text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * sonic.c
   *
   * (C) 2005 Finn Thain
   *
   * Converted to DMA API, added zero-copy buffer handling, and
   * (from the mac68k project) introduced dhd's support for 16-bit cards.
   *
   * (C) 1996,1998 by Thomas Bogendoerfer (tsbogend@alpha.franken.de)
   *
   * This driver is based on work from Andreas Busse, but most of
   * the code is rewritten.
   *
   * (C) 1995 by Andreas Busse (andy@waldorf-gmbh.de)
   *
   *    Core code included by system sonic drivers
   *
   * And... partially rewritten again by David Huggins-Daines in order
   * to cope with screwed up Macintosh NICs that may or may not use
   * 16-bit DMA.
   *
   * (C) 1999 David Huggins-Daines <dhd@debian.org>
   *
   */
  
  /*
   * Sources: Olivetti M700-10 Risc Personal Computer hardware handbook,
   * National Semiconductors data sheet for the DP83932B Sonic Ethernet
   * controller, and the files "8390.c" and "skeleton.c" in this directory.
   *
   * Additional sources: Nat Semi data sheet for the DP83932C and Nat Semi
   * Application Note AN-746, the files "lance.c" and "ibmlana.c". See also
   * the NetBSD file "sys/arch/mac68k/dev/if_sn.c".
   */
  
  static unsigned int version_printed;
  
  static int sonic_debug = -1;
  module_param(sonic_debug, int, 0);
  MODULE_PARM_DESC(sonic_debug, "debug message level");
  
  static void sonic_msg_init(struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  
  	lp->msg_enable = netif_msg_init(sonic_debug, 0);
  
  	if (version_printed++ == 0)
  		netif_dbg(lp, drv, dev, "%s", version);
  }
  
  static int sonic_alloc_descriptors(struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  
  	/* Allocate a chunk of memory for the descriptors. Note that this
  	 * must not cross a 64K boundary. It is smaller than one page which
  	 * means that page alignment is a sufficient condition.
  	 */
  	lp->descriptors =
  		dma_alloc_coherent(lp->device,
  				   SIZEOF_SONIC_DESC *
  				   SONIC_BUS_SCALE(lp->dma_bitmode),
  				   &lp->descriptors_laddr, GFP_KERNEL);
  
  	if (!lp->descriptors)
  		return -ENOMEM;
  
  	lp->cda = lp->descriptors;
  	lp->tda = lp->cda + SIZEOF_SONIC_CDA *
  			    SONIC_BUS_SCALE(lp->dma_bitmode);
  	lp->rda = lp->tda + SIZEOF_SONIC_TD * SONIC_NUM_TDS *
  			    SONIC_BUS_SCALE(lp->dma_bitmode);
  	lp->rra = lp->rda + SIZEOF_SONIC_RD * SONIC_NUM_RDS *
  			    SONIC_BUS_SCALE(lp->dma_bitmode);
  
  	lp->cda_laddr = lp->descriptors_laddr;
  	lp->tda_laddr = lp->cda_laddr + SIZEOF_SONIC_CDA *
  					SONIC_BUS_SCALE(lp->dma_bitmode);
  	lp->rda_laddr = lp->tda_laddr + SIZEOF_SONIC_TD * SONIC_NUM_TDS *
  					SONIC_BUS_SCALE(lp->dma_bitmode);
  	lp->rra_laddr = lp->rda_laddr + SIZEOF_SONIC_RD * SONIC_NUM_RDS *
  					SONIC_BUS_SCALE(lp->dma_bitmode);
  
  	return 0;
  }
  
  /*
   * Open/initialize the SONIC controller.
   *
   * This routine should set everything up anew at each open, even
   *  registers that "should" only need to be set once at boot, so that
   *  there is non-reboot way to recover if something goes wrong.
   */
  static int sonic_open(struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  	int i;
  
  	netif_dbg(lp, ifup, dev, "%s: initializing sonic driver\n", __func__);
  
  	spin_lock_init(&lp->lock);
  
  	for (i = 0; i < SONIC_NUM_RRS; i++) {
  		struct sk_buff *skb = netdev_alloc_skb(dev, SONIC_RBSIZE + 2);
  		if (skb == NULL) {
  			while(i > 0) { /* free any that were allocated successfully */
  				i--;
  				dev_kfree_skb(lp->rx_skb[i]);
  				lp->rx_skb[i] = NULL;
  			}
  			printk(KERN_ERR "%s: couldn't allocate receive buffers\n",
  			       dev->name);
  			return -ENOMEM;
  		}
  		/* align IP header unless DMA requires otherwise */
  		if (SONIC_BUS_SCALE(lp->dma_bitmode) == 2)
  			skb_reserve(skb, 2);
  		lp->rx_skb[i] = skb;
  	}
  
