sk_mca.c

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	InitDscrs(dev);

	/* next RX descriptor to be read is the first one.  Since the LANCE
	   will start from the beginning after initialization, we have to 
	   reset out pointers too. */

	priv->nextrx = 0;

	/* no TX descriptors active */

	priv->nexttxput = priv->nexttxdone = priv->txbusy = 0;

	/* set up the LANCE bus control register - constant for SKnet boards */

	SetLANCE(dev, LANCE_CSR3,
		 CSR3_BSWAP_OFF | CSR3_ALE_LOW | CSR3_BCON_HOLD);

	/* write address of initialization block into LANCE */

	SetLANCE(dev, LANCE_CSR1, RAM_INITBASE & 0xffff);
	SetLANCE(dev, LANCE_CSR2, (RAM_INITBASE >> 16) & 0xff);

	/* we don't get ready until the LANCE has read the init block */

#if (LINUX_VERSION_CODE >= 0x02032a)
	netif_stop_queue(dev);
#else
	dev->tbusy = 1;
#endif

	/* let LANCE read the initialization block.  LANCE is ready
	   when we receive the corresponding interrupt. */

	SetLANCE(dev, LANCE_CSR0, CSR0_INEA | CSR0_INIT);
}

/* stop the LANCE so we can reinitialize it */

static void StopLANCE(struct SKMCA_NETDEV *dev)
{
	/* can't take frames any more */

#if (LINUX_VERSION_CODE >= 0x02032a)
	netif_stop_queue(dev);
#else
	dev->tbusy = 1;
#endif

	/* disable interrupts, stop it */

	SetLANCE(dev, LANCE_CSR0, CSR0_STOP);
}

/* initialize card and LANCE for proper operation */

static void InitBoard(struct SKMCA_NETDEV *dev)
{
	LANCE_InitBlock block;

	/* Lay out the shared RAM - first we create the init block for the LANCE.
	   We do not overwrite it later because we need it again when we switch
	   promiscous mode on/off. */

	block.Mode = 0;
	if (dev->flags & IFF_PROMISC)
		block.Mode |= LANCE_INIT_PROM;
	memcpy(block.PAdr, dev->dev_addr, 6);
	memset(block.LAdrF, 0, sizeof(block.LAdrF));
	block.RdrP = (RAM_RXBASE & 0xffffff) | (LRXCOUNT << 29);
	block.TdrP = (RAM_TXBASE & 0xffffff) | (LTXCOUNT << 29);

	SKMCA_TOIO(dev->mem_start + RAM_INITBASE, &block, sizeof(block));

	/* initialize LANCE. Implicitly sets up other structures in RAM. */

	InitLANCE(dev);
}

/* deinitialize card and LANCE */

static void DeinitBoard(struct SKMCA_NETDEV *dev)
{
	/* stop LANCE */

	StopLANCE(dev);

	/* reset board */

	ResetBoard(dev);
}

/* probe for device's irq */

static int ProbeIRQ(struct SKMCA_NETDEV *dev)
{
	unsigned long imaskval, njiffies, irq;
	u16 csr0val;

	/* enable all interrupts */

	imaskval = probe_irq_on();

	/* initialize the board. Wait for interrupt 'Initialization done'. */

	ResetBoard(dev);
	InitBoard(dev);

	njiffies = jiffies + 100;
	do {
		csr0val = GetLANCE(dev, LANCE_CSR0);
	}
	while (((csr0val & CSR0_IDON) == 0) && (jiffies != njiffies));

	/* turn of interrupts again */

	irq = probe_irq_off(imaskval);

	/* if we found something, ack the interrupt */

	if (irq)
		SetLANCE(dev, LANCE_CSR0, csr0val | CSR0_IDON);

	/* back to idle state */

	DeinitBoard(dev);

	return irq;
}

/* ------------------------------------------------------------------------
 * interrupt handler(s)
 * ------------------------------------------------------------------------ */

/* LANCE has read initialization block -> start it */

static u16 irqstart_handler(struct SKMCA_NETDEV *dev, u16 oldcsr0)
{
	/* now we're ready to transmit */

#if (LINUX_VERSION_CODE >= 0x02032a)
	netif_wake_queue(dev);
#else
	dev->tbusy = 0;
#endif

	/* reset IDON bit, start LANCE */

	SetLANCE(dev, LANCE_CSR0, oldcsr0 | CSR0_IDON | CSR0_STRT);
	return GetLANCE(dev, LANCE_CSR0);
}

/* did we loose blocks due to a FIFO overrun ? */

static u16 irqmiss_handler(struct SKMCA_NETDEV *dev, u16 oldcsr0)
{
	skmca_priv *priv = (skmca_priv *) dev->priv;

	/* update statistics */

	priv->stat.rx_fifo_errors++;

