le16_to_cpu(*(__le16 *) &ndev->dev_addr[4]);
652 
653 	arc_reg_set(priv, R_ADDRL, addr_low);
654 	arc_reg_set(priv, R_ADDRH, addr_hi);
655 }
656 
657 /**
658  * arc_emac_set_address - Set the MAC address for this device.
659  * @ndev:	Pointer to net_device structure.
660  * @p:		6 byte Address to be written as MAC address.
661  *
662  * This function copies the HW address from the sockaddr structure to the
663  * net_device structure and updates the address in HW.
664  *
665  * returns:	-EBUSY if the net device is busy or 0 if the address is set
666  *		successfully.
667  */
668 static int arc_emac_set_address(struct net_device *ndev, void *p)
669 {
670 	struct sockaddr *addr = p;
671 
672 	if (netif_running(ndev))
673 		return -EBUSY;
674 
675 	if (!is_valid_ether_addr(addr->sa_data))
676 		return -EADDRNOTAVAIL;
677 
678 	memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
679 
680 	arc_emac_set_address_internal(ndev);
681 
682 	return 0;
683 }
684 
685 static const struct net_device_ops arc_emac_netdev_ops = {
686 	.ndo_open		= arc_emac_open,
687 	.ndo_stop		= arc_emac_stop,
688 	.ndo_start_xmit		= arc_emac_tx,
689 	.ndo_set_mac_address	= arc_emac_set_address,
690 	.ndo_get_stats		= arc_emac_stats,
691 	.ndo_set_rx_mode	= arc_emac_set_rx_mode,
692 #ifdef CONFIG_NET_POLL_CONTROLLER
693 	.ndo_poll_controller	= arc_emac_poll_controller,
694 #endif
695 };
696 
697 int arc_emac_probe(struct net_device *ndev, int interface)
698 {
699 	struct device *dev = ndev->dev.parent;
700 	struct resource res_regs;
701 	struct device_node *phy_node;
702 	struct arc_emac_priv *priv;
703 	const char *mac_addr;
704 	unsigned int id, clock_frequency, irq;
705 	int err;
706 
707 
708 	/* Get PHY from device tree */
709 	phy_node = of_parse_phandle(dev->of_node, "phy", 0);
710 	if (!phy_node) {
711 		dev_err(dev, "failed to retrieve phy description from device tree\n");
712 		return -ENODEV;
713 	}
714 
715 	/* Get EMAC registers base address from device tree */
716 	err = of_address_to_resource(dev->of_node, 0, &res_regs);
717 	if (err) {
718 		dev_err(dev, "failed to retrieve registers base from device tree\n");
719 		return -ENODEV;
720 	}
721 
722 	/* Get IRQ from device tree */
723 	irq = irq_of_parse_and_map(dev->of_node, 0);
724 	if (!irq) {
725 		dev_err(dev, "failed to retrieve <irq> value from device tree\n");
726 		return -ENODEV;
727 	}
728 
729 
730 	ndev->netdev_ops = &arc_emac_netdev_ops;
731 	ndev->ethtool_ops = &arc_emac_ethtool_ops;
732 	ndev->watchdog_timeo = TX_TIMEOUT;
733 	/* FIXME :: no multicast support yet */
734 	ndev->flags &= ~IFF_MULTICAST;
735 
736 	priv = netdev_priv(ndev);
737 	priv->dev = dev;
738 
739 	priv->regs = devm_ioremap_resource(dev, &res_regs);
740 	if (IS_ERR(priv->regs)) {
741 		return PTR_ERR(priv->regs);
742 	}
743 	dev_dbg(dev, "Registers base address is 0x%p\n", priv->regs);
744 
745 	if (priv->clk) {
746 		err = clk_prepare_enable(priv->clk);
747 		if (err) {
748 			dev_err(dev, "failed to enable clock\n");
749 			return err;
750 		}
751 
752 		clock_frequency = clk_get_rate(priv->clk);
753 	} else {
754 		/* Get CPU clock frequency from device tree */
755 		if (of_property_read_u32(dev->of_node, "clock-frequency",
756 					 &clock_frequency)) {
757 			dev_err(dev, "failed to retrieve <clock-frequency> from device tree\n");
