Version:  2.0.40 2.2.26 2.4.37 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6

Linux/drivers/net/ethernet/arc/emac_main.c

  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  * arc_emac_tx_avail - Return the number of available slots in the tx ring.
 31  * @priv: Pointer to ARC EMAC private data structure.
 32  *
 33  * returns: the number of slots available for transmission in tx the ring.
 34  */
 35 static inline int arc_emac_tx_avail(struct arc_emac_priv *priv)
 36 {
 37         return (priv->txbd_dirty + TX_BD_NUM - priv->txbd_curr - 1) % TX_BD_NUM;
 38 }
 39 
 40 /**
 41  * arc_emac_adjust_link - Adjust the PHY link duplex.
 42  * @ndev:       Pointer to the net_device structure.
 43  *
 44  * This function is called to change the duplex setting after auto negotiation
 45  * is done by the PHY.
 46  */
 47 static void arc_emac_adjust_link(struct net_device *ndev)
 48 {
 49         struct arc_emac_priv *priv = netdev_priv(ndev);
 50         struct phy_device *phy_dev = priv->phy_dev;
 51         unsigned int reg, state_changed = 0;
 52 
 53         if (priv->link != phy_dev->link) {
 54                 priv->link = phy_dev->link;
 55                 state_changed = 1;
 56         }
 57 
 58         if (priv->speed != phy_dev->speed) {
 59                 priv->speed = phy_dev->speed;
 60                 state_changed = 1;
 61                 if (priv->set_mac_speed)
 62                         priv->set_mac_speed(priv, priv->speed);
 63         }
 64 
 65         if (priv->duplex != phy_dev->duplex) {
 66                 reg = arc_reg_get(priv, R_CTRL);
 67 
 68                 if (phy_dev->duplex == DUPLEX_FULL)
 69                         reg |= ENFL_MASK;
 70                 else
 71                         reg &= ~ENFL_MASK;
 72 
 73                 arc_reg_set(priv, R_CTRL, reg);
 74                 priv->duplex = phy_dev->duplex;
 75                 state_changed = 1;
 76         }
 77 
 78         if (state_changed)
 79                 phy_print_status(phy_dev);
 80 }
 81 
 82 /**
 83  * arc_emac_get_settings - Get PHY settings.
 84  * @ndev:       Pointer to net_device structure.
 85  * @cmd:        Pointer to ethtool_cmd structure.
 86  *
 87  * This implements ethtool command for getting PHY settings. If PHY could
 88  * not be found, the function returns -ENODEV. This function calls the
 89  * relevant PHY ethtool API to get the PHY settings.
 90  * Issue "ethtool ethX" under linux prompt to execute this function.
 91  */
 92 static int arc_emac_get_settings(struct net_device *ndev,
 93                                  struct ethtool_cmd *cmd)
 94 {
 95         struct arc_emac_priv *priv = netdev_priv(ndev);
 96 
 97         return phy_ethtool_gset(priv->phy_dev, cmd);
 98 }
 99 
100 /**
101  * arc_emac_set_settings - Set PHY settings as passed in the argument.
102  * @ndev:       Pointer to net_device structure.
103  * @cmd:        Pointer to ethtool_cmd structure.
104  *
105  * This implements ethtool command for setting various PHY settings. If PHY
106  * could not be found, the function returns -ENODEV. This function calls the
107  * relevant PHY ethtool API to set the PHY.
108  * Issue e.g. "ethtool -s ethX speed 1000" under linux prompt to execute this
109  * function.
110  */
111 static int arc_emac_set_settings(struct net_device *ndev,
112                                  struct ethtool_cmd *cmd)
113 {
114         struct arc_emac_priv *priv = netdev_priv(ndev);
115 
116         if (!capable(CAP_NET_ADMIN))
117                 return -EPERM;
118 
119         return phy_ethtool_sset(priv->phy_dev, cmd);
120 }
121 
122 /**
123  * arc_emac_get_drvinfo - Get EMAC driver information.
124  * @ndev:       Pointer to net_device structure.
125  * @info:       Pointer to ethtool_drvinfo structure.
126  *
127  * This implements ethtool command for getting the driver information.
128  * Issue "ethtool -i ethX" under linux prompt to execute this function.