  	for (i = 0; i < SONIC_NUM_RRS; i++) {
  		dma_addr_t laddr = dma_map_single(lp->device, skb_put(lp->rx_skb[i], SONIC_RBSIZE),
  		                                  SONIC_RBSIZE, DMA_FROM_DEVICE);
  		if (dma_mapping_error(lp->device, laddr)) {
  			while(i > 0) { /* free any that were mapped successfully */
  				i--;
  				dma_unmap_single(lp->device, lp->rx_laddr[i], SONIC_RBSIZE, DMA_FROM_DEVICE);
  				lp->rx_laddr[i] = (dma_addr_t)0;
  			}
  			for (i = 0; i < SONIC_NUM_RRS; i++) {
  				dev_kfree_skb(lp->rx_skb[i]);
  				lp->rx_skb[i] = NULL;
  			}
  			printk(KERN_ERR "%s: couldn't map rx DMA buffers\n",
  			       dev->name);
  			return -ENOMEM;
  		}
  		lp->rx_laddr[i] = laddr;
  	}
  
  	/*
  	 * Initialize the SONIC
  	 */
  	sonic_init(dev, true);
  
  	netif_start_queue(dev);
  
  	netif_dbg(lp, ifup, dev, "%s: Initialization done\n", __func__);
  
  	return 0;
  }
  
  /* Wait for the SONIC to become idle. */
  static void sonic_quiesce(struct net_device *dev, u16 mask, bool may_sleep)
  {
  	struct sonic_local * __maybe_unused lp = netdev_priv(dev);
  	int i;
  	u16 bits;
  
  	for (i = 0; i < 1000; ++i) {
  		bits = SONIC_READ(SONIC_CMD) & mask;
  		if (!bits)
  			return;
  		if (!may_sleep)
  			udelay(20);
  		else
  			usleep_range(100, 200);
  	}
  	WARN_ONCE(1, "command deadline expired! 0x%04x\n", bits);
  }
  
  /*
   * Close the SONIC device
   */
  static int sonic_close(struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  	int i;
  
  	netif_dbg(lp, ifdown, dev, "%s\n", __func__);
  
  	netif_stop_queue(dev);
  
  	/*
  	 * stop the SONIC, disable interrupts
  	 */
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RXDIS);
  	sonic_quiesce(dev, SONIC_CR_ALL, true);
  
  	SONIC_WRITE(SONIC_IMR, 0);
  	SONIC_WRITE(SONIC_ISR, 0x7fff);
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RST);
  
  	/* unmap and free skbs that haven't been transmitted */
  	for (i = 0; i < SONIC_NUM_TDS; i++) {
  		if(lp->tx_laddr[i]) {
  			dma_unmap_single(lp->device, lp->tx_laddr[i], lp->tx_len[i], DMA_TO_DEVICE);
  			lp->tx_laddr[i] = (dma_addr_t)0;
  		}
  		if(lp->tx_skb[i]) {
  			dev_kfree_skb(lp->tx_skb[i]);
  			lp->tx_skb[i] = NULL;
  		}
  	}
  
  	/* unmap and free the receive buffers */
  	for (i = 0; i < SONIC_NUM_RRS; i++) {
  		if(lp->rx_laddr[i]) {
  			dma_unmap_single(lp->device, lp->rx_laddr[i], SONIC_RBSIZE, DMA_FROM_DEVICE);
  			lp->rx_laddr[i] = (dma_addr_t)0;
  		}
  		if(lp->rx_skb[i]) {
  			dev_kfree_skb(lp->rx_skb[i]);
  			lp->rx_skb[i] = NULL;
  		}
  	}
  
  	return 0;
  }
  
  static void sonic_tx_timeout(struct net_device *dev, unsigned int txqueue)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  	int i;
  	/*
  	 * put the Sonic into software-reset mode and
  	 * disable all interrupts before releasing DMA buffers
  	 */
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RXDIS);
  	sonic_quiesce(dev, SONIC_CR_ALL, false);
  