758 			return -EINVAL;
759 		}
760 	}
761 
762 	id = arc_reg_get(priv, R_ID);
763 
764 	/* Check for EMAC revision 5 or 7, magic number */
765 	if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
766 		dev_err(dev, "ARC EMAC not detected, id=0x%x\n", id);
767 		err = -ENODEV;
768 		goto out_clken;
769 	}
770 	dev_info(dev, "ARC EMAC detected with id: 0x%x\n", id);
771 
772 	/* Set poll rate so that it polls every 1 ms */
773 	arc_reg_set(priv, R_POLLRATE, clock_frequency / 1000000);
774 
775 	ndev->irq = irq;
776 	dev_info(dev, "IRQ is %d\n", ndev->irq);
777 
778 	/* Register interrupt handler for device */
779 	err = devm_request_irq(dev, ndev->irq, arc_emac_intr, 0,
780 			       ndev->name, ndev);
781 	if (err) {
782 		dev_err(dev, "could not allocate IRQ\n");
783 		goto out_clken;
784 	}
785 
786 	/* Get MAC address from device tree */
787 	mac_addr = of_get_mac_address(dev->of_node);
788 
789 	if (mac_addr)
790 		memcpy(ndev->dev_addr, mac_addr, ETH_ALEN);
791 	else
792 		eth_hw_addr_random(ndev);
793 
794 	arc_emac_set_address_internal(ndev);
795 	dev_info(dev, "MAC address is now %pM\n", ndev->dev_addr);
796 
797 	/* Do 1 allocation instead of 2 separate ones for Rx and Tx BD rings */
798 	priv->rxbd = dmam_alloc_coherent(dev, RX_RING_SZ + TX_RING_SZ,
799 					 &priv->rxbd_dma, GFP_KERNEL);
800 
801 	if (!priv->rxbd) {
802 		dev_err(dev, "failed to allocate data buffers\n");
803 		err = -ENOMEM;
804 		goto out_clken;
805 	}
806 
807 	priv->txbd = priv->rxbd + RX_BD_NUM;
808 
809 	priv->txbd_dma = priv->rxbd_dma + RX_RING_SZ;
810 	dev_dbg(dev, "EMAC Device addr: Rx Ring [0x%x], Tx Ring[%x]\n",
811 		(unsigned int)priv->rxbd_dma, (unsigned int)priv->txbd_dma);
812 
813 	err = arc_mdio_probe(priv);
814 	if (err) {
815 		dev_err(dev, "failed to probe MII bus\n");
816 		goto out_clken;
817 	}
818 
819 	priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
820 				       interface);
821 	if (!priv->phy_dev) {
822 		dev_err(dev, "of_phy_connect() failed\n");
823 		err = -ENODEV;
824 		goto out_mdio;
825 	}
826 
827 	dev_info(dev, "connected to %s phy with id 0x%x\n",
828 		 priv->phy_dev->drv->name, priv->phy_dev->phy_id);
829 
830 	netif_napi_add(ndev, &priv->napi, arc_emac_poll, ARC_EMAC_NAPI_WEIGHT);
831 
832 	err = register_netdev(ndev);
833 	if (err) {
834 		dev_err(dev, "failed to register network device\n");
835 		goto out_netif_api;
836 	}
837 
838 	return 0;
839 
840 out_netif_api:
841 	netif_napi_del(&priv->napi);
842 	phy_disconnect(priv->phy_dev);
843 	priv->phy_dev = NULL;
844 out_mdio:
845 	arc_mdio_remove(priv);
846 out_clken:
847 	if (priv->clk)
848 		clk_disable_unprepare(priv->clk);
849 	return err;
850 }
851 EXPORT_SYMBOL_GPL(arc_emac_probe);
852 
853 int arc_emac_remove(struct net_device *ndev)
854 {
855 	struct arc_emac_priv *priv = netdev_priv(ndev);
856 
857 	phy_disconnect(priv->phy_dev);
858 	priv->phy_dev = NULL;
859 	arc_mdio_remove(priv);
860 	unregister_netdev(ndev);
861 	netif_napi_del(&priv->napi);
862 
863 	if (!IS_ERR(priv->clk)) {
864 		clk_disable_unprepare(priv->clk);
865 	}
866 
867 
868 	return 0;
869 }
870 EXPORT_SYMBOL_GPL(arc_emac_remove);
871 
872 MODULE_AUTHOR("Alexey Brodkin <abrodkin@synopsys.com>");
873 MODULE_DESCRIPTION("ARC EMAC driver");
874 MODULE_LICENSE("GPL");
875