129  */
130 static void arc_emac_get_drvinfo(struct net_device *ndev,
131                                  struct ethtool_drvinfo *info)
132 {
133         struct arc_emac_priv *priv = netdev_priv(ndev);
134 
135         strlcpy(info->driver, priv->drv_name, sizeof(info->driver));
136         strlcpy(info->version, priv->drv_version, sizeof(info->version));
137 }
138 
139 static const struct ethtool_ops arc_emac_ethtool_ops = {
140         .get_settings   = arc_emac_get_settings,
141         .set_settings   = arc_emac_set_settings,
142         .get_drvinfo    = arc_emac_get_drvinfo,
143         .get_link       = ethtool_op_get_link,
144 };
145 
146 #define FIRST_OR_LAST_MASK      (FIRST_MASK | LAST_MASK)
147 
148 /**
149  * arc_emac_tx_clean - clears processed by EMAC Tx BDs.
150  * @ndev:       Pointer to the network device.
151  */
152 static void arc_emac_tx_clean(struct net_device *ndev)
153 {
154         struct arc_emac_priv *priv = netdev_priv(ndev);
155         struct net_device_stats *stats = &ndev->stats;
156         unsigned int i;
157 
158         for (i = 0; i < TX_BD_NUM; i++) {
159                 unsigned int *txbd_dirty = &priv->txbd_dirty;
160                 struct arc_emac_bd *txbd = &priv->txbd[*txbd_dirty];
161                 struct buffer_state *tx_buff = &priv->tx_buff[*txbd_dirty];
162                 struct sk_buff *skb = tx_buff->skb;
163                 unsigned int info = le32_to_cpu(txbd->info);
164 
165                 if ((info & FOR_EMAC) || !txbd->data || !skb)
166                         break;
167 
168                 if (unlikely(info & (DROP | DEFR | LTCL | UFLO))) {
169                         stats->tx_errors++;
170                         stats->tx_dropped++;
171 
172                         if (info & DEFR)
173                                 stats->tx_carrier_errors++;
174 
175                         if (info & LTCL)
176                                 stats->collisions++;
177 
178                         if (info & UFLO)
179                                 stats->tx_fifo_errors++;
180                 } else if (likely(info & FIRST_OR_LAST_MASK)) {
181                         stats->tx_packets++;
182                         stats->tx_bytes += skb->len;
183                 }
184 
185                 dma_unmap_single(&ndev->dev, dma_unmap_addr(tx_buff, addr),
186                                  dma_unmap_len(tx_buff, len), DMA_TO_DEVICE);
187 
188                 /* return the sk_buff to system */
189                 dev_kfree_skb_irq(skb);
190 
191                 txbd->data = 0;
192                 txbd->info = 0;
193                 tx_buff->skb = NULL;
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         priv->txbd_curr = 0;
450         priv->txbd_dirty = 0;
451 
452         /* Clean Tx BD's */
453         memset(priv->txbd, 0, TX_RING_SZ);
454 
455         /* Initialize logical address filter */
456         arc_reg_set(priv, R_LAFL, 0);
457         arc_reg_set(priv, R_LAFH, 0);
458 
459         /* Set BD ring pointers for device side */
460         arc_reg_set(priv, R_RX_RING, (unsigned int)priv->rxbd_dma);
461         arc_reg_set(priv, R_TX_RING, (unsigned int)priv->txbd_dma);
462 
463         /* Enable interrupts */
464         arc_reg_set(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK);
465 
466         /* Set CONTROL */
467         arc_reg_set(priv, R_CTRL,
468                     (RX_BD_NUM << 24) | /* RX BD table length */
469                     (TX_BD_NUM << 16) | /* TX BD table length */
470                     TXRN_MASK | RXRN_MASK);
471 
472         napi_enable(&priv->napi);
473 
474         /* Enable EMAC */
475         arc_reg_or(priv, R_CTRL, EN_MASK);
476 
477         phy_start_aneg(priv->phy_dev);
478 
479         netif_start_queue(ndev);
480 
481         return 0;
482 }
483 
484 /**
485  * arc_emac_set_rx_mode - Change the receive filtering mode.
486  * @ndev:       Pointer to the network device.
487  *
488  * This function enables/disables promiscuous or all-multicast mode
489  * and updates the multicast filtering list of the network device.