  	SONIC_WRITE(SONIC_IMR, 0);
  	SONIC_WRITE(SONIC_ISR, 0x7fff);
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RST);
  	/* We could resend the original skbs. Easier to re-initialise. */
  	for (i = 0; i < SONIC_NUM_TDS; i++) {
  		if(lp->tx_laddr[i]) {
  			dma_unmap_single(lp->device, lp->tx_laddr[i], lp->tx_len[i], DMA_TO_DEVICE);
  			lp->tx_laddr[i] = (dma_addr_t)0;
  		}
  		if(lp->tx_skb[i]) {
  			dev_kfree_skb(lp->tx_skb[i]);
  			lp->tx_skb[i] = NULL;
  		}
  	}
  	/* Try to restart the adaptor. */
  	sonic_init(dev, false);
  	lp->stats.tx_errors++;
  	netif_trans_update(dev); /* prevent tx timeout */
  	netif_wake_queue(dev);
  }
  
  /*
   * transmit packet
   *
   * Appends new TD during transmission thus avoiding any TX interrupts
   * until we run out of TDs.
   * This routine interacts closely with the ISR in that it may,
   *   set tx_skb[i]
   *   reset the status flags of the new TD
   *   set and reset EOL flags
   *   stop the tx queue
   * The ISR interacts with this routine in various ways. It may,
   *   reset tx_skb[i]
   *   test the EOL and status flags of the TDs
   *   wake the tx queue
   * Concurrently with all of this, the SONIC is potentially writing to
   * the status flags of the TDs.
   */
  
  static int sonic_send_packet(struct sk_buff *skb, struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  	dma_addr_t laddr;
  	int length;
  	int entry;
  	unsigned long flags;
  
  	netif_dbg(lp, tx_queued, dev, "%s: skb=%p\n", __func__, skb);
  
  	length = skb->len;
  	if (length < ETH_ZLEN) {
  		if (skb_padto(skb, ETH_ZLEN))
  			return NETDEV_TX_OK;
  		length = ETH_ZLEN;
  	}
  
  	/*
  	 * Map the packet data into the logical DMA address space
  	 */
  
  	laddr = dma_map_single(lp->device, skb->data, length, DMA_TO_DEVICE);
  	if (!laddr) {
  		pr_err_ratelimited("%s: failed to map tx DMA buffer.\n", dev->name);
  		dev_kfree_skb_any(skb);
  		return NETDEV_TX_OK;
  	}
  
  	spin_lock_irqsave(&lp->lock, flags);
  
  	entry = (lp->eol_tx + 1) & SONIC_TDS_MASK;
  
  	sonic_tda_put(dev, entry, SONIC_TD_STATUS, 0);       /* clear status */
  	sonic_tda_put(dev, entry, SONIC_TD_FRAG_COUNT, 1);   /* single fragment */
  	sonic_tda_put(dev, entry, SONIC_TD_PKTSIZE, length); /* length of packet */
  	sonic_tda_put(dev, entry, SONIC_TD_FRAG_PTR_L, laddr & 0xffff);
  	sonic_tda_put(dev, entry, SONIC_TD_FRAG_PTR_H, laddr >> 16);
  	sonic_tda_put(dev, entry, SONIC_TD_FRAG_SIZE, length);
  	sonic_tda_put(dev, entry, SONIC_TD_LINK,
  		sonic_tda_get(dev, entry, SONIC_TD_LINK) | SONIC_EOL);
  
  	sonic_tda_put(dev, lp->eol_tx, SONIC_TD_LINK, ~SONIC_EOL &
  		      sonic_tda_get(dev, lp->eol_tx, SONIC_TD_LINK));
  
  	netif_dbg(lp, tx_queued, dev, "%s: issuing Tx command\n", __func__);
  
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_TXP);
  
  	lp->tx_len[entry] = length;
  	lp->tx_laddr[entry] = laddr;
  	lp->tx_skb[entry] = skb;
  
  	lp->eol_tx = entry;
  
  	entry = (entry + 1) & SONIC_TDS_MASK;
  	if (lp->tx_skb[entry]) {
  		/* The ring is full, the ISR has yet to process the next TD. */
  		netif_dbg(lp, tx_queued, dev, "%s: stopping queue\n", __func__);
  		netif_stop_queue(dev);
  		/* after this packet, wait for ISR to free up some TDAs */
  	}
  
  	spin_unlock_irqrestore(&lp->lock, flags);
  
  	return NETDEV_TX_OK;
  }
  
  /*
   * The typical workload of the driver:
   * Handle the network interface interrupts.
   */
  static irqreturn_t sonic_interrupt(int irq, void *dev_id)
  {
  	struct net_device *dev = dev_id;
  	struct sonic_local *lp = netdev_priv(dev);
  	int status;
  	unsigned long flags;
  
