sonic.c

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/*
 * 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 ([e-mail])
 *
 * This driver is based on work from Andreas Busse, but most of
 * the code is rewritten.
 *
 * (C) 1995 by Andreas Busse ([e-mail])
 *
 *    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 <[e-mail]>
 *
 */

/*
 * 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".
 */



/*
 * 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;

	if (sonic_debug > 2)
		printk("sonic_open: initializing sonic driver.\n");

	for (i = 0; i < SONIC_NUM_RRS; i++) {
		struct sk_buff *skb = dev_alloc_skb(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 (!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);

	netif_start_queue(dev);

	if (sonic_debug > 2)
		printk("sonic_open: Initialization done.\n");

	return 0;
}


/*
 * Close the SONIC device
 */
static int sonic_close(struct net_device *dev)
{
	struct sonic_local *lp = netdev_priv(dev);
	int i;

	if (sonic_debug > 2)
		printk("sonic_close\n");

	netif_stop_queue(dev);

	/*
	 * stop the SONIC, disable interrupts
	 */
	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)
{
	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_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);
	lp->stats.tx_errors++;
	dev->trans_start = jiffies;
	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.
 * Until some mutual exclusion is added, this code will not work with SMP. However,
 * MIPS Jazz machines and m68k Macs were all uni-processor machines.
 */

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 = lp->next_tx;

	if (sonic_debug > 2)
		printk("sonic_send_packet: skb=%p, dev=%p\n", skb, dev);

	length = skb->len;
	if (length < ETH_ZLEN) {
		if (skb_padto(skb, ETH_ZLEN))
			return 0;
		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) {
		printk(KERN_ERR "%s: failed to map tx DMA buffer.\n", dev->name);
		dev_kfree_skb(skb);
		return 1;
	}

	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);

	/*
	 * Must set tx_skb[entry] only after clearing status, and
	 * before clearing EOL and before stopping queue
	 */
	wmb();
	lp->tx_len[entry] = length;
	lp->tx_laddr[entry] = laddr;
	lp->tx_skb[entry] = skb;

	wmb();
	sonic_tda_put(dev, lp->eol_tx, SONIC_TD_LINK,
				  sonic_tda_get(dev, lp->eol_tx, SONIC_TD_LINK) & ~SONIC_EOL);
	lp->eol_tx = entry;

	lp->next_tx = (entry + 1) & SONIC_TDS_MASK;
	if (lp->tx_skb[lp->next_tx] != NULL) {
		/* The ring is full, the ISR has yet to process the next TD. */
		if (sonic_debug > 3)
			printk("%s: stopping queue\n", dev->name);
		netif_stop_queue(dev);
		/* after this packet, wait for ISR to free up some TDAs */
	} else netif_start_queue(dev);

	if (sonic_debug > 2)
		printk("sonic_send_packet: issuing Tx command\n");

	SONIC_WRITE(SONIC_CMD, SONIC_CR_TXP);

	dev->trans_start = jiffies;

	return 0;
}

/*
 * 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;

	if (!(status = SONIC_READ(SONIC_ISR) & SONIC_IMR_DEFAULT))
		return IRQ_NONE;

	do {
		if (status & SONIC_INT_PKTRX) {
			if (sonic_debug > 2)
				printk("%s: packet rx\n", dev->name);
			sonic_rx(dev);	/* got packet(s) */
			SONIC_WRITE(SONIC_ISR, SONIC_INT_PKTRX); /* clear the interrupt */
		}

		if (status & SONIC_INT_TXDN) {
			int entry = lp->cur_tx;
			int td_status;
			int freed_some = 0;

			/* At this point, cur_tx is the index of a TD that is one of:
			 *   unallocated/freed                          (status set   & tx_skb[entry] clear)
			 *   allocated and sent                         (status set   & tx_skb[entry] set  )
			 *   allocated and not yet sent                 (status clear & tx_skb[entry] set  )
			 *   still being allocated by sonic_send_packet (status clear & tx_skb[entry] clear)
			 */

			if (sonic_debug > 2)
				printk("%s: tx done\n", dev->name);

			while (lp->tx_skb[entry] != NULL) {
				if ((td_status = sonic_tda_get(dev, entry, SONIC_TD_STATUS)) == 0)
					break;

				if (td_status & 0x0001) {
					lp->stats.tx_packets++;
					lp->stats.tx_bytes += sonic_tda_get(dev, entry, SONIC_TD_PKTSIZE);
				} else {
					lp->stats.tx_errors++;
					if (td_status & 0x0642)
						lp->stats.tx_aborted_errors++;
					if (td_status & 0x0180)
						lp->stats.tx_carrier_errors++;
					if (td_status & 0x0020)
						lp->stats.tx_window_errors++;
					if (td_status & 0x0004)
						lp->stats.tx_fifo_errors++;
				}

				/* We must free the original skb */
				dev_kfree_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;
			SONIC_WRITE(SONIC_ISR, SONIC_INT_TXDN); /* clear the interrupt */
		}

		/*
		 * check error conditions
		 */
		if (status & SONIC_INT_RFO) {
			if (sonic_debug > 1)
				printk("%s: rx fifo overrun\n", dev->name);
			lp->stats.rx_fifo_errors++;
			SONIC_WRITE(SONIC_ISR, SONIC_INT_RFO); /* clear the interrupt */
		}
		if (status & SONIC_INT_RDE) {
			if (sonic_debug > 1)
				printk("%s: rx descriptors exhausted\n", dev->name);
			lp->stats.rx_dropped++;
			SONIC_WRITE(SONIC_ISR, SONIC_INT_RDE); /* clear the interrupt */
		}
		if (status & SONIC_INT_RBAE) {
			if (sonic_debug > 1)
				printk("%s: rx buffer area exceeded\n", dev->name);
			lp->stats.rx_dropped++;
			SONIC_WRITE(SONIC_ISR, SONIC_INT_RBAE); /* clear the interrupt */
		}

		/* counter overruns; all counters are 16bit wide */
		if (status & SONIC_INT_FAE) {
			lp->stats.rx_frame_errors += 65536;
			SONIC_WRITE(SONIC_ISR, SONIC_INT_FAE); /* clear the interrupt */