490  */
491 static void arc_emac_set_rx_mode(struct net_device *ndev)
492 {
493         struct arc_emac_priv *priv = netdev_priv(ndev);
494 
495         if (ndev->flags & IFF_PROMISC) {
496                 arc_reg_or(priv, R_CTRL, PROM_MASK);
497         } else {
498                 arc_reg_clr(priv, R_CTRL, PROM_MASK);
499 
500                 if (ndev->flags & IFF_ALLMULTI) {
501                         arc_reg_set(priv, R_LAFL, ~0);
502                         arc_reg_set(priv, R_LAFH, ~0);
503                 } else {
504                         struct netdev_hw_addr *ha;
505                         unsigned int filter[2] = { 0, 0 };
506                         int bit;
507 
508                         netdev_for_each_mc_addr(ha, ndev) {
509                                 bit = ether_crc_le(ETH_ALEN, ha->addr) >> 26;
510                                 filter[bit >> 5] |= 1 << (bit & 31);
511                         }
512 
513                         arc_reg_set(priv, R_LAFL, filter[0]);
514                         arc_reg_set(priv, R_LAFH, filter[1]);
515                 }
516         }
517 }
518 
519 /**
520  * arc_free_tx_queue - free skb from tx queue
521  * @ndev:       Pointer to the network device.
522  *
523  * This function must be called while EMAC disable
524  */
525 static void arc_free_tx_queue(struct net_device *ndev)
526 {
527         struct arc_emac_priv *priv = netdev_priv(ndev);
528         unsigned int i;
529 
530         for (i = 0; i < TX_BD_NUM; i++) {
531                 struct arc_emac_bd *txbd = &priv->txbd[i];
532                 struct buffer_state *tx_buff = &priv->tx_buff[i];
533 
534                 if (tx_buff->skb) {
535                         dma_unmap_single(&ndev->dev,
536                                          dma_unmap_addr(tx_buff, addr),
537                                          dma_unmap_len(tx_buff, len),
538                                          DMA_TO_DEVICE);
539 
540                         /* return the sk_buff to system */
541                         dev_kfree_skb_irq(tx_buff->skb);
542                 }
543 
544                 txbd->info = 0;
545                 txbd->data = 0;
546                 tx_buff->skb = NULL;
547         }
548 }
549 
550 /**
551  * arc_free_rx_queue - free skb from rx queue
552  * @ndev:       Pointer to the network device.
553  *
554  * This function must be called while EMAC disable
555  */
556 static void arc_free_rx_queue(struct net_device *ndev)
557 {
558         struct arc_emac_priv *priv = netdev_priv(ndev);
559         unsigned int i;
560 
561         for (i = 0; i < RX_BD_NUM; i++) {
562                 struct arc_emac_bd *rxbd = &priv->rxbd[i];
563                 struct buffer_state *rx_buff = &priv->rx_buff[i];
564 
565                 if (rx_buff->skb) {
566                         dma_unmap_single(&ndev->dev,
567                                          dma_unmap_addr(rx_buff, addr),
568                                          dma_unmap_len(rx_buff, len),
569                                          DMA_FROM_DEVICE);
570 
571                         /* return the sk_buff to system */
572                         dev_kfree_skb_irq(rx_buff->skb);
573                 }
574 
575                 rxbd->info = 0;
576                 rxbd->data = 0;
577                 rx_buff->skb = NULL;
578         }
579 }
580 
581 /**
582  * arc_emac_stop - Close the network device.
583  * @ndev:       Pointer to the network device.
584  *
585  * This function stops the Tx queue, disables interrupts and frees the IRQ for
586  * the EMAC device.
587  * It also disconnects the PHY device associated with the EMAC device.
588  */
589 static int arc_emac_stop(struct net_device *ndev)
590 {
591         struct arc_emac_priv *priv = netdev_priv(ndev);
592 
593         napi_disable(&priv->napi);
594         netif_stop_queue(ndev);
595 
596         /* Disable interrupts */
597         arc_reg_clr(priv, R_ENABLE, RXINT_MASK | TXINT_MASK | ERR_MASK);
598 
599         /* Disable EMAC */
600         arc_reg_clr(priv, R_CTRL, EN_MASK);
601 
602         /* Return the sk_buff to system */
603         arc_free_tx_queue(ndev);
604         arc_free_rx_queue(ndev);
605 
606         return 0;
607 }
608 
609 /**
610  * arc_emac_stats - Get system network statistics.
611  * @ndev:       Pointer to net_device structure.
612  *
613  * Returns the address of the device statistics structure.