  	/* The lock has two purposes. Firstly, it synchronizes sonic_interrupt()
  	 * with sonic_send_packet() so that the two functions can share state.
  	 * Secondly, it makes sonic_interrupt() re-entrant, as that is required
  	 * by macsonic which must use two IRQs with different priority levels.
  	 */
  	spin_lock_irqsave(&lp->lock, flags);
  
  	status = SONIC_READ(SONIC_ISR) & SONIC_IMR_DEFAULT;
  	if (!status) {
  		spin_unlock_irqrestore(&lp->lock, flags);
  
  		return IRQ_NONE;
  	}
  
  	do {
  		SONIC_WRITE(SONIC_ISR, status); /* clear the interrupt(s) */
  
  		if (status & SONIC_INT_PKTRX) {
  			netif_dbg(lp, intr, dev, "%s: packet rx\n", __func__);
  			sonic_rx(dev);	/* got packet(s) */
  		}
  
  		if (status & SONIC_INT_TXDN) {
  			int entry = lp->cur_tx;
  			int td_status;
  			int freed_some = 0;
  
  			/* The state of a Transmit Descriptor may be inferred
  			 * from { tx_skb[entry], td_status } as follows.
  			 * { clear, clear } => the TD has never been used
  			 * { set,   clear } => the TD was handed to SONIC
  			 * { set,   set   } => the TD was handed back
  			 * { clear, set   } => the TD is available for re-use
  			 */
  
  			netif_dbg(lp, intr, dev, "%s: tx done\n", __func__);
  
  			while (lp->tx_skb[entry] != NULL) {
  				if ((td_status = sonic_tda_get(dev, entry, SONIC_TD_STATUS)) == 0)
  					break;
  
  				if (td_status & SONIC_TCR_PTX) {
  					lp->stats.tx_packets++;
  					lp->stats.tx_bytes += sonic_tda_get(dev, entry, SONIC_TD_PKTSIZE);
  				} else {
  					if (td_status & (SONIC_TCR_EXD |
  					    SONIC_TCR_EXC | SONIC_TCR_BCM))
  						lp->stats.tx_aborted_errors++;
  					if (td_status &
  					    (SONIC_TCR_NCRS | SONIC_TCR_CRLS))
  						lp->stats.tx_carrier_errors++;
  					if (td_status & SONIC_TCR_OWC)
  						lp->stats.tx_window_errors++;
  					if (td_status & SONIC_TCR_FU)
  						lp->stats.tx_fifo_errors++;
  				}
  
  				/* We must free the original skb */
  				dev_consume_skb_irq(lp->tx_skb[entry]);
  				lp->tx_skb[entry] = NULL;
  				/* and unmap DMA buffer */
  				dma_unmap_single(lp->device, lp->tx_laddr[entry], lp->tx_len[entry], DMA_TO_DEVICE);
  				lp->tx_laddr[entry] = (dma_addr_t)0;
  				freed_some = 1;
  
  				if (sonic_tda_get(dev, entry, SONIC_TD_LINK) & SONIC_EOL) {
  					entry = (entry + 1) & SONIC_TDS_MASK;
  					break;
  				}
  				entry = (entry + 1) & SONIC_TDS_MASK;
  			}
  
  			if (freed_some || lp->tx_skb[entry] == NULL)
  				netif_wake_queue(dev);  /* The ring is no longer full */
  			lp->cur_tx = entry;
  		}
  
  		/*
  		 * check error conditions
  		 */
  		if (status & SONIC_INT_RFO) {
  			netif_dbg(lp, rx_err, dev, "%s: rx fifo overrun\n",
  				  __func__);
  		}
  		if (status & SONIC_INT_RDE) {
  			netif_dbg(lp, rx_err, dev, "%s: rx descriptors exhausted\n",
  				  __func__);
  		}
  		if (status & SONIC_INT_RBAE) {
  			netif_dbg(lp, rx_err, dev, "%s: rx buffer area exceeded\n",
  				  __func__);
  		}
  
  		/* counter overruns; all counters are 16bit wide */
  		if (status & SONIC_INT_FAE)
  			lp->stats.rx_frame_errors += 65536;
  		if (status & SONIC_INT_CRC)
  			lp->stats.rx_crc_errors += 65536;
  		if (status & SONIC_INT_MP)
  			lp->stats.rx_missed_errors += 65536;
  