	/* reset MISS bit */

	SetLANCE(dev, LANCE_CSR0, oldcsr0 | CSR0_MISS);
	return GetLANCE(dev, LANCE_CSR0);
}

/* receive interrupt */

static u16 irqrx_handler(struct SKMCA_NETDEV *dev, u16 oldcsr0)
{
	skmca_priv *priv = (skmca_priv *) dev->priv;
	LANCE_RxDescr descr;
	unsigned int descraddr;

	/* run through queue until we reach a descriptor we do not own */

	descraddr = RAM_RXBASE + (priv->nextrx * sizeof(LANCE_RxDescr));
	while (1) {
		/* read descriptor */
		SKMCA_FROMIO(&descr, dev->mem_start + descraddr,
			     sizeof(LANCE_RxDescr));

		/* if we reach a descriptor we do not own, we're done */
		if ((descr.Flags & RXDSCR_FLAGS_OWN) != 0)
			break;

#ifdef DEBUG
		PrTime();
		printk("Receive packet on descr %d len %d\n", priv->nextrx,
		       descr.Len);
#endif

		/* erroneous packet ? */
		if ((descr.Flags & RXDSCR_FLAGS_ERR) != 0) {
			priv->stat.rx_errors++;
			if ((descr.Flags & RXDSCR_FLAGS_CRC) != 0)
				priv->stat.rx_crc_errors++;
			else if ((descr.Flags & RXDSCR_FLAGS_CRC) != 0)
				priv->stat.rx_frame_errors++;
			else if ((descr.Flags & RXDSCR_FLAGS_OFLO) != 0)
				priv->stat.rx_fifo_errors++;
		}

		/* good packet ? */
		else {
			struct sk_buff *skb;

			skb = dev_alloc_skb(descr.Len + 2);
			if (skb == NULL)
				priv->stat.rx_dropped++;
			else {
				SKMCA_FROMIO(skb_put(skb, descr.Len),
					     dev->mem_start +
					     descr.LowAddr, descr.Len);
				skb->dev = dev;
				skb->protocol = eth_type_trans(skb, dev);
				skb->ip_summed = CHECKSUM_NONE;
				priv->stat.rx_packets++;
#if LINUX_VERSION_CODE >= 0x020119	/* byte counters for >= 2.1.25 */
				priv->stat.rx_bytes += descr.Len;
#endif
				netif_rx(skb);
			}
		}

		/* give descriptor back to LANCE */
		descr.Len = 0;
		descr.Flags |= RXDSCR_FLAGS_OWN;

		/* update descriptor in shared RAM */
		SKMCA_TOIO(dev->mem_start + descraddr, &descr,
			   sizeof(LANCE_RxDescr));

		/* go to next descriptor */
		priv->nextrx++;
		descraddr += sizeof(LANCE_RxDescr);
		if (priv->nextrx >= RXCOUNT) {
			priv->nextrx = 0;
			descraddr = RAM_RXBASE;
		}
	}

	/* reset RINT bit */

	SetLANCE(dev, LANCE_CSR0, oldcsr0 | CSR0_RINT);
	return GetLANCE(dev, LANCE_CSR0);
}

/* transmit interrupt */

static u16 irqtx_handler(struct SKMCA_NETDEV *dev, u16 oldcsr0)
{
	skmca_priv *priv = (skmca_priv *) dev->priv;
	LANCE_TxDescr descr;
	unsigned int descraddr;

	/* check descriptors at most until no busy one is left */

	descraddr =
	    RAM_TXBASE + (priv->nexttxdone * sizeof(LANCE_TxDescr));
	while (priv->txbusy > 0) {
		/* read descriptor */
		SKMCA_FROMIO(&descr, dev->mem_start + descraddr,
			     sizeof(LANCE_TxDescr));

		/* if the LANCE still owns this one, we've worked out all sent packets */
		if ((descr.Flags & TXDSCR_FLAGS_OWN) != 0)
			break;

#ifdef DEBUG
		PrTime();
		printk("Send packet done on descr %d\n", priv->nexttxdone);
#endif

		/* update statistics */
		if ((descr.Flags & TXDSCR_FLAGS_ERR) == 0) {
			priv->stat.tx_packets++;
#if LINUX_VERSION_CODE >= 0x020119	/* byte counters for >= 2.1.25 */
			priv->stat.tx_bytes++;
#endif
		} else {
			priv->stat.tx_errors++;
			if ((descr.Status & TXDSCR_STATUS_UFLO) != 0) {
				priv->stat.tx_fifo_errors++;
				InitLANCE(dev);
			}
				else
			    if ((descr.Status & TXDSCR_STATUS_LCOL) !=
				0) priv->stat.tx_window_errors++;
			else if ((descr.Status & TXDSCR_STATUS_LCAR) != 0)
				priv->stat.tx_carrier_errors++;
			else if ((descr.Status & TXDSCR_STATUS_RTRY) != 0)
				priv->stat.tx_aborted_errors++;
		}