614  * Statistics are updated in interrupt handler.
615  */
616 static struct net_device_stats *arc_emac_stats(struct net_device *ndev)
617 {
618         struct arc_emac_priv *priv = netdev_priv(ndev);
619         struct net_device_stats *stats = &ndev->stats;
620         unsigned long miss, rxerr;
621         u8 rxcrc, rxfram, rxoflow;
622 
623         rxerr = arc_reg_get(priv, R_RXERR);
624         miss = arc_reg_get(priv, R_MISS);
625 
626         rxcrc = rxerr;
627         rxfram = rxerr >> 8;
628         rxoflow = rxerr >> 16;
629 
630         stats->rx_errors += miss;
631         stats->rx_errors += rxcrc + rxfram + rxoflow;
632 
633         stats->rx_over_errors += rxoflow;
634         stats->rx_frame_errors += rxfram;
635         stats->rx_crc_errors += rxcrc;
636         stats->rx_missed_errors += miss;
637 
638         return stats;
639 }
640 
641 /**
642  * arc_emac_tx - Starts the data transmission.
643  * @skb:        sk_buff pointer that contains data to be Transmitted.
644  * @ndev:       Pointer to net_device structure.
645  *
646  * returns: NETDEV_TX_OK, on success
647  *              NETDEV_TX_BUSY, if any of the descriptors are not free.
648  *
649  * This function is invoked from upper layers to initiate transmission.
650  */
651 static int arc_emac_tx(struct sk_buff *skb, struct net_device *ndev)
652 {
653         struct arc_emac_priv *priv = netdev_priv(ndev);
654         unsigned int len, *txbd_curr = &priv->txbd_curr;
655         struct net_device_stats *stats = &ndev->stats;
656         __le32 *info = &priv->txbd[*txbd_curr].info;
657         dma_addr_t addr;
658 
659         if (skb_padto(skb, ETH_ZLEN))
660                 return NETDEV_TX_OK;
661 
662         len = max_t(unsigned int, ETH_ZLEN, skb->len);
663 
664         if (unlikely(!arc_emac_tx_avail(priv))) {
665                 netif_stop_queue(ndev);
666                 netdev_err(ndev, "BUG! Tx Ring full when queue awake!\n");
667                 return NETDEV_TX_BUSY;
668         }
669 
670         addr = dma_map_single(&ndev->dev, (void *)skb->data, len,
671                               DMA_TO_DEVICE);
672 
673         if (unlikely(dma_mapping_error(&ndev->dev, addr))) {
674                 stats->tx_dropped++;
675                 stats->tx_errors++;
676                 dev_kfree_skb(skb);
677                 return NETDEV_TX_OK;
678         }
679         dma_unmap_addr_set(&priv->tx_buff[*txbd_curr], addr, addr);
680         dma_unmap_len_set(&priv->tx_buff[*txbd_curr], len, len);
681 
682         priv->txbd[*txbd_curr].data = cpu_to_le32(addr);
683 
684         /* Make sure pointer to data buffer is set */
685         wmb();
686 
687         skb_tx_timestamp(skb);
688 
689         *info = cpu_to_le32(FOR_EMAC | FIRST_OR_LAST_MASK | len);
690 
691         /* Make sure info word is set */
692         wmb();
693 
694         priv->tx_buff[*txbd_curr].skb = skb;
695 
696         /* Increment index to point to the next BD */
697         *txbd_curr = (*txbd_curr + 1) % TX_BD_NUM;
698 
699         /* Ensure that tx_clean() sees the new txbd_curr before
700          * checking the queue status. This prevents an unneeded wake
701          * of the queue in tx_clean().
702          */
703         smp_mb();
704 
705         if (!arc_emac_tx_avail(priv)) {
706                 netif_stop_queue(ndev);
707                 /* Refresh tx_dirty */
708                 smp_mb();
709                 if (arc_emac_tx_avail(priv))
710                         netif_start_queue(ndev);
711         }
712 
713         arc_reg_set(priv, R_STATUS, TXPL_MASK);
714 
715         return NETDEV_TX_OK;
716 }
717 
718 static void arc_emac_set_address_internal(struct net_device *ndev)
719 {
720         struct arc_emac_priv *priv = netdev_priv(ndev);
721         unsigned int addr_low, addr_hi;
722 
723         addr_low = le32_to_cpu(*(__le32 *)&ndev->dev_addr[0]);
724         addr_hi = le16_to_cpu(*(__le16 *)&ndev->dev_addr[4]);
725 
726         arc_reg_set(priv, R_ADDRL, addr_low);
727         arc_reg_set(priv, R_ADDRH, addr_hi);
728 }
729 
730 /**
731  * arc_emac_set_address - Set the MAC address for this device.