  		/* transmit error */
  		if (status & SONIC_INT_TXER) {
  			u16 tcr = SONIC_READ(SONIC_TCR);
  
  			netif_dbg(lp, tx_err, dev, "%s: TXER intr, TCR %04x\n",
  				  __func__, tcr);
  
  			if (tcr & (SONIC_TCR_EXD | SONIC_TCR_EXC |
  				   SONIC_TCR_FU | SONIC_TCR_BCM)) {
  				/* Aborted transmission. Try again. */
  				netif_stop_queue(dev);
  				SONIC_WRITE(SONIC_CMD, SONIC_CR_TXP);
  			}
  		}
  
  		/* bus retry */
  		if (status & SONIC_INT_BR) {
  			printk(KERN_ERR "%s: Bus retry occurred! Device interrupt disabled.\n",
  				dev->name);
  			/* ... to help debug DMA problems causing endless interrupts. */
  			/* Bounce the eth interface to turn on the interrupt again. */
  			SONIC_WRITE(SONIC_IMR, 0);
  		}
  
  		status = SONIC_READ(SONIC_ISR) & SONIC_IMR_DEFAULT;
  	} while (status);
  
  	spin_unlock_irqrestore(&lp->lock, flags);
  
  	return IRQ_HANDLED;
  }
  
  /* Return the array index corresponding to a given Receive Buffer pointer. */
  static int index_from_addr(struct sonic_local *lp, dma_addr_t addr,
  			   unsigned int last)
  {
  	unsigned int i = last;
  
  	do {
  		i = (i + 1) & SONIC_RRS_MASK;
  		if (addr == lp->rx_laddr[i])
  			return i;
  	} while (i != last);
  
  	return -ENOENT;
  }
  
  /* Allocate and map a new skb to be used as a receive buffer. */
  static bool sonic_alloc_rb(struct net_device *dev, struct sonic_local *lp,
  			   struct sk_buff **new_skb, dma_addr_t *new_addr)
  {
  	*new_skb = netdev_alloc_skb(dev, SONIC_RBSIZE + 2);
  	if (!*new_skb)
  		return false;
  
  	if (SONIC_BUS_SCALE(lp->dma_bitmode) == 2)
  		skb_reserve(*new_skb, 2);
  
  	*new_addr = dma_map_single(lp->device, skb_put(*new_skb, SONIC_RBSIZE),
  				   SONIC_RBSIZE, DMA_FROM_DEVICE);
  	if (!*new_addr) {
  		dev_kfree_skb(*new_skb);
  		*new_skb = NULL;
  		return false;
  	}
  
  	return true;
  }
  
  /* Place a new receive resource in the Receive Resource Area and update RWP. */
  static void sonic_update_rra(struct net_device *dev, struct sonic_local *lp,
  			     dma_addr_t old_addr, dma_addr_t new_addr)
  {
  	unsigned int entry = sonic_rr_entry(dev, SONIC_READ(SONIC_RWP));
  	unsigned int end = sonic_rr_entry(dev, SONIC_READ(SONIC_RRP));
  	u32 buf;
  
  	/* The resources in the range [RRP, RWP) belong to the SONIC. This loop
  	 * scans the other resources in the RRA, those in the range [RWP, RRP).
  	 */
  	do {
  		buf = (sonic_rra_get(dev, entry, SONIC_RR_BUFADR_H) << 16) |
  		      sonic_rra_get(dev, entry, SONIC_RR_BUFADR_L);
  
  		if (buf == old_addr)
  			break;
  
  		entry = (entry + 1) & SONIC_RRS_MASK;
  	} while (entry != end);
  
  	WARN_ONCE(buf != old_addr, "failed to find resource!\n");
  
  	sonic_rra_put(dev, entry, SONIC_RR_BUFADR_H, new_addr >> 16);
  	sonic_rra_put(dev, entry, SONIC_RR_BUFADR_L, new_addr & 0xffff);
  
  	entry = (entry + 1) & SONIC_RRS_MASK;
  
  	SONIC_WRITE(SONIC_RWP, sonic_rr_addr(dev, entry));
  }
  
  /*
   * We have a good packet(s), pass it/them up the network stack.
   */
  static void sonic_rx(struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  	int entry = lp->cur_rx;
  	int prev_entry = lp->eol_rx;
  	bool rbe = false;
  
  	while (sonic_rda_get(dev, entry, SONIC_RD_IN_USE) == 0) {
  		u16 status = sonic_rda_get(dev, entry, SONIC_RD_STATUS);
  
