Version:  2.0.40 2.2.26 2.4.37 3.8 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

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 /**
 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 

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