732  * @ndev:       Pointer to net_device structure.
733  * @p:          6 byte Address to be written as MAC address.
734  *
735  * This function copies the HW address from the sockaddr structure to the
736  * net_device structure and updates the address in HW.
737  *
738  * returns:     -EBUSY if the net device is busy or 0 if the address is set
739  *              successfully.
740  */
741 static int arc_emac_set_address(struct net_device *ndev, void *p)
742 {
743         struct sockaddr *addr = p;
744 
745         if (netif_running(ndev))
746                 return -EBUSY;
747 
748         if (!is_valid_ether_addr(addr->sa_data))
749                 return -EADDRNOTAVAIL;
750 
751         memcpy(ndev->dev_addr, addr->sa_data, ndev->addr_len);
752 
753         arc_emac_set_address_internal(ndev);
754 
755         return 0;
756 }
757 
758 static const struct net_device_ops arc_emac_netdev_ops = {
759         .ndo_open               = arc_emac_open,
760         .ndo_stop               = arc_emac_stop,
761         .ndo_start_xmit         = arc_emac_tx,
762         .ndo_set_mac_address    = arc_emac_set_address,
763         .ndo_get_stats          = arc_emac_stats,
764         .ndo_set_rx_mode        = arc_emac_set_rx_mode,
765 #ifdef CONFIG_NET_POLL_CONTROLLER
766         .ndo_poll_controller    = arc_emac_poll_controller,
767 #endif
768 };
769 
770 int arc_emac_probe(struct net_device *ndev, int interface)
771 {
772         struct device *dev = ndev->dev.parent;
773         struct resource res_regs;
774         struct device_node *phy_node;
775         struct arc_emac_priv *priv;
776         const char *mac_addr;
777         unsigned int id, clock_frequency, irq;
778         int err;
779 
780         /* Get PHY from device tree */
781         phy_node = of_parse_phandle(dev->of_node, "phy", 0);
782         if (!phy_node) {
783                 dev_err(dev, "failed to retrieve phy description from device tree\n");
784                 return -ENODEV;
785         }
786 
787         /* Get EMAC registers base address from device tree */
788         err = of_address_to_resource(dev->of_node, 0, &res_regs);
789         if (err) {
790                 dev_err(dev, "failed to retrieve registers base from device tree\n");
791                 return -ENODEV;
792         }
793 
794         /* Get IRQ from device tree */
795         irq = irq_of_parse_and_map(dev->of_node, 0);
796         if (!irq) {
797                 dev_err(dev, "failed to retrieve <irq> value from device tree\n");
798                 return -ENODEV;
799         }
800 
801         ndev->netdev_ops = &arc_emac_netdev_ops;
802         ndev->ethtool_ops = &arc_emac_ethtool_ops;
803         ndev->watchdog_timeo = TX_TIMEOUT;
804         /* FIXME :: no multicast support yet */
805         ndev->flags &= ~IFF_MULTICAST;
806 
807         priv = netdev_priv(ndev);
808         priv->dev = dev;
809 
810         priv->regs = devm_ioremap_resource(dev, &res_regs);
811         if (IS_ERR(priv->regs))
812                 return PTR_ERR(priv->regs);
813 
814         dev_dbg(dev, "Registers base address is 0x%p\n", priv->regs);
815 
816         if (priv->clk) {
817                 err = clk_prepare_enable(priv->clk);
818                 if (err) {
819                         dev_err(dev, "failed to enable clock\n");
820                         return err;
821                 }
822 
823                 clock_frequency = clk_get_rate(priv->clk);
824         } else {
825                 /* Get CPU clock frequency from device tree */
826                 if (of_property_read_u32(dev->of_node, "clock-frequency",
827                                          &clock_frequency)) {
828                         dev_err(dev, "failed to retrieve <clock-frequency> from device tree\n");
829                         return -EINVAL;
830                 }
831         }
832 
833         id = arc_reg_get(priv, R_ID);
834 
835         /* Check for EMAC revision 5 or 7, magic number */