  		/* If the RD has LPKT set, the chip has finished with the RB */
  		if ((status & SONIC_RCR_PRX) && (status & SONIC_RCR_LPKT)) {
  			struct sk_buff *new_skb;
  			dma_addr_t new_laddr;
  			u32 addr = (sonic_rda_get(dev, entry,
  						  SONIC_RD_PKTPTR_H) << 16) |
  				   sonic_rda_get(dev, entry, SONIC_RD_PKTPTR_L);
  			int i = index_from_addr(lp, addr, entry);
  
  			if (i < 0) {
  				WARN_ONCE(1, "failed to find buffer!\n");
  				break;
  			}
  
  			if (sonic_alloc_rb(dev, lp, &new_skb, &new_laddr)) {
  				struct sk_buff *used_skb = lp->rx_skb[i];
  				int pkt_len;
  
  				/* Pass the used buffer up the stack */
  				dma_unmap_single(lp->device, addr, SONIC_RBSIZE,
  						 DMA_FROM_DEVICE);
  
  				pkt_len = sonic_rda_get(dev, entry,
  							SONIC_RD_PKTLEN);
  				skb_trim(used_skb, pkt_len);
  				used_skb->protocol = eth_type_trans(used_skb,
  								    dev);
  				netif_rx(used_skb);
  				lp->stats.rx_packets++;
  				lp->stats.rx_bytes += pkt_len;
  
  				lp->rx_skb[i] = new_skb;
  				lp->rx_laddr[i] = new_laddr;
  			} else {
  				/* Failed to obtain a new buffer so re-use it */
  				new_laddr = addr;
  				lp->stats.rx_dropped++;
  			}
  			/* If RBE is already asserted when RWP advances then
  			 * it's safe to clear RBE after processing this packet.
  			 */
  			rbe = rbe || SONIC_READ(SONIC_ISR) & SONIC_INT_RBE;
  			sonic_update_rra(dev, lp, addr, new_laddr);
  		}
  		/*
  		 * give back the descriptor
  		 */
  		sonic_rda_put(dev, entry, SONIC_RD_STATUS, 0);
  		sonic_rda_put(dev, entry, SONIC_RD_IN_USE, 1);
  
  		prev_entry = entry;
  		entry = (entry + 1) & SONIC_RDS_MASK;
  	}
  
  	lp->cur_rx = entry;
  
  	if (prev_entry != lp->eol_rx) {
  		/* Advance the EOL flag to put descriptors back into service */
  		sonic_rda_put(dev, prev_entry, SONIC_RD_LINK, SONIC_EOL |
  			      sonic_rda_get(dev, prev_entry, SONIC_RD_LINK));
  		sonic_rda_put(dev, lp->eol_rx, SONIC_RD_LINK, ~SONIC_EOL &
  			      sonic_rda_get(dev, lp->eol_rx, SONIC_RD_LINK));
  		lp->eol_rx = prev_entry;
  	}
  
  	if (rbe)
  		SONIC_WRITE(SONIC_ISR, SONIC_INT_RBE);
  }
  
  
  /*
   * Get the current statistics.
   * This may be called with the device open or closed.
   */
  static struct net_device_stats *sonic_get_stats(struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  
  	/* read the tally counter from the SONIC and reset them */
  	lp->stats.rx_crc_errors += SONIC_READ(SONIC_CRCT);
  	SONIC_WRITE(SONIC_CRCT, 0xffff);
  	lp->stats.rx_frame_errors += SONIC_READ(SONIC_FAET);
  	SONIC_WRITE(SONIC_FAET, 0xffff);
  	lp->stats.rx_missed_errors += SONIC_READ(SONIC_MPT);
  	SONIC_WRITE(SONIC_MPT, 0xffff);
  
  	return &lp->stats;
  }
  
  
  /*
   * Set or clear the multicast filter for this adaptor.
   */
  static void sonic_multicast_list(struct net_device *dev)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  	unsigned int rcr;
  	struct netdev_hw_addr *ha;
  	unsigned char *addr;
  	int i;
  
  	rcr = SONIC_READ(SONIC_RCR) & ~(SONIC_RCR_PRO | SONIC_RCR_AMC);
  	rcr |= SONIC_RCR_BRD;	/* accept broadcast packets */
  
  	if (dev->flags & IFF_PROMISC) {	/* set promiscuous mode */
  		rcr |= SONIC_RCR_PRO;
  	} else {
  		if ((dev->flags & IFF_ALLMULTI) ||
  		    (netdev_mc_count(dev) > 15)) {
  			rcr |= SONIC_RCR_AMC;
  		} else {
  			unsigned long flags;
  