		/* go to next descriptor */
		priv->nexttxdone++;
		descraddr += sizeof(LANCE_TxDescr);
		if (priv->nexttxdone >= TXCOUNT) {
			priv->nexttxdone = 0;
			descraddr = RAM_TXBASE;
		}
		priv->txbusy--;
	}

	/* reset TX interrupt bit */

	SetLANCE(dev, LANCE_CSR0, oldcsr0 | CSR0_TINT);
	oldcsr0 = GetLANCE(dev, LANCE_CSR0);

	/* at least one descriptor is freed.  Therefore we can accept
	   a new one */
	/* inform upper layers we're in business again */

#if (LINUX_VERSION_CODE >= 0x02032a)
	netif_wake_queue(dev);
#else
	dev->tbusy = 0;
	mark_bh(NET_BH);
#endif

	return oldcsr0;
}

/* general interrupt entry */

static void irq_handler(int irq, void *device, struct pt_regs *regs)
{
	struct SKMCA_NETDEV *dev = (struct SKMCA_NETDEV *) device;
	u16 csr0val;

	/* read CSR0 to get interrupt cause */

	csr0val = GetLANCE(dev, LANCE_CSR0);

	/* in case we're not meant... */

	if ((csr0val & CSR0_INTR) == 0)
		return;

#if (LINUX_VERSION_CODE >= 0x02032a)
#if 0
	set_bit(LINK_STATE_RXSEM, &dev->state);
#endif
#else
	dev->interrupt = 1;
#endif

	/* loop through the interrupt bits until everything is clear */

	do {
		if ((csr0val & CSR0_IDON) != 0)
			csr0val = irqstart_handler(dev, csr0val);
		if ((csr0val & CSR0_RINT) != 0)
			csr0val = irqrx_handler(dev, csr0val);
		if ((csr0val & CSR0_MISS) != 0)
			csr0val = irqmiss_handler(dev, csr0val);
		if ((csr0val & CSR0_TINT) != 0)
			csr0val = irqtx_handler(dev, csr0val);
		if ((csr0val & CSR0_MERR) != 0) {
			SetLANCE(dev, LANCE_CSR0, csr0val | CSR0_MERR);
			csr0val = GetLANCE(dev, LANCE_CSR0);
		}
		if ((csr0val & CSR0_BABL) != 0) {
			SetLANCE(dev, LANCE_CSR0, csr0val | CSR0_BABL);
			csr0val = GetLANCE(dev, LANCE_CSR0);
		}
	}
	while ((csr0val & CSR0_INTR) != 0);

#if (LINUX_VERSION_CODE >= 0x02032a)
#if 0
	clear_bit(LINK_STATE_RXSEM, &dev->state);
#endif
#else
	dev->interrupt = 0;
#endif
}

/* ------------------------------------------------------------------------
 * driver methods
 * ------------------------------------------------------------------------ */

/* MCA info */

static int skmca_getinfo(char *buf, int slot, void *d)
{
	int len = 0, i;
	struct SKMCA_NETDEV *dev = (struct SKMCA_NETDEV *) d;
	skmca_priv *priv;

	/* can't say anything about an uninitialized device... */

	if (dev == NULL)
		return len;
	if (dev->priv == NULL)
		return len;
	priv = (skmca_priv *) dev->priv;

	/* print info */

	len += sprintf(buf + len, "IRQ: %d\n", priv->realirq);
	len += sprintf(buf + len, "Memory: %#lx-%#lx\n", dev->mem_start,
		       dev->mem_end - 1);
	len +=
	    sprintf(buf + len, "Transceiver: %s\n",
		    MediaNames[priv->medium]);
	len += sprintf(buf + len, "Device: %s\n", dev->name);
	len += sprintf(buf + len, "MAC address:");
	for (i = 0; i < 6; i++)
		len += sprintf(buf + len, " %02x", dev->dev_addr[i]);
	buf[len++] = '\n';
	buf[len] = 0;

	return len;
}

/* open driver.  Means also initialization and start of LANCE */

static int skmca_open(struct SKMCA_NETDEV *dev)
{
	int result;
	skmca_priv *priv = (skmca_priv *) dev->priv;

	/* register resources - only necessary for IRQ */
	result =
	    request_irq(priv->realirq, irq_handler,
			SA_SHIRQ | SA_SAMPLE_RANDOM, "sk_mca", dev);
	if (result != 0) {
		printk("%s: failed to register irq %d\n", dev->name,
		       dev->irq);
		return result;