836         if (!(id == 0x0005fd02 || id == 0x0007fd02)) {
837                 dev_err(dev, "ARC EMAC not detected, id=0x%x\n", id);
838                 err = -ENODEV;
839                 goto out_clken;
840         }
841         dev_info(dev, "ARC EMAC detected with id: 0x%x\n", id);
842 
843         /* Set poll rate so that it polls every 1 ms */
844         arc_reg_set(priv, R_POLLRATE, clock_frequency / 1000000);
845 
846         ndev->irq = irq;
847         dev_info(dev, "IRQ is %d\n", ndev->irq);
848 
849         /* Register interrupt handler for device */
850         err = devm_request_irq(dev, ndev->irq, arc_emac_intr, 0,
851                                ndev->name, ndev);
852         if (err) {
853                 dev_err(dev, "could not allocate IRQ\n");
854                 goto out_clken;
855         }
856 
857         /* Get MAC address from device tree */
858         mac_addr = of_get_mac_address(dev->of_node);
859 
860         if (mac_addr)
861                 memcpy(ndev->dev_addr, mac_addr, ETH_ALEN);
862         else
863                 eth_hw_addr_random(ndev);
864 
865         arc_emac_set_address_internal(ndev);
866         dev_info(dev, "MAC address is now %pM\n", ndev->dev_addr);
867 
868         /* Do 1 allocation instead of 2 separate ones for Rx and Tx BD rings */
869         priv->rxbd = dmam_alloc_coherent(dev, RX_RING_SZ + TX_RING_SZ,
870                                          &priv->rxbd_dma, GFP_KERNEL);
871 
872         if (!priv->rxbd) {
873                 dev_err(dev, "failed to allocate data buffers\n");
874                 err = -ENOMEM;
875                 goto out_clken;
876         }
877 
878         priv->txbd = priv->rxbd + RX_BD_NUM;
879 
880         priv->txbd_dma = priv->rxbd_dma + RX_RING_SZ;
881         dev_dbg(dev, "EMAC Device addr: Rx Ring [0x%x], Tx Ring[%x]\n",
882                 (unsigned int)priv->rxbd_dma, (unsigned int)priv->txbd_dma);
883 
884         err = arc_mdio_probe(priv);
885         if (err) {
886                 dev_err(dev, "failed to probe MII bus\n");
887                 goto out_clken;
888         }
889 
890         priv->phy_dev = of_phy_connect(ndev, phy_node, arc_emac_adjust_link, 0,
891                                        interface);
892         if (!priv->phy_dev) {
893                 dev_err(dev, "of_phy_connect() failed\n");
894                 err = -ENODEV;
895                 goto out_mdio;
896         }
897 
898         dev_info(dev, "connected to %s phy with id 0x%x\n",
899                  priv->phy_dev->drv->name, priv->phy_dev->phy_id);
900 
901         netif_napi_add(ndev, &priv->napi, arc_emac_poll, ARC_EMAC_NAPI_WEIGHT);
902 
903         err = register_netdev(ndev);
904         if (err) {
905                 dev_err(dev, "failed to register network device\n");
906                 goto out_netif_api;
907         }
908 
909         return 0;
910 
911 out_netif_api:
912         netif_napi_del(&priv->napi);
913         phy_disconnect(priv->phy_dev);
914         priv->phy_dev = NULL;
915 out_mdio:
916         arc_mdio_remove(priv);
917 out_clken:
918         if (priv->clk)
919                 clk_disable_unprepare(priv->clk);
920         return err;
921 }
922 EXPORT_SYMBOL_GPL(arc_emac_probe);
923 
924 int arc_emac_remove(struct net_device *ndev)
925 {
926         struct arc_emac_priv *priv = netdev_priv(ndev);
927 
928         phy_disconnect(priv->phy_dev);
929         priv->phy_dev = NULL;
930         arc_mdio_remove(priv);
931         unregister_netdev(ndev);
932         netif_napi_del(&priv->napi);
933 
934         if (!IS_ERR(priv->clk))
935                 clk_disable_unprepare(priv->clk);
936 
937         return 0;
938 }
939 EXPORT_SYMBOL_GPL(arc_emac_remove);
940 
941 MODULE_AUTHOR("Alexey Brodkin <abrodkin@synopsys.com>");
942 MODULE_DESCRIPTION("ARC EMAC driver");
943 MODULE_LICENSE("GPL");
944 

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