  			netif_dbg(lp, ifup, dev, "%s: mc_count %d\n", __func__,
  				  netdev_mc_count(dev));
  			sonic_set_cam_enable(dev, 1);  /* always enable our own address */
  			i = 1;
  			netdev_for_each_mc_addr(ha, dev) {
  				addr = ha->addr;
  				sonic_cda_put(dev, i, SONIC_CD_CAP0, addr[1] << 8 | addr[0]);
  				sonic_cda_put(dev, i, SONIC_CD_CAP1, addr[3] << 8 | addr[2]);
  				sonic_cda_put(dev, i, SONIC_CD_CAP2, addr[5] << 8 | addr[4]);
  				sonic_set_cam_enable(dev, sonic_get_cam_enable(dev) | (1 << i));
  				i++;
  			}
  			SONIC_WRITE(SONIC_CDC, 16);
  			SONIC_WRITE(SONIC_CDP, lp->cda_laddr & 0xffff);
  
  			/* LCAM and TXP commands can't be used simultaneously */
  			spin_lock_irqsave(&lp->lock, flags);
  			sonic_quiesce(dev, SONIC_CR_TXP, false);
  			SONIC_WRITE(SONIC_CMD, SONIC_CR_LCAM);
  			sonic_quiesce(dev, SONIC_CR_LCAM, false);
  			spin_unlock_irqrestore(&lp->lock, flags);
  		}
  	}
  
  	netif_dbg(lp, ifup, dev, "%s: setting RCR=%x\n", __func__, rcr);
  
  	SONIC_WRITE(SONIC_RCR, rcr);
  }
  
  
  /*
   * Initialize the SONIC ethernet controller.
   */
  static int sonic_init(struct net_device *dev, bool may_sleep)
  {
  	struct sonic_local *lp = netdev_priv(dev);
  	int i;
  
  	/*
  	 * put the Sonic into software-reset mode and
  	 * disable all interrupts
  	 */
  	SONIC_WRITE(SONIC_IMR, 0);
  	SONIC_WRITE(SONIC_ISR, 0x7fff);
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RST);
  
  	/* While in reset mode, clear CAM Enable register */
  	SONIC_WRITE(SONIC_CE, 0);
  
  	/*
  	 * clear software reset flag, disable receiver, clear and
  	 * enable interrupts, then completely initialize the SONIC
  	 */
  	SONIC_WRITE(SONIC_CMD, 0);
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RXDIS | SONIC_CR_STP);
  	sonic_quiesce(dev, SONIC_CR_ALL, may_sleep);
  
  	/*
  	 * initialize the receive resource area
  	 */
  	netif_dbg(lp, ifup, dev, "%s: initialize receive resource area\n",
  		  __func__);
  
  	for (i = 0; i < SONIC_NUM_RRS; i++) {
  		u16 bufadr_l = (unsigned long)lp->rx_laddr[i] & 0xffff;
  		u16 bufadr_h = (unsigned long)lp->rx_laddr[i] >> 16;
  		sonic_rra_put(dev, i, SONIC_RR_BUFADR_L, bufadr_l);
  		sonic_rra_put(dev, i, SONIC_RR_BUFADR_H, bufadr_h);
  		sonic_rra_put(dev, i, SONIC_RR_BUFSIZE_L, SONIC_RBSIZE >> 1);
  		sonic_rra_put(dev, i, SONIC_RR_BUFSIZE_H, 0);
  	}
  
  	/* initialize all RRA registers */
  	SONIC_WRITE(SONIC_RSA, sonic_rr_addr(dev, 0));
  	SONIC_WRITE(SONIC_REA, sonic_rr_addr(dev, SONIC_NUM_RRS));
  	SONIC_WRITE(SONIC_RRP, sonic_rr_addr(dev, 0));
  	SONIC_WRITE(SONIC_RWP, sonic_rr_addr(dev, SONIC_NUM_RRS - 1));
  	SONIC_WRITE(SONIC_URRA, lp->rra_laddr >> 16);
  	SONIC_WRITE(SONIC_EOBC, (SONIC_RBSIZE >> 1) - (lp->dma_bitmode ? 2 : 1));
  
  	/* load the resource pointers */
  	netif_dbg(lp, ifup, dev, "%s: issuing RRRA command\n", __func__);
  
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RRRA);
  	sonic_quiesce(dev, SONIC_CR_RRRA, may_sleep);
  
  	/*
  	 * Initialize the receive descriptors so that they
  	 * become a circular linked list, ie. let the last
  	 * descriptor point to the first again.
  	 */
  	netif_dbg(lp, ifup, dev, "%s: initialize receive descriptors\n",
  		  __func__);
  
  	for (i=0; i<SONIC_NUM_RDS; i++) {
  		sonic_rda_put(dev, i, SONIC_RD_STATUS, 0);
  		sonic_rda_put(dev, i, SONIC_RD_PKTLEN, 0);
  		sonic_rda_put(dev, i, SONIC_RD_PKTPTR_L, 0);
  		sonic_rda_put(dev, i, SONIC_RD_PKTPTR_H, 0);
  		sonic_rda_put(dev, i, SONIC_RD_SEQNO, 0);
  		sonic_rda_put(dev, i, SONIC_RD_IN_USE, 1);
  		sonic_rda_put(dev, i, SONIC_RD_LINK,
  			lp->rda_laddr +
  			((i+1) * SIZEOF_SONIC_RD * SONIC_BUS_SCALE(lp->dma_bitmode)));
  	}
  	/* fix last descriptor */
  	sonic_rda_put(dev, SONIC_NUM_RDS - 1, SONIC_RD_LINK,
  		(lp->rda_laddr & 0xffff) | SONIC_EOL);
  	lp->eol_rx = SONIC_NUM_RDS - 1;
  	lp->cur_rx = 0;
  	SONIC_WRITE(SONIC_URDA, lp->rda_laddr >> 16);
  	SONIC_WRITE(SONIC_CRDA, lp->rda_laddr & 0xffff);
  
  	/*
  	 * initialize transmit descriptors
  	 */
  	netif_dbg(lp, ifup, dev, "%s: initialize transmit descriptors\n",
  		  __func__);
  
  	for (i = 0; i < SONIC_NUM_TDS; i++) {
  		sonic_tda_put(dev, i, SONIC_TD_STATUS, 0);
  		sonic_tda_put(dev, i, SONIC_TD_CONFIG, 0);
  		sonic_tda_put(dev, i, SONIC_TD_PKTSIZE, 0);
  		sonic_tda_put(dev, i, SONIC_TD_FRAG_COUNT, 0);
  		sonic_tda_put(dev, i, SONIC_TD_LINK,
  			(lp->tda_laddr & 0xffff) +
  			(i + 1) * SIZEOF_SONIC_TD * SONIC_BUS_SCALE(lp->dma_bitmode));
  		lp->tx_skb[i] = NULL;
  	}
  	/* fix last descriptor */
  	sonic_tda_put(dev, SONIC_NUM_TDS - 1, SONIC_TD_LINK,
  		(lp->tda_laddr & 0xffff));
  
  	SONIC_WRITE(SONIC_UTDA, lp->tda_laddr >> 16);
  	SONIC_WRITE(SONIC_CTDA, lp->tda_laddr & 0xffff);
  	lp->cur_tx = 0;
  	lp->eol_tx = SONIC_NUM_TDS - 1;
  
  	/*
  	 * put our own address to CAM desc[0]
  	 */
  	sonic_cda_put(dev, 0, SONIC_CD_CAP0, dev->dev_addr[1] << 8 | dev->dev_addr[0]);
  	sonic_cda_put(dev, 0, SONIC_CD_CAP1, dev->dev_addr[3] << 8 | dev->dev_addr[2]);
  	sonic_cda_put(dev, 0, SONIC_CD_CAP2, dev->dev_addr[5] << 8 | dev->dev_addr[4]);
  	sonic_set_cam_enable(dev, 1);
  
  	for (i = 0; i < 16; i++)
  		sonic_cda_put(dev, i, SONIC_CD_ENTRY_POINTER, i);
  
  	/*
  	 * initialize CAM registers
  	 */
  	SONIC_WRITE(SONIC_CDP, lp->cda_laddr & 0xffff);
  	SONIC_WRITE(SONIC_CDC, 16);
  
  	/*
  	 * load the CAM
  	 */
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_LCAM);
  	sonic_quiesce(dev, SONIC_CR_LCAM, may_sleep);
  
  	/*
  	 * enable receiver, disable loopback
  	 * and enable all interrupts
  	 */
  	SONIC_WRITE(SONIC_RCR, SONIC_RCR_DEFAULT);
  	SONIC_WRITE(SONIC_TCR, SONIC_TCR_DEFAULT);
  	SONIC_WRITE(SONIC_ISR, 0x7fff);
  	SONIC_WRITE(SONIC_IMR, SONIC_IMR_DEFAULT);
  	SONIC_WRITE(SONIC_CMD, SONIC_CR_RXEN);
  
  	netif_dbg(lp, ifup, dev, "%s: new status=%x\n", __func__,
  		  SONIC_READ(SONIC_CMD));
  
  	return 0;
  }
  
  MODULE_LICENSE("GPL");
  